库车坳陷迪北地区致密砂岩孔喉形态特征及其对储层的影响

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

林潼 冉启贵 魏红兴 孙雄伟 王蓉

Lin Tong Ran Qigui Wei Hongxing Sun Xiongwei Wang Rong

中化石油勘探开发有限公司, 北京 100031 2. 中国石油勘探开发研究院廊坊分院, 河北廊坊 065007 3. 中国石油塔里木油田分公司勘探开发研究院, 新疆库尔勒 841000

Sinochem Petroleum E & P Co Ltd, Beijing 100031, China 2. Research Institute of Petroleum Exploration and Development-Langfang, PetroChina, Langfang, Hebei 065007, China 3. Research Institute of Exploration and Development, Tarim Oilfield Company, PetroChina, Kuerle, Xinjiang 834000, China

通过铸体薄片、扫描电镜、激光共聚焦显微镜、微纳米CT扫描等直观分析手段,对库车坳陷迪北地区致密砂岩气储层中的孔喉微观形态特征开展了系统研究。观测结果显示,该区致密砂岩储层中发育大量的狭长、扁平状孔喉,其中微纳米级的喉道、黏土矿物晶间孔是本区主要的储集空间。同时借助低温氮气吸附测试、恒速压汞试验、覆压条件下储层物性分析等定量研究手段,显示迪北致密砂岩储层中喉道大小分布在1~4μm,喉道体积占总孔隙体积的2/3。综合研究认为储层的渗流能力受喉道大小、孔喉比值影响,直观地反映了孔喉形态对渗流能力的影响;孔喉中黏土矿物对储层的渗流能力起到重要的影响。

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.

国家重大科技专项"中国大型气田形成条件、富集规律及目标评价(二期)"项目(2011ZX05007)资助。

https://doi.org/10.11781/sysydz201506696