Study and Application on ROP-Enhancing Technology of Ordovician-Cambrian Dolomite Strata in Tarim Basin

Abstract

The Ordovician-Cambrian dolomite formation in Tarim basin has certain characteristics such as poor drillability, long drilling cycle, difficulty in selecting drill bit and accelerating tool. In order to meet the requirements of efficient exploration and development of Cambrian oil and gas reservoirs, there is an urgent need to design high ROP bit and acceleration tool suitable for dolomite formation, optimize drilling parameters and improve ROP to form the technical scheme of drilling acceleration in dolomite formation. Therefore, the drillability of the Cambrian dolomite strata was studied. The experimental analysis was carried out according to the geological characteristics and rock mechanical parameters. Dual index drillability analysis method was used to evaluate the formation compactness, abrasiveness and other formation drillability characteristics. A new type of PDC bit was designed to improve the impact resistance and eddy resistance of single tooth, a three-dimensional vibration acceleration tool was selected to reduce the vibration of the bit, and combined with the optimization of drilling parameters, the technical scheme for acceleration of the Ordovician -Cambrian dolomite formation in Tarim Basin was finally formed, which was successfully field tested in Well A of Tarim Basin. The research results show that compared with the adjacent well B section, the average footage and the average ROP are increased by 47.8% and 32.0% respectively. Compared with the adjacent well C section, the average footage and average ROP increased by 37.0% and 29.5% respectively. The results provide technical reference and support for the efficient exploration and development of Ordovician - Cambrian reservoirs in Tarim Basin.