Research On Gas Drainage And Gas Recovery Technology In Kela Beautiful Gas Field

Kelameili gas reservoir in which vertical wells and horizontal wells produced belongs toⅡ,Ⅲ classes.These wells belong to middle-low industrial gas well.Because of fast production decline,different levels of fluid(water and gas condensate)produced,and the early gas production of some parts of wells is less than critical carrying fluid gas rate,some parts of gas wells cannot normally produce.Particularly,gas wells in DX14,DX17,DX18 wellblocks are all in different degree of producing liquid,ranging from 0.5 to 100 m3/d.Gas wells are mainly due to producing liquid,insufficient energy and high outlet pressure,causing gas wells intermittent production,or to fail to put into production.Therefore,this article is to solve the problem of liquid producing in gas wells within Kelameili gas field,performing gas-lift drainage gas recovery process design and optimization of gas distribution technology research.Mainly work finished is the following:(1)Using 73 different gas-liquid two phase flow pressure and temperature test data of process test wells,adopting new evaluation method which considers different weight coefficients,7 kinds of two-phase flow pressure drop calculation methods commonly used in engineering have been evaluated thus.(2)Analysis of gas and liquid production,tube pressure and case pressure variation of five test wells,using Li-min model and Turner model for calculating the critical carrying fluid gas rate,combined with actual production condition,it makes the conclusion that Turner model is more suitable for prediction liquid load in wells of Kelameili gas field.According to the production data,estimating the average liquid producing index of each well,this can provide basic data for follow process design of gas lift.(3)Analyzed gas lift response curves of gas test wells influenced by six kinds of sensitive parameters,formation pressure,wellhead tube pressure,water cut,injected gas type,gas liquid ratio in formation,fluid productivity index respectively,it is concluded that at different stages and different production conditions of test wells,how the sensitive parameters influence gas lift technology parameters,such as gas injection rate,gas injection pressure.(4)According to the process of test wells,3 wells needing to unload to reproduce are performed blank tube unloading simulation by injecting nitrogen and natural gas,and constractively analyzing simulation results.Finally,case collapse strength of gas injection unloading is analyzed.(5)According to sensitivity parameters analysis results of gas lift response curve,the appropriate distribution of gas lift valves design parameters is obtained.On the basis of choice principle of continuous gas lift wells and method of distributing valves of continuous gas lift well,gas lift valve distribution of 3 wells of high start-up pressure is designed.(6)Using high order polynomial fitting out of the objective function in mathematical model of optimization gas distribution of block,three kinds of mathematical models including four kinds of constraint conditions are established.Using four kinds of algorithms to calculate the maximum liquid production model,and the objective function of the model on the degree of active constraint conditions are analyzed.For the actual situation of Kelameili gas field,this paper has carried out researches,from the aspects above,formed a set of gas-lift drainage gas recovery technology suitable for this field.To maintain the long-term stable production and to improve the ultimate recovery of gas field are of great significance.