Research On Reservoir Geological Characteristics And Damage Mechanism Of LS Group In HD1-1 Gas Field

HD1-1 gas field started producting in 1996 and there are a huge amount of natural gas,.At present,the remaining reserves are considerable.The main reservoir LS group of the gas field belongs to the high temperature and low pressure system,which has the characteristics of small scale,poor physical property,mud weight,fracture development,thin reservoir,and poor connectivity.After 20 years of development,the formation pressure continued to decline in the gas field,the production rate of single well also decreased,the whole production of liquid and water-gas ratio rised and gas flooding and so on.This paper mainly aims at the early situation,take the HD1-1 gas field in LS group as the research object,systematic analysis of the geological characteristics of the reservoir,combined with static and dynamic data in drilling in the process of production,make sure the damage types and mechanism of low permeability and low permeability reservoir and put forward the protection suggestions and measures of high differential pressure reservoir,and provide the basis for inefficient wells to increase production efficiency,which is very important to the production of gas field.The low pressure and low permeatability reservoir of HD1-1 gas field has many geological characristics such as week velocity sensitivity,moderately strong water-sensitivity,critical salinity is 22800mg/L and medium acid sensitivity.Combined with the existing gas well operation history,there are different degrees of sensitivity damage in the process of drilling and completion,so considering the factors of water sensitivity damage,so it is necessary to have anti swelling measures to reduce the reservoir damage.The LS2 gas field has many faults and the gas production time is so long that the formation pressure failure is serious which makes the drilling and completion fluid invasion into gas reservoir under high positive pressure difference and cause water lock and solid plugging damage.So in the later development of well design,we should add special crack protective agent to drilling fluid system,protect the seepage capacity of crack in the gas reservoir.lt is of great significance to improve the productivity of single well in gas wells and develop low permeability and low pressure reservoirs.