Genetic model and characteristics of the Cambrian Shorebulake reservoir in Bachu area, Tarim Basin

Knowledge of the Cambrian Shorebulake reservoirs in the Bachu area of Tarim Basin is limited at present. Core and microscopic observations as well as geochemical analyses showed that grain dolomites and microcrystalline dolomites are common in the Shorebulake Formation. Reservoir physical properties were obviously influenced by rock structure, and the porosity and permeability of fine-grained and powdery dolomites are the best. The reservoir space in the Shorebulake Formation was mainly composed of intergranular pores, dissolution holes and fractures, with low discharge pressure and fine to medium pore-throats, showing a good reservoir capacity. The diagenetic transformation of the reservoir was dominated by buried dolomitization, and partially affected by hydrothermal activity. The Himalayan movement added fractures to the study area, which enhanced communication of residual pores and helped acid fluid transform reservoirs, increasing reservoir volume to a certain extent and resulting in the present favorable reservoirs. The superimposed area of multi-phase tectonic fractures is considered as a favorable place for the Shorebulake reservoir in the Bachu uplift.