海上钻井井控期间液气分离器处理能力研究

Study on the treatment capacity of liquid-gas separator during the well control of offshore drilling

任美鹏 杨向前 刘书杰 王元娇 丁矿

REN Meipeng YANG Xiangqian LIU Shujie WANG Yuanjiao DING Kuang

中海油研究总院有限责任公司 中国石油物资公司

CNOOC Research Institute Company Limited, Beijing 100027, China China Petroleum Materials Corporation, Beijing 100029, China

钻井液气分离器是钻井过程中重要的井控设备，如果使用不当导致可燃气体到达平台，将威胁人员及设备的安全。针对目前钻井井喷期间井喷最大流量主要靠经验来估算，钻井所用分离器主要借鉴油气生产分离器的相关标准等问题，根据多相流理论，给出了钻井井控期间气体和液体的最大流量估算方法；通过对液气分离器的结构和工作原理的研究，考虑分离器的内径和高度、连接管线的尺寸、液封段的高度、钻井液性能、分离器内部气液流速以及分离器的冲蚀，得到钻井井控期间分离器失效的关键因素，指出分离器的失效存在4种形式：钻井液被气体携带排出，气体从排液管排出，钻井液从排气管排出和分离器冲蚀等，结合井喷条件给出了多因素融合的分离器评估方法，以案例的形式给出了老旧分离器改造的措施，保证钻井井控期间分离器的合理安全的使用。

Drilling liquid-gas separator is an important well control device in the process of drilling. If it is not operated appropriately, the combustible gas will flow to the platform and consequently threaten personnel and equipment safety. At present, the maximum flow rate during drilling blowout is estimated mainly based on experience, and the separators used in the drilling are mainly in reference to the standards related to oil and gas production separators. To solve these problems, a method to estimate the maximum flow rate of gas and liquid during the well control of drilling was established according to multi-phase flow theories. After the structure and working principle of liquid-gas separator were studied, ID and height of separator, size of connection pipe, height of liquid seal section, property of drilling fluid, gas and liquid flow rate inside the separator and erosion of separator were analyzed to determine the key factors resulting in separator failure during the well control of drilling. It was pointed out that there are four forms of separator failure, i.e., carrying and discharge of drilling fluid with the gas, discharge of gas through the drainage pipe, discharge of drilling fluid through the vent pipe, and erosion of separator. Finally, based on blowout conditions, a multi-factor fusion based separator evaluation method was formulated and the measures to transform old separators were prepared on the basis of case study, so as to ensure the reasonable and safe operation of the separators during the well control of drilling.

10.13639/j.odpt.2020.02.009