深水钻井当量循环密度影响规律分析

Analysis on influence law of equivalent circulating density in deepwater drilling

深水钻井中,由于深水段的影响,上覆岩层压力低,钻井液密度窗口窄,当量循环密度(ECD)的预测和控制较难。针对南海深水井通过水力学分析软件进行ECD计算模拟,并对增压泵的影响进行了分析,揭示了深水钻井ECD的影响规律,为深水钻井水力参数设计和现场作业提供了依据。研究表明:深水钻井中,不仅要通过大排量和控制机械钻速来保持井眼清洁和控制ECD,还需要考虑温度对ECD的影响,尤其是在有增压泵的情况下,ECD随着增压泵排量的增大会逐渐增大。

In deepwater drilling, owing to the impact of deepwater section, the overburden pressure is low, and the density window of drilling lfuid is narrow, so that the prediction and control of Equivalent Circulating Density (ECD) becomes more dififcult. ECD computational simulation is carried out through hydraulic analysis software for deepwater wells in South China Sea, and the impact of booster pump is analyzed, and the inlfuence laws for ECD in deepwater drilling is discovered, so as to provide the basis for hydraulic parameter design and ifeld operation of deepwater drilling. The research indicates that:in deepwater drilling, it is not only necessary to keep the wellbore clean and control the ECD by adopting the large displacement and controlling the penetration rate, but also necessary to consider the impact by temperature on ECD. In particular, under the circumstance that there is booster pump, ECD will increase gradually as the displacement of booster pump increases.