Study On Interlayer Interference Mechanism Of Water Injection Reservoirs

During the development of water-injection reservoirs with multiple oil layers,due to the inter-layer heterogeneity of the oil layers and the difference in viscosity of the oil layers in the oil layers,the use of oil layers varies greatly in different oil layers.Interlayer interference phenomenon,based on the above problems,this paper studies the inter-layer interference mechanism of water-injected reservoirs.The main research contents are as follows:(1)Using the sand-filled tube core parallel displacement model to carry out water flooding experiments.During the experiment,the difference of permeability grade was used as the variable to study the influence of the change of grade difference on the water flooding recovery of heterogeneous reservoirs.The analysis results show that with the increase of the permeability difference,the water flooding efficiency is lower,most of the injected water flows inefficiently along the high permeability,and the total recovery degree of the reservoir is not ideal;the different grades affect the interlayer of different permeability reservoirs.The degree of interference is different.The greater the difference of the level difference,the smaller the influence of the interlayer interference on the high permeability layer,followed by the medium permeability reservoir,while the utilization of the low permeability reservoir is the most affected;the permeability difference is increased to 4.At the above time,the injected water is basically unable to enter the low permeability reservoir.Comprehensive analysis of recovery loss and recovery degree shows that in order to avoid the influence of interlayer interference,the reservoir can be fully exploited and utilized to reduce the adverse effects caused by interlayer interference.Keep below 3.(2)For multi-layer heterogeneous reservoirs,the development of low-permeability crude oil is an important issue to be addressed if developed by means of combined mining.The start of crude oil mainly depends on the pressure difference between the injection and production wells,and the starting pressure difference of the crude oil is also called the starting pressure.This section studies the phenomenon of starting pressure during the multi-layer mining process.Permeability grade difference and viscosity are the most important factors affecting the starting pressure.The effects of these two factors on the starting pressure of low permeability layer crude oil were tested experimentally.Based on the results of indoor physical simulation experiments,a multi-layer and multi-permeability reservoir model was established.The model fully considers the effect of interlayer interference on oil production capacity of oil wells Finally,a new well productivity formula is obtained.Finally,the actual reservoir conditions are taken as examples to verify the validity of the formula(3)When multi-layer heterogeneous reservoirs are developed by means of multi-layer combined oil recovery,the pressure between the various strata within the reservoir will spontaneously reach equilibrium.This pressure balance is unfavorable The heterogeneity of each layer will cause a large gap between the liquid absorption capacity of each layer and various parameters in the water flooding process,thus reducing the oil production in the water flooding stage.This requires real-time monitoring of reservoir development status,timely evaluation of inter-layer interference during reservoir development,and correction of development strategies so that each layer of crude oil reserves can be balancedly developed.In order to reasonably solve the inter-layer conflicts in the development stage of heterogeneous reservoir water flooding,based on the pressure and water saturation changes in different small layers,a multi-factor map for evaluating the mining degree of each small-layer reserve is drawn The overall development should ensure that all small reservoirs within the reservoir can be used and there should not be a large gap.The water saturation change and pressure distribution of each small layer in the water flooding process have an important impact on the overall reservoir production.Therefore,the influence of these two factors on the reservoir exploitation should be analyzed.The oil recovery rate was selected as the evaluation index.Because the oil recovery rate can not only reflect the oil production capacity of the oil well,but also express the reserves of each small layer of the whole reservoir.At the same time,referring to the concept of inter-layer interference coefficient,the formula for calculating the interference coefficient of oil production speed is given.Finally,it is shown that this parameter can accurately measure the degree of equilibrium of the reserves of each layer,and provides a valuable reference for the re-division of the strata and the fine division of the strata in the subsequent development process.