低渗致密气藏束缚水条件下应力敏感性  

STRESS SENSITIVITY OF THE LOW-PERMEABILITY TIGHT GAS RESERVOIRS WITH IRREDUCIBLE WATER

作　　者：杨朝蓬[1] 吴志伟 孙盈盈[3] 方立春[1] 陈礼 桑国强[3] 

机构地区：[1]中国石油勘探开发研究院,北京100083 [2]中石油长城钻探工程有限公司,北京100101 [3]提高石油采收率国家重点实验室,北京100083

出　　处：《大庆石油地质与开发》2015年第5期68-72,共5页Petroleum Geology & Oilfield Development in Daqing

基　　金：国家科技重大专项基金(2011ZX05013-002)

摘　　要：目前对应力敏感性研究主要是针对不含束缚水的储层,而低渗致密气藏普遍含有束缚水,束缚水条件下的应力敏感性研究对于气藏的合理开发有重要的意义。对选自苏里格低渗致密气藏的岩心建立了不同的束缚水饱和度,应用高压加湿器保证气体渗流实验中束缚水饱和度不发生变化,采用定围压变内压的方法进行了束缚水条件下应力敏感性研究。束缚水条件下低渗致密气藏具有较强的应力敏感性,渗透率越小,束缚水饱和度越高,应力敏感性越强。通过实验研究了应力敏感性系数与储层绝对渗透率和束缚水饱和度的关系,得出了定量表征苏里格低渗致密气藏束缚水条件下应力敏感性系数的公式。在此基础上建立了束缚水条件下低渗致密气藏考虑应力敏感性的产能模型,通过计算不同束缚水饱和度下的气井产能,发现应力敏感性会造成气井产能的损失,并且束缚水饱和度越高,应力敏感造成产能损失越大。因此控制压力下降速度或者降低储层束缚水饱和度可以减少应力敏感性对低渗致密气藏开发的影响。The current researches on the stress sensitivity are mainly focused on the reservoirs without the irreducible water. But the irreducible water widely exists in low-permeability tight gas reservoirs; the corresponding stress sensitivity researches possess very important significances for the reasonable development of the gas reservoirs. Various irreducible water saturations of the cores from Sulige low-permeability tight gas reservoirs are established. The high pressureproof humidifier is used in the gas flow experiment to keep the irreducible water saturation invariable, the method of unchanged confining pressure and changed pore pressure is adopted simultaneously in the above special experiment. The stress sensitivity of low-permeability tight gas reservoirs with the irreducible water is rather strongly, and increases with the decrease of the permeability and rise of the irreducible water saturation. The relationships between the stress sensitivity coefficients and the absolute permeability and irreducible water saturation are studied through the experiments and the formula is established to quantificationally characterize the stress sensitivity with the irreducible water for Sulige low-permeability tight gas reservoirs. On this basis, the productivity model considering the stress sensitivity with the irreducible water is built for the reservoirs. By calculating the productivity of the gas wells of with different irreducible water saturations, it can be found that the productivity loss results from the stress sensitivity, and moreover the higher the saturation is, the more serious the productivity damage will be. Therefore, with the help of controlling the pressure drawdown rate or decreasing the saturation, the influences of the stress sensitivity on the gas reservoir development can be decreased.

关 键 词：低渗致密气藏 束缚水 应力敏感性 含水饱和度 产能 

分 类 号：TE312[石油与天然气工程—油气田开发工程]