井下循环温度及其影响因素的数值模拟研究

Numerical Simulation of Circulating Temperature and It's Impacting Parameters

井下循环温度不但直接影响钻井液的流变性、密度及化学稳定性等,而且与井内压力平衡、循环压耗、套管和钻柱强度设计等有关,因此准确确定钻井作业时井内循环温度的分布和变化规律对钻井循环压耗、井控和安全快速钻进具有极其重要的意义。根据能量守恒原理,针对井筒内热量传递的特点,建立了钻井循环时井内温度的数学模型,并用有限体积法对该模型进行了求解,最后用实测的井筒温度对模型预测结果进行了验证。同时对影响井下循环温度的参数进行了敏感性分析,分析结果表明,钻井液和地层的热物性参数以及钻井液入口温度、循环流量等因素对井内温度分布有较大影响,掌握这些参数值对准确预测井内温度分布至关重要。

Bottom-hole circulating temperature not only directly impacting rheological properties,density and chemical stability of drilling fluid,etc.,is also related to borehole pressure balance,circulating pressure loss,casing and drilling string strength designs,etc.Therefore the calculation of the distribution and variation of the bottom-hole circulating temperature is very important for calculating pressure loss,well control and safety and efficient drilling.According to the energy conservation and borehloe heat-transfer property,a mathematic model was created to predict the well temperature distribution during drilling fluid circulating and solved with the finite volume method（FVM）.Then predicted results were validated by the measured wellbore temperature.The impacting parameters were analyzed.The analysis results indicate that drilling fluid and formation thermal physical parameters,mud inlet temperature and flow rates impact the downhole temperature greatly.Knowing these parameters is very important to predict the wellbore temperature distribution.