Practical Well Log Standardsfor Acquisition Curves

Paul Maton, POSCJim Theriot, POSC

Alan Doniger, POSCApril 2005

Outline

• Business Drivers, Challenges• Phase 1 outcomes• Phase 2 approaches, results, examples• Next Steps

Well Logs: Business IssuesHuge numbers of curves (information overload)

Most oil company customers only load a small sub-set of curves into their data stores

Huge numbers of curves (information overload) Most oil company customers only load a small sub-set of curves into their data stores

Complex naming at BOTH Curve and Tool level Confusing even to petrophysicists Others got lost years ago!

Complex naming at BOTH Curve and Tool level Confusing even to petrophysicists Others got lost years ago!

Hard to find up to date information in public domain Isolated lists, complex language

Hard to find up to date information in public domain Isolated lists, complex language

Expert (petrophysicist) and generalist users have different requirements

Expert (petrophysicist) and generalist users have different requirements

Information Overload - Business Value

Most CommonlyLoaded

RarelyLoaded

Loaded Curve Names

Load Frequency High Business ValueMost oil company customers only load a small sub-set of curves into their data stores

Medium Business ValueLoaded for specialist applications

Note: Business Value does not take account of usage. It deals with the ‘average’ case

Log Data Management: Challenges• Nomenclature

– Logging companies’ Vocabularies– Oil companies’ Dictionaries

• Classification for– Tools– Curves

• Value– Who uses ...– Which logs...– How often ...– For what ...

PWLS Version 1

• Classified ~2500 curves for ~100 tools from 3 logging companies

• Defined business value – high, medium, low

PWLS Version 2 Objectives• Clarify and refine Version 1 results• Initial focus on two primary use cases:

– Classify acquisition curve instances based on logging company mnemonics

– Use curve classifications to search for relevant acquisition curve instances

• Additional areas of work– Recommended mnemonics for oil company generated

curves: joined and interpreted– Classification of well log services and tools, e.g. for log

header classification

Company:

Service Class:

Tool Series:

Service-Channel Xref:

Company Channel:

Generic Service/Tool Class: Generic Curve Class:

Channel, Curve and Property‘Company’nomenclature

Maps to

Company Channel Class

RP66 Org codeCo. MnemonicDescriptionBusiness valueClassificationQuantity & UoM

‘Industry’ nomenclature

Well Log Curve Class

Generic Name-----------------ObjectPropertyTechniqueModifier(s)Function

Property Class

NameParent ClassDescription

Subsetof

Curve Class Attributes• What is the object (or thing) whose properties we are measuring?

– Formation, casing, cement, wellbore, acquisition, etc.• What (pure) property of the object are we measuring?

– Density, porosity, velocity, etc.• What technique are we using to make the measurement (with the

tool)?– Neutron, acoustic, etc.

• Modifiers (or qualifiers) qualifying the (pure) Property– Deep / shallow; maximum / average / minimum, etc.

• Function– Mathematical derivation / calculation, e.g. ratio, std. Deviation

• Generic Curve Name– Composite “tag” based the most important attribute value used only for the

small subset of highest value types of curves, e.g. neutron, resistivity

Some Company Curve ClassesRP66 Org.code

Mnemonic Description Value Curve Class (Property Type)

Units Class

150 GR Gamma Ray HIGH Gamma_Ray API_Gamma_Ray

440 SP Spontaneous Potential HIGH Spontaneous_ Potential

Low_Electric_Potential

150 CAL Caliper HIGH Caliper Cylinder_Diameter

150 RD Deep resistivity MED Deep_Laterolog_Resistivity

Resistivity

150 RS Shallow resistivity MED Shallow_Laterolog_Resistivity

Resistivity

150 RMLL Micro-laterolog resistivity HIGH Micro_Laterolog_Resistivity

Resistivity

More Company Curve ClassesRP66 Org.code

Mnemonic Description Value Curve Class (Property Type)

Units Class

150 RMLL Micro-laterolog resistivity HIGH Micro_Laterolog_Resistivity

Resistivity

150 CNC Borehole CorrectedCompensated Neutron Porosity

HIGH Neutron_Porosity

Porosity

150 ZDEN Compensated Bulk Density

HIGH Bulk_Density Density

150 ZCOR Bulk Density Correction HIGH Bulk_Density_ Correction

Density

150 PE Photo-electric cross section

HIGH Photoelectric_Factor

Photoelectric_Factor

Channel, Curve Example 1

‘Company’nomenclature

Maps to

Company Channel Class

RP66 Org code: 150Co. Mnemonic: GRDescription: Gamma RayClassification: Gamma_Ray Units Class: API_Gamma_Ray

‘Industry’ nomenclature

Curve Class

Generic Name: Gamma_Ray--------------------------------------------Object: Formation Property: Gamma Ray Technique: -Modifier(s): -Function: -

Channel, Curve Example 2

‘Company’ nomenclature

Maps to

Company Channel Class

RP66 Org code: 440Co. Mnemonic: PCALDescription: Caliper from Phase Shift ImbalanceBusiness Value: HighClassification: Electromagnetic _Caliper Units Class: Cylinder_Diameter

‘Industry’ nomenclature

Curve Class

Generic Name: Electromagnetic_Caliper---------------------------------------------------Object: Borehole Property: Caliper Technique: Electromagnetic Modifier(s): - Function: -

Links

• PWLS General Web Link• Property Type Browser• Company Data Views• Industry Data Views

– Channel to Curve Class Browser• Schema for PWLS Reference Data

Current Focus: Usage• Users

– Oil companies– Log analysts, Consultants– Data management repositories, companies

• Suppliers– Logging contractors (Acquisition, Processing …)– Software developers and vendors

• Evolve– User communities use PWLS and provide feedback– Revise specifications and implementations– Maintain Property, Curve and Tool catalogues