Anisotropy characteristics of element composition in Upper Triassic Chang 8 shale in Jiyuan district of Ordos Basin, China: Microscopic evidence for the existence of predominant fracture zone

FUEL

卷:253

Article

Du, Shuheng^1,2  Xu, Feng^3,8  Taskyn, Abitkazy^4,5  Zhou, Bo^6,7  Kou, Gen^6,7  Shi, Yongmin^4,5 

[1] Chinese Acad Sci, Inst Mech, State Key Lab Nonlinear Mech, Beijing 100190, Peoples R China

[2] Chengdu Univ Technol, State Key Lab Oil & Gas Reservoir Geol & Exploita, Chengdu 610059, Sichuan, Peoples R China

[3] China Natl Oil & Gas Explorat & Dev Corp, Beijing 100034, Peoples R China

[4] Peking Univ, Sch Earth & Space Sci, Beijing 100871, Peoples R China

[5] Peking Univ, Oil & Gas Inst, Beijing 100871, Peoples R China

[6] Xinjiang Lab Petr Reserve Conglomerate, Karamay 834000, Xinjiang, Peoples R China

[7] PetroChina Xinjiang Oilfield Co, Res Inst Expt & Detect, Karamay 834000, Xinjiang, Peoples R China

[8] PetroChina Res Inst Petr Explorat & Dev, Beijing 100083, Peoples R China

关键词: Shale;    Anisotropy;    Element composition;    Predominant fracture zone;   

DOI  :  10.1016/j.fuel.2019.05.031

来源: Elsevier

【 摘 要 】

This study quantified the anisotropy of element composition in Upper Triassic Chang 8 shale in Jiyuan district of Ordos Basin, China and provided the microscopic evidence for the existence of dominant fracture zone. Element quantification was carried out ensuring both observational resolution and sample representativeness. Results show that for shale slices in two directions which are 45 degrees (225 degrees) and 0 degrees (180 degrees /360 degrees), the distribution of elements is significantly different from that in other directions. The minimum of element contents often occurs in 45 degrees (225 degrees) and the maximum of element contents often occurs in 0 degrees (180 degrees/360 degrees). The brittleness parameter value stays at a high level from 0 degrees (180 degrees/360 degrees) to 22.5 degrees (202.5 degrees). The maximum value occurs in 0 degrees (180 degrees/360 degrees), and the minimum value occurs in 45 degrees (225 degrees) which has obvious significance in shale stimulation. The conclusion proved that the existence of predominant fracture zone in shale has the microscopic evidence in micro-scale brittle minerals.

【 授权许可】

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