埕海一区大位移水平井固井技术与应用

Cementing technology and application of extended reach horizontal well in Chenghai block

伴随密集丛式井布井的日益深入,埕海一区大位移水平井ϕ311.1 mm井眼裸眼段长度、水平位移、稳斜角度不断增加。受浅地层井眼扩大、易漏失,大井斜套管不易居中、井眼不规则,长封固段施工时间长、易窜槽等多个因素的综合影响,致使ϕ244.5 mm套管固井质量难以保障。通过对制约因素和提升方向进行分析,针对性采取提高顶部低密度水泥强度、使用防窜增韧水泥浆技术和可固化隔离液技术、开展居中度设计优化等固井工艺优化措施,成功解决了套管不易居中、顶替效率低、顶部水泥早期强度发展慢等技术难点。现场连续应用固井工艺优化措施2井次,固井合格率较优化前提升20%,固井质量明显改善,可为埕海区块油气勘探开发提供有力技术支持。

With the development of dense cluster well deployment,in an open hole section of extended reach horizontal well with a borehole diameter of 311.1 mm in Chenghai District 1,open well length,horizontal displacement,and hold angle were constantly increasing.Due to various factors including expanded and easy-to-leak borehole in shallow strata,difficult standoff of large inclination casing,irregular borehole,time-consuming construction of long sealing sections,and easy-to-occur channeling,it was difficult to guarantee the cementation quality of casing with a diameter of 244.5 mm.By analyzing constraints and improvement directions,targeted cementing process optimization methods were carried out:strength improvement of low-density cement at the top,employment of toughening and anti-channeling cement slurry technology and solidifiable spacer fluid technology,as well as casing standoff optimization design.Technical difficulties such as difficult casing standoff,low top displacement efficiency,and slow early strength development of top cement were successfully solved.Cementing qualification rate was increased by 20%compared to that before application,and cementing quality was significantly improved,providing strong technical support for oil and gas exploration and development in Chenghai Block.