Research On Well Pattern Reconstruction Plan For M Reservoir

M reservoir is an extra-low permeability reservoir,because of poor reservoir property,production fell down rapidly relying on natural depletion.M reservoir start water flooding from March 2002,the liquid production and oil production increased in the early time,while effect become worse after many years,and recovery factor is less than 10%.M reservoir is developed with rectangular well pattern,there are 6 production wells and 3 injection wells.Based on the control degree of water driving is low and well pattern is imperfect,M reservoir pattern reconstruction is put forward.This paper mainly summarizes the structure of the reservoir characteristics,sedimentary characteristics,reservoir characteristics,oil reservoir characteristics,fluid properties and temperature-pressure system of M reservoir,and water flooding development effect has been analysed,which include:(1)recovery factor is forecasted through empirical formula method,water drive characteristic curve method,analogy method and Tong's engraving method;(2)regularity of production decline has been studied by Arps decline method and grey theory GM(1,1)model;(3)Moisture content,water cut rising rate,net injection percent,as well as water consumption rate are calculated.As water flooding effect has been evaluated,remaining oil distribution is studied by numerical simulation.And remaining oil distribution results are gotten through successful history matching.The results shows that residual oil is mainly concentrated in the B32 and B41 two major reservoir,these two layers are in low recovery degree,so the remaining oil potential is very large.The influence factors of remaining oil distribution also have been analysed,and sedimentary microfacies,reservoir heterogeneity,fault and well pattern perfection are thought to be the main influence factors.Based on above research,the reasonable injection-production parameters and well pattern have been studied.So the reasonable flowing bottomhole pressure,wellhead pressure of injection,injection-production ratio,ratio of production wells to injection wells,production of a single well,oil recovery rate and well spacing are confirmed.Then well pattern,well spacing,liquid production and injection-production ratio are optimized by orthogonal test,and well network reconfiguration scheme is made based on original well pattern.The scheme is now being implemented,it is significative to development M reservoir and improve recovery.