川西页岩气藏新型水基钻井液体系的性能评价及现场应用

Performance evaluation and field application of new water-based drilling fluid system in western Sichuan shale gas reservoir

关键词:  水基钻井液  抑制性能  封堵性能  润滑性能  抗污染性能 

Key words:  water-based drilling fluid  inhibition property  plugging property  lubrication property  anti-pollution property

摘要:

针对川西页岩气藏微裂缝发育,多为硬脆性泥页岩的成藏特征,提出了一种新型的水基钻井液体系——强抑制强封堵聚胺仿油基水基钻井液体系(CXWBM-1),并通过室内实验评价了其全性能、抑制性能、封堵性能、润滑性能以及抗污染性能。结果 表明,CXWBM-1钻井液体系对川西页岩岩样第二次回收率达到95%以上,能有效封堵0.5～15 μm微裂缝或微孔,钻井液体系的API失水在2 mL以内；体系的黏滞系数和摩阻系数均较低,润滑性能好；体系具有一定的抗盐、抗钙和抗岩屑污染能力。在川西XYHF-1井页岩气层的应用表明,研制的新型水基钻井液体系能够很好地预防页岩层的吸水膨胀和缩径垮塌,可确保钻井的施工安全。该钻井液体系在同类页岩气藏的钻井开发过程中,具有很好的应用前景。 

Abstract:

Aiming at the reservoir characteristics of micro fractures developed and brittle shale in western Sichuan shale gas reservoir, a new water-based drilling fluid system was prepared, which named strong inhibition and strong blocking polyamine imitation oil-based water-based drilling fluid system CXWBM-1. The full performance, property of inhibition, plugging, lubrication and anti pollution were evaluated through laboratory experiments. The results show that the second recovery rate of western Sichuan shale sample for CXWBM-1 drilling fluid system was over 95%, and CXWBM-1 can effectively block micro cracks or pores of 0.5-15 μm, the API loss of drilling fluid systems can be controlled in 2 mL. CXWBM-1 system has low viscosity coefficient and low friction coefficient, the system has good lubricating property. CXWBM-1 system also has salt resistance ability, calcium resistance ability and debris contamination resistance. The application in XYHF-1 well of Chuanxi shale gas reservoir showed that the new developed water-based drilling fluid system can prevent swelling of shale and collapse necking, this can ensure the safety drilling. The system has broad application prospects in drilling and development of similar shale gas reservoirs.