渤海超大位移井水平段裸眼延伸极限预测及影响因素分析

Prediction of open-hole extension limit and influencing factors analysis of horizontal section of mega-extended-reach well in Bohai Sea

喻贵民 霍宏博 谢涛 宋闯 李进

中海石油（中国）有限公司天津分公司海洋石油高效开发国家重点实验室，天津 300459 西南石油大学油气藏地质及开发工程国家重点实验室，四川 成都 610500

State Key Laboratory of Offshore Oil Efficient Development, Tianjin Branch of CNOOC Ltd., Tianjin 300459, China State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu 610500, China

为解决渤海复杂地质条件下浅层超大位移井到底能打多远的问题，文中综合考虑岩屑、井筒环境、水化效应对井壁稳定性的影响，建立了海上超大位移井水平段裸眼延伸极限预测模型，分析了不同因素对水平段裸眼延伸极限的影响，并进行了因素敏感性和钻井方案优化措施分析。结果表明：考虑岩屑影响的水平段裸眼延伸极限明显小于不考虑岩屑影响的延伸极限；水平段裸眼延伸极限随破裂压力当量密度、钻井液稠度系数、钻杆转速、温度增量的增加而增大，随钻井液密度、钻井液流性指数、机械钻速、固相（岩屑）密度、固相体积分数、压力增量、水化应力的增加而减小，随钻井液排量的增大先增大后减小。敏感性分析结果表明，破裂压力当量密度、钻井液流性指数、钻井液稠度系数对延伸极限的影响较大。通过优化各参数取值，可改善钻井液性能，提高井筒清洁能力，合理控制钻进参数，从而延长超大位移井水平段裸眼延伸极限，为平台位置优选、井网布置、复杂结构井开发方式选择提供帮助。

In order to solve the problem of how far mega-extended-reach wells can be drilled under complex geological conditions in the Bohai Sea, the prediction model of the horizontal section open-hole extension limit of mega-extended-reach wells in the Bohai Sea was established by considering the influence of cuttings, wellbore condition and hydration effect on the wellbore stability. This paper analyzed the influence of different factors on the open-hole extension limit of horizontal section, and conducted factor sensitivity and drilling program optimization analysis. The results show that the open-hole extension limit length of the horizontal section with cuttings taken into account is obviously smaller than that without cuttings. The open-hole extension limit of the horizontal section increases with the increase of fracture pressure equivalent density, drilling fluid consistency coefficient, rod rotation speed and temperature increment. It decreases with the increase of drilling fluid density, drilling fluid fluidity index, ROP, solid （cuttings） density, solid volume fraction, pressure increment and hydration stress. It first increases and then decreases with the increase of drilling fluid displacement. The results of the sensitivity analysis show that the fracture pressure equivalent density, drilling fluid fluidity index and the drilling fluid consistency coefficient have greater effects on the extension limit. This study optimizes the value of each parameter, improves the drilling fluid performance, enhances the wellbore cleaning capacity and reasonably controls the drilling parameters to extend the open-hole extension limit of the horizontal section of mega-extended-reach wells, which will be helpful for the optimization of platform location, well pattern layout and development method for complex structure wells.

10.6056/dkyqt202302022