The Reaserch And Application Of Increasing The ROP In The Eastern Part Of Junggar Basin

Xinjiang Oilfield belongs to the CNPC, its production of crude oil stands the forth among onshore oilfields in China and the total volume is more than200million tons oil. Xinjiang Oilfield is located in the Junggar Basin where exists rich oil and gas. The exploration there is promising and it has a huge potential of development. After30years’ overall development, drilling technology of the principle part has been complete and mature. With reinforcing the exploring strength, the exploration trends focus on complex and medium-deep oil deposit where geological conditions are more complex, which makes technological problems more and more outstanding. In order to deal with the main problems such as poor drill ability of Carboniferous strata in the surface layer, well deviation in high and cliffy formation and inefficiency of bit applying, we do the research to propose a comprehensive drilling technology to improve the ROP, including bit optimization, combined drilling technique, anti-deflection and improving ROP and air drilling.A good fit bit is able to improve rock-breaking efficiency to improve the ROP. In this research, through literature researches and data collection, we apply mechanical specific energy theory and principle component analysis to optimize bit to suit for different stratum and lithology, including Quaternary, Tertiary, Cretaceous, Jurassic, Triassic and Permain and Carboniferous.Screw composite drilling means bit is powered by screw and rotary table.Its outstanding merit is able to protect drilling tool meanwhile provide a much higher rotate speed. Through the combination with a PDC bit, it can dramatically improve the ROP. This technology has been applied in part of wells in this area, such as FD14and FD071.Through comparing and analyzing the ROP which well section applying screw composite drilling or not, it pronounces effect on improving the ROP.Well deviation directly influences well trajectory and cementing quality, which restrict ROP. High stratigraphic dip and fault zone make eastern part of Junggar basin’ condition more complex. It is necessary to apply vertical drilling system (Power-V, Domestic vertical drilling system) to solve these problems. According to the analysis of vertical drilling system applying on FK1and HB2, it can effectively prove the nice effect on dealing with well deviation.The thickness of Carboniferous system is very large in the square of uplift veil fault-fold belt, from1000m to2500m, which is of poor drill ability. All lead to a lower ROP. Increasing the ROP is a main method to decrease the drilling cycle. After a comprehensive assessment, applying air drilling on well HB021and HB022, the ROP is about5m/h which is3to4times higher than agent wells.