Shale pore characteristics and controls in well Qian XY 1, Zunyi City, Guizhou Province

Twenty-two intact shale core samples from 1 029.91-1 140.4 m in the well Qian XY 1 in the Zunyi City of the Guizhou Province were studied using FE-SEM combined with PerGeos. Qualitative and quantitative analyses of pore development characteristics and main controlling factors were identified based on the organic matter content and maturity, as well as the energy spectrum data of mineral components. The Longmaxi Formation shale in the well Qian XY 1 has a high organic matter abundance and is highly mature to over mature. It mainly developed three types of pores:inorganic mineral pores, organic pores and micro-cracks. The inorganic mineral pores include intragranular, intergranular, intracrystalline, mold and dissolution pores, while the micro-cracks include structural micro-cracks, diagenetic shrinkage joints, organic matter hydrocarbon-discharge joints and artificial cracks. The main controlling factors affecting shale pore development are organic matter content, thermal evolution of organic matter and burial depth.