scholarly journals Geological and Geochemical Characteristics of the First Member of the Cretaceous Qingshankou Formation in the Qijia Sag, Northern Songliao Basin, Northeast China: Implication for Its Shale Oil Enrichment

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-20
Author(s):  
Fei Xiao ◽  
Jianguo Yang ◽  
Shichao Li ◽  
Fanhao Gong ◽  
Jian Zhang ◽  
...  
Keyword(s):  
Organic Matter ◽  
Saturated Hydrocarbon ◽  
Saturation Index ◽  
Effective Porosity ◽  
Songliao Basin ◽  
Geochemical Characteristics ◽  
Type I ◽  
Shale Oil ◽  
Oil Saturation ◽  
Extractable Organic Matter

The Qijia Sag, a secondary tectonic unit in the northern Songliao Basin, developed plentiful shale oil resources in the first member of the Cretaceous Qingshankou Formation (K2qn1) as its main target layer. However, the systematic study on the geological and geochemical characteristics of K2qn1 in the sag has not been carried out. Taking the core samples from the SYY1 well covering the whole K2qn1 as the main study object and concerning some relevant intervals from the SYY1HF well and other earlier wells, petrologic features, organic geochemical characteristics, oil-bearing property, and reservoir characteristics of K2qn1 were analyzed in detail. The results show that the lithology of K2qn1 is mainly dark mudstone genera accounting for more than 90% of the formation thickness with few macrostructural fractures, indicating that K2qn1 developing in deep to semideep lacustrine facies of the Qijia Sag belongs to the typical matrix reservoirs for shale oil. According to lithology features and logging curves, K2qn1 can be divided into three submembers consisting of K2qn11, K2qn12, and K2qn13 from above to below. Compared to the K2qn11 submember, the K2qn12 and K2qn13 submembers obviously are more enriched in shale oil, which is supported by the following three aspects: (i) the average TOC (total organic carbon) values of K2qn11, K2qn12, and K2qn13 are 1.96%, 2.42%, and 2.72%, respectively. The organic matter types of K2qn12 and K2qn13 are mainly type I and type II1, while those of K2qn11 are mainly type II1 and type II2. K2qn1 is at the end of the oil window with a R o (vitrinite reflectance) average of 1.26%, and the maturity of K2qn12 and K2qn13 is slightly higher than that of K2qn11. (ii) The average OSI (oil saturation index) values of K2qn11, K2qn12, and K2qn13 are 110.54 mg/g, 171.74 mg/g, and 150.87 mg/g, respectively, which all reach the zone of oil crossover. The saturated hydrocarbon of EOM (extractable organic matter) in K2qn12 and K2qn13 is of higher content than that in K2qn11, while it is the opposite for the aromatic hydrocarbon, nonhydrocarbon, and asphaltene, indicating better oil mobility for K2qn12 and K2qn13. The average oil saturation values of K2qn11, K2qn12, and K2qn13 are 24.77%, 32.86%, and 35.54%, respectively. (iii) The intragranular dissolution pores and organic pores in K2qn12 and K2qn13 are more developed than those in K2qn11. The average effective porosity values of K2qn11, K2qn12, and K2qn13 interpreted from NMR logging are 4.88%, 6.26%, and 5.86%, respectively. Based on the above-mentioned analyses, the lower K2qn12 and the upper K2qn13 are determined as the best intervals of shale oil enrichment for K2qn1 vertically in the Qijia Sag. There is a certain horizontal heterogeneity of TOC, S 1 , and effective porosity in the drilling horizontal section of K2qn1 of the SYY1HF well. Therefore, the lower K2qn12 and the upper K2qn13 in the area with relatively weak horizontal reservoir heterogeneity of the study area should be selected as the preferential targets for shale oil exploration.

Pore structure of the Cretaceous lacustrine shales and shale-oil potential assessment in the Songliao Basin, Northeast China

2021 ◽  
Vol 9 (1) ◽  
pp. T21-T33
Author(s):  
Weizhu Zeng ◽  
Guoyi Zhou ◽  
Taotao Cao ◽  
Zhiguang Song
Keyword(s):  
Pore Structure ◽  
Saturation Index ◽  
Great Influence ◽  
Micropore Volume ◽  
Songliao Basin ◽  
Hydrocarbon Generation ◽  
Shale Oil ◽  
Oil Saturation ◽  
Positive Correlation ◽  
Layer Mineral

Aiming to study the pore structure and its impact on shale oil enrichment, a total of nine lacustrine shales (including one immature shale and eight mature shales) from the Qingshankou Formation in the Songliao Basin were subjected to low-pressure gas sorption (LPGS) of CO2 and N2 and mercury intrusion capillary pressure (MICP) measurements. The combination of the LPGS and MICP methods demonstrates that the pore volumes of these shales are mainly associated with mesopores, whereas the micropores and macropores are relatively undeveloped. The correlation between the shale compositions and pore volumes of LPGS suggests that the micropores and mesopores are mainly contributed by illite/smectite mixed layer mineral. On the contrary, we have found that the oil/bitumen and carbonates could occupy the micropores and mesopores, respectively, and reduce these pore volumes significantly. The oil saturation index (OSI) was found to display a positive correlation with the maturity Ro value in the range of 0.37%–1.24%, and this may suggest that the shale-oil content is controlled by hydrocarbon generation. However, the pore structure also exerts a great influence on the shale oil enrichment. We suggested that the porosity of MICP could be considered as an index for appraising the shale-oil potential of a given shale player because there is a good positive correlation between the porosity of MICP and the OSI value. Furthermore, a negative correlation between the micropore volume and the OSI value may imply that the shale oil could be adsorbed in micropores, whereas a good positive correlation between the OSI value and the Hg-retained ratio suggests that shale oil is a kind of residual hydrocarbon, which is closely related with the mesopore volume of these shales.

The Evaluation of Potential of Shale Oil Resources in K1qn1 Formation of Southern Songliao Basin

2014 ◽  
Vol 1006-1007 ◽  
pp. 107-111
Author(s):  
Yan Wang ◽  
Wen Biao Huang ◽  
Min Wang
Keyword(s):  
Organic Matter ◽  
Source Rock ◽  
Thermal Evolution ◽  
Songliao Basin ◽  
Mature Stage ◽  
Type I ◽  
Hydrocarbon Generation ◽  
Shale Oil ◽  
Oil Resources ◽  
Geochemical Method

Based on the analysis of source rock geochemical index, with K1qn1 Formation of southern Songliao basin as the research objective layer, it’s concluded that the mean TOC value of shale in K1qn1 Formation is higher, generally more than 1%, which belongs to the best source rock. Most of shale organic matter types are type I and type II1. The thermal evolution degree of organic matter is generally in the mature stage: a stage of large hydrocarbon generation. With logging geochemical method applied, the calculated total resources of shale oil in K1qn1 formation are 15.603 billion tons. The II level of resources are 8.765 billion tons, which is more than 50% of the total resources. The I level of resources are 4.808 billion tons while the III level of resources 2.03 billion tons. Overall, the southern Songliao Basin still has a certain degree of prospecting and mining value.

scholarly journals The Influence of Reservoir Composition on the Pore Structure of Continental Shale: A Case Study from the Qingshankou Formation in the Sanzhao Sag of Northern Songliao Basin, NE China

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-21
Author(s):  
Jianguo Yang ◽  
Liu Wang ◽  
Shichao Li ◽  
Cheng Zuo ◽  
Fei Xiao ◽  
...  
Keyword(s):  
Organic Matter ◽  
Pore Structure ◽  
Clay Minerals ◽  
Influencing Factors ◽  
Gas Adsorption ◽  
Songliao Basin ◽  
Organic Carbon Content ◽  
Type I ◽  
Shale Oil ◽  
Distribution Diagram

Determining the pore structure characteristics and influencing factors of continental shale reservoir in the oil generation stage is of great significance for evaluating the shale oil reservoir space and analyzing shale oil enrichment mechanism. In this paper, shale from the first member of the Upper Cretaceous Qingshankou Formation (K2qn1) in the Songliao Basin was selected. X-ray diffraction (XRD), Rock-Eval pyrolysis, total organic carbon content (TOC), scanning electron microscopy (SEM), nitrogen gas adsorption (N2GA), and high-pressure mercury injection (HPMI) were used to clarify the composition characteristics of inorganic minerals and organic matter and determine the influencing factors of pore development in the K2qn1 shale. The results show that intergranular pores related to clay minerals and quartz, intragranular dissolution pores related to feldspar, and other mineral intragranular pores are developed. The organic matter pore is less developed, mainly composed of intragranular pores and crack pores of organic matter. Mesopores related to clay minerals are widely developed, rigid quartz particles can protect and support mesopores and macropores, and carbonate cementation can inhibit pore development. Although the TOC contents of shale are commonly less than 2.5%, it has a good positive correlation with porosity; TOC is greater than 2.5%, and the increase of residual oil fills part of the pores, leading to a decrease in porosity with the increase of TOC. Three types (types I, II, and III) of the reservoir space were classified by the combined pore size distribution diagram of N2GA and HPMI. By comparing the characteristics of pore structure parameters, it is found that Type I reservoir space is favorable for shale oil enrichment. It provides scientific guidance for shale oil exploration in the Songliao Basin.

scholarly journals Bazhenov formation phosphate containing interlayers as potential collectors

2016 ◽  
pp. 60-66
Author(s):  
A. G. Kalmykov ◽  
E. A. Manuilova ◽  
G. A. Kalmykov ◽  
V. S. Belokhin ◽  
N. I. Korobova ◽  
...  
Keyword(s):  
Organic Matter ◽  
Pore Space ◽  
Saturation Index ◽  
Geochemical Characteristics ◽  
Productivity Index ◽  
Oil Reservoir ◽  
Oil Saturation ◽  
Bazhenov Formation ◽  
Reservoir Rocks ◽  
Reservoir Type

Possible reservoir type of Bazhenov formation relative to the intervals with increased content of phosphate is described in the resent work. It is shown that phosphate formations have highly connected pore space, porosity may achieve values up to 14%. These rocks also have explicit geochemical characteristics of oil reservoir rocks in comparison with other rock samples in the well. For example, the productivity index and oil saturation index for phosphates is twice higher. The composition of such species may slightly vary, fluorine may present in phosphate minerals, meanwhile rocks are always maintain high content of organic matter (more than 8 wt%).

scholarly journals Organic Geochemical Characteristics of the Upper Cretaceous Qingshankou Formation Oil Shales in the Fuyu Oilfield, Songliao Basin, China: Implications for Oil-Generation Potential and Depositional Environment

Energies ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4778 ◽  
Author(s):  
Wentong He ◽  
Youhong Sun ◽  
Wei Guo ◽  
Xuanlong Shan ◽  
Siyuan Su ◽  
...  
Keyword(s):  
Organic Matter ◽  
Carbon Cycle ◽  
Depositional Environment ◽  
Global Carbon Cycle ◽  
Songliao Basin ◽  
Oil Generation ◽  
Oil Shales ◽  
Extractable Organic Matter ◽  
The Impact ◽  
Global Carbon

The Cretaceous Era has always been a focus of geologic and palaeoenvironmental studies. Previous researchers believed that the impact of the global carbon cycle represents significant short-term global biogeochemical fluctuations, leading to the formation of a large number of organic rich sediments in the marine environment. During the Turonian, a large number of organic-rich oil shales were deposited in the lakes of the Songliao Basin in the Qingshankou Formation. How the depositional environment affected the formation of oil shales in continental lakes and the characteristics of these oil shales remain controversial. In this paper, through sampling of Qingshankou Formation strata, various testing methods are used to provide a variety of new data to study the characteristics of oil shales and palaeoenvironment evolution history in the Songliao Basin. The research of the sediments in the Qingshankou Formation in the Fuyu oilfield, Songliao Basin, via result analysis revealed that the oil shales possess an excellent oil-generation potential with moderate-high total organic carbon (TOC) levels (0.58–9.43%), high hydrogen index (HI) values (265–959 mg hydrocarbons (HC)/g TOC), high extractable organic matter (EOM) levels (2.50–6.96 mg/g TOC) and high hydrocarbon fractions (48–89%). The sources of the organic matter were mainly zooplankton, red algae and higher plants (including marine organisms). The aqueous palaeoenvironment of the Qingshankou Formation was a saline water environment with a high sulfate concentration, which promoted an increase in nutrients and stratification of the water density in the lake basin. Oxygen consumption in the bottom water layer promoted the accumulation and burial of high-abundance organic matter, thus forming the high-quality oil shales in the Qingshankou Formation. The global carbon cycle, warm-humid palaeoclimate, dynamic local biogeochemical cycling and relative passive tectonism were the most likely reasons for the TOC increase and negative δ13Corg deviation.

PETROLEUM SOURCE ROCKS IN THE ROPER GROUP OF THE MCARTHUR BASIN: SOURCE CHARACTERISATION AND MATURITY DETERMINATIONS USING PHYSICAL AND CHEMICAL METHODS

1994 ◽  
Vol 34 (1) ◽  
pp. 279 ◽  
Author(s):  
Dennis Taylor ◽  
Aleksai E. Kontorovich ◽  
Andrei I. Larichev ◽  
Miryam Glikson
Keyword(s):  
Organic Matter ◽  
Chemical Evolution ◽  
Oil And Gas ◽  
Source Rocks ◽  
Type I ◽  
Peak Oil ◽  
Gas Generation ◽  
Oil Generation ◽  
Physical And Chemical ◽  
Extractable Organic Matter

Organic rich shale units ranging up to 350 m in thickness with total organic carbon (TOC) values generally between one and ten per cent are present at several stratigraphic levels in the upper part of the Carpentarian Roper Group. Considerable variation in depositional environment is suggested by large differences in carbon:sulphur ratios and trace metal contents at different stratigraphic levels, but all of the preserved organic matter appears to be algal-sourced and hydrogen-rich. Conventional Rock-Eval pyrolysis indicates that a type I-II kerogen is present throughout.The elemental chemistry of this kerogen, shows a unique chemical evolution pathway on the ternary C:H:ONS diagram which differs from standard pathways followed by younger kerogens, suggesting that the maturation histories of Proterozoic basins may differ significantly from those of younger oil and gas producing basins. Extractable organic matter (EOM) from Roper Group source rocks shows a chemical evolution from polar rich to saturate rich with increasing maturity. Alginite reflectance increases in stepwise fashion through the zone of oil and gas generation, and then increases rapidly at higher levels of maturation. The increase in alginite reflectance with depth or proximity to sill contacts is lognormal.The area explored by Pacific Oil and Gas includes a northern area where the Velkerri Formation is within the zone of peak oil generation and the Kyalla Member is immature, and a southern area, the Beetaloo sub-basin, where the zone of peak oil generation is within the Kyalla Member. Most oil generation within the basin followed significant folding and faulting of the Roper Group.

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.

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