深层碳酸盐岩地层长水平段钻井井筒温度分布模型研究

Wellbore Temperature Distribution Model during Long Horizontal Section Drilling in Deep Carbonate Formation

为克服深层海相碳酸盐岩地层长水平段钻井作业过程中的井下高温问题,结合深层海相碳酸盐岩气藏长水平段钻井过程的特点,建立了综合考虑多源项、非牛顿流体螺旋流动、变热物性参数的钻井井筒瞬态温度分布数值模型。基于该模型,研究了水平段长度、循环时间、钻井液排量、入口温度对井筒温度分布的影响规律。结果表明:随着水平段长度的增加,井底温度会显著增加;增加循环时间、增加循环排量、降低钻井液入口温度等措施对降低深层长水平段井底温度的作用有限。可见,为保障深层碳酸盐岩油气资源开发的顺利进行,须提高旋转导向工具的耐温极限。

In order to overcome the downhole high temperature problem during the drilling process of long horizontal section in deep Marine carbonate formation,a transient numerical model of wellbore temperature distribution during drilling process was established,and multi-source terms,non-Newtonian fluid helical flow and variations of thermophysical properties in combination with the characteristics of long horizontal section drilling in deep Marine carbonate gas reservoir were considered.Based on the model,the effects of horizontal section length,circulation time,drilling fluid displacement,and inlet temperature on the wellbore temperature distribution during horizontal well drilling were studied.The results show that the bottom-hole temperature will increase significantly with the increase of horizontal section length;measures such as increasing circulation time,increasing circulation displacement and lowering drilling fluid inlet temperature have little effect on decreasing bottom-hole temperature in deep long horizontal sections.It can be seen that in order to ensure the smooth development of deep carbonate oil and gas resources,the temperature tolerance limit of rotary steerable tools should be increased.