定容性稠油油藏压井工艺技术应用

Application of killing well technology of constant volume heavy oil reservoir

定容性油藏在修井施工常规压井工序中,如果压井过程注入的压井液激活了定容体效应,改变了定容体内液体的压力平衡状态,则井口压力越压越高,压井液密度越用越大,导致压井失败。定容性稠油油藏生产井的压井作业,因稠油黏度受温度影响较大,一旦稠油上返,极易发生粘卡等严重工程事故。作业过程中发现定容体效应被激活后,不宜采用加大压井液密度强行压井的方式,应及时采用泄压法压井,释放定容体储层能量。现场实践证明,在定容体效应被激活的井中采用泄压法压井技术,能够顺利实现压井,缩短了压井时间,减少压井液的用量及对储层的污染。

During the conventional killing well process of constant volume reservoir, if kill fluid activates constant volume effect and changes pressure balance of constant volume, the wellhead pressure will be higher and higher and the density of kill fluid will be bigger and bigger, which cause the failure of killing well. For constant volume heavy oil reservoir, the viscosity of heavy oil is greatly influenced by temperature, accordingly, if heavy oil returns, serious engineering accident such as wall sticking may happen. During operation process, if constant volume bulk effect is activated, force killing well method of increasing kill fluid density should not be adopted, in addition, killing well by pressure relief method should be adopted timely to release reservoir energy of constant volume. Field application shows that, when constant volume effect activates in the wells, killing well technology by pres- sure relief method is adopted to successfully complete killing well, which can shorten kill time and reduce the dosage of kill fluid and the pollution in reservoir.