Formation Mechanism of Fractures in Tight Sandstone Reservoirs of the Second Member of Xujiahe Formation in the North of Western Sichuan Foreland Basin

2013 ◽  
Vol 868 ◽  
pp. 26-29
Author(s):  
Shuai Gao ◽  
Shi Zhong Ma ◽  
Yan Liu ◽  
Lian Bo Zeng ◽  
Lei Gong

Fractures control the distribution of tight sandstone gas reservoirs in the Second Member of Xujiahe Formation in the north of western Sichuan foreland basin. According to the data of filed outcrops, cores, image logs, slice and experimental analysis, we analyzed the genetic types, development characteristics, formation periods and forming mechanism of the fractures in the study area. Tectonic fracture and diagenesis fracture are the two types of fracture in the Second Member of Xujiahe tight sandstones. Between the two types, tectonic fracture is the main. They are mostly shear fractures with three sets of NEE-SWW, NNE-SSW and NW-SE orientations. Structural shear fractures mostly developed under the tectonism of the end of Indosinian, Yanshan and Himalaya stage. The force that formed tectonic fractures came from compression of Longmen Mountain and Micang-Daba Mountain, overpressure formed from deep buried and stress caused by uplift.

Minerals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 510 ◽  
Author(s):  
Valery Vernikovsky ◽  
Georgy Shemin ◽  
Evgeny Deev ◽  
Dmitry Metelkin ◽  
Nikolay Matushkin ◽  
...  

The geodynamic development of the north–western (Arctic) margin of the Siberian craton is comprehensively analyzed for the first time based on our database as well as on the analysis of published material, from Precambrian-Paleozoic and Mesozoic folded structures to the formation of the Mesozoic-Cenozoic Yenisei-Khatanga sedimentary basin. We identify the main stages of the region’s tectonic evolution related to collision and accretion processes, mainly subduction and rifting. It is demonstrated that the prototype of the Yenisei-Khatanga basin was a wide late Paleozoic foreland basin that extended from Southern Taimyr to the Tunguska syneclise and deepened towards Taimyr. The formation of the Yenisei-Khatanga basin, as well as of the West-Siberian basin, was due to continental rifting in the Permian-Triassic. The study describes the main oil and gas generating deposits of the basin, which are mainly Jurassic and Lower Cretaceous mudstones. It is shown that the Lower Cretaceous deposits contain 90% of known hydrocarbon reserves. These are mostly stacked reservoirs with gas, gas condensate and condensate with rims. The study also presents data on oil and gas reservoirs, plays and seals in the Triassic, Jurassic and Cretaceous complexes.


2010 ◽  
Vol 37 (2) ◽  
pp. 146-157 ◽  
Author(s):  
Zhao Wenzhi ◽  
Wang Hongjun ◽  
Xu Chunchun ◽  
Bian Congsheng ◽  
Wang Zecheng ◽  
...  

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7225
Author(s):  
Chuantong Ruan ◽  
Jing Ba ◽  
José M. Carcione ◽  
Tiansheng Chen ◽  
Runfa He

Low porosity-permeability structures and microcracks, where gas is produced, are the main characteristics of tight sandstone gas reservoirs in the Sichuan Basin, China. In this work, an analysis of amplitude variation with offset (AVO) is performed. Based on the experimental and log data, sensitivity analysis is performed to sort out the rock physics attributes sensitive to microcrack and total porosities. The Biot–Rayleigh poroelasticity theory describes the complexity of the rock and yields the seismic properties, such as Poisson’s ratio and P-wave impedance, which are used to build rock-physics templates calibrated with ultrasonic data at varying effective pressures. The templates are then applied to seismic data of the Xujiahe formation to estimate the total and microcrack porosities, indicating that the results are consistent with actual gas production reports.


Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Jimei Deng ◽  
Huan Zeng ◽  
Peng Wu ◽  
Jia Du ◽  
Jixian Gao ◽  
...  

Research on tight gas reservoirs in the eastern margin of the Ordos Basin, China, has recently become a hot spot. This paper mainly studies the reservoir characteristics of tight sandstone in the north-central area close to the provenance in eastern Linxing. Cast thin section, scanning electron microscopy, high-pressure mercury injection, and X-ray diffraction (XRD) were applied to discriminate the tight sandstone reservoir differences between the Permian Taiyuan and Shanxi formations in the study area. The results show that the deltaic tight sandstones in the Shanxi Formation are dominated by lithic quartz sandstone and lithic sandstone with an average porosity of 2.3% and permeability of 0.083 mD. The epicontinental tight sandstones in the Taiyuan Formation are mainly lithic sandstone and lithic quartz sandstone, with average porosities and permeabilities of 6.9% and 0.12 mD, respectively. The pore type is dominated by secondary dissolution pores, containing a small number of primary pores, and fractures are not developed. The capillary pressure curves of the Taiyuan Formation sandstone are mainly of low displacement pressure, high mercury saturation, and mercury withdrawal efficiency, while the Shanxi Formation sandstone is mainly of high displacement pressure, low mercury saturation, and withdrawal efficiency. The diagenetic evolution of sandstone in the Shanxi Formation is in meso-diagenesis stage A, and the Taiyuan Formation has entered meso-diagenesis stage B. The siliceous cement in the Taiyuan Formation sandstone enhanced the sandstone resistance to compaction and retained some residual intergranular pores. The pore types in the Shanxi Formation sandstone are all secondary pores, while secondary pores in the Taiyuan Formation sandstone account for approximately 90%. The results can be beneficial for tight gas production in the study area and similar basins.


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