*CONTENTSCORE ANALYSIS FLOW CHARTGEOLOGICAL CORE DESCRIPTIONPETROGRAPHIC ANALYSISLABORATORY MEASUREMENTCORE-LOG COMPARISONSGEOLOGICAL INTERPRETATION1. FACIES & DEP ENVIRONMENT2. STRATIGRAPHIC SEQUENCES

*CORE ANALYSIS FLOW CHART

*OBJECTIVES FOR CORINGPetrologySedimentologyFracture studiesPorosity and permeability (Storage and flow capacity)Biostratigraphy Geochemistry Establishing presence of hydrocarbons Establishing reservesLog correlation Geological mapping

*OBJECTIVES FOR CORING

Confirm presence of economic basementEstablish likely oil recovery and residual oil saturation.Examine reservoir suitability for enhanced oil recovery.Examine reservoir rock for type and extend of likely formation damage (permeability reduction or skin) mechanism.

*CORING METHOD

The most common methods :Conventional Sidewall (percussion or drilled)

Unconsolidated conventional core (sleeved) :Rubber sleeveFiberglassPlastic sleeveAluminium Sleeve

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*CORING FLUIDS

Water based :Fresh waterSalt waterOil emulsion

Oil based :Lease crudeDieselMineral oil

CORE PRESERVATION

Plastic lay-flat tubingSaran wrap, aluminium foil, core sealSubmerging under de-aerated waterSubmerging under non-oxidised crude or mineral oilFreezing in dry ice

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1. Total Gamma RayGamma ray measurement at the surface of the core

PRELIMINARY CORE CHARACTERIZATION

*2. Core SPECTRAL GAMMA to detect gamma radiaton from K, U, Th

Application :- depth matching- shale indicator- fracture or source rock detection as shown by U activity

PRELIMINARY CORE CHARACTERIZATION

*3. X-RAY Computerized Tomography(CT Scanning)- scan core encased in a sleeve- detect of radial fractures- detect of dense streraks- observation of flow tests

PRELIMINARY CORE CHARACTERIZATION

*4. CORE PHOTOGRAPHY & IMAGING- Determination of net selected - Determination of sample quality - Evaluation of mud filtrate invasion into acore- Aid in geological studiesPRELIMINARY CORE CHARACTERIZATION

*GEOLOGICAL CORE DESCRIPTION

Lithology Rock colourMineralogyTextureSedimentary structuresVisible porosity typeFracture definitonPresence or absence of oil (fluorosence)

*GEOLOGICAL CORE DESCRIPTION

Formation thickness (tops & bottom)Facies & depositional environmentFossils content Stratigraphic sequences Formation agePaleomagnetism

*LITHOLOGY

SHALESANDSTONECONGLOMERATESBRECCIASCARBONATE ROCKSVOLCANIC ROCKS

*LITHOLOGYSHALESedimentary rock formed by induration of a clay, silty clay, or silty clay loam deposit and having the tendency to split into thin layers, i.e., fissility .

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*2. SANDSTONESedimentary rock containing dominantly sand-size clastic particles

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*3. CONGLOMERATESA coarse-grained, clastic sedimentary rock composed of rounded to subangular rock fragments larger than 2 mm, commonly with a matrix of sand and finer material; cements include silica, calcium carbonate, and iron oxides. The consolidated equivalent of gravel

*4. BRECCIAS

A coarse-grained, clastic rock composed of angular rock fragments (larger than 2 mm) commonly bonded by a mineral cement in a finer-grained matrix of varying composition and origin. The consolidated equivalent of rubble.

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*5. CARBONATE ROCKS

a. LIMESTONEA sedimentary rock consisting chiefly (more than 50 percent) of calcium carbonate, primarily in the form of calcite. Limestones are usually formed by a combination of organic and inorganic processes and include chemical and clastic (soluble and insoluble) constituents; many contain fossils

*b. DOLOSTONEA carbonate sedimentary rock consisting chiefly (more than 50 percent by weight or by areal percentages under the microscope) of the mineral dolomite

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*6. VOLCANIC ROCKS

a. PYROCLASTICSPertaining to fragmental materials produced by usually explosive, aerial ejection of clastic particles from a volcanic vent. Such materials may accumulate on land or under water b. LAVAA solidified body of rock formed from the lateral, surficial outpouring of molten lava from a vent or fissure, often lobate in form.

c. TUFFA generic term for any consolidated or cemented deposit that is > 50 percent volcanic ash (< 2 mm); various types of tuff can be recognized based on composition: acidic tuff is predominantly composed of acidic particles; basic tuff is predominantly composed of basic particles.

*MINERALOGY1. SHALE

*MINERALOGY2. SANDSTONE

*MINERALOGY3. CARBONATE ROCKS

*TEXTURE1. NON-CLASTICS TEXTURE

a. Amorphb. Oolithicsc. Pisolhiticsd. Sacharoidale. Crystalin

*TEXTURE2. CLASTICS TEXTURES

a. Grain sizeb. Grain shapec. Sortationd. Fabrics

*a. Grain size

*b. Grain shape

*c. Sortation

*d. Fabrics

*3. CARBONATE TEXTURES/STRUCTURES

*SEDIMENTARY STRUCTURES

*STRATIFICATION

*CROSS-STRATIFICATION

*HUMMOCKY CROSS-STRATIFICATION

*RIPPLES

*GROOVE CASTS

*FLUTE CASTS

*LOAD CASTS & FLAME

*MUD CRACKS

*SLUMP/CONVOLUTE

*DEWATERING

*POROSITY TYPEINTERGRANULARINTRAGRANULARINTERCRYSTALLINEVUGULAR/MOLDICFRACTUREMICROPOROSITY

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*FRACTURE DEFINITONDEPTH & OCCURRENCEWIDTH & LENGTHDIP ANGLE & AZIMUTHMINERALIZATIONSTAINNING

*FOSSILS CONTENTTYPES OF FOSSILSBATHIMETRYAGE OF FOSSILS

*PETROGRAPHIC ANALYSISANALYSIS INCLUDE

COMPOSITIONTEXTUREFRAMEWORK GRAINSCEMENTMATRIXPOROSITYDIAGENESIS

*Quartz in sandstone

*Feldspart in sandstone

*Rock fragment in sandstone

*Other detrital in sandstone(heavy minerals)

*Sandstone, Potsdam Formation, St. Lawrence County, New York Crossed polarizers with gypsum plate

*OOLITIC SANDSTONE Whirlpool Formation Monroe County, New York

*RECYCLED SANDSTONE Potsdam Formation Washington County, New York

*FOSSILS IN MUD Becraft Limestone Greene County, New York

*Calcite

*characteristic cleavage in calcite

*secondary calcite

*Dolomitic sandstone

*LABORATORY MEASUREMENTPOROSITYPERMEABILITYWATER SATURATIONWETTABILITYCAPILLARY PRESSUREOIL & CONDENSATE ANALYSIS, etc.

*POROSITY

*POROSIMETER

*PERMEABILITY

*Sandstone matrix permeability anisotropy. B) Fracture permeabilityanisotropy (Keelan and Marschall, 1989).

*Permeability and porosity trends for various rock types (Keelan and Marschall, 1989)

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*WATER SATURATION

*WETTABILITY

*CAPILLARY PRESSURE

*GEOLOGICAL INTERPRETATIONFACIES & DEP ENVIRONMENT

*Offshore and transitional zone

General Environmental Setting: Marine offshore to transitional zoneRock Description: Fine grained sandstone and mudstone. Bioturbation and compaction. May locally contain gas-disrupted bedding.Depositional Environment Represented: Shoreface to shallow offshore.Other envi where rock type is typically found: Any moderate to low energy environment including lakes, lagoons and shallow marine environments.

*Offshore and transitional zone

General Environmental Setting: Marine offshore transitional zoneRock Description: Parallel bedded sandstone and mudstone (base). Because the mudstone and sandstone beds are parallel it is likely that the beds were close to horizontal at deposition. Thus the apparent dip of the beds in the core is a result of the beds not being drilled perpendicularDepositional Environment Represented: Shallow offshoreOther env where rock type is typically found: Not found in other environments

*Beach

General Environmental Setting:Marine shoreface - beachRock Description:Parallel bedded-rippled sandstone. Note horizontal burrow near bottom (probably Paleophycus)Depositional Environment Represented:Upper shoreface/beachOther environments where rock type is typically found:Paleophycus burrows only found in marine environments. Marine shoals, washovers, tidal deltas.

*Beach

General Environmental Setting:Marine shoreface - beachRock Description:Bioturbated sandstone. Original rock-interbedded clean sandstone and mudstone.Depositional Environment Represented:Foreshore to offshoreOther environments where rock type is typically found:Interbedded clean sandstone and shale typical of lower foreshore to offshore environments or tidal areas where periodic high current velocities occur. Vertical burrows typical of transitional marine environments where filter feeders are dominant.

*Braided River

General Environmental Setting:Non marine: fluvialRock Description:Ripple cross-bedded sandstone (only lee side of ripple preserved)Depositional Environment Represented:ChannelOther environments where rock type is typically found:Any moderate energy environment in which migrating ripples occur but most commonly preserved in tidal and non-marine facies.

*Braided River

General Environmental Setting:Non marine: fluvialRock Description:ConglomerateDepositional Environment Represented:Braided channelOther environments where rock type is typically found:Such coarse conglomerates are restricted to very high energy channels. In mass flow deposits the degree of rounding of clasts evident in this sample will not occur.

*FLUVIAL-CHANNEL

General Environmental Setting:Non marine: fluvialRock Description:Granular sandstone Depositional Environment Represented:ChannelOther environments where rock type is typically found:Clean well sorted granular sandstones also common in high energy beach and bar facies.

*FLUVIAL-CHANNEL

General Environmental Setting:Non marine: fluvialRock Description:Cross-bedded sandstoneDepositional Environment Represented:ChannelOther environments where rock type is typically found:High energy environments where migrating dunes of megaripples occur (foreshore, aeolian, channel).

*OVERBANK

General Environmental Setting:Nonmarine - overbankRock Description:Horizontal-ripple cross-laminated sandstone with mudstone partings. Only lee side of ripples preservedDepositional Environment Represented:Overbank deposit (levee or splay).Other environments where rock type is typically found:Not found in other environments

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General Environmental Setting:Nonmarine - overbankRock Description:Convolute (soft-sediment structures) and horizontal bedded sandstone. Note the syn-depositional fault near the baseDepositional Environment Represented:Channel of proximal crevasse-splayOther environments where rock type is typically found:Any moderate to high energy facies characterized by rapid deposition.

*Wave Dominated Delta

General Environmental Setting:Marine shoreface - beachRock Description:Cross-bedded sandstoneDepositional Environment Represented:Upper shoreface or distributary channelOther environments where rock type is typically found:Moderate to high current velocity areas such as marine shoals, fluvial and tidal point bars, channel bottoms, distributary mouth bars, tidal inlets, tidal deltas and shelf sand ridges.

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General Environmental Setting:Marine and transitional marine to tidal flatRock Description:Ripple cross-bedded and convolute-bedded sandstone interbedded with mudstoneDepositional Environment Represented:Tidal flat to shallow subtidalOther environments where rock type is typically found:Areas of alternating high (sand deposition) and low energy (mud deposition) such as splays or some subtidal areas influenced by storms.

*Shoreface

General Environmental Setting:Marine offshore transitional zoneRock Description:Bioturbated sandstone. Burrows are similar to Paleophycus.Depositional Environment Represented:Shoreface - moderate energy environment. The presence of alternating laminae of mud and sand indicate periods of low and high energy deposition.Other environments where rock type is typically found:Not found in other environments

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General Environmental Setting:Marine offshore transitional zoneRock Description:Horizontal bedded and bioturbated sandstone. Burrows are similar to PaleophycusDepositional Environment Represented:Shoreface - moderate energy environment. Presence of laminae of mudstone indicate periods of low energyOther environments where rock type is typically found:Any moderate energy environment but with burrows is typical of lower foreshore to shallow offshore facies.

*Tidal Flat

General Environmental Setting:Marine and transitional marine to tidal flat Rock Description:Parallel bedded sandstone with large vertical to 'U' shaped burrows (probably Diplocrateron or Rhizocorallum). Parallel bedding defined by thin laminae of carbonaceous material and reddish brown siderite pelletsDepositional Environment Represented:Marine shoal/shoreface.Other environments where rock type is typically found:Not found in other environments

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General Environmental Setting:Marine and transitional marine to tidal flatRock Description:Lenticular and flaser bedding: sandstone and mudstoneDepositional Environment Represented:Typical of tidal flatsOther environments where rock type is typically found:flaser and lenticular bedding indicate both sand and mud are available and that periods of at least moderate current activity (sand deposition) alternate with periods of quiescence (mud deposition). These conditions are characteristic of subtidal and intertidal areas.