Application of the New Drilling Technology for Increasing Penetration Rate in Deep and Ultra-Deep Wells

Abstract

The rotary percussion drilling technology can greatly increase the penetration rate of deep and ultra-deep wells; however, the short service life of the impactor limits its wide application. Therefore, the turbine type hydraulic impactor developed by the China University of Petroleum (Beijing) for the deep and ultra-deep wells was used to extend life of impactor. Based on the analysis of pressure field and velocity field under different flow conditions, the drilling fluid flow range of rotary percussion drilling was optimized to be 32-41 L/s. In this range, it can ensure that the wearing parts of the turbine hydraulic impactor can fully exert the impact of the impactor and high rock breaking efficiency without serious erosion. Application of deep well sections in ultra-deep wells in Tarim Oilfield achieved that the penetration rate of the rotary percussion drilling increased by more than 60% compared with the composite drilling technology. At the same time, the normal working life of the turbine hydraulic impactor was more than 140 hours, which is more than 2 times of the life of the screw drill. The results of field application show that the turbine hydraulic impactor has a wide application prospect in deep and ultra-deep wells drilling.