基于三维温度场的热采井水泥环完整性破坏的研究及对策

稠油热采井固井问题一直是制约稠油资源开发的关键技术难题之一，注蒸汽高温热载荷作用下的水泥环完整性破坏导致的井口抬升现象普遍存在于海上稠油热采井开发过程中，危害极大，严重影响油井生产寿命和井控风险。以渤海热采井固井水泥环完整性为研究背景，基于热传导分析，建立了热采井注热井筒三维温度场分析模型和热载荷、注氮载荷和非均匀地应力耦合条件下的水泥环完整性分析模型，并从水泥浆体系、工艺技术、隔热油管性能等方面提出了增强热采井水泥环完整性的应对措施。应用表明，该套理论可有效模拟热采井注蒸汽三维温度场剖面，判断热载荷条件下的水泥环完整性破坏机理及失效形式，为新开发热采井提供借鉴与参考，应用前景广阔。 

Study on and Countermeasures to the Loss of Cement Sheath Integrity in Thermal Production Wells Based on 3-D Temperature Field

In thermal production heavy oil well cementing operations, loss of cement sheath integrity caused by high heat load produced during steam injection results in wellhead uplift. This phenomenon, which is widely found in the development of offshore thermal production heavy oil wells, and is of great harm, imposes great impact on the production life of the well and results in well control risks. Research work has been conducted on the cement sheath integrity of the thermal production wells in Bohai oilfeld. Based on heat transfer analyses, a 3D temperature feld analysis model for heat injection wellbore and a model for the cement sheath integrity analysis under the condition of coupling of heat load, load of nitrogen injection and non-uniform in-situ stresses have been developed. Measures for enhancing the integrity of cement sheath in thermal production well have been presented from drilling fluid, feld operation techniques and the performance of the thermal insulated tubing etc. Application of the models and the measures showed that the 3D temperature feld profle of a thermal production steam injection well can be effectively simulated, the damage mechanisms of the integrity of the cement sheath and the failure type of the cement sheath under heat load can be determined. This study is of reference to the development of new thermal production wells, and has wide application prospects.