苏里格致密砂岩气藏直井缝网压裂适应性研究

The Adaptability Study on Network Fracturing of Vertical Well in Dense Sandstone in Sulige Gas Field

针对苏里格气田产量日益下降的趋势,提出了直井缝网压裂技术以提高单井产量.据此,首先从岩石的矿物组成与脆性指数、天然裂缝、水平应力差异及敏感性等方面对盒8、山1储层缝网压裂可行性进行了分析,苏里格储层岩石脆性矿物含量大于59.2%,脆性指数40~65,微裂缝部分发育,水平应力差系数小,且储层岩石水敏、速敏均为弱-中等偏弱,表明缝网压裂改造在地质上是可行的;接着,从流体黏度的选择、高低施工净压力的实现以及大排量施工作业等方面分析论证,表明缝网压裂在工艺上是行的通的,为苏里格致密砂岩缝网压裂的实施提供理论支撑;最后,在总结的基础上,给出了苏里格致密砂岩缝网压裂可行性建议方案：滑溜水＋线性胶＋冻胶混液油管注入,该方案对于苏里格气藏直井缝网压裂的现场实施具有重要的指导意义.

For the declining trend of gas production in Sulige gas field,the technology of network fracturing of vertical well was proposed to improve the single well production. Firstly,on the above basis,the feasibility of network fracturing in Box 8 and mountain 1 reservoir were analyzed from some aspects such as mineral composition of rock,brittleness index,natural fracture,horizontal stress difference and sensitivity and so on. In Sulige gas field,the brittle mineral content is more than 59. 2%,the brittleness index is 40-65,micro cracks partly developed,horizontal stress difference coefficient is low,the water sensitivity and the velocity sensitivity of the rock reservoir belongs to weak and medium weak,all of these show that network fracturing is feasible in geology. Secondly,analysis and demonstration had been carried out from some aspects such as choice of fluid viscosity,implementation of high net construction pressure and large displacement construction and so on,all of above analysis show that network fracturing is feasible in technology and provide theoretical support for the implementation of net-work fracturing in dense sandstone in Sulige gas field. Finally,on the basis of summary,the scheme of the feasibility of network fracturing in dense sandstone in Sulige gas field was proposed by injection of slick water,linear gel and gel mixed liquid in tubing. The scheme has an important guiding significance for the implementation of network fracturing of vertical well in Sulige gas field.