scholarly journals Hydrocarbon generation and expulsion of Middle Jurassic lacustrine source rocks in the Turpan–Hami Basin, NW China: Implications for tight oil accumulation

2020 ◽  
pp. 014459872095629
Author(s):  
Yue Feng ◽  
Zhilong Huang ◽  
Tianjun Li ◽  
Enze Wang ◽  
Hua Zhang ◽  
...  
Keyword(s):  
Middle Jurassic ◽  
Potential Method ◽  
Source Rocks ◽  
Western China ◽  
Tight Oil ◽  
Hydrocarbon Generation ◽  
Pore Throat ◽  
Throat Radius ◽  
Oil Accumulation ◽  
Average Pore

In recent years, new oil reservoirs have been discovered in the middle Jurassic tight mixed rocks of the Turpan–Hami Basin. However, the generation potential of the J2q2 source rocks remains poorly understood. Petrographic, petrological, and geochemical analyses were carried out to assess the quality of the J2q2 source and reservoir rocks. The hydrocarbon generation potential method was utilized to evaluate the hydrocarbon generation and expulsion potentials. The results indicated that the rocks can be classified as high-quality source rocks with a relative lower degree of maturity. The hydrocarbon bearing zones are classified as tight reservoirs (average porosity of 5.90% and permeability of 0.18 mD) with an average pore throat radius >150 nm, which is higher than the cut-off pore-throat radius. The source rocks start to expel hydrocarbons when Ro% is 0.56%. Bulk hydrocarbon generation and expulsion intensities in the center of the study area were calculated with the values of 900 × 104 t/km2 and 400 × 104 t/km2, while the weights of these hydrocarbons were 48.8 × 108 t and 27.3 × 108 t, respectively. The tight oil reservoir-forming conditions are superior, and the hydrocarbon generation and expulsion intensities are more remarkable in controlling the tight oil distribution. This study provides an important example for the Jurassic source rocks in Western China, and indicates that middle Jurassic lacustrine source rocks deserve attention in future exploration.

Radius threshold of pore throat for tight oil accumulation

2014 ◽  
Vol 31 (1) ◽  
pp. 103 ◽  
Author(s):  
Yanjie Gong ◽  
Shaobo Liu ◽  
Shihu Fang ◽  
Lin Jiang ◽  
Xuanjun Yuan ◽  
...  
Keyword(s):  
Tight Oil ◽  
Pore Throat ◽  
Oil Accumulation

scholarly journals Assessment of hydrocarbon potential of Jurassic and Cretaceous source rocks in the Tarnogród-Stryi area (SE Poland and W Ukraine)

2012 ◽  
Vol 63 (4) ◽  
pp. 319-333 ◽  
Author(s):  
Paweł Kosakowski ◽  
Dariusz Więcław ◽  
Adam Kowalski ◽  
Yuriy Koltun
Keyword(s):  
Organic Matter ◽  
Middle Jurassic ◽  
Sedimentary Cover ◽  
Source Rocks ◽  
Hydrocarbon Potential ◽  
Hydrocarbon Generation ◽  
Hydrocarbon Source Rock ◽  
Core Samples ◽  
Se Poland ◽  
Geochemical Parameters

Assessment of hydrocarbon potential of Jurassic and Cretaceous source rocks in the Tarnogród-Stryi area (SE Poland and W Ukraine) The Jurassic/Cretaceous stratigraphic complex forming a part of the sedimentary cover of both the eastern Małopolska Block and the adjacent Łysogóry-Radom Block in the Polish part as well as the Rava Rus'ka and the Kokhanivka Zones in the Ukrainian part of the basement of the Carpathian Foredeep were studied with geochemical methods in order to evaluate the possibility of hydrocarbon generation. In the Polish part of the study area, the Mesozoic strata were characterized on the basis of the analytical results of 121 core samples derived from 11 wells. The samples originated mostly from the Middle Jurassic and partly from the Lower/Upper Cretaceous strata. In the Ukrainian part of the study area the Mesozoic sequence was characterized by 348 core samples collected from 26 wells. The obtained geochemical results indicate that in both the south-eastern part of Poland and the western part of Ukraine the studied Jurassic/Cretaceous sedimentary complex reveals generally low hydrocarbon source-rock potential. The most favourable geochemical parameters: TOC up to 26 wt. % and genetic potential up to 39 mg/g of rock, were found in the Middle Jurassic strata. However, these high values are contradicted by the low hydrocarbon index (HI), usually below 100 mg HC/g TOC. Organic matter from the Middle Jurassic strata is of mixed type, dominated by gas-prone, Type III kerogen. In the Polish part of the study area, organic matter dispersed in these strata is generally immature (Tmax below 435 °C) whereas in the Ukrainian part maturity is sufficient for hydrocarbon generation.

Pore characteristics of lacustrine mudstones from the Cretaceous Qingshankou Formation, Songliao Basin

2017 ◽  
Vol 5 (3) ◽  
pp. T373-T386 ◽  
Author(s):  
Min Wang ◽  
Shuangfang Lu ◽  
Wenbiao Huang ◽  
Wei Liu
Keyword(s):  
Organic Matter ◽  
Source Rock ◽  
Gas Adsorption ◽  
Total Pore Volume ◽  
Songliao Basin ◽  
Hydrocarbon Generation ◽  
Shale Oil ◽  
Pore Characteristics ◽  
Oil Accumulation ◽  
Average Pore

Cretaceous Qingshankou ([Formula: see text]) mudstone of lacustrine origin is the major source rock for conventional hydrocarbon currently being produced in the Daqing and Jilin oilfields of the Songliao Basin, which is one of the largest continental basins in the world. Therefore, elucidating the geochemical and petrological characteristics of the [Formula: see text] mudstone is important to help determine its quality as an economically viable source for shale oil production. In our study, eight dark mudstone core samples from the [Formula: see text] formation were subjected to total organic carbon (TOC), Rock-Eval pyrolysis, X-ray diffraction, scanning electron microscopy (SEM), field emission SEM (FE-SEM), and low-pressure [Formula: see text] gas adsorption (LPGA-[Formula: see text]) experiments. Geochemical and petrological analysis results indicated the presence of a high TOC content, which originated mainly from alginate and some plant-derived organic matter, whereas bitumen was frequently present in mudstones with thermal maturity in the oil-generation stage. The [Formula: see text] mudstones were comprised mainly of clay minerals, followed by quartz, feldspar, and carbonates. The LPGA-[Formula: see text] experiments revealed the presence of nanoscale slit-shaped pores, and the contribution from mesopores to the total pore volume was the highest in most of the samples. The average pore diameters (APDs) of the mudstone samples were all smaller than 20 nm (4.36–17.79 nm). We determined that there was a clear positive correlation between the APD and the free oil content; however, there were no clear correlations between the APDs and the quartz, carbonate, and TOC contents. FEM studies revealed the presence of intergranular pores with widths of approximately 10 μm, micron-level autogenetic organic matter pores within spores, organic matter pores caused by the hydrocarbon generation effect within organic matter or clay-organic complexes, and intraparticle pores within clays or pyrite framboids. The microlevel intergranular pores might play an important role in shale oil accumulation from source rock of lacustrine origin.

scholarly journals Quantitative Analysis of Micron-Scale and Nano-Scale Pore Throat Characteristics of Tight Sandstone Using Matlab

2018 ◽  
Vol 8 (8) ◽  
pp. 1272 ◽  
Author(s):  
Bo Jiu ◽  
Wenhui Huang ◽  
Mingqian He ◽  
Chenhang Lv ◽  
Fei Liang
Keyword(s):  
Coordination Number ◽  
Pore Space ◽  
Pore Throat ◽  
Tight Sandstone ◽  
Throat Radius ◽  
Average Pore ◽  
Nano Scale ◽  
Intercrystalline Pores ◽  
Quartz Grains ◽  
Median Pore

Based on micro-scale casting thin sections, nano-scale SEM images, and the pore distribution map identified through a binary image in Matlab, the pore size distribution and pore throat coordination number of the strata of Upper Paleozoic He8 section tight sandstone in the southeastern Ordos Basin were quantitatively analyzed with the above experimental data. In combination with a high-pressure mercury injection experiment, the pore throat distribution, the pore throat ratio, and the relationships between the characteristics, parameters, and pore permeability were investigated clearly. The results show that the tight sandstone pore space in the study area is dominated by micron-sized intergranular pores, dissolved pores, and intragranular pores. The nano-scale pore throat consisted of clay minerals, intercrystalline pores, and the flake intergranular pores of overgrowth quartz grains. Kaolinite and illite intercrystalline pores occupy the pore space below 600 nm, while the ones above 800 nm are mainly dominated by the intergranular pores of overgrowth quartz grains, and the 600–800 nm ones are transitional zones. The permeability of tight sandstone increases with the average pore throat radius, sorting coefficient, median pore throat radius, and average pore throat number. The porosity is positively correlated with the average pore radius and the average pore throat coordination number, and negatively correlated with the median pore throat radius.

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