Study On Perforation And Layer Selection Method Of Infill Adjustment Well In Block X

After years of water injection development,X block has entered the stage of ultra-high water cut development.While maintaining stable crude oil production,the liquid production and comprehensive water content are increasing year by year,and the development effect is getting worse year by year.In order to improve the effect of water flooding development and enhance oil recovery in X block,after the reservoir conditions,residual potential,well pattern deployment and other factors are determined,the selection of single well perforation horizon is very important for the production effect of new wells.However,the existing perforation schemes are mostly based on field experience,lacking theoretical guidance combined with field practice.Therefore,it is necessary to study the single well perforation layer selection method for infill adjustment wells in the block.In this paper,through the reservoir geological conditions and development conditions,combined with the dynamic and static data of oil and water wells in the field,taking the existing production well network in X block as the research object,the perforation layer selection method of infill adjustment new wells is studied.The main work and conclusions are as follows:(1)The reservoir profile and development status of X block were investigated.The block profile includes reservoir physical properties,fluid properties and block dynamic and static data.The development history includes well pattern evolution and development status,and the production dynamic curves of each well pattern are drawn.Through investigation,it is found that the porosity and permeability and oil saturation of the block are low,and the remaining oil distribution is scattered,and it is difficult to identify and tap the potential.There are 346 oil and water wells in the four well patterns of the block,and 104 layers are drilled.The recovery degree is high,and the comprehensive water content is above 94%.(2)According to the divided injection-production relationship,5750 injection-production units are obtained,and the water injection volume of the water injection well is divided.The Buckley-Leverett non-piston water flooding theory is used to establish a multi-layer commingled production development index prediction method.The injection-production unit is divided into several flow,and the water flooding dynamic simulation of each flow tube is carried out.After history matching,the layered dynamic index of each small layer is obtained.The results show that the average fitting error of the initial oil production of 106 infill wells in the block is 0.03m~3/d,and the prediction method of multi-layer commingled production development index is suitable for X block.(3)Using the gray correlation method,combined with the dynamic index and dynamic and static data of each layer,the influencing factors are analyzed,and the main controlling factors affecting the perforation selection of single well are determined.Physical parameters include formation coefficient,thickness of small layer sandstone,effective thickness of small layer,porosity of small layer and permeability of small layer.Oil-bearing parameters include reserves abundance of small layer,water saturation of production and water content before production.Injection-production parameters include influence coefficient of sedimentary facies,thickness of connected sandstone,injection-production well spacing and number of connected directions.The main control factors combined with the multi-level comprehensive fuzzy evaluation principle to study the comprehensive decision-making method of perforation layer selection optimization.This method is used to calculate the perforation suitability of each small layer of 106 infill wells in X block,which is used to evaluate the perforation potential of small layers and screen out the optimized perforation combination.(4)The optimized perforation combination is used to predict the production of 106 infill adjustment wells in X block.Compared with the measured data,the average initial oil production of single well is increased by 0.61m~3/d,which verifies the applicability of the comprehensive decision-making method of perforation layer selection optimization in X block.The optimization method of single well perforation layer in X block is applied to three infill adjustment wells of the same type in adjacent blocks.Compared with the wells with perforation scheme formulated by field experience,the average initial oil production of single well is increased by 0.45m~3/d,indicating that this method is suitable for perforation and layer selection of infill adjustment wells in similar ultra-high water cut blocks.In summary,through the study of single well perforation layer selection method in X block,a comprehensive decision-making method for perforation layer selection optimization of infill adjustment wells is formed,which can improve the water flooding development effect and enhanced oil recovery of ultra-high water cut development blocks,and provide scientific basis for perforation layer selection.