储气库救援井文23-6J井钻井液技术

Drilling Fluid Technology for Well Wen23-6J

文23-6J井是中石油股份公司的一口针对文23-6X井的重点平行连通救援井,目的是确保文23气藏盖层的密封性,采取新钻救援井方式,从鱼底下方通过科学定向方法导入原井眼,然后从井筒注入堵漏水泥浆对原井眼进行封固.为了实现和文23-6X井连通,在文23-6J井三开从不同方位不同井段侧钻4次,形成5支井眼,连同落鱼井眼总计6支井眼,使得井眼中心距最小处不到20 cm.该区域明化镇组～东营组地层存在着大段泥岩,成岩性较差,地层黏土易水化,造浆性较强;沙河街组地层泥岩易水化掉块、坍塌;石盒子组地层极易发生井漏、井垮.为了保证施工安全,该井采用了强抑制低摩阻的防塌钻井液,通过在钻进中及时加入足量的防塌剂WFT108、CFF-1和降滤失剂SMP-Ⅰ、KJAN和NFA-25,同时加入高效润滑剂GFR-1、RT-9051,降低滤矢量,加强封堵防塌,并采取合理的维护处理措施,增强了钻井液造壁性及悬浮携带性,较好地满足了井眼净化和长时间防塌、防卡要求,全井钻井施工安全顺利.

The well Wen 23-6J is a relief well for the well Wen 23-6x, aimed at ensuring the sealing capacity of the reservoir cap rock formation. The well Wen 23-6J was planned to be directed to the well Wen 23-6x by drilling beneath the bottom of the fish, and then spot cement slurry through the relief well to plug the Wen 23-6x. To realize the connection of the two wells, the 3rd interval of the relief well was sidetracked four times at different depths to drill five laterals, with the minimum center distance between two holes less than 20 cm. In these depths, long sections of claystones, which are water sensitive and soft, exist in the Minghuazhen – Dongying formations. The Shahejie formation is also water sensitive and borehole instability has been encountered in the past. Another problem is lost circulation, which has been encountered in the Shihezi formation. A modified polymer sulfonate drilling fluid was used during drilling. A salt-resistant filtrate reducer Redul, a non-fluorescent shale inhibitor CFF-1 and a non-fluorescent white asphalt NFA-25 were introduced to prevent borehole wall from collapsing by enhancing the sealing and plugging capacity of the drilling fluid. The mud properties were carefully maintained during drilling. Lone period of exposing of open hole to drilling fluid left no downhole problem and the drilling operation was successful.