无隔水管钻井泥浆举升系统管路特性计算与分析

Calculation and Analysis on Pipeline Feature of Riserless Mudlift System

无隔水管钻井技术使用海底泵举升系统将钻井液和岩屑通过返回管线泵送回海面钻井船,能解决深水钻井地层破裂导致的相关问题,在国外获得了广泛的应用。选用冥律流体沿程压力损失算法,确定了深水泥浆返回管路所需压头的计算方法;对影响管路特性的因素进行深入分析,得出系统的工作水深、钻井液密度和工作流量是设计泥浆举升系统最重要的参数;同时应充分考虑钻井过程中钻井液固相颗粒体积分数、流性指数和稠度系数变化带来的影响,为深水泥浆举升系统的设计提供了理论基础。

Riserless drilling technology uses subsea pump module to return drilling fluid and cut- tings to drilling ship via mud return line. It can solve deep-water drilling issue,; related to forma- tion fracture and obtain a wide range of applications at abroad. Based on a large number of calcula- tions, this paper optimizes the method to calculate friction losses along the way in power-law flu- id,and determines the pipeline feature calculation of deepwater mud return pipeline. It also con- ducts in-depth analysis of affections of pipeline feature and concludes that operating depth, drilling fluid density and operating flow are the most important parameters for designing the mudlift sys- tem. We should also fully consider the impact of changes in volume fraction of solid-phase, flow behavior index and consistency index of the drilling fluid. It provides theoretical basis for the de- sign of deepwater riserless mudlift system.