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Nick Nelson

Geologist / SEM Engineer

Whiting Petroleum Corporation

October 8th 2013

Outline

My Experience

What is Mudlogging ? ? ?

Data Collection Procedure

How to Read a Mudlog

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Experience

B.S. in Geology from Fort Lewis College

Softrock Geological Services 2005-06

Datalog / International Logging 2006-07

Redwine Resources 2007-09

GeoSearch Logging 2009

Whiting Petroleum 2010-Present

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What is Mudlogging ? ? ?

Mudlogger or Wellsite Geologist

Eyes and ears of the office Geologist

Monitor gas levels while drilling

Identification of potential pay zones

Safety of rig personnel

Describe cuttings properties for

preliminary reservoir characterization

White Light

UV

What data is collected

Rock Data

Drilling Data

ROP

Gamma

Directional Information

Two gas Curves

Total Gas

Chromatograph Gas

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Open Pits

Circulation Pits

Flare

Shaker / Possum Belly

Shakers

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Shakers

Rock Samples

Gas Trap

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Gas Trap / Mud Gas

Gas Detector Gas Detector

Possum Belly

Pumps Flow Line

Pits

Shakers

Mudlogging

Trailer

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What is Gas ? ? ?

Total Gas is exactly what it says

All hydrocarbons are burned together on a

Hot Wire (filament)

Does not distinguish between gas species

Continuous Reading

Chromatograph Gas

Separates out C1 to C5 (standard)

Can separate C1-C10 (mass spec)

3-5 minutes per sample run

Gas 101

Methane CH4

Ethane C2H6

Propane C3H8

Butane C4H10

Pentane C5H12

C

H

H

H

H

C

H

H

H

C

H

H

C

H

H

H

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Gas Trap Flow

Helium Carrier Gas

Partition or Column

C2 C1 C4 C3

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Lag Time

The time it takes for Gas and Rock

samples to make it from the drill bit to

the surface, and ultimately the shaker

and gas detection equipment

Increases with depth and amount of

open hole, not behind casing

Always an estimate except when:

Lag Bomb

Diagnostic formation appearance

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Known Information

- Time / Pump Strokes from Surface to bit

- Time / Pump Strokes from casing to surface

Unknown Information

- Time / Pump Strokes fluid spends in open

hole environment

- How much washout has occurred

Lithology Description

Rock Type Sandstone, Limestone, Shale, Evaporates

Color

Shape Rounded, Angular, Blocky

Grain Size and Sorting

Minerals Pyrite

Extra Important Information Cut, Fractures, Fossils, Metal

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Cut

Can and should be described under

White Light or by Ultra Violet Light

Gives a relative Porosity and

Permeability measurement

Types / Names of Cut

Streaming

Pooling / Rimming

Even

Spotted

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Cryptic Descriptions

Siltstone: Medium Grey, Sub Blocky, Grading to Sandstone Translucent to Off White

to Salt and Pepper, Fine to Very Fine Grained, Sub Rounded to Sub Angular, Poorly

Sorted, Poor Cement, Calcite, Abundant Coal, Abundant Carbonaceous, Really Rare

Crystalline Calcite

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Cryptic Descriptions

Sandstone: Off White-Tan-Salt and Pepper in color, Very Fine-Fine Grained,

Subangular-Subrounded, Well Sorted, Moderate Cement, Slight to Moderate amount

of Calcite, Some White Clay Filled pores, Trace Yellow Mineral Fluorescence,

Trace ????, No Stain or Cut