Reaserch On Key Techniques For Improving Drilling Speed Of The Complex And Deep Well In The Southern Edge Of The Junggar Basin

The southern edge of the Junggar Basin region has abundant oil and gas resources and huge exploration potential in Xinjiang Oilfield. However, because of the oil and gas reservoirs of the area being buried deeply, complex geological conditions, prominent high and steep structure development, exploration and drilling is difficult. Improving ROP and shortening drilling cycle is an effective way to speed up the process of exploration and development in the area. To solve the above problems, key technology research was carried out in this article to improve the drilling speed of the complex deep well in the southern margin, The well structure optimized design, deviation control, fast technique, bit selection techniques and NDS drilling technology were included.The southern edge of the Junggar Basin exploration geological characteristics were analyzed and summarized in the paper. Through collection and analysis of the drilling data in the southern edge of the region, it was found that in the middle and upper strata where the drilling speed technology has been matured, ROP increased every year, while the production rate rose from70%to90%, the application is better. But overall ROP is still low,and complex accident rate of drilling is still high, there is a big space to improve the drilling speed. By complex geological features and drilling accident statistical analysis, we analyzed the difficulties of drilling in the southern edge of the region.The drilling characteristics of adjacent wells and complicated downhole conditions were studied and analyzed, combined with analysis of the complex deep well’s pressure systems and the essential point of closure, the principles of structural design were determined. And the optimized well structure was given, also the effect and applicability of the unconventional wellbore structure were analyzed.To master results of the deviation control and fast drilling in different geological conditions, the application of the conventional technology of deviation control and fast drilling was analyzed. Based on the fact the PowerV tool was applied in part of the southern edge region, field analysis was carried out. It came out that, compared to the composite drilling technology, the deviation control of PowerV tool was better. But because of the high rate of tool and equipment problems and great cost, the application of the PowerV tool is not good.Through the collection of drilling and logging data and screening of the bit data, based on the geological stratification and lithology, using specific energy and improved gray correlation method, the drilling bits which had been used in the southern margin were optimized, and the preferred bit solution and the bit sequence were given.To overcome complex formation pressure, easy to leakage and other problems of the Anjihaihe group, the NDS technology was tested in Huo003in the southern edge of the area. The NDS technology works well, greatly shortens the drilling cycle, and decreases the underground complex accidents which played an important role in the risk prevention, technically meeting requirements of drilling in the region. But the technology is not enough mature and the application cost is too high.The study provides a theoretical basis and technical support for increasing drilling speed, speeding up the process of exploration and development in the southern edge of the Junggar Basin.