Tower Pressure Sensitivity Reservoir Of Well Control

In the stress-sensitive reservoir of Central Tarim, because of the narrow security window of mud density, it usually causes lost circulation and well kick by turns. The static equilibrium of wellbore pressure can not be effectively established. After the well kick occurred, lost circulation will happen during the application of conventional well kick method. The results of it making the well pressure further reduced and increase the overflow, the vicious cycle lead to fail of well kick and the more complex situation that threats wellbore safety. Through the method of sealing before well killing, the problem of alternate lost circulation and well kick is solved in the foreign country, but the effect is not good. So it is great significance to explore well control method that adapts to stress-sensitive reservoir.Base on the reservoir characteristics of Central Tarim,I research a unconventional well control techniques to avoid the appearance of complications during the operation and to improve the success rate of well kick in this paper. Research mainly includes:1) Through analyzing the rule of overflow and lost circulation in the stress-sensitive reservoir of Central Tarim, establishing the theoretical foundation and the technical architecture of well control in stress-sensitive reservoir of Central Tarim, ascertaining the effective well kill methods and engineering measures;2) According to the principle of pressure back method, I establish a physical model and mathematical model. At the same time, I accomplish the design method and design process of main parameters;3) According to the principle of heavy mud cap method, I establish a physical model and a mathematical model. At the same time, I accomplish the design method and design process of main parameters;4) By using the well kick example of lungu NO.34 well of Tarim Oilfield, the reliability of design methods and procedures is verifed, as well as the feasibility of engineering measures.The results show that the unconventional well control techniques for stress-sensitive reservoir of Central Tarim not only can improve the successful rate of well kick and shorten the drilling cycle but also can save the mud and reduce drilling costs. It can also avoid the occurrence of complicated accidents.