涪陵页岩气田油基钻井液随钻堵漏技术

涪陵页岩气田焦石坝区块三开水平段采用油基钻井液钻进过程中，因堵漏材料与现场钻井液配伍性差导致堵漏成功率低、易复漏，针对该问题，研究了油基钻井液随钻防漏堵漏体系。基于"刚柔并济，变形封堵，细粒充填及限制渗透"的堵漏原理，通过室内试验，优选了JHCarb刚性堵漏剂、HIFlex变形颗粒与H-Seal弹性封堵剂，并配制了油基钻井液用随钻防漏堵漏体系。该体系与油基钻井液配伍性好，耐油耐温性能佳，可长时间在井浆中循环，预防渗透性漏失，封堵宽度小于3.0 mm的裂缝，承压能力大于7 MPa。该体系在焦石坝区块页岩气水平井水平段油基钻井液钻进过程中进行了应用，有效防止了易漏地层的渗透性漏失，成功解决了钻进过程中漏速10.0 m3/h左右的漏失问题。研究结果表明，该油基钻井液随钻堵漏技术能解决页岩地层的漏失问题，有效提高了地层承压能力，保证了固井作业顺利进行。 

Plugging while Drilling Technology Using Oil-Based Drilling Fluid in Fuling Shale Gas Field

The horizontal interval in the 3rd Section drilled by using oil-based drilling fluids during the development of the Jiaoshiba Block in Fuling Shale Gas Field was susceptible to low success rates in plugging operations and the reoccurrence of lost circulation due to incompatibility of lost circulation materials (LCM) and drilling fluids.Accordingly,lost circulation systems for oil-based drilling fluids were developed.Based on working principles characterized by "Joint application of rigidity and flexibility,plugging through deformation and filling by fine particles",lab tests were conducted to select JHCarb rigid LCM,HIFlex deformation particles and H-Seal elastic plugging additives to prepare plugging while drilling systems for oil-based drilling fluids.Highly compatible with oil-based drilling fluids and with outstanding performances in oil and temperature resistance,the newly developed systems may be circulated for prolonged periods in drilling fluids to eliminate the possibility of lost circulation.With pressure-bearing capacities over 7 MPa,the system could be deployed to plug fractures with widths below 3.0 mm.The system has been deployed during drilling of the horizontal well interval for shale gas development in Jiaoshiba Block by using oil-based drilling fluids.The system was proved to be capable of effectively eliminating lost circulation with velocities around 10.0 m3/h during drilling.Research results showed the plugging while drilling system of oil-based drilling fluids could effectively enhance the pressure-bearing capacities of formations and protect shale formations from lost circulation.Eventually,the system might facilitate execution of well cementation operations.