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Lithology Reference Standards Houston 22 March 2006 Stavanger 13 June 2006 Aberdeen 21 June 2006 Paul Maton (POSC) © Copyright 2006 POSC Outline • Introduction • Practical Taxonomy of Lithologies for E&P • Conclusions © Copyright 2006 POSC Introduction • An initial Lithology Reference Data Standard (Phase 1) was defined to support Mud Logging. This was published with WITSML 1.3 in early 2005. • A plan to define a more comprehensive Lithology Reference Data Standard (Phase 2) during 2005 was deferred in favour of other priorities. • We propose to form a Lithology Work Group to move this work forward. • We seek participants with subject knowledge who support the premise that increased usage of industry reference standards, such as for Lithology, can improve data quality “at the source.” This can reduce ambiguity and the need for future remedial data clean-up efforts. © Copyright 2006 POSC Introduction • The Work Group membership already includes resources from HRH, ONGC, Shell, Statoil. – Interested parties should contact Paul Maton – Work Group Deliverables • Review and contribute to draft specifications of lithological names, abbreviations, classifications. • Conduct wider review among subject experts leading to publication as an industry reference standard. • Encourage usage and participate in deployment activities. • Please participate in this collaborative effort. • Contribute your experience and expertise. • Position your organization to obtain value from the resulting industry standards and best practices. © Copyright 2006 POSC Practical Taxonomy of Lithologies for E&P • Geological reference sources contains many classification systems for the rocks encountered while exploring for hydrocarbons. • Common practice is to use relevant portions of these sources. • Seeking an industry standard – requires agreeing on one or more levels of “practicality”. • Mud loggers tend to use a less extensive vocabulary than is used for later petrographic analysis – And defining mappings between vocabularies in use and the emerging industry standard © Copyright 2006 POSC Business Drivers • Operator Point of View – Standard vocabulary and semantics for lithologies will improve the following processes • • • • Assimilating results of outsourced work Information exchanges with partners, regulators Reduction of ambiguity and uncertainty in data Common nomenclature used for mudlog, core and other rock sample descriptions • Service Company Point of View – Enable use of same nomenclature and classifications in services and software for many customers • Cost savings in software engineering and maintenance • Cost savings and consistency in information produced © Copyright 2006 POSC Case in Point • Consider a large producing field – Over time, many wells may be drilled that probably intersect a fairly consistent sequence of rock formations • If different vocabularies are used by the same or, more likely, different geologists, problems may result – Similarities may appear to be differences – Real differences, for example, in mineral composition, may not be recognized • Corollary Objective: Unify the vocabulary used by geologists and data managers © Copyright 2006 POSC Lithological Reference Sources • Landmark Graphics – List of Lithology Classes with Qualifiers and Symbol Codes • Norwegian Petroleum Directorate – Reporting requirements for Digital Well Data: Lithological Codes • Shell – 1995 Standard Legend • Clastic Rock Classification: Pettijohn, Potter, and Siever (1987) • Carbonate Classification: Dunham (1962) • Statoil – Current Listing of Lithological codes © Copyright 2006 POSC Common Lithological Descriptors Used in Phase 1 • Primary and secondary lithologies • Use of the following characteristics as Qualifiers •Mineral content •Fossil content •Cement •Grain size •Sorting •…~ 10 others © Copyright 2006 POSC Phase 1 Lithology types Andesite Coal Granite Anhydrite Conglomerate Gravel Arkose Diabase Greenstones Basalt Diorite Greywacke Breccia Dolerite Gumbo Calcarenite Dolomite Gypsum Calcilutite Dolomite, Calcareous Halite Calcisiltite Chalk Chert Clay Claystone Extrusive Rock (Volcanic) Feldspar Gabbro Glauconite Gneiss © Copyright 2006 POSC Igneous Intrusvie Rock (Plutonic) Lignite Limestone Limestone, Argillaceous Phase 1 Lithology types Limestone, Dolomitic Potassium and Magnesium Salts Siltstone Limestone, Sandy Quartzite Syenite Marble Rhyolite Tillite (Diamictite) Marl Salt Trachyte Metamorphic Rocks Sand Tuff Mudstone Sandstone Ultrabasic No Description Schist No Sample Serpentine Ophiolites Shale Peat Silicilyte Phosphate Silt © Copyright 2006 POSC Slate Phase 1 Qualifiers Anhydrite Chalky Dolomitic Argillaceous Chamosite Feldspar Barite Chert Ferruginous/Illite Belemnitic Chlorite Fissile Bioturbated Concretions Forams gen Bituminous Conglomeratic Fossil Frags Bryozoans Conglomeritic Fossils gen Burrowed Coral Glauconite Calcareous Crinoids Glauconitic Calcite concr Diatoms Gravelly Calcitic Dolomite concr Gypsiferous Carbonaceous Dolomite Stringer Halite © Copyright 2006 POSC Phase 1 Qualifiers Kaolinite Pelletal Siderite Lignite Pellets Siderite concr Limestone stringer Peloidal Silty Lithic frags Phosphates Spicular Marly Plant Remains Stylolitic Mica Potassium salt Tuffaceous Microfossils Pyrite Tuffite No Description Quartz None Radiolaria Oolithic Salty Ostrocods Sandy Pebbly Shells © Copyright 2006 POSC Plans for Phase 2 Lithological Classification • Approach – Base Phase 2 on Shell ’95 standard legend – Add sedimentary rock types with names, descriptions, abbreviations and adjectives – Add mineral types, names, abbreviations and adjectives – Use consistent capitalization and appropriate granularity – Possibly provide images of rocks as go-bys – Avoid over-complication • Validation by practicing geologists – Work Group – From Industry © Copyright 2006 POSC Material Classification Material Property Mineral Sedimentary Rock Composition Fossil Igneous Fluid Metamorphic Property and Composition are attribute sets inherited by Minerals and Rocks etc, but the sets have additional attributes in, and appropriate to, each sub-class (simplified from Epicentre data model) © Copyright 2006 POSC Scope of Definitions • Consolidated Rock Types – Lithology type, e.g. sandstone, limestone, shale – Definitions addressing mineral composition and other pertinent characteristics – Abbreviation, e.g. sst, lst, sh – Adjective form, where appropriate, e.g. sandy, calcareous, shaly – (possibly) typical specimen images • Unconsolidated Rock Types – Name, abbreviation, and adjective form, where appropriate, e.g. sand, gravel, mud © Copyright 2006 POSC Scope of Definitions • Minerals – Family name and individual name, e.g. feldspar, plagioclase – Abbreviation, e.g. fld – Adjective form, where appropriate, e.g. feldspathic • Fossils – Name as used in E&P, e.g. foraminifera • Usually at a high level in the Linnean classification system – Abbreviation, foram – Adjective form, where appropriate, foraminiferal © Copyright 2006 POSC Common Attributes of Sedimentary Rocks - 1 • Textural & Compositional – Grain size • Modified Wentworth scale – – – – – Sorting Roundness Sphericity Compaction Non-skeletal particles (lithic fragments) – Pellets and grains – Skeletal particles, parts and fragments of fossil material © Copyright 2006 POSC • Porosity & Permeability – Qualitative and quantitative – Fabric and non-fabric selective – Archie classification and types • Color – Names, abbreviations & qualifiers • Based on Munsell system Examples • Sorting – – – – – – – – – unsorted [((srt))] very poorly sorted [((srt))] poorly sorted [(srt)] poorly to moderately well sorted [(srt)-srt] moderately well sorted [srt] well sorted [srt] very well sorted [srt] unimodally sorted [unimod srt] bimodally sorted [bimod srt] • Compaction – – – – – – – not compacted [not cmp] slightly compacted [(cmp)] compacted [ cmp ] strongly compacted [cmp] friable [ fri ] indurated [ ind ] hard [ hd ] • Color – green [ gn ], dark [ dk ] [Note: Entire abbreviations, including parentheses, are in Square Brackets] © Copyright 2006 POSC Common Attributes of Sedimentary Rocks - 2 • Accessory Minerals – References extensible list and abbreviations of mineral class names – e.g.: Feldspar (Fld) • Fossil content – References extensible list and abbreviations of fossil class names – e.g.: Bryozoa (Bry) © Copyright 2006 POSC Common Attributes of Sedimentary Rocks - 3 • Stratification and Sedimentary Features – – – – – – – – – Bedding thickness and appearance Character of base of bed Large non-bedded features: lens, bioherm etc Cross bedding and lamination Ripplemarks Planar laminations Graded bedding Soft sediment deformation Syn-depositional features © Copyright 2006 POSC Common Attributes of Sedimentary Rocks - 4 • Post-depositional features – – – – – Consolidation, cementation, Joints, fracturing and slickensiding Weathering and oxidation Diagenetic structures Nodules and concretions • Note: Values may be either or both qualitative and quantitative – To be practical, qualitative values will be proposed in most cases with quantative values or ranges for important characteristics, e.g. grain size, density, porosity, and permeability, using recognized classifications © Copyright 2006 POSC Igneous and Metamorphic Rocks • Minimal treatment given that these are not often of primary interest in E&P • Names, descriptions, abbreviations and adjectival forms of ~12 types in each category – Examples – Granite, (Gr), granitic – Schist, (Sch or sch???), schistose © Copyright 2006 POSC Outline • Introduction • Practical Taxonomy of Lithologies for E&P. • Conclusions © Copyright 2006 POSC Phase 2: Next Steps • Form Work Group of practising geologists from US, Europe, India (Volunteers sought) - 2Q2006 • Produce, review and revise specifications, including WITSML format XML enumeration file - 3Q2006 • Submit to WITSML TT as change request for Version 1.3.n - 3Q2006 • Conduct public review • Publish as POSC Reference Data Standard - 3Q2006 © Copyright 2006 POSC Thank you! More information from Paul Maton Alan Doniger Gary Masters © Copyright 2006 POSC [email protected] [email protected] [email protected] +44 1932 828794 +1 713 267 5124 +1 713 267 5111