Numerical simulation of productivity characteristics of fractured horizontal wells in tight water-rich condensate gas reservoirs
JI7 block of Tuha gas field is a deep tight sandstone water-rich condensate gas reservoir characterized by extremely low porosity and permeability,high pore water saturation,and high condensate oil content in fluid.In this paper,the distribution characteristics and strong stress sensitivity of fracturing-induced fractures and natural fractures in the reservoir stimulation area were considered,and a numerical simulation model for component fluid of dual porosity and dual permeability multi-stage fracturing horizontal wells was established,achieving historical fitting and productivity prediction of the flow back production stage after early-stage fracturing.Simulation analysis shows that in the early stage of gas well production,oil and gas production is high during the overpressure flow back stage,mainly supplied by fractures of the stimulation area.Due to the strong stress sensitivity of fractures,the rapid decrease in fracture pressure leads to a decrease in permeability and a rapid decrease in oil and gas production capacity.As production progresses,the matrix within the stimulation area gradually flows towards the fracture channeling for fluid supply,and the production capacity of the gas well tends to stabilize.However,the oil and gas in the matrix outside the stimulation area are difficult to be effectively recovered due to low permeability.After a short period of development,there are condensate oil precipitating in the formation of condensate gas reservoir,but the precipitation mainly occurs in fractures of the stimulation area,and the retrograde condensation damage caused to seepage is relatively low.Water-rich condensate gas reservoirs convert part of the elastic expansion energy of flowing water into oil and gas production.Under the same formation pressure,the degree of oil and gas depletion recovery of water-rich condensate gas reservoirs is higher than that of bound water gas reservoirs,but the flow of oil and gas is more difficult,which is not conducive to the development of condensate gas reservoirs.The research results and understandings have important guiding significance for the development of similar tight water-rich condensate gas reservoirs.
tight gas reservoirwater-rich gas reservoirnumerical simulationfracturing horizontal well
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