Characterization of Rock Types With Mixed Wettability Using Log and Core Data - DOE Project Welch Field, Dawson County, Texas

Abstract The Ladakh Himalayan ophiolites preserve remnants of the eastern part of the Neo-Tethyan Ocean, in the form of Dras, Suru Valley, Shergol, Spongtang and Nidar ophiolitic sequences. In Kohistan region of Pakistan, Muslim Bagh, Zhob and Bela ophiolites are considered to be equivalents of Ladakh ophiolites. In western Ladakh, the Suru–Thasgam ophiolitic slice is highly dismembered and consists of peridotites, pyroxenites and gabbros, emplaced as imbricate blocks thrust over the Mesozoic Dras arc complex along the Indus Suture Zone. The Thasgam peridotites are partially serpentinized with relict olivine, orthopyroxene and minor clinopyroxene, as well as serpentine and iron oxide as secondary mineral assemblage. The pyroxenites are dominated by clinopyroxene followed by orthopyroxene with subordinate olivine and spinel. Gabbros are composed of plagioclase and pyroxene (mostly replaced by amphiboles), describing an ophitic to sub-ophitic textural relationship. Geochemically, the studied rock types show sub-alkaline tholeiitic characteristics. The peridotites display nearly flat chondrite-normalized rare earth element (REE) patterns ((La/Yb)N = 0.6–1.5), while fractionated patterns were observed for pyroxenites and gabbros. Multi-element spidergrams for peridotites, pyroxenites and gabbros display subduction-related geochemical characteristics such as enriched large-ion lithophile element (LILE) and depleted high-field-strength element (HFSE) concentrations. In peridotites and pyroxenites, highly magnesian olivine (Fo88.5-89.3 and Fo87.8-89.9, respectively) and clinopyroxene (Mg no. of 93–98 and 90–97, respectively) indicate supra-subduction zone (SSZ) tectonic affinity. Our study suggests that the peridotites epitomize the refractory nature of their protoliths and were later evolved in a subduction environment. Pyroxenites and gabbros appear to be related to the base of the modern intra-oceanic island-arc tholeiitic sequence.

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A Machine Learning Methodology for Rock-Typing Using Relative Permeability Curves

10.2118/205989-ms ◽

2021 ◽

Author(s):

Carlos Esteban Alfonso ◽

Frédérique Fournier ◽

Victor Alcobia

Keyword(s):

Machine Learning ◽

Capillary Pressure ◽

Relative Permeability ◽

Fractional Flow ◽

Flow Curves ◽

Rock Types ◽

Rock Typing ◽

Relative Permeability Curves ◽

Permeability Data

Abstract The determination of the petrophysical rock-types often lacks the inclusion of measured multiphase flow properties as the relative permeability curves. This is either the consequence of a limited number of SCAL relative permeability experiments, or due to the difficulty of linking the relative permeability characteristics to standard rock-types stemming from porosity, permeability and capillary pressure. However, as soon as the number of relative permeability curves is significant, they can be processed under the machine learning methodology stated by this paper. The process leads to an automatic definition of relative permeability based rock-types, from a precise and objective characterization of the curve shapes, which would not be achieved with a manual process. It improves the characterization of petrophysical rock-types, prior to their use in static and dynamic modeling. The machine learning approach analyzes the shapes of curves for their automatic classification. It develops a pattern recognition process combining the use of principal component analysis with a non-supervised clustering scheme. Before this, the set of relative permeability curves are pre-processed (normalization with the integration of irreducible water and residual oil saturations for the SCAL relative permeability samples from an imbibition experiment) and integrated under fractional flow curves. Fractional flow curves proved to be an effective way to unify the relative permeability of the two fluid phases, in a unique curve that characterizes the specific poral efficiency displacement of this rock sample. The methodology has been tested in a real data set from a carbonate reservoir having a significant number of relative permeability curves available for the study, in addition to capillary pressure, porosity and permeability data. The results evidenced the successful grouping of the relative permeability samples, according to their fractional flow curves, which allowed the classification of the rocks from poor to best displacement efficiency. This demonstrates the feasibility of the machine learning process for defining automatically rock-types from relative permeability data. The fractional flow rock-types were compared to rock-types obtained from capillary pressure analysis. The results indicated a lack of correspondence between the two series of rock-types, which testifies the additional information brought by the relative permeability data in a rock-typing study. Our results also expose the importance of having good quality SCAL experiments, with an accurate characterization of the saturation end-points, which are used for the normalization of the curves, and a consistent sampling for both capillary pressure and relative permeability measurements.

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Sedimentology and Reservoir Characterization of the Upper Cretaceous Lance and Upper Mesaverde Intervals from Core Data in Pinedale Field, Wyoming

Pinedale Field ◽

10.1306/13511891m1071510 ◽

2016 ◽

pp. 175-245 ◽

Cited By ~ 4

Author(s):

Mark A. Chapin ◽

Nicholas W. Brandon ◽

Gustavo Ugueto ◽

Andrew Govert

Keyword(s):

Upper Cretaceous ◽

Reservoir Characterization ◽

Core Data

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Characterization of Mixed Wettability at Different Scales and its Impact on Oil Recovery Efficiency

10.2172/790847 ◽

2002 ◽

Author(s):

Mukul M. Sharma ◽

George J. Hirasaki

Keyword(s):

Oil Recovery ◽

Recovery Efficiency ◽

Mixed Wettability

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Petrophysics Analysis for Reservoir Characterization of Upper Plover Formation in the Field “A”, Bonaparte Basin, Offshore Timor, Maluku, Indonesia

Journal of Applied Geology ◽

10.22146/jag.26959 ◽

2016 ◽

Vol 1 (1) ◽

pp. 43 ◽

Cited By ~ 1

Author(s):

Sugeng Sapto Surjono ◽

Indra Arifianto

Keyword(s):

Reservoir Characterization ◽

Water Saturation ◽

Reservoir Rock ◽

Reservoir Properties ◽

Core Data ◽

Class A ◽

Rock Types ◽

Rock Typing ◽

Volume Porosity ◽

Potential Reservoir

Hydrocarbon potential within Upper Plover Formation in the Field “A” has not been produced due to unclear in understanding of reservoir problem. This formation consists of heterogeneous reservoir rock with their own physical characteristics. Reservoir characterization has been done by applying rock typing (RT) method utilizing wireline logs data to obtain reservoir properties including clay volume, porosity, water saturation, and permeability. Rock types are classified on the basis of porosity and permeability distribution from routines core analysis (RCAL) data. Meanwhile, conventional core data is utilized to depositional environment interpretations. This study also applied neural network methods to rock types analyze for intervals reservoir without core data. The Upper Plover Formation in the study area indicates potential reservoir distributes into 7 parasequences. Their were deposited during transgressive systems in coastal environments (foreshore - offshore) with coarsening upward pattern during Middle to Late Jurassic. The porosity of reservoir ranges from 1–19 % and permeability varies from 0.01 mD to 1300 mD. Based on the facies association and its physical properties from rock typing analysis, the reservoir within Upper Plover Formation can be grouped into 4 reservoir class: Class A (Excellent), Class B (Good), Class C (Poor), and Class D (Very Poor). For further analysis, only class A-C are considered as potential reservoir, and the remain is neglected.

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Multiscale Characterization of the Caney Shale — An Emerging Play in Oklahoma

Midcontinent Geoscience ◽

10.17161/mg.v2i.15911 ◽

2021 ◽

Vol 2 ◽

pp. 33-53

Author(s):

Yulun Wang ◽

Guofan Luo ◽

Mercy Achang ◽

Julie Cains ◽

Conn Wethington ◽

...

Keyword(s):

Clay Content ◽

High Energy ◽

Rock Properties ◽

Carbonate Content ◽

Petrographic Analysis ◽

Thin Sections ◽

X Ray ◽

Rock Types ◽

Rebound Hardness

From a hydrocarbon perspective, the Caney Shale has historically been evaluated as a sealing unit, which resulted in limited studies characterizing the rock properties of the Caney Shale and its suitability for hydraulic fracturing. The objective of our research is to help bridge the current knowledge gap through the integration of multiscale laboratory techniques and to characterize the macro- and microscale rock properties of the Caney Shale. We employed an integrated approach for the characterization of the Caney using 200 ft (61 m) of Caney core from a target well in southern Oklahoma. Core observation and petrographic analysis of thin sections were combined to characterize the general rock types and associated fabrics and textures. Mineralogical composition, pore system architecture, and rock fabric were analyzed using x-ray diffraction (XRD), scanning electron microscopy/energy dispersive x-ray spectroscopy (SEM/EDS), and focused ion beam (FIB)-SEM. In addition, rebound hardness and indentation testing were carried out to determine rock hardness (brittleness) and elasticity, respectively. With the integrated multiscale characterization, three mixed carbonate-siliciclastic rock types were identified — mudstone, calcareous siltstone, and silty carbonate — likely representing a spectrum of deposition from low to relatively high energy environments in the distal portions of a ramp system. Silty carbonate contains mostly interparticle pores. The calcareous siltstones and silty mudstones contain a combination of organic matter pores and interparticle pores. Each of the rock types shows unique mineralogical compositions based on XRD. The mudstone lithofacies has the highest clay content and the least carbonate content. Calcareous siltstones show moderate carbonate and clay content. Silty carbonate indicates the highest carbonate content with the least clay content. In an order of mudstone, calcareous siltstone, and silty carbonate, rebound hardness and Young’s modulus show an increasing trend. As a result of rock-fluid interactions, there are potential scaling reactions during completion and production that could ultimately affect permeability and production rates. Overall, the proposed multiscale integration approach is critical for the geologic characterization of most rocks. However, in shale reservoirs dominated by microporosity and microstructure where engineered fractures are expected to provide permeability at a reservoir scale, successful integration is essential. An optimized, integrated geological characterization of the Caney Shale that is well aligned with the engineering designs in drilling, completing, and producing wellbores will ultimately lead to optimal production while providing safe and environmentally responsible operations.

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Pétrographie characterization of rocks from the Mirabello bay region, Crete, and its application to Minoan archaeology: the provenance of stone implements from Minoan sites

Bulletin of the Geological Society of Greece ◽

10.12681/bgsg.17123 ◽

2007 ◽

Vol 40 (4) ◽

pp. 1768 ◽

Cited By ~ 2

Author(s):

H. M. Dierckx ◽

B. Tsikouras

Keyword(s):

Raw Materials ◽

Igneous Rocks ◽

Metamorphic Rocks ◽

Rock Samples ◽

Rock Types ◽

Source Regions ◽

Time Period

The Minoans of East Crete used a variety of igneous and metamorphic rocks as stone implements. These were probably procured in dry riverbeds and beaches located in a region along the Bay of Mirabello or from an onlap conglomerate, which geologically dominates that region and contains rock types of igneous, metamorphic and sedimentary origin. Several rock samples were collected for pétrographie investigation to examine and confirm the source for the igneous rocks. Detailed pétrographie description of natural samples provides the identification of the rocks employed by Minoans and confirms the source of their origin. Apparently the Minoans were able to evaluate the hardness of the stones procured according to the desirable usage and their expected fatigue, thus avoiding unnecessary timeconsuming treatment. The identification of the variable lithotypes used for these implements and the verification of their source regions reveal the time it took to procure the raw materials as well as the time period during which the rocks were employed.

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