深层环境下固井水泥水化放热特性及井周温度场演化规律研究

Research on the Evolution of Temperature Field Around the Wellbore During Cement Slurry Hydration in Deep Formation

塔里木盆地已建成我国最大的超深层油气生产基地,深层环境会对水泥水化放热特性产生一定的影响,研究深层环境下水泥水化放热及传热特性对明确井周温度场演化规律至关重要。文章首先根据现场实测资料建立了塔里木油田近井和远井地层温度方程,根据不同地层深度的温度分布情况,开展了不同温度下G级水泥水化放热实验,基于Krstulovic-Dabic(K-D)经典水化动力学模型,结合水泥成核结晶与晶体生长、相边界反应以及扩散三过程反应特征推导了不同温度下水泥水化放热预测曲线,进一步推导了套管-水泥环-地层热传导模型,并将放热曲线作为热源代入到有限元模型中,得到了不同井深的套管与水泥在水化放热与高温地层的共同作用下温度场的变化情况。研究结果可为下一步分析有限局部空间的温度场变化对地层压力和套管变形影响提供技术支持。

The Tarim Basin has been built into the largest ultra-deep oil and gas production base in China,and the deep environment would have a certain impact on the exothermic character of hydration cement,and it is very important to study the exothermic reaction and heat transfer characteristics of cement hydration at deep ambient temperature to clarify the evolution law of the temperature field around the well.Firstly,according to the field measurement data,the formation temperature equations of near and far wells in Tarim area were established,and according to the temperature distribution of different depths,G-grade cement hydration exothermic reaction experiments at different temperatures were carried out,and based on the Krstulovic-Dabic(K-D)classical hydration kinetic reaction model,combined with the reaction characteristics of cement NG,I and D,the prediction curve of cement hydration exothermic reaction at different temperatures was derived.Furthermore,the casing-cement sheath-formation heat conduction model is derived,and the exothermic reaction curve is substituted into the finite element model as the heat source,and the temperature field changes of casing and cement under the combined action of hydration exothermic reaction and high temperature formation of different well depths are obtained.The research results provide preliminary data support for analyzing the impact of local finite space temperature field changes on formation pressure and casing deformation characteristics in the next step.