Physical and Numerical Modeling of the Stability of Deep Caverns in Tahe Oil Field in China

Abstract

Cave collapses emerge during the process of oil reservoir development, seriously affecting oil production. To reveal the collapse and failure mechanism of the carbonate cavern with a buried depth of 5600 m in Tahe Oil Field, using a self-developed ultra-high pressure model test system with the intelligent numerical control function, the model simulation material of carbonate rocks developed to carry out the 3D geo-mechanical model test. The model test and numerical results indicate that: (1) collapse and failure mechanism of the deep-buried caves mainly involve the failure mode of tensile shear. The rupture plane on the side wall is approximately parallel to the direction of maximum principal compressive stress. The V-type tension and split rupture plane then emerges. (2) In the process of forming holes in the model caverns, micro cracks are generated at the foot of the left and right side walls of the caverns, and the roof panels are constantly moving downward. The shorter the distance to the cave wall, the severer the destructiveness of the surrounding rocks will be. (3) The displacement of the top of the model cavern is relatively large and uniform, indicating that the cave roof moves downward as a whole. The area of the cavity suffering damage is 2.3 times as large as the cave span. The research results in this paper lay a solid test basis for revealing the cave collapse and failure mechanism in super depth.

Surface Deformations Caused by the Convergence of Large Underground Gas Storage Facilities

“…Wang et al [13] carried out numerical analyses for the two adjacent caverns and their mutual influence on stability. Numerical analyses for determining the stability of the pillar separating the two adjacent caverns were also conducted [19] however, numerical methods were not the only engineering tool for assessing the behaviour of underground gas storage facilities [20]. The growing interest in neural networks encouraged scientists to use them also for UGS analyses [21].…”

Geomechanical Model Test and Energy Mechanism Analysis of Zonal Disintegration in Deep Surrounding Rock

“…The geomechanical characteristics of the medium sandstone from the coal mine are shown in Table 1. To simulate the mechanical properties of sandstone, a new typed cementations geotechnical similar material called iron crystal sand cementation material (IBSCM) [19,20] was proposed based on the similarity principle and the mechanical parameters of the rock. The iron powder, the barite powder and the quartz sand are selected as the aggregate of IBSCM.…”

The differential collapse–filling evolution process of the paleo-underground river in the Northern Uplift of the Tarim Basin

“…Geochemical analysis of fillings is the common method used to distinguish karst stages, such as the analysis of trace elements in sand-mud filling , isotopic analysis of cave macrocrystalline calcite (Liu et al, 2008), strontium isotope (Zhang et al, 2005;Liu et al, 2006;Liu et al, 2007;Zhang and Cai, 2007), carbon and oxygen isotopes (Winter and Knauth, 1992;Chen, 1994;Wang and Al-Aasm, 2002;Xia and Tang, 2004;Xia et al, 2006;Qian et al, 2008;Ainsaar et al, 2010;Wu et al, 2010;Li et al, 2011;Meng et al, 2011;Xia et al, 2011;Haeri-Ardakani et al, 2013), aqueous inclusion homogenization temperature (Xia and Tang, 2004;Xia et al, 2006;Wu et al, 2010;Xia et al, 2011;Li et al, 2012;Li et al, 2013), and autogenous illite K-Ar dating (Xu et al, 2012). Combined with the analysis of regional tectonic evolution and associated quantitative parameters (Xu et al, 2012;Zhang, 2020), a comprehensive application of a variety of geochemical methods (Zhang et al, 2012;Wang et al, 2017;Lyu et al, 2020) was also used to distinguish collapse-filling stages. However, there is still a lack of suitable methods to classify karst stages in detail by integrating core, isotope, and other means.…”