Research on rock mechanics parameters of the Jurassic-Cretaceous reservoir in the Sikeshu sag, Junggar Basin, China

Abstract

Structural analysis and reservoir evaluation has become increasingly important as petroleum exploration keeps making breakthroughs in the foreland of the southern Junggar Basin. However, the research on rock mechanical parameters which is closely related to them is rare. Based on the drilling core data, logging and seismic data of the Jurassic-Cretaceous in the Sikeshu sag, using the rock mechanics experiment and three-dimensional rock mechanics inversion, we defined the rock mechanics parameters in this study. The dynamic and static Young′s modulus shows a positively correlated linear relationship with the Poisson′s ratio. The rock mechanical parameters are controlled by the lithological variation. The lower K1q and J2t, J2x, J1b Formations have a higher Young′s modulus and a lower Poisson′s ratio, while the upper K1q and J1s Formations have a lower Young′s modulus and a higher Poisson′s ratio. When the Young′s modulus increases and the Poisson′s ratio decreases, the rock compressive strength increases. The inversion results of rock mechanical parameters in the Gaoquan area show that the higher the Young′s modulus and the lower the Poisson′s ratio, the higher the fracture index. The fracture index of the upper K1q and J1s Formations is lower than 0.4, indicating poor fracture development and petroleum display; while the fracture index of the lower K1q and J2t, J2x, J1b Formations is higher than 0.4, suggesting good fracture development and petroleum display. Therefore, the research results are instructive for the deep petroleum exploration in the study area.

Keywords

• rock mechanical parameters
• fractures
• jurassic
• cretaceous
• junggar basin
• north tianshan