脉冲振动固井技术研究

A New Technique of Top Cementing Pulsation

为提高水泥浆胶结质量,防止固井后油气水窜,提出了脉冲振动固井新技术。研制开发了新型脉冲振动固井室内评价装置,通过脉冲振动可以有效地改善水泥浆性能,水泥石的胶结强度平均提高了11%～22%,水泥浆的初凝时间平均缩短了3%,初终凝过渡时间平均缩短了12%～17%,水泥石的抗压强度平均提高了10%～14%,水泥浆稠度系数K平均降低了16%～63%;利用电镜扫描、X射线衍射、压汞实验等分析手段,对比分析了脉冲振动处理后的水泥石微观结构、水化产物和水泥石孔隙特征的变化规律,脉冲振动促进了水泥水化反应,改善了水泥石的微观结构;分析了水泥水化过程中水泥浆失重特性,根据水泥浆静胶凝强度与水泥浆失重的关系,阐述了利用脉冲振动固井技术减少水泥浆失重和防止环空气窜的机理;为实现对候凝过程中的水泥浆实施脉冲振动,研制开发了新型井口脉冲振动固井装置,经过10余口井的现场应用,取得了良好的固井效果。

A new technique of Top Cementing Pulsation （TCP） is developed to improve the bonding quality and prevent annular gas migration in the cementing operation. A new patented hydraulic pulsation test instrument is developed to test the performance of the cement slurry under the pulsation treatment. By means of the instrument, the properties of different cement slurries were tested. The results indicate that the performance of the cement slurry can be greatly improved with the pulsation treatment, and the bonding strength and the compressive strength of cement are increased by 11-22 percent and 10-14 percent on average, respectively, and the time of initial set, the time interval between initial set and finial set, the consistence factor K are reduced by 3 percent, 12-17 percent, 16-63 percent on average, respectively. With core analysis techniques such as electron microscope, X-ray diffraction and mercury intrusion method, the microstructure change of the cement stone and its hydration product and the pore characteristics were studied. Experimental results reveal that pulsation vibration can accelerate the hydration of the cement slurry and improve its microstructure. In addition, based on the analysis of the hydration of cement, the property of cement weight loss during the hydration and the relation between the static gel strength and the weight loss of cement slurry, the mechanism of pulsation in improving the static shear strength of cement slurry, diminishing the cement slurry weight loss and preventing gas migration is clarified in this paper. A patented surface pulsation cementing device was developed and were used in more than 10 wells, which indicates that the cement slurry bonding quality is greatly improved and the annular gas migration is effectively prevented after cementing.