Published May 2019
On showing elimination during drilling
R.G. VeliyevThe trend of rejection using extra-heavy materials appears during oil-gas wells drilling, as well as while productive reservoir completion for prevention of show¬ings. The paper offers a new method the essence of which lies in the following: before the fluids through the drilling well in bottomhole zone is created a hydraulic barrier consisting of high-viscous Newtonian or viscous-plastic dead (degassed) heavy oil, which for a long time (few months) prevents fluids entry from reservoir into the drilling well or limits its discharge . At the first signs of showings during productive reservoir completion via drill¬ing well, the control and monitoring on drilling cuttings quality are enhanced; in case if the showing becomes intensive, the dead oil is injected immediately in cal¬culated volume and displaced beneath by the drilling mud. When the oil reaches to productive reservoir, the drilling is stopped and the preventer closed; the oil is totally displaced to the reservoir, the preventer closed and the drilling goes on. For comparison of both variants, numerical calculations have been carried out and it was defined that during the well isolation via viscous-plastic oil, the duration of next showing is longer, which creates favorable conditions for the drilling with¬out impediments.
