Calcareous shale

In most organic-rich shale reservoirs, dolomite is widely distributed and has different types and crystal sizes. However, the characteristics and formation mechanism of the dolomites in organic-rich shale are still poorly understood. Petrographic and geochemical analyses were performed to interpret the formation of dolomite in the lacustrine organic-rich shale of the Shahejie Formation ...

As a general tendency, the carbonate–shale cycles become increasingly calcareous up to the top of the Comblain-au-Pont Fm, where the last 10-cm-thick, slightly argillaceous limestone intercalation is overlain by a massive c. 1-m-thick bed of crinoidal grainstone containing quartz grains and intraclasts (bed 37 in Chanxhe III section, Fig. 3 ...Geology.com describes how shale can have different colors, depending on what's in the original mix of sediments. Organic content of just a few percent produces a black shale; calcareous minerals turn shale gray or light gray; and iron oxide or iron hydroxide can cause reddish, yellow or brown colors.If large dissolution pores develop, organic-rich calcareous shales might become the optimal shale oil reservoirs, referred to as self-generation and self-storage shale oil reservoirs. Therefore, siliceous-rich and organic-rich calcareous shales are considered favorable reservoirs for shale oil in the Dongying Sag, Bohai Bay Basin.Shale is a sedimentary rock composed of very fine clay particles. Clay forms from the decomposition of the mineral feldspar. Other minerals present in.Sequatchie Formation - Grayish-red, grayish-green, and yellowish-gray thin-bedded calcareous shale and calcareous mudstone containing interbedded fossiliferous limestone, and medium-gray to moderate-red partly sandy and glauconitic, medium to coarse-grained bioclastic limestone. In Jackson County, includes the Leipers Limestone and Inman Formation. Calcareous shale in massive layers, containing more or less grit, with a few intercalated thin layers of fine-grained sandstone: 155: Heavy bed of dense gray limestone, with chert lenses and nodules: 4: Pink calcareous shale: 24: Alternating layers of gray limestone and pinkish shale.

Geology.com describes how shale can have different colors, depending on what's in the original mix of sediments. Organic content of just a few percent produces a black shale; calcareous minerals turn shale gray or light gray; and iron oxide or iron hydroxide can cause reddish, yellow or brown colors.Shale. Shale is the most abundant of all sedimentary rocks. It is composed primarily of soft clay minerals, but may include variable amounts of organic matter, calcareous material, and quartz grains. Shale may be any color, but is generally greenish gray to grayish black. It is relatively soft and has a smooth, greasy feel when freshly exposed ...According to the X-ray diffraction (XRD) results (Table 1), the samples from the bottom and upper (S1–S8 and S20–S24, respectively) parts of the Dalong Formation are calcareous shales and marlstones enriched in calcite and depleted in quartz, with average calcite contents of 57.77% and 44.8% and quartz contents of 12.94% and 14.23% ...Found mainly in basalt, calcareous shale, dolomite, and limestone, this type of geode is created when gasses vent, leaving a small cavity. Conversely, organic matter buried in the sediments may decay to leave a cavity. Once the cavity is formed, various minerals accumulate and form crystals, such as amethyst or quartz.In fact, Buday suggested that the sandy-calcareous sediments encountered in the Buzurghan-Abu Ghirab area might be correlated with the younger Ghar Formation in Dujaila Field rather ... Marl, calcareous shale and clay sediments are found in areas more to the offshore (Alsharhan and Nairn 1997). These strata represent the deeper parts and, …Calcareous sandstone 614 Dolomitic sandstone 615 Loess 616 Silt, siltstone, or silty shale 617 Calcareous siltstone 618 Dolomitic siltstone 619 Sandy or silty shale 620 Clay or clay shale 621 Cherty shale 622 Dolomitic shale 623 Calcareous shale or marl 624 Carbonaceous shale 625 Oil shale 626 Chalk 627 Limestone 628 Clastic limestone 629 ...Aug 2, 2020 ... Shale is classified based on its mineral content. There is siliceous shale (silica), calcareous shale (calcite or dolomite), limonitic or ...Laminated calcareous shale, vein-like fibrous calcite, and dolomitic shale intervals have a higher number of pores that are larger than 10 nm. The non-laminated and poorly laminated shale intervals are dominated by small-sized pores. The adsorption-desorption isotherms indicate that the pore morphology varied among different shale intervals ...

The Ottosee shale of Ulrich is basal calcareous member of typical Sevier shale. In early reports and folios of southwestern Virginia the younger Martinsburg shale was erroneously mapped as Sevier shale. Named from exposures in Sevier Co., eastern TN. Extends into western NC, and southwestern VA. Age is Early Ordovician (Chazy).Shale is a fine-grained sedimentary rock that forms from the compaction of silt and clay-size mineral particles that we commonly call "mud." ... However, gray shales can also be rocks that contain calcareous materials or simply clay minerals that result in a gray color.The Posidonia shale formation from the. Lower Saxony Basin is a fine-grained calcareous shale that contains high amounts of organic matter (Type II kerogen). In ...May 1, 2021 · Calcareous shale. The calcareous shale is grey to black with concretions and bands of carbonates (Fig. 7 d). High angle cross stratifications are also observed around the concretions. This lithofacies has high carbonate contents ranging from 40% to 82% with an average of 60% (Fig. 8 c). The silica minerals vary from 12% to 16% (averages 14%). A total of four shale lithofacies are identified in the Luo-69 Well from top to bottom based on core observations in this area: organic-rich mixed shale (ORMS) (lack of bedding, lamination or structural features), organic-rich bedded mixed/calcareous shale (ORBMS–ORBCS), organic-rich laminated calcareous shale (ORLCS), and organic-fair ...

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Sep 1, 2022 · A total of four shale lithofacies are identified in the Luo-69 Well from top to bottom based on core observations in this area: organic-rich mixed shale (ORMS) (lack of bedding, lamination or structural features), organic-rich bedded mixed/calcareous shale (ORBMS–ORBCS), organic-rich laminated calcareous shale (ORLCS), and organic-fair ... This unit is overlain unconformably by the sixth unit (Chia Gara Formation), which is formed of alternating calcareous shale and bedded limestone with argillaceous limestone. The depositional setting of the formation was probably deep outer shelf to carbonate slope environments (Mohialdeen 2008 ), dated as Tithonian-Berriasian (Early …Wills Creek Shale - Olive to yellowish-gray, thin-bedded mudstone, calcareous shale, argillaceous limestone, and sandstone; thickness 450 feet in west, increases to 600 feet in east; and Bloomsburg Formation - Bright red, hematitic, thin- to thick-bedded sandstone and shale; some dark sandstone and green shale; Cedar Creek Limestone Member ...Shale cliff and talus communities occur on shale, tend to be steeper and usually sparsely vegetated, and typically have few to no trees. Whereas, calcareous talus slope woodlands occur on less steep talus slopes composed of calcareous rock such as limestone or dolomite, and have at least 25% cover of trees.

The microscopic pore throat structure of shale reservoir rocks directly affects the reservoir seepage capacity. The occurrence and flow channels of shale gas are …The Eagle Ford Shale (also known as the Eagle Ford Formation) is a black calcareous shale with a high organic carbon content that underlies much of southeastern Texas. In some parts of the area underlain by the Eagle Ford Shale, heat and pressure have converted organic material within the shale into oil and natural gas.Shale is a laminated or fissile clastic sedimentary rock that composed of predominance of silt and clay other minerals , especially quartz and calcite. Characteristic properties of shale is breaks along thin laminae or parallel layering or bedding called fissility. It is most abundant sedimentary rock.depositional systems alternate with calcareous shale enriched with biogenic material (Baumgardner et al., 2016; Brown, 1969; Meissner, 1972; Hamlin et al., 2012). The Wolfcamp formation, deposited during late Pennsylvanian through late Wolfcampian time, is distributed across the entire Permian Basin. The paleogeographic setting was a deepwaterThe shale samples were collected from the Es3x shale (lower third part of the Es3 member) of the Eocene Shahejie Formation, Zhanhua Sag in the BBB. 43 samples of core were obtained for this research work from the Luo-69 well in the Zhanhua Sag . It is mainly composed of gray to dark gray calcareous shale.Calcareous sandstone 614 Dolomitic sandstone 616 Silt, siltstone, or shaly silt 617 Calcareous siltstone 618 Dolomitic siltstone 619 Sandy or silty shale 620 Clay or clay shale 621 Cherty shale 622 Dolomitic shale 623 Calcareous shale or marl 624 Carbonaceous shale 625 Oil shale 626 Chalk 627 Limestone 628 Clastic limestone 629 Fossiliferous ...Provenance and depositional environment of organic-rich calcareous black shale of the Late Ordovician Macasty Formation, western Anticosti Basin, eastern Canada.Black shale. A dark, thinly laminated carbonaceous shale, exceptionally rich in organic matter (5% or more carbon content) and sulfide (esp. iron sulfide, usually pyrite), and often containing unusual concentrations of certain trace elements (U, V, Cu, Ni). Alabama - Arizona - Illinois - Indiana - Kentucky - Massachusetts - Maryland - Maine ... Conclusions. In this study, calcareous oil shale was investigated as a potential raw material for the production of low-carbon cement. It was demonstrated that …

Calcareous sandstone 614 Dolomitic sandstone 616 Silt, siltstone, or shaly silt 617 Calcareous siltstone 618 Dolomitic siltstone 619 Sandy or silty shale 620 Clay or clay shale 621 Cherty shale 622 Dolomitic shale 623 Calcareous shale or marl 624 Carbonaceous shale 625 Oil shale 626 Chalk 627 Limestone 628 Clastic limestone 629 Fossiliferous ...

The lower part of the Pelplin Shale Fm. (Figure 2(b)) is dominated by dark gray, gray, and black shales; in some cases, calcareous interbeds and lenses of marly limestones can also be observed. The upper part is composed of gray and gray-green laminated shales, which are typically calcareous. Subordinate bentonite laminae occur within the shales.It has provided a revised conceptual model that acknowledges the microstructural differences between calcareous mudstones and their argillaceous counterparts. The model has been implemented using mean-field homogenisation schemes, taking the Eagle Ford shale as example of an anisotropic calcareous mudstone.Nov 18, 2021 · The shale samples are preliminarily divided into calcareous shale, siliceous shale, clay shale, and mixed shale. Among the four major types of lithofacies, the samples in the study area mainly developed calcareous shale facies, siliceous shale facies, and mixed shale facies, while clay shale facies were rarely developed ( Figure 8 ). Calcareous sandstone 614 Dolomitic sandstone 616 Silt, siltstone, or shaly silt 617 Calcareous siltstone 618 Dolomitic siltstone 619 Sandy or silty shale 620 Clay or clay shale 621 Cherty shale 622 Dolomitic shale 623 Calcareous shale or marl 624 Carbonaceous shale 625 Oil shale 626 Chalk 627 Limestone 628 Clastic limestone 629 Fossiliferous ...Mar 22, 2015 ... Shale is a sedimentary rock composed of fine grained sediments mainly silt and clay particles ranges at size of 1/256 millimetre.In botany Calcareous grassland is a form of grassland characteristic of soils containing much calcium carbonate from underlying chalk or limestone rock. In medicine The term is used in pathology, for example in calcareous …The shale samples are preliminarily divided into calcareous shale, siliceous shale, clay shale, and mixed shale. Among the four major types of lithofacies, the samples in the study area mainly developed calcareous shale facies, siliceous shale facies, and mixed shale facies, while clay shale facies were rarely developed ( Figure 8 ).Nov 18, 2021 · shale lithofacies in the lower part to calcareous shale lithofacies in. the upper part. Ek. 2 3. is dominated by siliceous shale lithofacies. and mixed shale lithofacies, which accounts for more ...

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The calcareous shales are present in the lower and upper portions of the section (Mohialdeen, 2008). These calcareous shales are rich in pyrite and characterised by bitumen staining ( Fig. 3 b). Pyrite grains, such as framboids and cubical crystals, are abundant along the section, and pyritisation of radiolarians is also present in most of the ...La Casita Group; Limestone, sandy clay, and calcareous shale; shale is laminated to fissile; sandstone is fine-grained and has hematite and calcareous concretions cored by ammonites and pelecypods. Lower contact with Zuloaga Group is sharp; contact with overlying Taraises Formation is transitional. About 300 m thick.Sep 2, 2021 ... Calcareous shales are (C-1, C-2, and C-3) mainly composed of carbonate minerals which are dominated by dolomite, mainly developed in Ek21, ...Murree has rocks of fragile nature, interspersed with calcareous shale (Malik and Farooq 1996) and are therefore prone to landslides (Qasim et al. 2018). Hill slopes in Murree are often covered by colluvium of different thickness. Therefore, excavation for building construction at such places at foot of a slope destabilizes the rocks and leads ...The Santiago shale is an authigenic-calcareous, lenticular wavy-parallel laminated mudstone, mainly composed of carbonates, quartz, clay, OM, and pyrite. A distinctive rock fabric resulting from tectonic shortening was observed from the micrometer to the centimeter scale in each of the three directions analyzed.Gray, Calcareous Shale With Sandstone interbeds and Minor Limestone Menggala Fm. F3 F2 Telisa Fm. "A" Marker "B" Marker 13.8 Barisan Compressional Phase S a g P h a s e Bangko Fm. Medium to Coarse Grained Sandstone and Minor Shale M.Y. BP Duri Gravel, Sand and Clay NE Greenish Gray Shale, P e t a n i G r o u p Sandstone and Siltstone …Jun 22, 2020 ... They've all got soils that are variously described as chalky, decomposed limestone, and calcareous. In chemical terms, all are high in calcium ...Oct 19, 2020 · The geomechanical integrity of shale overburden is a highly significant geological risk factor for a range of engineering and energy-related applications including CO $$_2$$ 2 storage and unconventional hydrocarbon production. This paper aims to provide a comprehensive set of high-quality nano- and micro-mechanical data on shale samples to better constrain the macroscopic mechanical properties ... Light brown calcareous shale Depositional environment-Deep sea,marine environment Calcareous shale is a sedimentary rock formed by chemical precipitation. ….

The lower part of the Pelplin Shale Fm. (Figure 2(b)) is dominated by dark gray, gray, and black shales; in some cases, calcareous interbeds and lenses of marly limestones can also be observed. The upper part is composed of gray and gray-green laminated shales, which are typically calcareous. Subordinate bentonite laminae occur within the shales.MIP analyses were performed on 16 cube-shaped shale samples at the China University of Petroleum (East China) using a mercury porosimeter in accordance with the GB/T 21650.1–2008 standard to measure the pore structure characteristics of shale samples. Before the MIP tests, 16 shale samples were cut into a cube shape (1 cm × 1 …Calcareous clay Argillaceous soil with carbonate of lime content that neutralizes the clay’s intrinsic acidity. Its low temperature also delays ripening, so wines produced on this type of soil tend to be more acidic. Calcareous soil Any soil, or mixture of soils, with an accumulation of calcium and magnesium carbonates. Essentially alkaline ...Calcareous sandstone 614 Dolomitic sandstone 616 Silt, siltstone, or shaly silt 617 Calcareous siltstone 618 Dolomitic siltstone 619 Sandy or silty shale 620 Clay or clay shale 621 Cherty shale 622 Dolomitic shale 623 Calcareous shale or marl 624 Carbonaceous shale 625 Oil shale 626 Chalk 627 Limestone 628 Clastic limestone 629 Fossiliferous ...Shale samples were measured for T 2 spectra, the relaxation time distributions of water-saturated shale samples range from 0.01 ms to 1000 ms and the T 2 spectra at water-saturated for shales showed a unimodal and bimodal distribution, supplemented with a few trimodal distribution (Fig. 12).This study investigates the nano to core-scale geomechanical properties of a maturity series of organic-rich, calcareous shales buried to 100°C–180°C, with a focus on: (a) the mechanical properties of organic matter; (b) the elastic response and anisotropy of the shale composite at micro and core scale; and (c) the creep response.Mar 3, 2022 · The Es3x shale is classified into six lithofacies types based on mineral compositions, TOC contents, and sedimentary structures, that is, organic-rich laminated clay-bearing aragonitic shale (LF1), organic-rich non-laminated clay-bearing calcareous shale (LF2), organic-fair non-laminated calcite-bearing argillaceous shale (LF3), organic-rich ... Mar 11, 2010 · The lower unit consists of 13 feet of dark-gray, soft, papery shale that contains thin calcareous shale partings and some lenses of Inoceramus-prism limestone. A concretionary zone marks the top of this unit. The somewhat calcareous nature of this lower shale suggests that it is the northwesternmost lithologic equivalent of the Fairport Member. Dec 1, 2012 · The black materials are mainly clay minerals rich in organic matters, which, mixed together with clay minerals, is difficult to distinguish from each other under microscope (Fig. 4g-h). 2.3.3 Calcareous shale The content of calcite in calcareous shale ranges from 25… to 50…, with limy fracture surface visible in hand specimens. Red calcareous mudrock and siltstone; white sandstone at the top. Sevier Formation: 2,000: Greenish-gray calcareous shale, sandstone, and calcarenite. Chota Formation: 700-1,000: Dark-red to reddish-gray quartzose calcarenite. Tellico Formation: 3,400: Greenish-gray calcareous shale; persistent calcareous sandstone units. … Calcareous shale, Four organic rich shale samples from the Bakken Formation in the Williston Basin, North Dakota, USA, are selected that have different levels of thermal maturity for this study. ... Geomechanical characterisation of organic-rich calcareous shale using AFM and nanoindentation. Rock Mech. Rock Eng. (2020), pp. 1-18. View in Scopus Google Scholar ..., The Immature calcareous shale in the south slope of Dongying sag, Jiyang depression, plays a significant role in immature oil genesis, and is sampled to make simulation experiment. The geochemical characters of the products of soluble organic matter and kerogen are researched respectively. The yields of the two components and their relations are made out. The …, The sediments are grey mudstone, siltstone, and calcareous siltstone, with thin-bedded intercalations of coal beds. The formation yields foraminifera, dinoflagellates, and ostracods. The Oligocene Huagang Formation is composed of grey to dark-grey mudstone, siltstone, and calcareous shale., Reedsville Formation. Olive-gray to dark-gray shale, siltstone, and fine-grained, thin-bedded sandstone having graded bedding; upper sandstone is very fossiliferous; includes Antes Formation (black calcareous shale) at base along Nittany Arch. State. Pennsylvania., Calcareous shale lithofacies (CSL) are also categorized as organic-rich shale because TOC content in this lithofacies ranges from 1.26 to 8.35 % with an average of 2.53 % (Table 1). Primary sedimentary structures (laminations) are also observed in some sections while some sections lack laminations (10C D)., The calcareous shales are present in the lower and upper portions of the section (Mohialdeen, 2008). These calcareous shales are rich in pyrite and characterised by bitumen staining ( Fig. 3 b). Pyrite grains, such as framboids and cubical crystals, are abundant along the section, and pyritisation of radiolarians is also present in most of the ..., The Eagle Ford Shale (also known as the Eagle Ford Formation) is a black calcareous shale with a high organic carbon content that underlies much of southeastern Texas. In some parts of the area underlain by the Eagle Ford Shale, heat and pressure have converted organic material within the shale into oil and natural gas. Between 2008 and …, Calcareous Concretions. Calcareous concretions are spherical to oval-shaped calcium carbonate concretions that are flattened parallel to the bedding planes. They can range in size from 3 cm to 8 m in diameter. They most often precipitate around a nucleus of fossilized material including plant matter, shells, or even remains of fish., Sep 2, 2021 ... Calcareous shales are (C-1, C-2, and C-3) mainly composed of carbonate minerals which are dominated by dolomite, mainly developed in Ek21, ..., Sep 1, 2022 · A total of four shale lithofacies are identified in the Luo-69 Well from top to bottom based on core observations in this area: organic-rich mixed shale (ORMS) (lack of bedding, lamination or structural features), organic-rich bedded mixed/calcareous shale (ORBMS–ORBCS), organic-rich laminated calcareous shale (ORLCS), and organic-fair ... , The main fossiliferous horizon is restricted to a calcareous shale bed at the lower Sinsk Formation of 0.5 m in thickness (Fig. 2). The shale is dark brown, thinly laminated with calcitic and clayey laminae. Only organisms with rigid enough covers (envelopes and cuticles) such as seaweeds, palaeoscolecidans, some cnidarians, arthropods and ..., Metacarbonate protoliths may be clastic or chemical sedimentary rocks. They are mostly limestones and dolostones, dominated by carbonate minerals. Less commonly, the protoliths are calcareous shales and mudstones (both often called marls ), or calcareous siltstones or sandstones. Figure 15.1 shows the range of compositions projected onto the ..., Calcareous Concretions. Calcareous concretions are spherical to oval-shaped calcium carbonate concretions that are flattened parallel to the bedding planes. They can range in size from 3 cm to 8 m in diameter. They most often precipitate around a nucleus of fossilized material including plant matter, shells, or even remains of fish., Vicksburg Group (undifferentiated) (Oligocene) at surface, covers < 0.1 % of this area. Brown to gray liginitic clays with thin interbeds of lignite or micaceous sands; calcareous shale, petrified wood, and bluish fossilferous clay locally. Overlain by 1-9 meters of loess., Shale is a fine-grained sedimentary rock that forms from the compaction of silt and clay-size mineral particles that we commonly call "mud." ... However, gray shales can also be rocks that contain calcareous materials or simply clay minerals that result in a gray color., Hydrophilic process function of calcareous shale. Fig. 2 clearly shows that the hydrophilic behaviors of calcareous shale with time could be well described by a power function, and the regression coefficient is |R | > 0.99. The relationship can be expressed as (1) Q = 0 t = 0 a t b t ≠ 0., and calcareous shales in southwestern Iran, as gypsiferous red beds in southern Iran and as sandstones, shales and coral limestones in southeastern Iran. Jurassic period is represented in general by bedded limestones, dolomites and massif limestones. There are Carboniferous shale, sandstone and conglomerate in-, Shale is a rock composed mainly of clay-size mineral grains. These tiny grains are usually clay minerals such as illite, kaolinite, and smectite. Shale usually contains other clay-size mineral particles such as quartz, chert, and feldspar. Other constituents might include organic particles, carbonate minerals, iron oxide minerals, sulfide ... , Oct 4, 2022 · The average Barrett−Joyner−Halenda pore size of calcareous shale is 6.5−22.8 nm, and the Brunauer−Emmett−Teller cumulative specific surface area is 0.7588−4.744 m 2/g. According to the ... , Calcareous sandstone 614 Dolomitic sandstone 616 Silt, siltstone, or shaly silt 617 Calcareous siltstone 618 Dolomitic siltstone 619 Sandy or silty shale 620 Clay or clay shale 621 Cherty shale 622 Dolomitic shale 623 Calcareous shale or marl 624 Carbonaceous shale 625 Oil shale 626 Chalk 627 Limestone 628 Clastic limestone 629 Fossiliferous ..., Shale: finely fissile; may include much silt Clay Shale (Argillaceous shale): chiefly clay minerals Argillite: highly indurated; incipiently recrystallized Bentonite: swells and disaggregates in water. Silica Opal, Chalcedony, Quartz: Chert: chalcedony or opal; bedded, nodular, massive Diatomite (Diatomaceous earth): diatom tests , Conclusions. In this study, calcareous oil shale was investigated as a potential raw material for the production of low-carbon cement. It was demonstrated that …, Wills Creek Shale - Olive to yellowish-gray, thin-bedded mudstone, calcareous shale, argillaceous limestone, and sandstone; thickness 450 feet in west, increases to 600 feet in east; and Bloomsburg Formation - Bright red, hematitic, thin- to thick-bedded sandstone and shale; some dark sandstone and green shale; Cedar Creek Limestone Member ..., The upper Member 4 of Shahejie Formation (Es4u) is dominated by brown-greyish and grey-blackish shales, calcareous shales, calcareous mudstones, and mudstones. The middle to lower of Member 3 of Shahejie Formation (Es3m-l) is mainly consisted of calcareous mudstones, dark-grey mudstones and oil shales (Liang et al., …, Reedsville Formation. Olive-gray to dark-gray shale, siltstone, and fine-grained, thin-bedded sandstone having graded bedding; upper sandstone is very fossiliferous; includes Antes Formation (black calcareous shale) at base along Nittany Arch. State. Pennsylvania., shale, is a sequence, 380 feet thick, of noncalcareous and calcareous shale and bentonite beds; the Sage Hen limestone member of Lupton and Lee (1921), a thin persistent bed of concretions, is at the base of the Niobrara. Conformably overlying the Colorado shale is 130 to 235 feet of sandy shale and, Mahantango Formation. The Devonian Mahantango Formation is a mapped bedrock unit in Pennsylvania, West Virginia, and Maryland. [1] [2] [3] It is named for the North branch of the Mahantango Creek in Perry and Juniata counties in Pennsylvania. It is a member of the Hamilton Group, along with the underlying the Marcellus Formation Shale. [4], A total of four shale lithofacies are identified in the Luo-69 Well from top to bottom based on core observations in this area: organic-rich mixed shale (ORMS) (lack of bedding, lamination or structural features), organic-rich bedded mixed/calcareous shale (ORBMS–ORBCS), organic-rich laminated calcareous shale (ORLCS), and organic-fair ..., Wills Creek Shale - Olive to yellowish-gray, thin-bedded mudstone, calcareous shale, argillaceous limestone, and sandstone; thickness 450 feet in west, increases to 600 feet in east; and Bloomsburg Formation - Bright red, hematitic, thin- to thick-bedded sandstone and shale; some dark sandstone and green shale; Cedar Creek Limestone Member ..., The Bakken shale consists of three parts: shale beds in the upper part and the lower part are high-quality source rocks with a strong capability of generating hydrocarbons; the middle part mainly comprises dolomitic siltstone and calcareous sandstone (Miller et al., 2008; Sonnenberg and Pramudito, 2009). This kind of reservoiring pattern ..., However, the actual drilling results have revealed this formation is thin interbeds of shale, calcareous shale and calcareous sandstone with almost no effective pores. This discrepancy between the interpretation result and the drilling result may be attributed to the effect of limestone volume on the compressional-wave velocity., 25.6 %, whereas the calcareous and ferruginous sandstones are discriminated by their elevated average matrix density of 3.07 g/cm3, and they have a wide range of clay volume. Neutron versus density crossplot (Fig. 3B) shows that sandstone is the main lithology in the lower Bahariya with some interbeds of calcareous shale, limestone (3), calcareous shale (7), marine limestone (8), and shale containing clay ironstone bands and thin limestones (9) are absent in the type section of the Dorr Run shale. Possibly the shale bearing the fossil clams (27) is a feeble representa-tion of the calcareous shale (7) of a complete cyclothem.