苏里格地区致密砂岩地层水赋存状态和产出机理探讨

Occurrence state and production mechanism of formation water in tight sandstone reservoirs of Sulige area, Ordos Basin

王晓梅 赵靖舟 刘新社

Wang Xiaomei Zhao Jingzhou Liu Xinshe

西北大学地质学系, 西安710069 2. 西安石油大学地球科学与工程学院, 西安710065 3. 中国石油长庆油田分公司, 西安710021

Department of Geology, Northwest University, Xi'an, Shaanxi 710069, China 2. School of Earth Sciences and Engineering, Xi'an Shiyou University, Xi'an, Shaanxi 710065, China 3. Changqing Oilfield Branch Company, PetroChina, Xi'an, Shaanxi 710021, China

鄂尔多斯盆地苏里格气区是中国最大的非常规准连续型致密砂岩大气区,该地区西部和北部上古生界产水普遍,气藏内无统一气水界面,气水分布十分复杂。该文以致密砂岩成藏动力学为出发点,综合成藏要素、现今储层微观孔隙结构和流体的渗流机理,探索了苏里格地区的地层水赋存状态和产出机理。研究认为,苏里格地区气、水分布规律复杂性的主要原因即生烃膨胀力和储层毛细管阻力的差异。研究区致密砂岩储层地层水存在束缚水、毛细管水和自由水3种赋存状态,束缚水区基本位于生气强度大的东部地区,试气井主要为产气井;毛细管水基本分布在生气强度小的西部和北部地区,试气井主要为气水同产井;自由水呈零星分布。

The Sulige gas field in the Ordos Basin is the largest unconventional continuous tight sandstone reservoir in China.There are many water-producing gas wells in the Upper Paleozoic strata in the west and the north of Sulige region,where the reservoir has no unitive gas-water interface.The intrinsic rules of gas-water distribution are complicated in this area.Based on the dynamics of hydrocarbon accumulation in tight sandstone,integrating oil and gas accumulation elements and reservoir present microscopic pore structure and fluid flow mechanism,the occurrence state and production mechanism of formation water in Sulige region have been discussed in this paper.It has been showed that the main reason for complicated gas-water distribution is the difference between hydrocarbon generation expansive force and capillary pressure.The occurrence state of formation water in this area behaves 3 types,i.e.irreducible water,capillary water and free water.The irreducible water is basically located in the high gas generation intensity area in the east of Sulige region,where the testing gas wells are mainly gas-producing ones.The capillary water is normally located in the low gas generation intensity area in the west and the north of Sulige region,where the testing gas wells are mainly gas/water-producing ones.The free water is sporadically located in the area.

国家科技重大专项(2008ZX05007-005);西安石油大学青年科技创新基金项目(2010QN004)资助

https://doi.org/10.11781/sysydz201204400