Cementing Catalog

Cementing Servicesand Products Catalog

Cementing Services and Products Catalog

Schlumberger 2003

Schlumberger225 Schlumberger DriveSugar Land, Texas 77478

All rights reserved. No part of this book may be reproduced, stored in a retrieval system, or transcribed in any form or by any means, electronic or mechanical, including photo-copying and recording, without prior written permission of the publisher.

TSL-4274

An asterisk (*) is used throughout this document to denote a mark of Schlumberger.NExT is a mark of NExT.InstanSeal is a mark of Den norske stats oljeselskap a.s. (Statoil).Netscape is a registered trademark of Netscape Communications Corporation.Window is a registered trademark of Microsoft Corp.

Cementing Services and Products Contents iii

Contents

Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ixReservoir solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ixResearch and development . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xQuality, health, safety and environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xiTraining . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xiKey cementing technology highlights . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xii

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1Services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Deepwater cementing products and services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3Deepwater slurries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

DeepCRETE deepwater cementing solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4FlexSTONE Cement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4DeepCEM additives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Well stress analysis software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5CemCADE software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Advanced plug placement module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5Offshore cementing skids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5DeepSea EXPRES offshore plug launching system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6Benefits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6Surface dart launcher . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7Subsea tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

A gas migration control serviceGASBLOK service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9Benefits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9Gas flow risk analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Routes for gas migration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10CemCADE softwareplacement and postplacement risk analysis . . . . . . . . . . 10

Cement slurry design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11High risk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11Low risk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11Slurry properties for gas migration control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Cement placement design and execution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13Lost circulation systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Lost Circulation Advisor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14Benefits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

InstanSeal system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15Benefits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

InstanSeal Cement system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16ShearSEAL lost circulation fluid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16


PERMABLOK system for plugging zones . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17CemNET advanced fiber cement to control losses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17


ZONELOCK S sealing system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18ZONELOCK SC permanent system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Mud removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19WELLCLEAN II engineering solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19


Pipe centralization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19Displacement regimes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20Fluids design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20WELLCLEAN II simulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20


WELLCLEAN II advisor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21Chemical washes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21


MUDPUSH spacers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24Benefits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

InterACT wellsite monitoring and control system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25Benefits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26System requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

iv Cementing Services and Products

Cementing Services and Products Contents v

Software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29CemCADE cementing design and evaluation software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29Benefits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Stress analysis model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33Benefits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

i-Handbook oilfield data handbook . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33Materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

CemCRETE concrete-based oilwell cementing technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40LiteCRETE low-density slurry system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41


DeepCRETE deepwater cementing solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43Benefits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

DensCRETE advanced cement technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45Benefits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

SqueezeCRETE remedial cementing solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46Benefits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

CemSTONE Advanced Cement Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47FlexSTONE Advanced Cement Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49


DuraSTONE Advanced Cement Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51Benefits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Cementing slurry systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53Lightweight cements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

LiteCRETE cement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54D049 lightweight cement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54Foamed cement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

Improved bonding cements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55FlexSTONE cementadvanced flexible cement technology . . . . . . . . . . . . . . . . 55WELBOND cementimproved bonding cement system . . . . . . . . . . . . . . . . . . . . 55SALTBOND cementcement system for cementing across salt zones . . . . . . 55RFC regulated fill-up cement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56SELFSTRESS expanding cement system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

Fast strength development . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56DeepCEM Cement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56ARCTICSET cementcement system for use through permafrost . . . . . . . . . . 57Right-angle set cement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

Cements for harsh environments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58Acid-resistant cement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58Carbon dioxide-resistant cement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58Synthetic cement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

UniSLURRY cement systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59Benefits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60UNIFLAC unified fluid-loss additive for cement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60


UNISET set control additives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62Benefits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

Cementing additives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63Accelerators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63Antifoam and defoam agents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63Antigelation agents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63DeepCEM additives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64Dispersants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64Expanding additives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64Extenders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64Fluid-loss control additives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64Gas migration control additives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64Lost circulation control materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64Retarders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64Surfactants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65Special additives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65Suspending and antisettling agents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65Thixotropic additives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65UniSLURRY additives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65Weighting agents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65Spacers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65Chemical washes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

vi Cementing Services and Products

Cementing Services and Products Contents vii

Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77CemSTREAK land cementing unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78Benefits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

CPF-376 double-pump cement trailer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79Benefits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

CPT-372 double-pump cement truck . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81Benefits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

Offshore cementing skids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81Standard equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82Optional equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

LAS liquid additive system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83Benefits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

CemCAT cementing computer-aided treatment software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84Benefits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

SFM-C process control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86Benefits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

Nonradioactive densitometer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88Benefits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

Evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89Execution analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89Postcementing analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89Cement evaluation services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

Sonic services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90SlimAccess tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91Benefits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

SCMT Slim Cement Mapping Tool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91Benefits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

Ultrasonic services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

USI UltraSonic Imager . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

Cement integrity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92Pipe integrity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

Benefits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93Nonstandard environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97Marks of Schlumberger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

viii Cementing Services and Products

Reservoir solutionsSchlumberger has been supplying products and services to the oil and gas industry for more than75 years. Our trained, highly qualified professionals team with operating companies to maximizeasset values with reservoir solutions that combine best practices and advanced oilfield tech-nologies with service quality and environmentally sound operations.

As exploration and production activities have expanded, our relationships with operatingcompanies have evolved. Today, we provide many services which help in finding hydrocarbons,constructing and completing wells to produce them, and stimulating the wells to maximize theirproduction. We do this from service locations in all oil- and gas-producing areas of the world. Weare committed to providing real-time solutions that make the finding and production of oil andgas more cost effective and that maximize recoverable reserves.

With the movement toward a more holistic approach to oil and gas development, geoscientistsand engineers gain a thorough understanding of the reservoir by using exploration and produc-tion product technology, field services, and project management skills along with software andinformation management services integrated with information technology (IT). Using thisapproach, the value of the reservoir is increased and the capital expenditures and negative cashflow are minimized.

Cementing Services and Products Preface ix

Preface

Cashflow

Reservoir optimization Traditional development

Time

Development MaturityDelineation

Accelerateproduction

Minimizecapex

Minimizeopex

Deferabandonment

Maximizeproduction

Maximizerecovery

Exploration

+

Cementing plays a role in this process by providing zonal isolation in the wellbore. High-quality zonal isolation allows more accurate well testing to define the reservoir, maximizes recov-ery at the least cost (reduced costs for produced water and its disposal), and provides moreeffective stimulation through placement focused on the reservoir, more effective enhanced recov-ery and reduced abandonment costs.

Research and developmentResearch has been a fundamental commitment since Schlumberger was founded in 1927. Despitefluctuations in business activity, our long-term commitment to research and development (R&D)is unwavering. During the market turndown in the late 1980s, we continued to spend heavily inR&D and we now invest nearly $1 million a day in research for oil and gas applications.

Schlumberger employs top-level scientists, engineers and support personnel recruited fromthe best technical universities worldwide. Our research teams are multidisciplinary, embracingphysics, chemistry, materials science, mathematics, statistics, computer science, signal process-ing, instrumentation, earth science, and solid and fluid mechanics.

Our global R&D network provides a stimulating environment for the development of advancedtechnologies. This network includes Schlumberger-Doll Research, Ridgefield, Connecticut, a center of excellence for oilfield

research since the 1940s Schlumberger Cambridge Research, Cambridge, England, which has been developing new

concepts and techniques to help oil and gas companies find and produce hydrocarbons since 1981

Schlumberger Austin Research, Austin, Texas, at the leading edge of information technologydevelopment since 1989

Schlumberger Stavanger Research, Stavanger, Norway, established in 1999 as our firstresearch satellite to conduct research activities at strategic locations around the world

Moscow Research, established in Moscow, Russia, in 2002 Dhahran Research, established in Dhahran in 2001 Schlumberger Reservoir Completions Center, near Houston, Texas, launched in 1999 to

develop products and services for intelligent completions.

x Cementing Services and Products

Quality, health, safety and environmentAt Schlumberger we strive to continually improve the quality of our products and services; to pro-tect the health, safety and property of our employees, our customers, our contractors and thirdparties; and to safeguard the environment in communities where we live and work. This proac-tive approach results in greater efficiency; reduced accidents, pollution and waste; and a morehealthful workplace.

Quality, health, safety and environment (QHSE) training, provided through state-of-the-artlearning techniques, is mandatory for all Schlumberger personnel. All new employees receiveboth general and job-specific QHSE orientation prior to their first work assignments, andemployees transferring to new positions or locations receive formal orientation about specificQHSE issues related to their new work environment. Our suppliers and contractors are evaluated,qualified and selected based on their ability to deliver a quality product or service in a safe,healthy and environmentally acceptable manner.

Schlumberger practices go beyond environmental compliance. As stewards of the environ-ment, we take proactive steps toward recognizing and eliminating detrimental practices.

QHSE requirements are incorporated into all stages of product design, development anddelivery. Prior to initiating a project or delivering a service, a formal assessment is conducted toensure that all QHSE aspects have been addressed.

TrainingSchlumberger training is continuousemployees receive both formal and on-the-job trainingthroughout their careers. We periodically assess all our training programs for content, quality andeffectiveness, and we employ the latest technology to ensure that our training remains best inclass.

Our training emphasizes the use of IT. We have developed on-line and CD-ROM training modulesand achieve full use of IT by providing worldwide connectivity to the internal Schlumbergercommunications network and to the Internet. Both new employees and those studying foradvancement can use the Internet for their training courses.

Schlumberger technical training programs sponsor on-line, in-house and field training in allphases of equipment selection, application and operation, as well as effective design, executionand evaluation. Structured training programs and seminars provide the latest information andtechnical knowledge, and we conduct directed learning programs and seminars around theworld.

Within Schlumberger, no education is ever really complete. Methods and techniques change,as do market conditions and regulatory guidelines. Following formal university and in-housetraining, employees continue to gain knowledge through experience and pre- and postjob ses-sions in which principles and practices are continually improved.

The NExT Network of Excellence in Training, an alliance of Heriot-Watt University inScotland, Texas A&M University, the University of Oklahoma and Schlumberger, provides trainingthat fills a learning gap for working professionals, both within and outside the company, to helpthem diversify their skill sets and learn about emerging technologies. Delivery methods includetraditional classrooms, mentor-supported on-line distance learning, CD-ROM self-study programsand custom on-site courses.

Our policy is to attract the very best graduates, then train and develop them. The majority ofSchlumberger managers started in the field directly after graduating.

Preface xi

Key cementing technology highlightsOur high-quality cementing solutions are based on application of best practices, environmentallysound wellsite operations and innovative technology with safety as a highest priority. That tech-nology includes Advanced Cement Technology, CemSTREAK* rapid deployment cementers, deep-water cementing with DeepCRETE* cement and DeepCEM* additives, and UniSLURRY* cementsystems.

Advanced Cement Technology increases the solids content of slurries by optimizing blends ofseveral particles with different sizes in which the smallest particles fill the spaces between largerparticles. Because of the higher solids content, the cement has greater strength, reduced per-meability and greater resistance to corrosive fluids.

The CemSTREAK unit is a lightweight, low-maintenance truck with four-wheel drive. It canhandle almost any cementing application, even in hard-to-reach well locations. Equipmentdesign makes rig-up, rig-down, cleanup and movement to next location fast and efficient. Thisdesign allows a single unit and crew to cement as many as six wells in one day.

In deepwater cementing, DeepCRETE slurries, with their excellent slurry and set-cementproperties, are combined with DeepCEM additives, providing improved rheology, rapid strengthdevelopment and high strength. Compared with conventional cement technology, these tech-nologies reduce the risk of shallow flow and shorten the waiting-on-cement (WOC) time and itsassociated high cost.

UniSLURRY systems can be used for all types of cementing operations, including casing, liner,squeeze and plug cementing. Similarly, the additives are functional throughout the range of appli-cation conditions. This versatility simplifies the logistics of offshore cementing by reducing thenumber and quantity of additives that have to be transported and stored.

xii Cementing Services and Products

Schlumberger provides high-quality services for well construction and remedial applications.These services are based on best practices, environmentally sound wellsite operations andinnovative technology and always have safety as a first priority.

Cementing is a process used to support and protect the casings in a well and to achieve orrenew zonal isolation. Zonal isolation is required to prevent liquids or gases from flowing fromone zone to another within the wellbore. This isolation allows the completion and productionand subsequent abandonment of the well at the lowest possible cost. Isolation allows moreaccurate well testing to define the reservoir, maximum recovery at the least cost (reduced costsfor produced water and disposal), more effective stimulation through placement focused on thereservoir, more effective enhanced recovery and reduced abandonment costs. Without isolation,the cost of each of these processes is increased and its effectiveness is reduced.

When isolation is not achieved by the primary cement job (cementation of the casing string)a squeeze job is required to correct the deficiency. Squeeze jobs are also used during the wellslife to meet changing objectives as the well and field age.

Occasionally, cement plugs are set in the well to allow changes in drilling. Plugs are also usedto isolate intervals within the well when it is depleted and abandoned.

All these cementing treatments require careful design of the cement systems to provide therequired properties of the slurry before setting and of the cement once it is in place and set.Designs must consider the conditions in the well at the time of cement placement as well asconditions that may occur at any time during the life of the well. In addition to the design of theslurry and set-cement properties, the mechanics of the placement process must be designed toaccomplish optimal mud removal and cement placement. On location, the cement must beproperly mixed to achieve the required properties and pumped into place, maintaining theintegrity of the well.

To achieve the cementing objectives, various additives can be used to modify the slurry andset-cement properties. Specific cement slurry systems are employed to meet especially demand-ing applications. A new, innovative approach to cementing is Advanced Cement Technology. Thistechnology utilizes principles from the concrete industry, specially adapted for oilfield use, to for-mulate slurries with lower water content. These advanced principles eliminate the problems ofconventional slurries, which require high water content for optimal pumpability that ultimatelyreduces the compressive strength of the set cement.

This Advanced Cement Technology has two families; CemCRETE* concrete-based oilwellcementing technology and CemSTONE* technology. CemCRETE technology increases the solidscontent of the slurry using a custom-designed particle-size distribution. More solids in thecement mean greater compressive strength, reduced permeability and greater resistance tocorrosive fluids. CemSTONE technology uses this high solids content together with particleshaving specific properties to modify the set-cement performance (such as durability, flexibilityand expansion) to the needs of the well. Using stress analysis modeling software, cements canbe designed with properties to provide isolation for the life of the well.

Cementing Services and Products Introduction 1

Introduction

Our cementing software is used worldwide by Schlumberger engineers. CemCADE* cement-ing design and evaluation software, which allows simulation based on well data and formationconditions, is used to plan the proper placement of the slurries and ensure the integrity of thewell is not compromised. DESC* design and evaluation services for clients improves communi-cations and solutions development by placing a dedicated Schlumberger engineer in the client'soffice with access to information hubs, technology centers and the most complete family ofapplication software in the industry.

Purpose-built and highly specialized mixing and pumping equipment is employed to properlyexecute the treatment, while the CemCAT* monitoring and recording system provides a recordof the treatment. Use of the CemCAT record, along with design parameters and placement andisolation evaluations such as those provided by USI* UltraSonic Imager logs, allows the designengineer and service team to make performance enhancements and use principles of continuousimprovement to enhance the value of the cementing process.

2 Cementing Services and Products

Deepwater cementing products and servicesDeepwater drilling poses unique challenges for cementing. Large-diameter casings are set inpoorly consolidated formations, frequently with a narrow pore-fracture pressure window andhigh potential for shallow-flow hazards (water or gas). Compounding the problems is the lowtemperature found at the sea bottom and the first few thousand feet below mudline. With sub-sea wellheads, launching cement wiper plugs is also more complicated. Logistically, the distancefrom shore makes versatility in cement slurry design an important consideration. Add to this thedifficulty of remedial work in the deepwater environment, and annular sealing throughout thelife of the well becomes more critical.

Abnormally pressured sands, with a high probability of shallow-water or gas flow, character-ize many deepwater geological environments. Such flows present problems in cementing opera-tions, affecting the integrity of the well. Consequences of uncontrolled shallow flows includesubsidence, compromised seafloor stability, loss of well support and buckling of structural cas-ing, and compromised wellbore integrity, resulting in well control problems and potential loss ofthe well and supporting structures.

Schlumberger provides innovative products and services for solutions to deepwater cement-ing challenges. DeepCRETE slurries, DeepCEM additives and GASBLOK* gas migration controlslurries deliver the properties necessary to provide rapid setting, control of potential flows andthe long-term isolation needed to ensure the integrity of the well and protect the environment.The DeepSea EXPRES* offshore plug launching system allows the efficient release of bottom andtop wiper plugs in subsea cementing heads to prevent cement contamination and control dis-placement. Engineers use CemCADE software, proven over two decades, for placement designand to assure well security and control. Offshore cementing skids, built for performance and reli-ability, provide the means to efficiently mix and pump the high-quality slurries required in thistough cementing environment.

Innovative deepwater cementing solutions provide effective and efcient cementationof wells drilled in deepwater.

Cementing Services and Products Services 3

Services


Deepwater slurriesDeepCRETE cement slurry systems are based on CemCRETE Advanced Cement Technology.DeepCEM additives minimize risk of shallow flow, enhance strength development, reduce WOCtime and provide low permeability of the set cement.

When needed, FlexSTONE* Advanced Cement Technology slurries can be employed to provideset-cement durability, with annular cement sheaths able to withstand changing downholestresses without failing.

DeepCRETE deepwater cementing solutionThe DeepCRETE deepwater cementing solution is a combination of efficient technologies pro-ducing slurries that let you cement weak deepwater zones where low temperature and potentialshallow flow exist, yet quickly return to drilling. DeepCRETE technology, which provides low-density slurries with excellent strength and low permeability, is ideal in the environment encoun-tered in deepwater well construction. Without requiring special equipment or personnel,DeepCRETE slurries isolate the formation with a light cement that develops strength rapidly.This is done using the CemCRETE concept and DeepCEM liquid additives to deliver short tran-sition time and rapid setting at low temperatures. With CemCRETE technology, permeabilityand strength are independent of slurry density and superior to those of conventional cements.

See page 40 for additional information on CemCRETE Advanced Cement Technology.

FlexSTONE CementFlexSTONE systems offer mechanical properties that can be engineered to meet the changingstresses in the wellbore; excellent flexibility and chemical resistance while maintaining lowerpermeability and good compressive strength. FlexSTONE systems, with these properties cus-tomized to the well, will resist stresses and maintain isolation. These slurries also expand to sealany microannulus. FlexSTONE cements are engineered to be more flexible than the formationthey seal, and expansion of the cement sheath occurs both outwards (toward the formation) andinwards (toward the casing), thus assuring complete hydraulic isolation.

See page 48 for additional information on FlexSTONE Advanced Cement Technology.

DeepCEM additivesDeepCEM liquid cementing additives were created for short transition time and early compres-sive strength development. Such properties are necessary for isolation and early casing releaseto ensure successful cementation in the unconsolidated, low-temperature environment of thesurface and conductor casings in deepwater wells. When combined with Schlumberger GASBLOKgas migration control technology, DeepCEM slurries provide the solution to shallow gas or waterflow control. These additives can be used in foamed cement slurries.

Use of these systems allows elimination of the special blends often needed to overcome chal-lenges related to low temperature in deep ocean drilling.

DeepCEM additives include the nonretarding dispersant (D185) and cement set enhancer(D186). The nonretarding dispersant provides the dispersion required for good slurry designwithout retardation at low temperatures. Even at the low temperatures encountered in deep-water wells, D186 set enhancer is more effective for early strength development than standardcement accelerators such as calcium chloride.

Services 5

Well stress analysis softwareStress analysis modeling software is used to identify potential well stresses and their magnitudethroughout the life of the well. Engineers then design the appropriate set-cement properties towithstand these stresses. Where required, FlexSTONE systems are designed with the propertiesidentified using this software. FlexSTONE systems are purpose-built to offer control over proper-ties not possible with conventional oilwell cement. These include such set properties as flexi-bility and expansion for continuous well integrity and zonal isolation for the life of the well.

CemCADE softwareCemCADE software can be used to design all primary cementing operations, from large-diameterconductor casing to the deepest liners. Use of CemCADE software helps the engineer ensure thatwell security is respected at all times and at all points in the well during the cementing treat-ment. By coupling centralization calculations with a numerical fluid placement simulator,CemCADE software allows easy flow regime and annular flow rate selection. It also aids in designof wash, spacer and slurry for optimum displacement of mud and cement placement.Displacement optimization helps to prevent channeling, ensuring zonal isolation.

The program utilities and underlying physics are enhanced continually to reflect the latestdevelopments in cementing technology. Of particular interest for deepwater operations are thetemperature simulator, gas migration predictor, and swab and surge pressures calculator. Thetemperature simulator allows a calculation of fluid and wellbore temperatures that considerswellbore environment parameters such as seawater temperature and current. Better knowledgeof the temperature makes selection of retarder or accelerator concentration more accurate aswell as allows WOC time determination based on modeled wellbore temperatures.

Advanced plug placement module Due to the high operating cost in deepwater, time for any operation must be minimized. This isespecially true when setting cement plugs. A module assists engineers in designing plugs tominimize contamination during placement, resulting in much higher plug-setting success. Thissuccess minimizes the need for repeat plugging operations, thus saving valuable rig time.

See page 29 for additional information on CemCADE software.

Offshore cementing skidsThe performance and versatility of Schlumberger skid-mounted cementing units make them thebest option for offshore, high-pressure pumping services. These state-of-the-art units, capable ofdelivering up to 1490 kW [2000 hhp] of power, can be used as backup or supplemental mud pumpsas well as efficient cementing units. Power to drive the pumps comes from high-performancediesel engines or air-cooled electric motors.

These units are fitted with state-of-the-art sensors for data acquisition and monitoring, and anoptional remote control system permits operation of the unit from an adjacent control room.When a Schlumberger SLURRY CHIEF* cement mixer is used in combination with the skid,cement-mixing rates of more than 1.9 m3/min [12 bbl/min] can be achieved for optimal job exe-cution.

See page 83 for additional information on offshore cementing skids.

Liquid additive metering systems provide versatility in the ability to adjust cement slurry prop-erties right up to the time of the cementing treatment. This is especially beneficial in deepwateroperations, because the requirements may not be known until the hole section is drilled. If dry-blended cements were used, there would be considerable time spent waiting for testing, blend-ing and delivery if requirements are not known until the section is drilled.

DeepSea EXPRES offshore plug launching systemThe Schlumberger DeepSea EXPRES offshore plug launching system is a remotely operated sys-tem for releasing cementing wiper plugs from a subsea tool. It combines a design for safety withhighly functional, high-quality plugs to provide a reliable system for launching plugs in a subseasystem. This system uses solid plugs, which are more reliable than the flow-through type. Plugsare released with minimum or no shutdown of the cementing operation.

Applications Casings hung from subsea hangers Top and bottom plug operation in casing sizes from 244 to 508 mm [958 to 20 in.]

Benets Dart release takes only seconds, reducing rig time. Uninterrupted pumping improves mud removal. High pumping rates allow improved mud removal. Casing pressure test can be combined with bump. Casing running tool can be activated without removing treating lines. Remote operation improves safety.

Features Wiper plugs are efficiently designed. Fluids are not pumped through the plugs. Plugs do not contact casing wall during rig-up. Surface pressure provides positive indication of each plug release. Plug launch qualified at flow rates up to 1.9 m3/min [12 bbl/min]. Optional three plugs separate up to four fluids.

Cement mixing and pumping units are specially designed for use on offshore drilling rigs.


Surface dart launcher A surface dart launcher (SDL) holds the darts, which are launched during the cementing opera-tion. When they reach the subsea tool, these darts release the casing wiper plugs. The standardconfiguration can hold two darts up to 610 mm [24 in.] long. The SDL is modular, so additionalhardware can be added to launch more darts.

Fluids are pumped around the outside of the dart holder. To launch a dart, the EXPRES*system power pack, operated from the rig floor, rotates the valve a quarter turn. This rotationaligns a hole in the valve body with the dart and launches the dart.

The SDL offers full top-drive compatibility. The fluid inlet swivel provides two 50.8-mm [2-in.]WECO connections and permits pipe rotation with the treating lines attached. The 114.3-mmNC50 [412-in. IF] connections at top and bottom allow the entire string to be supported androtated. Both circulating mud and displacement fluid can be pumped through the topdrive.

Darts offer several advantages over free fall balls. The darts wipe the inside of the drillpipeand separate the fluids to prevent contamination. They also provide positive fluid displacement.The time and uncertainty spent waiting for a ball to reach the downhole assembly are eliminated.

DeepSea EXPRESS offshore plug launching system is a reliable tool for releasing cement wiperplugs when subsea hangers are used.

Services 7


Subsea toolThe subsea tool (SST) retains the casing wiper plugs until they are released by the arrival of thedarts. Hydraulic pressure acting through the dart and a rod releases the plugs. The SST acceptsup to three plugs for 219- to 340-mm [858- to 1338-in.] casing or two plugs for 406- to 508-mm[16- to 20-in.] casing.

The deepwater cementing products and services portfolio of Schlumberger provides all thecomponents required to provide zonal isolation for the life of the well.

A gas migration control serviceGASBLOK serviceGas migration, or annular gas flow, is a problem that has plagued the industry for many years.There is no one cause of gas migration, nor is there any one solution to it. To effectively controlgas migration, the nature of the problem must be understood so that the proper techniques canbe applied. This implies a careful analysis of the potential for flow as well as an integratedapproach to its control. During this analysis, one must consider not only the potentially produc-tive intervals, but also the intervals that may not be economically productive, including gasstringers, which can exist behind any casing string.

Among the reasons for gas migration are an uncemented channel, failure to maintain over-balance pressure before and during cementing, loss of overbalance pressure after cement place-ment, development of flow paths after cement setting, and insufficiently low permeability toprevent gas from flowing through the set-cement matrix. Obviously, each of these arises from dif-ferent mechanisms. Therefore, control of gas migration must address the totality of the sourcesfor flow.

Controlling gas migration takes much more than just complex cement slurry design. Slurrydesign addresses only one facet of the complex problem, albeit a very key one. An element of theoverall process of controlling gas flow is achieving zonal isolation through the intervals contain-ing the gas. An additional element is maintaining overbalance pressure during the critical tran-sition period. The final element is preventing gas from migrating along the annulus. TheGASBLOK service considers these elements as three phases of the process: remove the drillingfluid to provide the proper environment for zonal isolation, delay gas entry, impede propagationof the gas.

Services 9

Each of these phases requires careful analysis and design to achieve the desired overallresulta well that is free of gas migration. The first step, that of achieving zonal isolation, isaccomplished by the cement, but only after the drilling fluid has been removed from the wellboreto allow cement to fully occupy the annulus between the borehole and the casing. Mud removalis accomplished by techniques that have been developed by Schlumberger through the years, cul-minating in the WELLCLEAN II* engineering solution for mud removal. This solution considersthe factors that impact mud removal and provides a systematic approach to removal of mud.

The second step is to design the placement process so that an overbalanced condition is main-tained until late in the transition of the cement from a liquid to a solid. The nature of the settingprocess makes it difficult to maintain overbalanced pressure; after placement, cement undergoesa gradual gelation, resulting in loss of hydrostatic pressure. Ideally, the pressure is maintainedabove formation pressure until the cement is set. In practical terms, this is extremely difficult todo. Another option is to minimize the time between development of gel strength and setting whilemaximizing the overbalanced pressure (without risking breaking the well down). This is done byanalyzing the pressures in the well and employing options that maximize the overbalanced pres-sure. Several tools in CemCADE cementing design and evaluation software assist in this step.Obviously, a component of this step is the design of the slurry.

The third step, impeding propagation of the gas, depends on the use of slurries with specialproperties so that gas cannot invade and migrate along the cemented annulus. Special proper-ties, such as those provided by GASBLOK slurries, are required during the critical transitionperiod as well as after setting. Additionally, to maintain isolation for the life of the well,CemSTONE Advanced Cement Technology may be required.

Applications Zonal isolation in gas wells Prevention of annular gas migration from nuisance gas stringers

Benets Minimized risk of gas migration Long-term solution Reduced exposure to hazardous gas flow More trouble-free operations

Features Tailored to specific well conditions Effective at any density Effective at any temperature Compatible with CemCRETE and CemSTONE technologies Integrated solution employing materials and techniques Materials with low environmental impact Engineering tools to assess risk and tailor treatment to severity


Gas ow risk analysisA risk analysis is an important element in the design for gas migration control. Such an analysisincorporates knowledge of all the gas sources (from openhole logs and drilling logs), the poten-tial for gas flow from each source and the potential routes through which gas can migrate.

Routes for gas migrationGas migrates in a well when the pressure becomes underbalanced. If the cement is in place andset when this occurs, the potential for flow depends on the integrity of the cement, both its com-plete filling of the annulus and its mechanical durability. Paths for gas flow develop as a result ofincomplete mud removal (a mud channel), free fluid development in the cement slurry, or aninterfacial gap (microannulus) at the cement-pipe or cement-formation interface. An additionalpath can be created if the cement fails mechanically, producing a crack along its length. Thesepaths can also be created by changing mechanical stresses in the well.

A path can be created if the well becomes underbalanced before the cement has developedsufficient strength to prevent its propagation through the column; that is, while the cement isunset. In this case, gas can migrate through the unset cement, forming a channel.

CemCADE softwareplacement and postplacement risk analysis CemCADE cementing design and evaluation software has two tools that aid in preventing gasinvasion of the cement before it has developed adequate strength to control gas flow. The first isa tool common to most cementing simulators, an analysis of the fluids and pressures in the wellduring and after the cementing process to determine well security and control. If an underbal-anced condition develops during cement placement, a warning is given and the fluids and/orplacement process are redesigned.

A second tool, called postplacement analysis module, provides the design engineer with anindication of the relative risk of gas migration based on the degree of overbalance and the wellgeometry. The engineer can then assess variations in slurry placement and treatment executionvariables to propose the lowest-risk method of cementing the well. In cases where the risk isjudged to be small, less-aggressive solutions can be proposed; conversely, if the risk is judged tobe high, more aggressive solutions should be considered.

Postplacement analysis provides the design engineer with a relative degree of risk for use in selection ofmethods of controlling gas migration.

Very critical Critical Moderate Low Very low

25 Pa50 lbf/100 ft2

75 Pa150 lbf/100 ft2

150 Pa300 lbf/100 ft2

250 Pa500 lbf/100 ft2

Services 11

Cement slurry designSlurry design for controlling gas migration requires attention to the entire realm of slurry and set-cement properties. These include free fluid, fluid loss, rheology, thickening time, gel strengthdevelopment, setting profile and set mechanical properties including permeability. In wells witha high risk of flow, slurries with special properties to stop gas invasion and flow may be required.Their use is normally based on the perceived risk of gas flow.

After assessment of risk, the design engineer develops the slurry design and placementaccordingly. For scenarios with low risk, control of free fluid, rheology, gel strength developmentand fluid loss may be adequate to control gas flow. Where the risk is higher (or uncertain), theuse of more complex slurries with special properties to contain the gas are required.

High riskSchlumberger slurries for high-risk gas migration scenarios have very special properties. Theseslurries are called GASBLOK slurries, proven for over two decades. GASBLOK slurries are part ofthe overall GASBLOK technology, a systematic approach to solving the gas migration problem.These slurries use either a specially designed and patented latex additive or a customized micro-gel polymer.

The latex provides unique properties to cement slurries and the set cement. Being a suspen-sion of solids, the latex provides excellent rheological properties and control of gelation withoutaffecting the hydration process. Free fluid is easily controlled and setting is rapid. The finelydivided latex particles provide efficient pore-blocking in the developing cement matrix during thetransition from liquid to solid and in the set cement. This pore-blocking minimizes the invasionof the cement by gas and prevents its movement. Microgels provide similar effects, but with spe-cially designed hydrated polymer particles.

The GASBLOK family of additives includes D500 GASBLOK LT additive, D600G GASBLOK MTadditive, and D700 GASBLOK HT additive for low, moderate and high temperatures, respectively.A surfactant, D701 GASBLOK stabilizer, is used to control transition time and setting in certaincases. These additives, used so successfully in controlling gas migration for the past two decades,have been modified to make them acceptable in more environmentally sensitive areas, such asthe North Sea.

Low riskWhen the risk of gas migration is judged to be low, less-aggressive designs are required. Slurriescan be designed with more conventional fluid loss additives in place of the GASBLOK latices ormicrogel. Besides fluid loss control, excellent slurry and set properties must still be maintained.

Slurry properties for gas migration controlLaboratory and field evaluations have demonstrated that several properties of cement slurriesare critical in controlling gas migration.

Fluid loss control is important, because maintaining the proper ratio of water to solids is crit-ical to maintaining the rheological properties for effective placement of the slurry as well as pre-venting premature gelation. Premature gelation will lead to long transitions to a set matrix andresult in unacceptably early hydrostatic pressure decay. Such hydrostatic pressure decay wouldin turn lead to an underbalanced condition. If occurring before the cement develops a solidmatrix, this situation can easily lead to gas invasion of the cement and migration along the annu-lus to points of lower pressure.

Simultaneously, the proper water/cement ratio must be designed and maintained to controlslurry stability. An unstable slurry can allow the development of free fluid and/or solid sedimen-tation. Free fluid can create a water channel in the column of cement, leading to gas flow.Sedimentation can lead to changes in density of the slurry and result in inadequate fluid pres-sure to control the formation pressure. An additional impact of the water/cement ratio is that ofthe slurry and set-cement permeability. As the water/cement ratio increases, so does the perme-ability of the cement matrix. A permeable cement matrix makes control of gas more difficult; ifpermeability is sufficiently high, there may be migration through the matrix after setting.

Many slurry properties must be correctly designed for success in cementing acrossgas-bearing formations.


Result Interzonal communication Pressure-charged formations Gas to surface Blowout

Poor mudremoval

(rheology)

Freefluid

Highfluidloss

Cementhydration

Gelstrength

development

Bulkshrinkage

Chemicalcontraction

Gaschanneling

withincementmatrix

Gaschanneling

alonginterfaces

Unplanned costs Remedial work Lost production Damage to equipment and facilities

Services 13

The setting behavior of the cement is important for several reasons. Initially, early settingdetermines the relationship of strength development to hydrostatic pressure decay (and under-balance and gas flow initiation). Subsequently, permeability, shrinkage, expansion and long-termdurability are controlled by the setting behavior. As discussed previously, permeability must bekept low to minimize or prevent gas flow through the set-cement matrix. Shrinkage can resultin the development of microannuli between the cement and pipe or wellbore wall. Shrinkagecan also result in radial cracking of the cement, which provides another path for gas to flow.Long-term durability can be enhanced with CemCRETE and CemSTONE Advanced CementTechnology.

CemCRETE and CemSTONE slurries are highly effective in achieving the properties necessaryfor gas migration control. CemCRETE slurries provide low-permeability cement, even at very lowdensities. They also have excellent slurry properties (stability, rheology, etc.). CemSTONE slur-ries have very high durability and, if required, can be designed to expand. When coupled withGASBLOK technology, both slurry systems provide excellent properties to meet the demandingrequirements for gas migration control.

Cement placement design and executionThe control of gas migration requires more than special slurries. Successful control involvesmany elements.

Mud removal designMud removal is critical to achieving zonal isolation. Schlumbergerengineers use the advanced WELLCLEAN II technology for designing the flow regime, fluids andpumping schedule to achieve mud removal.

Coverage of zone of interestThere must be adequate slurry covering all the gas-bearing for-mations, not just the pay zone.

Maximize overbalanced pressurePressure decay, an unavoidable consequence of thechange from slurry to set cement, results in loss of overbalance. By maximizing the overbalancepressure, the age and therefore the strength of the cement is greater at the time an underbal-anced condition is reached. The Schlumberger engineer uses the postplacement tool inCemCADE cementing design software to optimize the overbalanced pressure.

Gas migration riskThe Schlumberger engineer uses the postplacement module of CemCADEsoftware to evaluate design and operational effects to lower risk of gas flow. Application ofpressure on the annulus following placement, as well as other operational procedure changes,can reduce the risk.

Well security and controlThroughout the cementing process, the pressures in the well mustbe sufficient to control the gas yet not be so high as to cause lost circulation. The U-tube simu-lator in CemCADE cementing design software provides a plot showing the pressures at all timesduring the cementing treatment and aids the engineer in maintaining security and control inthe well.

Hydrostatic-pressure-relieving devicesAt times, openhole casing packers are used to isolatesections of the wellbore. Care must be taken with these devices because they have the effect ofpreventing full hydrostatic pressure transmission and can aggravate the problem. Any loss of vol-ume below the packer (such as by fluid loss) can result in very rapid hydrostatic pressure lossand subsequent rapid gas migration through the entire section isolated by the packer. Gas pres-sure can build up beneath the packer and cause failure of the packer.

Well designAlthough not a common approach to solving gas migration, changes can be madeto the well design to change the level of risk. Using the postplacement module of CemCADE soft-ware, the Schlumberger engineer can work with the well design team to evaluate parameters andredesign the well for the lowest risk for gas flow. An example of a well parameter that plays a partin gas migration risk is the annular gap size. Increasing the annular gap will lower the risk of gasmigration.

Schlumberger engineers integrate all the elements of gas migration control. The risk analysis,the complete placement design and the optimum design of the cement slurries minimize the riskof gas migration, providing zonal isolation and well integrity.


Lost circulation systemsLost circulation is a frustrating, costly and time-consuming problem. Some of the major conse-quences of lost circulation include increased cost resulting from

poor or no removal of cuttings, requiring additional wiper trips stuck drill pipe excessive mud lost remedial work to cure losses rig time required to cure losses.

Reservoir damage and loss of well are also possible as a result of

lack of zonal isolation caused by poor cement coverage formation damage resulting from mud losses blowout after a drop in hydrostatic pressure.

To select the correct technique to effectively solve lost circulation, it is necessary to know thereasons for the losses; i.e., the type of loss and the drilling history.

Very often lost circulation treatments fail because of a lack of information such as the types oflosses and their relative depths. A lack of knowledge can lead to selection of the wrong treatment,which usually results in poor success, excessive costs and time, and the frustration caused byrepetitive failures.

Lost circulation can occur at any time in the life of the well. During construction, lost circu-lation can be encountered while drilling and while cementing. These problems are solved by dif-ferent methods. A tool for identifying the best solution is the Lost Circulation Advisor.

Lost Circulation AdvisorThe Lost Circulation Advisor is software developed jointly by Schlumberger and M-I, LLC. It is acase-based reasoning tool, used to analyze lost circulation problems and recommend the besttreatment to control the losses. The advisor is a knowledge-management software based on thefield experience and the lost circulation expertise of field engineers. Regardless of the loss type(partial or complete) and the operation (drilling or cementing), the advisor guides field person-nel toward the best lost circulation treatment. Based on the input data that include well data,previous lost circulation treatments, operation (drilling or cementing), estimated loss rate andopenhole stratigraphy, the advisor identifies the type of loss and its depth. Finally, the LostCirculation Advisor recommends the best lost circulation treatment from a list of generic andspecialized systems available from M-I, LLC and Schlumberger. Once the best lost circulationtreatment is identified, complete technical data are provided for the design of the treatment.

Applications All types of lost circulation

Benets A simple software based on knowledge management, not complicated mathematical models A systematic and analytical approach to lost circulation A guide to the best lost circulation treatment and the relative depths Validated cases for more precise solutions A low-cost solution to complex problem

Features Uses case-based reasoning Identifies whether the losses are to permeable formations, natural or induced fractures, vugs,

or cavernous formations Estimates the depth of losses Identifies the best lost circulation treatment based on the operation (drilling or cementing) Provides technical information for use in designing the recommended treatments

InstanSeal systemThe InstanSeal system is a unique technology for combating high mud losses. It is often moretime- and cost-effective than other lost circulation control methods. The InstanSeal system usesshear activation to trigger formation of a rigid gel. This unique activation method saves crucialdrilling time and money over other lost circulation methods.

The base fluid for InstanSeal lost circulation control is an emulsion. The emulsion containsgelling polymer and crosslinker in separate phases. The emulsion is converted when the slurry ispumped through the nozzles in the bit, crosslinking the polymer. This results in rapid action andexcellent control of polymer placement into the loss zone.

Applications Severe lost circulation

Benets Internally activated Valuable rig time savings Downhole mixing of fluids not required

Features Use to 95C [200F] Set time independent of bottomhole temperature (BHT) Can be weighted to 1440 kg/m3 [12 lbm/gal] Requires no tripping Set time short and adjustable Is acid-soluble when set Can be mixed up to 3 weeks before use

Activation of the InstanSeal system is by shearing force rather than chemical action.This technology makes placement across the loss zone more certain.

Services 15

500 psi

Emulsion Set gel

Water phase containing high concentration of polymer

Crosslinker particle

Oil phase

Cement


InstanSeal Cement systemThe InstanSeal Cement system is similar to the InstanSeal system, but has powdered cementadded to the oil phase. Once the emulsion is broken and the system forced into the loss zone, thecement will become wet with water and will set. This system is used when a more permanentsolution is required. InstanSeal Cement is stable to 110C [230F].

ShearSEAL lost circulation uidShearSEAL* shear-activated, high-temperature lost circulation fluid is a highly innovative lost circulation solution. The system can be used at temperatures to 163C [325F]. If necessary, it canbe weighted to 2040 kg/m3 [17 lbm/gal]. It can be mixed using batch-mixing techniques or con-tinuously with a static, in-line mixer. The crosslinked gel is not shear sensitive, has improved elas-ticity, exhibits no syneresis and is removable with light acid.

The base fluid for ShearSEAL lost circulation control is an emulsion. The emulsion containsgelling polymer and crosslinker in the oil phase. The emulsion is converted and the polymercrosslinked when the slurry is sheared through the nozzles in the bit. For activation, only a1725-kPa [250-psi] pressure drop at the bit is required. Activation at the bit results in rapidactivation and excellent control of placement of the gelling polymer into the loss zone.

In addition to use for lost circulation control, ShearSEAL system can be used to create supportbeneath a cement plug and to fill the rathole during cementing of the casing.

Applications Severe lost circulation Support for cement plugs

Benets Internally activated Rig time savings No downhole mixing of fluids

Features Use to 163C [325F] Set time independent of BHT Can be weighted to 2040 kg/m3 [17 lbm/gal] Requires no tripping Set time short and adjustable Is acid-soluble when set Can be mixed up to 3 weeks before use

CemNET bers are inert and require no special handling. They can be readily dispersed in water-base uids such as cement. An interlocking network is formed,allowing the cement to bridge and resume circulation.

PERMABLOK system for plugging zonesThe PERMABLOK* fluid system to permanently plug a zone is used to solve lost circulation prob-lems (either during drilling or before cementing), plug high-permeability zones and provide con-solidation of weak formations. Such high permeability can appear as interconnected porositywithin the matrix, or micro- or macrofissures including vugs.

PERMABLOK systems are internally activated solutions with very low initial viscosities. Thesolutions have controlled gelling (pumping) times and set to form a rigid, drillable gel. With atemperature limit of 79C [175F], these solids-free liquids have many applications, includingpumping through the bit. PERMABLOK systems can also be used to permanently plug formationsand to consolidate loose formations that threaten, slow or halt drilling.

CemNET advanced ber cement to control lossesWhen cement is pumped downhole, some of the cement can be lost into natural fractures, fis-sures, vugs or highly porous zones even when the fracture pressure is not exceeded. CemNET*advanced fiber cement is composed of an inert, fibrous material capable of forming a networkacross the loss zone, allowing circulation to be regained. The CemNET fibers are engineered toan optimal size for sealing such loss zones.

CemNET fiber (D095 or D096) is compatible with most cementing systems and additives anddoes not affect the cement properties. CemNET fiber is added to the slurry in the mixing tub ora batch mixer. If CemNET fibers to be used only in the portion of the slurry to be pumped down-hole where losses are expected to occur. Once dispersed in the slurry, the CemNET fibers createa physical network that forms a bridge when flowing past loss zones, resulting in control oflosses and improved fill of the cement during treatment.

CemNET fibers seal formations having potential for losses during treatment, reducing both theamount of cement used and disposal during cleanup. If CemNET fibers are not used, operatorsoften pump excess cement in anticipation of losses to fractures, fissures, vugs or highly porouszones. By adding CemNET fibers to the existing cementing program, well costs are lowered.These cost reductions are a result of smaller excesses of cement needed to achieve returns,reduced disposal of large excesses returned to surface and, more significantly, reduced remedialcementing in the event that cement is not returned to surface.

In some cases, the use of CemNET fiber in the cement has resulted in regained returns.

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Applications Regain circulation while cementing Most cement slurry formulations All temperatures Any slurry density

Benets Minimizes losses during cementing Raises cement tops Helps prevent cement fallback Reduces the need for costly remedial operations Reduces excess cement requirement Makes cement returns more predictable, thus decreasing disposal costs Provides coverage of loss zones during cementing operations

Features Fibers added directly to the slurry during mixing, without dry blending No effect on cement properties Compatible with most cementing systems and additives Forms bridging network in the slurry

ZONELOCK S sealing systemThe ZONELOCK* S permanent zone sealing system is a solution of silicate that forms a rigid,semipermanent gel when in contact with a heavy calcium or sodium brine. The system is com-posed of two solutions: one silicate and one calcium chloride. This system is very effective andworks independently of temperature. It can be used to effectively seal problem zones of brine pro-duction or lost circulation. The solutions can be pumped in multiple stages to cover the zonemore effectively.

ZONELOCK SC permanent system The ZONELOCK SC system includes the ZONELOCK S system followed by a spacer and thencement. When the cement contacts the gel resulting from the silicate-calcium brine solution, thecement sets very rapidly. This ZONELOCK SC system forms a permanent seal that can only beremoved by drilling.

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Mud removalWELLCLEAN II engineering solutionEffective mud removal is considered the most basic requirement for cementing success. Failureto achieve removal of mud can result in failure to isolate productive intervals, allowing produc-tion of unwanted fluids, misapplication of stimulation treatments, and chronic issues of sustainedcasing pressure and gas migration. When such conditions exist, additional costs and efforts areincurred.

Applications Mud removal in oil and gas wells, including deviated, extended-reach, horizontal and injection

wellbores Oil-base mud (OBM) or water-base mud (WBM)

Benets Enhances zonal isolation Eliminates production of unwanted downhole fluids Reduces occurrence of sustained casing pressure Minimizes casing corrosion through improved cement bonding Reduces remedial operations and their associated costs

Features An engineered approach using specialized tools and products Ability to assess the effect of all relevant parameters on the mud removal process A wide range of flexible preflush systems for all application conditions Proven results in the field Environmentally friendly spacers

Recognizing that effective mud removal cannot be achieved without considering the effect ofall relevant parameters, the WELLCLEAN II engineering solution utilizes innovative productsand tools to design cement placement for effective zonal isolation. These products and toolsinclude optimized chemical wash systems

a wide range of custom spacers for all applications

WELLCLEAN II simulator, CemCADE software and WELLCLEAN II advisor engineering tools

a testing methodology focused on evaluating the effectiveness of preflushes in removal ofdrilling fluids

Pipe centralizationBecause fluids in the annulus tend to flow more freely on the wide side, casing centralization iscritical to ensure continuous flow all around the annulus. Schlumberger engineers use the cen-tralization module of CemCADE software to desi

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