Research On The Well Control Technology Of Sulfur Gas Wells

With the further development of nature gas exploration,the difficulty of oil and gas drilling is more and more, the well control issue has become increasingly prominent.particularly the well control of high pressure,sulfur gas wells has been made more complicatedly due to its high formation pressure, narrow pressure window, coupled with formation fluid containing hydrogen sulfide gases. Therefore, Research on the well control of sulfur gas well is extremely important practical significance for enhancing the well control safety of sour gas well.Based on the analysis and summary of some domestic and foreign the well control design characteristics about sour gas wells,this paper presents safety design and construction requirements,including casing program,well control equipment,drilling fluid density,the appropriate personnel training.In order to ensure safe drilling in the formation containing sulfur, This paper introduces the drilling fluid closed-loop managed pressure drilling technology to solve this problem. And the technical advantages to deal with drilling safely in the formation containing sulfur were expounded in great detai, it also makes a detailed introduction in the use of equipment. Considered the effect of the wellhead back pressure,two-phase flow models based on the theory of gas-liquid flow in the wellbore are established under the condition of drilling with back pressure, kick,shut in,killing with back pressure.The drilling with back pressure calculation model is solved by numerical method,the wellbore pressure program is developed. The law of different back pressure suppressing gas expansion have been researched with the wellbore pressure program.On basis of this,the reasonable value of back pressure under the condition of drilling were obtained.In order to overcome the shortage of the conventional well killing method to deal with overflow in sour gas well,The well killing with back pressure technology was presented.the rate of gas kick,overflow,discharge capacity affected on wellhead back pressure and pit gain were stimulated during the well killing with back pressure.the variation of the above parameters were compared and analyzed.Combined with the results of simulation, a set of operating procedures for killing the overflow with back pressure under the condition of drilling was put forward.,the recommendations for field Application were given.Finally, when the hydrogen sulfide content is too high,bullheading is the best method. the bullheading construction process for high sulfur gas wells was reserched.it also proposes the needed attention during the construction process.