| Horizontal well gas has become the key technology for the development of the Kelameili gas field.The number of horizontal gas wells is 17,which account for 30%of the total production while the daily gas production of 114×104m3 accounts for 38%of the total production.However,with the deepening of gas reservoir development,the average reservoir pressure and gas production are decreasing year by year.Furthermore,the pipe sizes are 31/2" and 41/2",which make it difficult to continuous liquid removal,leading the cease of the wells.Therefore,accurate prediction of the critical gas rate and optimizing the tubing size is the key to extending the production period of horizontal wells in the Kelameili gas field.Currently,the research on the critical gas rate of horizontal wells is mainly obtained by modifying the analytical models used in the vertical well by adding angle term.If these models are directly used in the horizontal gas wells of Kelameili gas field,the calculation error is large.To this end,this paper combines physical simulation and theoretical research to study the mechanism of continuous liquid removal in horizontal wells,and can be described as follows:(1)The production conditions and problems of horizontal gas wells in Kelameili gas field were analyzed.The flow parameters were calculated according to the 17 horizontal wells,and the experimental parameter was designed based on Froude Number.(2)The simulation experiment of horizontal well loading phenomenon was conducted by using the visual experimental apparatus.It was found that liquid film reversal criterion is too conservative to predict liquid loading onset.Thus,a new criterion for prediction of liquid loading onset was proposed by considering the pressure drop and liquid holdup in Kelameili gas field.(3)Based on the liquid-film reversal criterion and the new theory,the calculation method of liquid film thickness at the bottom of inclined pipe was modified by using the vertical tube liquid film thickness calculation method and Beggs-Brill model.Then the theoretical model of critical gas velocity in the inclined pipe of the horizontal well was established.Besides,the influence of angle,pipe diameter,pressure and temperature on the critical gas velocity was analyzed,and then the plate of critical gas velocity in the horizontal wells in the Kelameili gas field was established.(4)Based on the pressure measurement data of horizontal wells in Kelameili gas field,the gas-liquid two-phase flow pressure models commonly used in engineering are evaluated,and the node system analysis method is introduced to optimize the production pipe size,and the development of the corresponding computer program provides an important design tool for the optimization of production in the beautiful gas field.(5)Taking X well as an example,the effects of different tubing sizes on wellbore pressure and critical gas velocity profile are systematically analyzed,and the influence of parameters such as tubing head pressure and gas-liquid ratio on production is predicted by node system.The research of this paper provides an important technical support for the efficient production of gas wells in Kelameili gas field,and has certain reference value for the theoretical of gas wells deliquification. |
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