Optimal and Fast Drilling Technologies for Ultra-Deep Horizontal Wells in the Fault Zones of the Shunbei Oil & Gas Field

Ultra-deep horizontal wells in the fault zones of the Shunbei Oil & Gas Field face problems such as leakage, collapse, gas cut, and low ability of temperature resistance of measure while drilling (MWD). In order to solve these problems, and to increase the drilling speed, and shorten the drilling period, the well-seismic identification technology and the modified three-pressure profile were employed to select the wellhead and determine the sealing point, and the casing program was optimized to a four-stage structure. Then, based on the fracture property analysis and laboratory experiments, the formula of anti-leakage and anti-collapse drilling fluid system was selected to ensure the stability of the long open hole wellbore. In addition, a vertical drilling system worked with a large torque screw to solve problems of high rock strength and easy well deviation in deep formation to achieve anti-deviation and fast drilling. Furthermore, a borehole profile of deflecting in the low-temperature section and holding in the high-temperature section were designed. Then, a slightly buildup drill assembly and targeted technical measures were adopted to solve the low temperature resistance of MWD. Finally, the low-density drilling fluid and the simple managed pressure drilling technology were applied to deal with the gas cut, kick, and circulation loss in the reservoir. Through technical research and targeted measures, optimal and fast drilling technologies suitable for ultra-deep horizontal wells in the fault zones of the Shunbei Oil & Gas Field were developed. These technologies have been applied in six ultra-deep horizontal wells in the fault zones of the Shunbei Oil & Gas Field, and the problems including leakage, collapse, gas cut, and low temperature resistance of MWD were basically solved. Compared with that of adjacent wells without using these technologies, the average rate of penetration (ROP) of these wells was increased by 116.2%, and the average drilling duration was reduced by 41.2%. Research and field application show that the optimal and fast drilling technologies for ultra-deep horizontal can address the problems in the drilling process of ultra-deep horizontal wells in the fault zones of the Shunbei Oil & Gas Field. They can also increase the ROP and shorten the drilling duration, which can provide technical support for exploring and developing the Shunbei Oil & Gas Field.