Research On System Optimization Design For Coiled Tubing Deliquification

When gas wells start producing, with the decline of formation pressure, gas reservoir will produce liquid seriously. If gas flow rate is lower than critical liquid carrying flow rate in production tubing, the downhole liquid will not be carried out wellhole effectively, then liquid accumulating more and more, gas well deliquify efficiency and production time will be influenced, and even causing gas wells production halts. The coiled tubing deliquification technology is injecting the small diameter coiled tubing into the original production tubing to replace original tubing production, this technology improves the situation of gas well liquid accumulation. Compared with the conventional killing well to replace small diameter tubing, the technology is in the case of fixed downhole production string to inject the coiled tubing to central gas reservoir, and utilizing stratum energy to lift gas and water production from downhole to wellhead through the coiled tubing, so as to realize the gas well liquid carrying production, the technology avoids the damage from killing well and the tubing drop risk from pulling out tubing, the operation is simple and practicable, and the gas well can recover production in short order.The technology need to match the coiled tubing diameter, wellhead pressure and gas production capacity, in order to give full play to the efficiency of gas reservoir production potential and coiled tubing deliquification efficiency. Consequently, the parameters in process of coiled tubing deliquification will be to optimize, and find degree of influence of each parameter and function of the law on gas production, to maximize energy efficiency of gas reservoir, and improve ultimate recovery of gas reservoir development and economic. Therefore this study has some significance for gas production.Through the study of gas well productivity analysis, gas well liquid accumulation diagnosis and critical liquid carrying model choice, to establish coiled tubing deliquification system optimization design model. Adopting system nodal analysis method, to calculate coiled tubing temperature and pressure distribution, and analyze the Influence of coiled tubing deliquification controllable parameters on gas production, to solve the optimization model, then obtain the optimized parameters on gas well production, and analyze the stress distribution of coiled tubing in the process down into the original coiled tubing, forecast the gas hydrate formation conditions and gas well terminate pressure.According to the optimization design model of coiled tubing deliquification system, programming the software of coiled tubing deliquification system optimization design, and analyzing the examples of actual production data on gas wells.The data calculated by the software is consistent with data of actual production, and these show the correctness of the optimization design method.