Pore-throat characteristics of tight sandstones and its influence on reservoirs in Dibei area of the Kuqa Depression

The pore-throat characteristics of tight sandstones from Dibei area of the Kuqa Depression were studied using cast thin section, scanning electron microscope, laser scanning confocal microscope and micro/nano CT analyses. A large amount of long, narrow and flat pore-throats were observed. Micro/nano throats and intercrystal pores in clay minerals are the most common in reservoirs. According to nitrogen adsorption, constant velocity mercury injection, and physical property analyses under overburden pressure, the throat radius ranges from 1 to 4μm, accounting for about 2/3 of the total reservoir space. The fluid flow in tight reservoirs is directly influenced by throat radius and pore/throat ratio. Clay minerals in pore-throats control fluid mobility.