The Design And Character Analysis Of Casing Drilling Retrievable BHA

Casing drilling being a new and creationary technique ,have already cause international ascend each big petroleum company of value. Retrievable bottom tool assembly technique is that retrievable and trip in well once more tool assembly drill.,its technical heart is retrievable bottom tool assembly, bit through the rope recovery equip descend go to the well bottom.and recover to the ground after the bit losing efficacy, go into well again to drill after replacing bit.This paper survey and analyse retrievable bottom tool assembly composition rule、work process, and the downhole tool string theory analysis.Forming a set of design features with our own type of casing drilling BHA recyclable, including: pilot drill bit, bit modular, high-intensity downhole reaming tools, runing and recovery into the instrument string. Through the indoor and field test proved recoverable casing drilling instrument portfolio structure to meet the design requirements of performance, simple structure, advanced technology, the principle of a viable, feasible, to meet the basic needs of the scene.Through the design study, completed recoverable casing drilling downhole tool string, salvage equipment, process design and key pieces of the mechanical calculation and analysis, achieved the combination of instrument locking mechanism and the structure of Reaming instrument innovation.Make a theoretical analysis of casing drilling BHA buildup characteristics. Analyzing and comparing the Casing Drilling Reaming while drilling tool with single, dual stabilizer BHA buildup characteristics, finally made a single stabilizer BHA. Make a simulation of the distribution of the stress, contact stress.etc of the RWD tool in process of job. The results show that The RWD tool in poor working conditions, the regional of reamer wing is a dangerous area; the friction between tools and rocks help to improve the tools force status, but too much friction would aggravate the wear and tear of reaming wing blade contact with the rock part; Reaming cutter axis inclination not be too big, about 10°to recommend appropriate; PDC cutting teeth in the rock breaking process was subject to non-uniform distribution of load, Cutting teeth severe local wear may be speed up the overall end-of-life; with the negative anterior angle increase ,cutting tooth effective stress gradually increased, but the rocks effective stress gradually decreased; with the depth of cut increase , PDC cutting tooth contact pressure, friction stress and effective stress gradually reduce ,but the rocks effective stress gradually increase. All of it would provide the basis for the use and design of the RWD and rock-breaking toolsThrough the indoor and field test proved recoverable casing drilling instrument could meet the design requirements, and with simple structure, advanced technology, the principle of a viable, feasible, could meet the basic needs of the field work.