摘要
相储7井是相国寺储气库区块上第一口先导注采试验井。固井有以下难点:①地层破裂压力低,易发生漏失;②产层压力系数低,易伤害;③储气库注采井要经受周期性高低压变化,注采管柱承受交变应力对层间封隔要求高;④井斜度大,套管不易居中,影响顶替效率。采取了以下措施:①采用正注反打工艺,防漏堵漏水泥浆、双凝双密度水泥浆、变排量施工等措施减少漏失、降低储层伤害;②优化水泥浆和水泥石性能,技术套管采用防漏增韧水泥浆体系,油层尾管采用双密度弹性水泥浆,确保固井质量长期稳定;③模拟套管在井下实况,优化扶正器安放、使用螺旋大倒角刚性扶正器,改变流场,提高顶替效率;④采用裸眼封隔器措施,延长注采井的使用寿命。通过采取以上措施,全井取得优异电测固井质量。
In Xiangguosi gas-storage block,Xiangchu 7 well is the first pilot-test injection-production one.Many problems may occur during its cementing,including that:(1) often leakage due to low breakdown pressure,(2) often formation damage due to low pressure coefficient of producing formation;(3) periodic high-low-pressure change for injection-production wells and high requirement of alternating stress endured by injection-production string to interlayer isolation;and(4) casing uneasily in the middle because of large well deviation,finally affecting displacement efficiency.So,some measures are taken in this study,including:(1) to adopt the positive-injection and back-cementing technique,the slurry system with leak proof and plugging capacity,the other slurry system with bi-setting and bi-density and variable displacement to reduce not only leakage but also formation damage;(2) to optimize the property of both slurry and slurry paste,to adopt the slurry system with leak proof and toughness reinforcement for intermediate casing and the other slurry system with bi-density and elasticity for reservoir liner to guarantee cementing-quality kept a long stability;(3) to model the actual downhole conditions for casing,to optimize the centralizer setting to either change flow field or increase displacement efficiency;(4) to adopt the openhole packer to prolong a service lift of injection-production well.The best cementing quality has been gained after taking these measures.
出处
《天然气勘探与开发》
2012年第2期65-69,90,共5页
Natural Gas Exploration and Development
关键词
天然气储存
注气井
固井
固井质量
gas storage,gas-injection well,cementing,cementing quality
