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.

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 Pore Characteristics of Lacustrine Shale Oil Reservoir in the Cretaceous Qingshankou Formation of the Songliao Basin, NE China

Energies ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 2027 ◽  
Author(s):  
Xiaomeng Cao ◽  
Yuan Gao ◽  
Jingwei Cui ◽  
Shuangbiao Han ◽  
Lei Kang ◽  
...  
Keyword(s):  
Pore Structure ◽  
Fractal Dimensions ◽  
Nitrogen Adsorption ◽  
Songliao Basin ◽  
Oil Reservoir ◽  
Shale Oil ◽  
Pore Characteristics ◽  
Oil Accumulation ◽  
Average Pore ◽  
Lacustrine Shale

Shale oil is hosted in nanopores of organic-rich shales, so pore characteristics are significant for shale oil accumulation. Here we analyzed pore characteristics of 39 lacustrine shale samples of the Late Cretaceous Qingshankou Formation (K2qn) in the Songliao Basin, which is one of the main shale oil resource basins in China, using field emission-scanning electron microscopy (FE-SEM), and low-pressure nitrogen adsorption. We accomplished fractal analysis, correlation analysis using correlation matrix and multidimensional scaling (MDS), and prediction of fractal dimensions, which is the first time to predict pore fractal dimensions of shales. Interparticle pores are highly developed in K2qn. These shales have mesoporous nature and slit-shaped pores. Compared with the second and third members (K2qn2,3), the first member of the Qingshankou Formation (K2qn1) has a larger average pore diameter, much smaller surface area, fewer micropores, simpler pore structure and surface indicated by smaller fractal dimensions. In terms of pore characteristics, K2qn1 is better than K2qn2,3 as a shale oil reservoir. When compared with marine Bakken Formation shales, lacustrine shales of the Qingshankou Formation have similar complexity of pore structure, but much rougher pore surface. This research can lead to an improved understanding of the pore system of lacustrine shales.

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 Effective source rock selection and oil–source correlation in the Western Slope of the northern Songliao Basin, China

2021 ◽  
Vol 18 (2) ◽  
pp. 398-415
Author(s):  
He Bi ◽  
Peng Li ◽  
Yun Jiang ◽  
Jing-Jing Fan ◽  
Xiao-Yue Chen
Keyword(s):  
Organic Matter ◽  
Source Rock ◽  
Thermal Evolution ◽  
Songliao Basin ◽  
Source Rocks ◽  
Crude Oils ◽  
Western Slope ◽  
Geochemical Parameters ◽  
Group I ◽  
Oil Source

AbstractThis study considers the Upper Cretaceous Qingshankou Formation, Yaojia Formation, and the first member of the Nenjiang Formation in the Western Slope of the northern Songliao Basin. Dark mudstone with high abundances of organic matter of Gulong and Qijia sags are considered to be significant source rocks in the study area. To evaluate their development characteristics, differences and effectiveness, geochemical parameters are analyzed. One-dimensional basin modeling and hydrocarbon evolution are also applied to discuss the effectiveness of source rocks. Through the biomarker characteristics, the source–source, oil–oil, and oil–source correlations are assessed and the sources of crude oils in different rock units are determined. Based on the results, Gulong and Qijia source rocks have different organic matter primarily detrived from mixed sources and plankton, respectively. Gulong source rock has higher thermal evolution degree than Qijia source rock. The biomarker parameters of the source rocks are compared with 31 crude oil samples. The studied crude oils can be divided into two groups. The oil–source correlations show that group I oils from Qing II–III, Yao I, and Yao II–III members were probably derived from Gulong source rock and that only group II oils from Nen I member were derived from Qijia source rock.

Liquid hydrocarbon characterization of the lacustrine Yanchang Formation, Ordos Basin, China: Organic-matter source variation and thermal maturity

2017 ◽  
Vol 5 (2) ◽  
pp. SF225-SF242 ◽  
Author(s):  
Xun Sun ◽  
Quansheng Liang ◽  
Chengfu Jiang ◽  
Daniel Enriquez ◽  
Tongwei Zhang ◽  
...  
Keyword(s):  
Organic Matter ◽  
Source Rock ◽  
Ordos Basin ◽  
Depositional Environments ◽  
Source Rocks ◽  
Type I ◽  
Hydrocarbon Generation ◽  
Type Ii ◽  
Thermal Maturity ◽  
Yanchang Formation

Source-rock samples from the Upper Triassic Yanchang Formation in the Ordos Basin of China were geochemically characterized to determine variations in depositional environments, organic-matter (OM) source, and thermal maturity. Total organic carbon (TOC) content varies from 4 wt% to 10 wt% in the Chang 7, Chang 8, and Chang 9 members — the three OM-rich shale intervals. The Chang 7 has the highest TOC and hydrogen index values, and it is considered the best source rock in the formation. Geochemical evidence indicates that the main sources of OM in the Yanchang Formation are freshwater lacustrine phytoplanktons, aquatic macrophytes, aquatic organisms, and land plants deposited under a weakly reducing to suboxic depositional environment. The elevated [Formula: see text] sterane concentration and depleted [Formula: see text] values of OM in the middle of the Chang 7 may indicate the presence of freshwater cyanobacteria blooms that corresponds to a period of maximum lake expansion. The OM deposited in deeper parts of the lake is dominated by oil-prone type I or type II kerogen or a mixture of both. The OM deposited in shallower settings is characterized by increased terrestrial input with a mixture of types II and III kerogen. These source rocks are in the oil window, with maturity increasing with burial depth. The measured solid-bitumen reflectance and calculated vitrinite reflectance from the temperature at maximum release of hydrocarbons occurs during Rock-Eval pyrolysis ([Formula: see text]) and the methylphenanthrene index (MPI-1) chemical maturity parameters range from 0.8 to [Formula: see text]. Because the thermal labilities of OM are associated with the kerogen type, the required thermal stress for oil generation from types I and II mixed kerogen has a higher and narrower range of temperature for hydrocarbon generation than that of OM dominated by type II kerogen or types II and III mixed kerogen deposited in the prodelta and delta front.

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.

scholarly journals Enrichment Factors and Resource Potential Evaluation of Qingshankou Formation Lacustrine Shale Oil in the Southern Songliao Basin, NE China

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-20
Author(s):  
Long Luo ◽  
Dongping Tan ◽  
Xiaojun Zha ◽  
Xianfeng Tan ◽  
Jing Bai ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Well Logging ◽  
Enrichment Factors ◽  
Songliao Basin ◽  
Hydrocarbon Generation ◽  
Shale Oil ◽  
Resource Potential ◽  
Potential Evaluation ◽  
Lacustrine Shale ◽  
Exploration And Development

China shale oil, which is preserved in lacustrine shale with strong heterogeneity and relatively low maturity, has been a research hotspot of unconventional resources. However, controlling factors of shale oil enrichment and resource potential evaluation restricted efficient exploration and development of lacustrine shale oil. On the basis of well logging data, TOC content, Rock-Eval pyrolysis values, thermal maturity, 100 oil saturation data, and pressure coefficient, the core observation, X-ray diffraction analysis, physical property analysis, scanning electron microscopy, CT scan, well logging interpretation, and volumetric genesis method depending on three-dimensional geological modeling were used to determine enrichment factors and evaluate the resource potential of Qingshankou Formation shale oil in the Southern Songliao Basin. Shale oil was mainly enriched in the semideep and deep lake shale of K2qn1, with the high capacity of hydrocarbon generation and favorable petrological and mineralogical characteristics, pore space characteristics, and physical properties in the low structural part of the Southern Songliao Basin. The three-dimensional geological resource model of Qingshankou Formation lacustrine shale oil was determined by the key parameters (Ro, TOC, and S 1 ) of shale oil in the favorable zone of the Southern Songliao Basin, northeast China. The geological resource of shale oil, which was calculated by two grid computing methods ( F 1 and F 2 ), was, respectively, 1.713 × 10 12   kg and 1.654 × 10 12   kg . The great shale oil resource indicates a promising future in the exploration and development of Qingshankou Formation shale oil of the Southern Songliao Basin.

Sign in / Sign up

Export Citation Format

Share Document