Research On The Characteristics And Development Of Fluid Interface Migration In Top Gas Edge Water Narrow Oil Ring Reservoirs

The top gas edge water narrow oil ring reservoir is a unconventional reservoir.There are three areas in the reservoir: top gas,oil ring,and edge water.The three regions maintain a relatively balanced state under stratigraphic conditions,but this balance is broken during reservoir development.The interaction of the three types of energy leads to the mutual channeling of oil,gas,and water,which seriously affects the reservoir development effect.JZ25-1S oilfield is a typical top gas edge water narrow oil ring reservoir.This paper establishes a three-dimensional physical model based on actual oilfield parameters,conducts depletion development simulation experiments,and studies the interfacial migration characteristics and remaining oil distribution rules of top gas edge water narrow oil ring reservoirs.Determine the optimal development method in the later stage of development through three-dimensional physical simulation experiments with different development methods.Finally,based on the geological parameters of JZ25-1S oilfield,an ideal geological model is established.Determine reasonable production parameters for the optimal development method through numerical simulation.The research results show that:During depletion development of top gas edge water narrow oil ring reservoirs,gas channeling takes precedence over water invasion,and the higher the permeability,the earlier the occurrence of gas channeling and water invasion.The occurrence of gas channeling and water invasion will seriously affect oil production,but the overall production situation is still that the higher the permeability,the higher the recovery degree.The migration of oil gas interface is faster than that of oil water interface,and the higher the permeability,the faster the gas and water break through the oil ring.On the plane,the oil gas and oil water interface presents a conical shape,with rapid movement in the middle and gradually expanding towards both ends.In the longitudinal direction,gas tends to protrude from the top of the structure towards the oil ring,while edge water tends to protrude from the bottom of the structure towards the oil ring.After depletion development of a top gas edge water narrow oil ring reservoirs,the remaining oil is mainly distributed on both sides of the gas channeling and water invasion channels.Most of the low permeability layers are free residual oil,while the high permeability layers are mainly bound residual oil.After depletion development,the direction for tapping the remaining oil should be both sides of the gas channeling and water invasion channels in low permeability layers.For the development of top gas edge water narrow oil ring reservoirs.The top gas injection method can be used to supplement the formation energy and expand the atmospheric displacement volume in the low permeability layer.Barrier water injection can be used to inhibit gas channeling and water invasion in medium and high permeability reservoirs to prolong stable production time.If the top gas energy is much greater than the edge water energy,gas production can be conducted first and then barrier water injection can be conducted.Simulate experimental results based on different development methods.Comprehensive consideration of water content,gas oil ratio,and oil recovery.Finally,the barrier water injection development method is selected as the best development method for JZ25-1S oilfield.Using reservoir numerical simulation methods,the reasonable barrier water injection timing is finally determined to be two years after depletion development.The reasonable oil recovery rate in the depleted development stage is4%.The reasonable oil recovery rate in the barrier water injection stage is 3%.The reasonable injection production ratio is 1.5.This article studies the characteristics of fluid interface migration and development methods in top gas edge water narrow oil ring reservoirs,providing necessary theoretical support for the development of such reservoirs and having important guiding significance for oilfield sites.