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  • PNNQI

    Petrophysical Interpretation Using Only PNN Data

    Zoran Markovic - ChombeHWLAC GmbH Wiesengasse 6

    7013 Klingenbach, AUSTRIA Tel.: +43 6763166824

    office@hwlac.com www.hwlac.com

    1

    Petrophysical Interpretation Using Only PNN Data/ Chombe

  • 2

    Title of the Slide

    Aim of the presentation:

    Show PNNQI features as New PNN Petrophysical Interpretation Software Package With Explaining Model and the Full Program Flow.

    Petrophysical Interpretation Using Only PNN Data/ Chombe

  • 3

    Title of the Slide- Old oil and gas fields become more interesting for development and additional production due to high oil price on the world markets.

    - In the past some minor reservoirs were not taken into account at all because of not enough economic reasons.

    - In existing reservoirs there were left a lot of bypassed zones or the depletion efficiency was low!

    - Those fields are of are often with very limited amount of available openhole logs.

    - In most cases covering basic electrical logging without any porosity logs. In some cases logs are lost or with bad quality.

    - In some new oil and gas fields are trying to cut the cost by limiting number of measured logs due to different reasons weather this is expense or it is well’s technical condition.

    Introduction

    Petrophysical Interpretation Using Only PNN Data/ Chombe

  • 4

    Title of the SlidePNN – Pulsed Neutron Neutron

    • The main purpose of PNN logging in wells is to determine water saturation in measured intervals.

    • PNN tool has several sensors enabling hydrocarbon saturation evaluation qualitatively or quantitatively.

    • To most is less known that PNN has some more sensors used for other interpretations like volume of shale and porosity.

    Introduction

    Petrophysical Interpretation Using Only PNN Data/ Chombe

  • 5

    Title of the SlidePulsed Neutron Neutron (PNN) measurement offers good set of curves that help us to cover the lack of data at these wells and to offer full petrophysical interpretation.

    Standard PNN interpretation is based on capture-cross section (Sigma) curve which combined with independent petrophysical interpretation (porosity, lithology) gives a good present quantitative saturation evaluation.

    However even in the cases when the good openhole interpretation is unavailable PNN measurements in most of cases are giving us another curves that enables us to perform the full petrophysical interpretation (porosity and lithology as well as saturation).

    Introduction

    Petrophysical Interpretation Using Only PNN Data/ Chombe

  • 6

    Title of the SlidePNNQI – The New Interpretation Model and Program

    • The new interpretation technique as well as algorithm and program PNNQI (PNN Quick Interpretation) is developed in order to enable us full petrophysical interpretation solely based on PNN data.

    • The aim of this paper is to fully describe the program and the usage with all relevant parameters as well as to show some interpretation examples.

    Introduction

    Petrophysical Interpretation Using Only PNN Data/ Chombe

  • 7

    Title of the SlideCurves Used

    • PNN tool contains several sensors which combined or independently gives us information of formation lithology, porosity and saturation.

    – GRPNN – Gamma Ray

    – RATIO - Ratio between Short and Long Spaced Count Rates

    – SIGMA - Capture Cross-Section

    • The new technique and program functionality will be in more details described in following Slides.

    Input Curves

    Petrophysical Interpretation Using Only PNN Data/ Chombe

  • 8

    Title of the Slide• The Interpretation Model This is newly developed interpretation method based on three-dimensional (3D) space with each dimension respectively presenting:

    – Sigma

    – Ratio

    – Gamma ray The model is based on spacing or positioning the model points in such designed 3D space. Points that are modeled and in the same bases for the interpretation are following:

    – W- Water (100% Porosity)

    – HC - Hydrocarbon (100% Porosity)

    – M1 – Matrix 1 (0% porosity mineral 1 point)

    – M2 – Matrix 2 (0% porosity mineral 2 point)

    – C – Clean (Clean point)

    – S – Shale (Shale point)

    – S1– Shale 1 (Shale 1 point) 3D space means determining for each-one of them the respective values for above mentioned three dimensions (Sigma, Ratio and Gamma Ray).

    Petrophysical Interpretation Using Only PNN Data/ Chombe

  • Sigma

    GR

    Ratio

    Matrix

    Shale

    Shale 1

    A

    B

    C

    D

    E

    9

    Petrophysical Interpretation Using Only PNN Data/ Chombe

    Sigma-Ratio-Gamma X-Plot

    Sigma-Gamma-Ratio X-Plot

    Ratio-Gamma-Sigma X-Plot

  • Title of the Slide

    10

    Title of the Slide

    Petrophysical Interpretation Using Only PNN Data/ Chombe

    PNNQI

    Flow Calculate RATPOR

    Calculate

    Dual Mineral Volumes

    Calculate Common Matrix

    Point

    Calculate Dual Volume of Shale

    Calculate Water Saturation

    Calculate SIGPOR Calculate

    Effective Porosity

    Apply SWIIR Correction

    Calculate Corrected Sigma

    Calculate Gross/Net/Net-Pay

    Save Curves

  • Title of the Slide

    PNNQI – Program Flow – Details → 1

    11

    1.) Start New Project [File → New] [ ] (Open DF)

    Petrophysical Interpretation Using Only PNN Data/ Chombe

  • Title of the Slide

    PNNQI – Program Flow – Details → 2

    12

    1.) File Oppened Automatically

    a) read all the relevant curves for the interpretation,

    b) populate all relevant logs with found input and output curves

    Petrophysical Interpretation Using Only PNN Data/ Chombe

  • Title of the Slide

    PNNQI– Program Flow – Details → 3

    13

    1.) File Oppened Automatically

    c) create and fill all relevant X-Plots

    Sigma-Ratio-Gamma X-Plot

    Sigma-Gamma-Ratio X-Plot

    Ratio-Gamma-Sigma X-Plot

  • Title of the Slide

    PNNQI – Program Flow – Details → 4

    14

    1.) File Oppened Automatically

    d) Create interpretation charts

    - Sigma Water

    - Sigma Oil

    - Sigma Gas

  • Title of the Slide

    PNNQI – Program Flow – Details → 5

    15

    1.) File Oppened Automatically

    d) Create Whole Interpretation Zone

    - Populates zone with default

    interpretation parameters

    Ready:

  • PNNQI– Program Flow – Details → 6

    16 PNNQI/ Chombe

    2.) Input (Output) Curves Selection Curve Default

    Name Description

    Capture Cross-Section (c.u.) SIGMA Input capture cross-section curve. Curve must exist in order to perform analysis!

    Gamma Ray PNN GRPNN Input PNN natural radioactivity curve as measure from PNN in cps.

    Ratio Curve from PNN RAT59 Input PNN Ratio Curve. It can be any ratio curve but preferably the best results are achieved using ratio from channels close to maximum thermalization point (5-9)

    Gas/Oil Interpretation Offset Curve LSN Input Offset curve for Gas/Oil calculations. Normally this is the LSN Curve but can be as well the PNN RATPOR neutron porosity!

    Gas/Oil Interpretation Base Curve SSN Input Base curve for Gas/Oil calculations. Normally this is the SSN Curve but can be as well the openhole neutron porosity!

  • PNNQI – Program Flow – Details → 7

    17

    2.) Parameters Edit/Selection

    Sigma Parameters Tab

    Name Abr. Min Max Defau lt

    Description

    Sigma Mineral 1 (c.u.) SgM1 0 20 12 Mineral 1 capture cross-section in capture units! Typical values are from 5-10 depending of bituminous content! Typical values for sandstones are from 6-11 and even for some sandstones higher depending on high capture cross-section minerals content! Limestones

    Sigma Mineral 2 (c.u.) SgM2 0 20 14 Mineral 2 capture cross-section in capture units! Typical values are from 5-20 depending of matrix composition! Typical values for sandstones are from 6-11 and even for some sandstones higher depending on high capture cross-section minerals content! Limestones

    Sigma Matrix (c.u.) SgM 2 22 16 Sigma Matrix Used for Shaliness Calculation. Should be as close to clean zone capture cross-section and not to be influenced by saturation and porosity!

    Sigma Shale (c.u.) SgSH 15 45 25 Shale capture cross-section in capture units! Typical values are from 16-40 depending of shale type! Look at the log in neigbouring shales for choosing correct value!

    Sigma Shale 1(c.u.) SgSH1 15 45 25 Shale 1 capture cross-section in capture units! Typical values are from 16-40 depending of shale type! Look at the log in neigbouring shales for choosing correct value! Have to be different than for main shale!

    Sigma Hydrocarbon (c.u.) SgH 5 25 18 Hydrocarbon capture cross-section in capture units! Typical values are from 5- 17 for gasses and 17-22 for oil! Look at the available chart for choosing correct value!

    Sigma Formation Water (c.u.)

    SgW 22 172 39 Formation water capture cross-section in captu

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