摘要
页岩气藏水平井固井要求水泥环不仅要有很高的强度,还要有较好的韧性,使之能满足大型分段加砂压裂增产作业对水泥环层间密封的要求。为此,针对性地开展了增韧材料的优选和高效冲洗剂的研制,先导性试验的3口井均采用了以下主要措施:①应用自主开发的增韧材料,配制出密度达1.95g/cm3的增韧水泥浆,实验结果表明,该水泥石抗冲击韧性超过常规水泥石20%、抗折强度提高了10%～15%、弹性模量则下降了约20%,显示出良好的增韧性能;②自主开发的油基介质下高效冲洗液,能在短时间内改变套管及井壁的润湿性,室内试验结果表明,该冲洗液对界面冲洗效果超过90%,达到了有效清除套管及井壁残留油泥、隔离油基钻井液与水泥浆的效果;③集成应用川渝地区旋流刚性扶正器、漂浮顶替等成熟固井技术实现水平井段有效顶替。纳入试验的3口井固井质量均满足了后期增产作业的技术要求,为页岩气藏水平井固井提供了技术支撑。
Horizontal well cementing in shale gas reservoirs requires not only strength in the cement sheath but also high toughness,allowing the sheath's sealing to meet the requirements of large-scale staged sand fracturing and enhancing gas recovery operations.Accordingly,toughening materials are selected and efficient cleaning agents are developed.The following measures are taken in three pilot-testing wells.(1) The self-developed toughening material is used to prepare a toughening cement slurry with the density of 1.95 g/cm3;from the experimental results,the impact toughness of this cement paste is 20% stronger than the conventional cement paste,the flexural strength is increased by 10%-15%,and the elastic modulus is decreased by about 20%,which all indicates a good toughening performance of this slurry.(2) The self-developed efficient cleaning agent dealing with oil-based drilling fluid is capable of quickly increasing the wetness of casing and borehole wall;laboratory test results show that the cleaning agent,with more than 90% surface-related flushing effect,effectively cleans up the residual sludge and isolates the oil-based drilling fluid from cement slurry on the casing and borehole wall.(3) The cyclone rigid centralizer,floating displacement cementing and other mature cementing technologies collected in Sichuan and Chongqing areas are adopted together for efficient displacement of horizontal intervals.The cementing quality of the above three pilot wells can all meet the technical standards required for further production increasing operations,providing technical support for horizontal well cementing in the development of shale gas reservoirs.
出处
《天然气工业》
EI
CAS
CSCD
北大核心
2012年第9期61-65,132-133,共5页
Natural Gas Industry
关键词
四川盆地
页岩气藏
水平井
增韧水泥浆
冲洗液
固井质量
强度
韧性
密封性
Sichuan Basin,shale gas reservoir,horizontal well,toughening cement slurry,cleaning agent,cementing quality,strength,ductility,tightness
