四川长宁区块页岩气水平井水基钻井液技术的研究与应用

Research and application of water-based drilling fluid technology of Sichuan Changning block shale-gas horizontal well

关键词:  页岩气水基钻井液  水平井  页岩  性能  现场应用 

Key words:  shale-gas water-based drilling fluid  horizontal well  shale  performance  field application

摘要:

长宁龙马溪页岩矿物组分分析表明,页岩矿物主要以石英、方解石和黏土矿物为主,属于硬脆性水敏地层。为了保证水基钻井液能够在长水平段页岩中钻进,且不发生井壁失稳、井壁垮塌等井下复杂情况,经过大量室内研究,研制出以疏水抑制剂CQ-SIA和高效液体润滑剂CQ-LSA为主要处理剂的页岩气水基钻井液体系。室内评价表明,该水基钻井液抑制能力优越,滚动回收率达到97.6%；在100 ℃温度下恒温静置48 h后,未出现重晶石沉降现象,流变性能稳定；能够抵抗30%(w)的岩屑污染。现场应用情况表明,该钻井液性能稳定,润滑性好,抑制能力强,保证了顺利钻进、电测、通井、下套管施工作业,能够满足长宁页岩气井钻井的需要。 

Abstract:

Changning Longmaxi shale mineral components are mainly composed of quartz, calcite and clay mineral, and it belongs to brittle and water sensitive formation. In order to satisfy the needs that water base drilling fluid can drill in the long horizontal section of shale, and also the underground complex situation such as well-bore instability and sidewall collapse can not happen, through a large number of laboratory studies, the drilling fluid system was formulated with a hydrophilically inhibitive agent CQ-SIA and a high performance lubricant CQ-LSA as the core additive of the formulation, which was suited to drilling in shale formation. The experimental results showed that the water base drilling fluid had excellent inhibition ability and the rolling recovery rate was 97.6%; after 48 hour static at 100 ℃, the phenomenon of barite settlement did not happen, and the rheological property was stability; the system could resist the 30% plus amount of debris pollution. The field application showed that the drilling fluid had stable performance, good lubrication performance, and strong inhibition ability. It could ensure the smooth drilling, electrical measurement, drifting and running casing construction operations. The system could meet the need of Changning shale gas well drilling.