深水浅部水合物储层水平井井筒温度计算模型

利用水平井开发水合物储层具有动用范围大,产气速率高,经济效益高的特点,但由于井下温度的变化,水合物易在钻井时发生分解,诱发井壁失稳。基于南海神狐海域储层和钻井基本参数,研究了水平井钻井过程中井筒热量传递过程,构建了泥浆循环过程中井筒温度剖面计算模型,研究了地面泥浆排量、密度、初始温度、水平位移等参数对井筒温度场的影响规律。研究发现:泥浆注入排量是影响井筒温度剖面的主要因素,而泥浆密度则是次要因素;水平位移越大,井筒内泥浆与地层的热传导越充分。该研究成果可为南海神狐海域水合物储层水平井试采时泥浆参数和井身结构设计提供参考依据。

Wellbore Temperature Calculation Model for Horizontal Wells in Shallow Hydrate Reservoirs in Deep Water

The development of hydrate reservoirs with horizontal wells has the characteristics of large producing range, high gas production rate, and high economic benefits. However, due to changes in downhole temperature, hydrates are prone to decompose during drilling, which induces instability of borehole wall. Based on the reservoir parameters and basic drilling parameters in the Shenhu area of the South China Sea, the heat transfer process in the wellbore during horizontal well drilling was studied, and the calculation model wellbore temperature profile during the mud circulation process was constructed. The influence law of displacement, density, initial temperature, and horizontal displacement of surface mud on wellbore temperature field was studied. The study finds that the mud injection displacement is the main factor that affects the temperature profile of the wellbore, while the mud density is the secondary factor. The greater the horizontal displacement, the more adequate the heat conduction between the mud and the formation in the wellbore. The research results can provide a reference basis for designing the mud parameters and designing well structure of horizontal wells in hydrate reservoirs in the Shenhu area of the South China Sea.