Hole Cleaning In Highly Deviated Wells And Application Analysis

With world economy developing, the demand for energy is increasing. Oil , as a major consumer products of energy, plays a vital role on the world economy. In the drilling process, particularly in highly deviated well drilling, hole cleaning conditions have great effect on the drilling and downhole safety.Based on the debris transport mechanism in highly deviated wells, three layer model of cuttings transport is established, which can be solved using the software program. It can be used to calculate thickness and transport speed of cuttings bed. Based on three layer model solution results, the borehole cleaning situation analysis software is developed, which can be used to analyze the situation and to optimize hole cleaning performance parameters during drilling. With hole cleaning model, it can be known that to increaseΦ6,Φ3, YP / PV and density of mud will improve hole cleaning conditions, but whenΦ6,Φ3, YP / PV increase to a certain extent, their contribution to hole cleaning is not great.Variation of the drilling parameters, including displacement, rotating speed and ROP, has quite obvious effect on hole cleaning situation. Variation of the diameter of the drill pipe, has a little impact on the hole cleaning conditions. 17-1/2 "hole section 12-1 / 4" hole section ,8-1 / 2 "hole section of Ledong 22-1 gas field and 17-1/2" hole section, 12 - 1 / 4 "hole section of Ledong 15-1 gas field has been confronted with hole cleaning problems in the existing drilling mud performance parameters . With the hole cleaning model engineering parameters are optimized and measures for improvement are proposed. Field applications show that by proper control of ROP, drilling fluids performance and effective engineering measures, the drilling speed is significantly increased and hole cleaning standards are greatly improved in Ledong 15-1 gas field, full realization of directly pulling out in 17-1 / 2 "hole section of 8 wells. Average pulling out speed in 12-1 / 4 "hole section of 8 deviated well is 98.57 m/ h, 19.65%faster than Ledong 22-1 gas field.