The Horizontal Well Technology Policy Research In Gas Field

Taking Kelameili gas field as a case study, technical researches related to the developmentof horizontal well of gas reservoir were done in this paper, which aim at the realistic problemsof lack of development experiences and models. Basic studies were done to the characteristics ofgeology, gas reservoir and development with multiple methods of different subjects; the form ofwell network, reasonable well-space, disposition of well network, deliverability well andhorizontal length of horizontal were demonstrated and optimized. Suitable theory and a methodfor horizontal wells of gas reservoir were obtained, as well as the following achievements:The types of the gas reservoir and the size of oil ring in Kelameili gas field were researchedwith various methods, the results of the research indicated that the gas field was gas reservoirwith moderate condensate oil and could be extracted in ordinary way.Well spacing density was fixed by analogy, economic limit, fracture half length,etc. Thewell spacing density of horizontal wells in Kelameili gas field was obtained through thecorrelation between the well spacing density of straight well and of horizontal well; reasonablewell spacing density of the four districts was calculated. Meanwhile, the form of network ofhorizontal well was studied, and the view that the irregular placing of wells was suitable for gasreservoir of volcanic rock because of characteristics of its fractures.Characteristics of infiltrating fluid of horizontal wells in fracture-pore reservoirs wereanalyzed, and the deliverability model of infinite double media of reservoir was built up andcomputed. Then the unsteady state deliverability model of infinite double media of gas aboutstraight wells and about horizontal wells were derived based on the work above, and verifiedthrough computer program. Deliverability of fracturing horizontal well and non-fracturinghorizontal well were calculated with relationship between gas productivity index and ratio ofDeliverability replacement.Horizontal length of horizontal well was optimized with analogy ,theory, numericalsimulation and a new method, which taking into account of the matching of per well productionand controlled reserve ,and optimizing the horizontal length of horizontal well considering theinfluence of factors of flow resistance etc. to Deliverability. The sensible factors, includingdrawdown pressure, gas producing index and diameter size of horizontal part were analyzed, andthe quantitative variation relation between horizontal length and the factors, which offered a newmethod and theoretical supervision for the design of horizontal length.Reasonable distribution of production proration about Horizontal well in Kelameili gas fieldwas achieved with methods of gas productivity , minimal ultimate output and maximum ultimate output, taking the marginal liquid-carrying capacity as the minimal ultimate output andthe marginal impact erosion output as the maximum ultimate output. Take the value range ofhorizontal length into the formula of the new method optimizing the design for horizontallength of horizontal well, then the related variation range of output were obtained.