The Feasibility Study On Air Injection After Water Flooding In Low Permeability Oil Reservoirs Of Shen-150Block

Shen-150block is a typical low permeability light oil reservoir with long productioninterval of well, the reservoir permeability is low and its physical properties are poor. Oil wellwater flooded phenomenon is serious under the condition of long-term water injection withhigh pressure, reserve utilization imbalance on vertical and plane of reservoir, remaining oildistribution is complex and difficult to dig. At present the block comprehensive water cutreach to69.2%, recovery degree is only3.33%, the contradiction in developmentis protruding. Craft measures implemented in the block such as fracturing, water pluggingand so on were not achieved significant effect, and water injection is still very difficult.Therefore, high pressure air injection feasibility study after water flooding exploitation hasbeen done in this block.According to the geologic features of the blocks and the logging parameters interpretationresult, we build up the3d geological model. On the basis of geological model, the numericalmode which can fit the data of oil well production history has been set up. It can study thedistribution and genetic types of residual oil, and influencing factors. By using thin pipe airinjection low-temperature oxidation experiment and combustion air injection of hightemperature oxidation experimental research, we make sure the component and content of thegas, oxygen consumption and the safety of the process when the crude oil through the lowtemperature oxidation air flooding. The high temperature oxidation properties of crude oiland the consumption of the air in the experimental zone have also been determined. Finally,make adaptability evaluation of air injection development of Shen-150block.Set up the air displacement numerical model. Then select reasonable gas injector groupand optimizes the injection volume, gas-water injection alternating cycle and water-gas ratio.Based on the optimization results, predict the gas driving production index of the whole block.Both the production index and economic evaluation results show that the block is fit for airdriving.The research results show that air injection in Shen-150block is much better than that ofwater flooding development, and it can provide reference for other low permeability light oilreservoir development.