| The DH gas field has proven natural gas geological reserves of 1066.53×108m3.The target of this study is its main layer H1.The proven geological reserves of the H1 layer are 491.6×108m3,accounting for 46.1%of the total reserves.Compared with the general sandstone gas reservoirs,the gas reservoir has its special characteristics.It belongs to the boundary water gas reservoir with deep burial depth(below 3500m),thick reservoir layer(more than 100m)and vertical heterogeneity,and the boundary water is relatively developed.The water-energy mechanism of the water body is unknown,and the mechanism of water flooding with thick rhythm differences is unclear.At present,the seepage theory developed by similar gas reservoirs has not yet been formed,and the development technology policy is difficult to determine.Based on the reservoir rhythm characteristics under high temperature and high-pressure conditions,a large-scale high temperature and high-pressure thick layer water intrusion profile displacement model and experimental method were established.The water intrusion process of gas reservoir profile was simulated by a physical experiment,and visual monitoring method was used.Real-time monitoring of water intrusion profiles is achieved.In addition,combined with numerical simulation technology,the effects of six factors,such as aquifer size,formation dip,production rate,reservoir opening degree,water-soluble gas,and stress sensitivity,on gas reservoir development are analyzed for the more complex reservoir characteristics.This will provide further technical guidance for the rational development of gas reservoirs.The main research results obtained in this paper are as follows:1.A method for making a thick layer of real rhythm artificial sand-filling model is established.The method mainly includes how to convert the actual reservoir profile into an experimental section,how to select the type of sand-filled particles and how to compact the compaction.2.Established a physical experimental method for the water intrusion profile under high temperature and high pressure.The method mainly includes how to establish the boundary water system,the water saturation detection system and the reservoir opening degree control system.3.Using numerical simulation software to simulate and analyze the impact of six factors on gas reservoir development.(1)The larger the energy of the boundary water size,the longer the stable production period,but the faster the aquifer invades along the high permeability layer,the earlier the water sees in the wellbore,and the lower the ultimate recovery rate.(2)The greater the dip angle of the formation,the later the water seepage time of the wellbore,the longer the non-exhaustive gas production period,the higher the recovery rate,for every 5 degrees of elevation of the formation,the recovery factor is increased by 2.9%.(3)If the production exceeds the assembly,the water seepage time of the wellbore will be greatly advanced,and the recovery factor will also decrease.The unobstructed flow rate of 1/15-1/10 is a reasonable allocation.(4)The degree of openness of the reservoir is too low,the production capacity of the gas well is insufficient,the degree of opening is too high,and the high permeability layer sees water quickly.When the reservoir opening degree is between 2/4 and 3/4,it can ensure reasonable production capacity and can delay the flooding time of the gas well to achieve the highest recovery factor.(5)The water-soluble gas has an obvious influence on the geological reserves of the gas reservoir.The larger the aquifer size is,the higher the water-soluble gas reserves are.The release of water-soluble gas will increase the recovery rate of the gas reservoir.(6)After considering the stress sensitivity,the stable production time of the gas well is reduced,the time of seeing the wellbore becomes longer,and the ultimate recovery factor is decreased by 4.51%. |
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