Research and Application of Drilling and Completion Technologies on Large-size Injection-production Well

Abstract The large-size injection-production well can increase the injection-production capacity to more than 3 times, compared with the conventional-size one. However, it had not been popularized and promoted for many years since it had the technical difficulties of long construction period, high engineering risk and large investment in a single well. The Liaohe double-6 gas storage planned to deploy 3 large-size horizontal wells, aiming at further improving injection-production capacity to satisfy peak shaving demand. To overcome the technical difficulties of large-size well, the drilling scheme was optimized according to geological characteristics of double-6 block in the paper. It included wellbore structure design, wellbore diameter control technology and hole cleaning technology. The optimized drilling scheme can not only improve the wellbore integrity, but also reduce the risk of engineering accidents and shorten the drilling period greatly. Besides, the cementing technology was optimized as well from the aspects of hierarchical cementing and cement slurry design, which can be used to solve the problems of high pressure at the bottom of well and large leaking risk of cement. On the basis, the above drilling and cementing technologies were applied to develop three large-size wells, and good practical results were achieved. The average completion period of the three well was 104 days, 36 days shorter than the planned period, which realized the applying effects that large-size wells can be designed, constructed, and produced in the same year. Moreover, the ultrasonic evaluation results showed that the average qualified rates of the three wells in technical casing was 92.8%, which was much higher than the industry standard. Besides, the test results showed that the injection and production volume of each large-size well in the paper can exceed 3 million cubic meters, solving the problem of insufficient injection-production capacity in the months with high peak shaving demand. Above all, the drilling and cementing technologies of large-size well had been optimized in the paper, which successfully reduced the well completion period, and improve the cementing quality and the safety of drilling construction. The researches can not only ensure the project quality of large-size well in Liaohe double-6 gas storage, but also provide technical support for promoting the drilling and completion engineering of large-size well in other domestic and foreign gas storages.