Drainage Gas Recovery Technique with Downhole Intelligent Robots in Low Pressure and Low Production Gas Wells

The output of low pressure and low production gas wells has been significantly reduced due to the presence of liquid loading, and it is difficult to maintain long-term stable production and to enhance gas recovery through conventional drainage gas recovery technologies, such as foam drainage, plunger gas lifting and liquid nitrogen gas lifting. To solve this problem, a novel downhole intelligent robot for drainage gas recovery was developed based on the principle of plunger gas lifting. The robot automatically segments and quantifies drainage by monitoring and tracking the dynamic liquid level within wellbore in real time, and then automatically controlling the opening and closing of the center channel in the device. It does so byenabling the downhole intelligent robot to go upward along the wellbore automatically. The robot was tried out in the field in one well in Dongsheng Gas Field. The results were positive. The robot is able to move around steadily and freely in the wellbore and achieve independent quantitative drainage and continuous gas recovery without shutting in the gas well. Using robotics, gas production ramped up steadily, the tubing/casing pressure difference dropped in a continuous manner, and liquid loading in the wellbore was mitigated. Thus robotics and automated control systems allowed long-term stable production and EOR of low pressure/low production gas well. The downhole intelligent robot effectively solved the technical problems encountered in conventional drainage gas recovery, and made it possible to have efficient development of low pressure and low production water-bearing gas reservoirs.