Key technology of directional drilling in the ultra-deep high-temperature IV belt, the Shunbei oilfield

The IV belt of the Shunbei oilfield is located in a slipping fault zone. Its reservoirs mostly of the Ordovician carbonate rocks are mainly recovered using horizontal/direction wells. The average vertical depth is nearly 8 000 m, with a maximum formation temperature of 174 °C, The ultra-high depth, high temperature and complex geology lead to technical challenges for directional drilling in this area, such as high difficulties in well trajectory control, high failure rates of devices and low timeliness to handle gas invasion. Under this background, the casing program was optimized to reduce difficulties in directional drilling, and the proportion of composite drilling was on average increased by 10%. The efficiency of well trajectory control was greatly improved, with a target hit rate of 100%, by optimizing the BHA and drilling parameters and applying the tool-face stable adjustment and control technology and seismic-assisted guiding-while-drilling technology. Based on the investigation of the well temperature field distribution, the MWD technology was improved, and the tool failure rate dropped from 23% to 9.3%. With the simplified MPD technology, the handling efficiency for the gas invasion was enhanced. The presented directional drilling technology was applied to 12 wells in the field. Compared with the drilling engineering design, the directional drilling duration of the reservoir is on average reduced by 14.3%, and the average rate of penetration is increased by 32.1%, compared with that of the adjacent block. Applications of the presented directional drilling technology should be further promoted.