摘要
长期以来,油气井压裂施工结束后压裂液返排时机的选择一直以压裂液的破胶时间作为主要依据,但相当数量井的返排效果并不理想。研究表明,压裂液返排时机不仅仅与压裂液破胶时间有关,更与储层物性,尤其是储层力学参数及应力等息息相关。首先从储层物性特征着手,返排的时机既要保证措施地层具有足够的返排能量,又要控制支撑剂回流;其次对压裂液快速破胶进行研究,主要包括室内研究、地层温度场的模拟及不同温度下压裂液破胶的变化情况研究。不同岩性的储层,压裂液返排时机选择依据不同:针对埋深较深、压实较好的刚性地层,应以压裂液的快速破胶作为依据;对于较疏松的地层,应兼顾地层闭合时间及压裂液破胶时间,首先取得准确的地层闭合时间,再以其作为调整压裂液破胶时间的主要依据,最后根据压裂液破胶时间确定开井返排时间。
For a long time,the flowback time has been determined mainly based on gel-breaking time of the fracturing fluid after fracturing in the oil-gas wells,but the flowback effect was not good in considerable amount of wells.The research shows that the flowback time of the fracturing fluid is related not only to the gel-breaking time of the fracturing fluid,but also to the reservoir physical property,especially to mechanism parameter and stress and so on.The flowback time should ensure sufficient energy for the fracturing fluid to flowback from the well and control proppant flowback according to the reservoir physical properties.Fast gel breaking of the fracturing fluid was researched including laboratory experiment,temperature field modeling of the formation and change of the gel breaking of the fracturing fluid under different temperatures.Selection foundation of the flowback time of the fracturing fluid is various for the reservoirs with different lithology.For the rigid formations with deep burial depth and good compression ,the fast gel breaking of the fracturing fluid should be the foundation.For the loose formations,formation closure time and gel-breaking time should be considered together,that is to say,the accurate formation closure time should be known first,then it will be the main foundation of adjusting the gel-breaking time of the fracturing fluid,at last the flowback time may be determined according to the gel-breaking time.
出处
《中外能源》
CAS
2017年第7期41-45,共5页
Sino-Global Energy
关键词
压裂液
返排时机
破胶时间
储层物性
选择依据
fracturing fluid
flowback time
gel-breaking time
reservoir physical property
selection foundation
