Research On Damage Mechanism And Stimulation Technology Of Low-efficiency Gas Wells In Sandstone Reservoirs Of X Gas Field

Taking X gas field as the research target,this paper studies the damage mechanism and stimulation technology of low efficiency gas wells in this gas field.At present,the gas field has entered the production decline period,and the production task is severe.Many production wells in gas fields are facing problems of fluid accumulation,sand production and reservoir damage after constant pressure reduction.At present,several production wells have been shut down or are close to shutdown.These wells are characterized by low daily gas production,liquid accumulation at the bottom of wells,intermittent well opening and low productivity in the production process,which seriously affects the stable production of gas fields and urgently needs to improve natural gas production in gas fields.Yield.This article mainly carries on the following work:(1)Experiments on water sensitivity damage,water lock damage and particulate migration damage were carried out to study the types and degree of reservoir damage.(2)Establish the critical fluid carrying capacity model of gas wells to verify whether the bottom hole fluid accumulation is condensate water.A water lock injury model was established to study the factors affecting water lock injury.(3)According to the reservoir characteristics,reservoir damage types and operation environment,the technology of matrix acidification and surfactant combined plugging removal and stimulation is put forward.(4)A set of high-efficiency acidizing fluid system and a set of high-efficiency water-releasing blocking agent which can not over-dissolve the reservoir and effectively improve the reservoir and permeability are studied,and a set of composite plugging-releasing fluid system is formed.Laboratory experiments are carried out to evaluate the composite plugging-releasing fluid system.(5)The technological process of increasing production was studied.The single well scheme design and field construction are carried out for the target gas field.According to the research,the following conclusions are obtained:there are water lock damage,particle migration and water sensitivity damage in target gas field reservoir,and the degree of water sensitivity damage is strong.When reservoir breaks through water,the degree of particle migration is greater and the degree of water lock damage is stronger.At the same time,particle migration and water sensitivity damage will increase the degree of water lock damage,and water lock damage is the main damage;the bottom of wellbore is condensate water,which causes formation damage.Major water sources,the main factors affecting water lock damage are production pressure difference,capillary force,permeability,etc.Compound plugging removal fluid system can effectively relieve reservoir damage and improve production.Completed matching production increase technology and single well program,field construction effect is good,gas well production increased significantly.