水力尖劈裂缝堵漏固井技术研究及应用

Study and application of preventing technology against lost-circulation into hydraulic fractures induced by primary cementing

高温高压、非常规套管结构井环空间隙小、安全压力窗口窄,固井时易发生水力尖劈裂缝漏失。传统裂缝堵漏评价仪不能真实模拟井下的堵漏效果,所选取的水泥浆堵漏材料对于水力尖劈裂缝的堵漏效果差。研制了新型动态裂缝堵漏评价仪,依托该评价仪优选出新型水力尖劈堵漏材料,并制定了配套固井工艺,成功解决了中国南海莺琼盆地高温高压、非常规套管结构井固井水泥浆漏失的问题。本文研究成果已成功应用于南海高温高压井、深水井、东海超深井等10多口窄压力窗口井的固井作业,有效解决了窄安全压力窗口固井的水力尖劈漏失难题,具有较好的推广应用价值。

High temperature and high pressure （HTHP） wells with an unconventional casing program have a small annulus and a narrow safety window？ and are likely to incur lost-circulation into hydraulic fractures induced by primary cementing. Conventional fractural lost-circulation evaluation apparatus could not simu-late the real downhole conditions, therefore the LCMs selected will not satisfactorily prevent the lost-circu-lation in many cases. A new dynamic fractural lost-circulation evaluation apparatus was developed, with which suitable LCMs were selected and applied together with the corresponding cementing technology in HTHP wells with an unconventional casing program in Yingqiong basin of South China Sea successfully. The above technology has been applied in over 10 wells including HTHP wells,deep water wells in South China Sea, and ultra-deep wells in East China Sea. It effectively solved the hydraulic fractural lost-circula-tion problem in wells with narrow safety windows and has good potential for dissemination.