Stress Distribution in the Upper Shihezi Formation from 1D Mechanical Earth Model and 3D Heterogeneous Geomechanical Model, Linxing Region, Eastern Ordos Basin, Central China

• Published in: Acta geologica Sinica (Beijing) 2021-06, Vol.95 (3), p.976-987
• Main Authors: JU, Wei, SHEN, Jian, QIN, Yong, WANG, Geoff, XU, Ke, LI, Guozhang, LI, Chao
• Format: Article
• Language: English
• Subjects: Distribution; Earth models; Error analysis; Gas production; Geomechanics; Heterogeneity; Hydraulic fracturing; Linxing region; Mechanical properties; Modulus of elasticity; numerical simulation; Oil and gas production; Ordos Basin; Rock mechanics; Sandstone; Sedimentary rocks; Stress; Stress concentration; Stress distribution; Three dimensional models; tight sandstone gas; Upper Shihezi Formation
• ISSN: 1000-9515; 1755-6724
• DOI: 10.1111/1755-6724.14411

The Upper Shihezi sedimentary rocks in the Linxing region has been estimated with a significant volume of tight sandstone gas. However, lateral distribution of the present‐day stress magnitude is poorly understood, which limits further gas production. Hence, a one‐dimensional mechanical earth model and a three‐dimensional heterogeneous geomechanical model are built to address this issue. The results indicate that the strike‐slip stress regime is dominant in the Upper Shihezi Formation. Relatively low stresses are mainly located around wells L‐60, L‐22, L‐40, L‐90, etc, and stress distributions exhibit the similarity in the Members H2 and H4. The differential stresses are relatively low in the Upper Shihezi Formation, suggesting that complex hydraulic fracture networks may be produced. Natural fractures in the Upper Shihezi Formation contribute little to the overall gas production in the Linxing region. In addition, the minimum principal stress gradient increases with Young's modulus, suggesting that the stiffer rocks commonly convey higher stress magnitudes. There is a strong interplay between stress distribution and heterogeneity in rock mechanics. Overall, the relative error between the predicted and measured results is less than 10%, implying that the predicted stress distribution is reliable and can be used for subsequent analysis in the Linxing region.