In recent years, large amounts of CO₂ emissions have led to many environmental problems. Developing a reasonable approach to carbon dioxide emissions is one of the most important issues for the sustainable development of human civilization. Compared with CO₂ geological storage, CO₂ flooding has greater advantages and a higher utilization efficiency. CO₂ flooding technology has been successfully applied to many types of reservoirs, such as conventional sandstone reservoirs, low-permeability reservoirs, and carbonates. In this paper, the feasibility of CO₂ flooding in glutenite reservoirs is studied. First, the glutenite reservoir is divided into fine stages, and reasonable vertical development units are determined. On this basis, the distribution scale, genetic environment and formation mode of the glutenite reservoir are characterized in detail and their spatial distribution rules are depicted in three dimensions. Then, the influencing factors of CO₂ flooding in the glutenite reservoir are analysed via reservoir numerical simulation technology. The effects of reservoir thickness, reservoir heterogeneity, macropores, dominant channels and fracturing on CO₂ flooding efficiency are evaluated individually, and a set of reasonable parameters constituting an evaluation system for CO₂ flooding in the glutenite reservoir is established. Finally, based on parameter optimization, the disadvantaged conditions of CO₂ flooding in glutenite reservoirs are optimized, and their effects are gradually eliminated. In view of the characteristics of glutenite reservoirs, a unique three-dimensional well pattern arrangement is designed, different injection modes are optimized, and suitable injection agents are tested. These methods are conducive to improving the effect of reservoir parameters on CO₂ flooding efficiency, allowing these reservoirs to be used for CO₂ flooding. Based on these new methods, the displacement effect of the Yanjia-Yongan glutenite reservoir is predicted. Our results show that the reservoir has been developed efficiently and achieved a high recovery rate, the displacement front of the CO₂ has become more uniform, and the sweep range has become wider. After extending the successful application of CO₂ flooding in this reservoir to all of the glutenite reservoirs in the entirety of the Bohaiwan Basin, we predict that the oil recovery rate may reach 40%, with a cumulative oil recovery rate of approximately 3.04 × 10⁸ t and a total CO₂ consumption of 1.672 × 10⁸ t. Thus, the proposed approach not only can improve the atmospheric environment but can also greatly improve the efficiency of oil displacement.

A large number of underground gas storage operating experience shows: the oil rim has a great impact on gas injection and production. Here, the underground gas storage in the Dagang Oilfield (G393) was taken as an example to study the oil rim impact mechanism. Firstly, the G393 gas reservoir developmental history was simulated, based thereon, the equations governing the distribution of gas, oil, and water in the reservoir before building the storage injection and production equipment was established. Then, the oil rim impact mechanism on the gas seepage of underground gas storage operation was studied using numerical simulation method and the factors affecting oil recovery from the oil rim for the gas diffusion were outlined. The result shows that oil rim may prevent seepage of gas, resulting in a one-way gas onrush, thus affecting the smooth operation of underground gas storage. In addition, crude oil recovery in the oil rim may affect the gas well’s production capacity, the lower the degree of recovery of crude oil, the harder for the underground gas storage to run quickly and smoothly. Finally, the most appropriate injection wells for the G393 fault-block gas storage were designed, by which process the oil production period was shortened to 8 years, ensuring stable and efficient operation of the underground gas storage.

A gas–water two-phase fluid is present in a reservoir before a water-flooded sandstone gas reservoir is rebuilt. Therefore, in the process of injection and production of the rebuilt underground gas storage, the injected gas is easily blocked by the water in the pores, and the efficiency is low, resulting in a significant loss of gas. The study completely utilizes the geological data and dynamic operation monitoring data of a water-flooded sandstone underground gas storage and clarifies the rule of the gas–water three-phase seepage in a high-intensity injection–production process. Moreover, the main control factors of the low efficiency of this type of underground gas storage are clarified. The lost gas generated in the injection–production process is described from two aspects: microcosmic experiment and macroscopic law analysis. The type, mechanism, and occurrence state of the loss gas are clearly defined, its main type is “water trapped gas”, it formed when the gas rushing into the water area under high pressure and surrounded by water, and its occurrence of this kind of lost gas is mainly sporadic or continuous free gas. A gas–water two-phase mathematical model that can simulate the high-intensity injection–production process is set up according to the experimental result, this model is used to simulate the operation process of the Ban 876 underground gas storage. Based on the simulation results, the gas–water macroscopic movement rule and macroscopic accumulation mode of the lost gas are defined, and then the collection area of the lost gas is predicted and quantitatively described. The calculation results show that the lost gas in one cycle is about 775 × 10⁴ m³, which are mainly concentrated in the inner of the gas-water transition zone. According to the numerical simulation result, six new wells have been designed to develop its internal lost gas, they all have good predictions, can increase the working gas volume of 3000 × 10⁴ m³ and reduce the single cycle lost gas by 50%, which is only 326 × 10⁴ m³. This provides guidance for the expansion and exploitation of the same type of water-flooded sandstone underground gas storage.

Sulige gas field has poor reservoir physical properties and strong heterogeneity. The existing development well pattern is difficult to realize the overall effective production of reserves, especially in block SuX. Therefore, this paper takes SuX block in the east of Sulige as an example to describe an effective method suitable for the development of well pattern in this area. Combined with logging and production data, the connectivity of gas wells in X infill area in the east of Sulige is determined from the aspects of pressure, sand body, logging, performance and well test. By using the method of dynamic and static analysis, the connectivity between wells of main gas reservoir is judged. Through the analysis of flow unit, the discharge area and the stable value of well-controlled reserves are determined. The degree of interference determined by curve fitting and the distribution characteristics of sand bodies are comprehensively analyzed. A new oil well interference degree model defined by mathematical expression of production is established. The interference degree is quantified by gas production through numerical simulation. Based on the comprehensive analysis of the connectivity, interference degree and other factors in the area, it is determined that 500 * 600 well pattern is a reasonable well pattern in SuX block, and the interference degree is about 20%. Based on the analysis of the connectivity between wells and the interference degree between production wells in SuX block, the distribution and connectivity of sand bodies in tight sandstone gas field under complex geological conditions are determined. It provides a reasonable basis for the network encryption development of tight sandstone gas in this block. It provides a powerful technical support for the efficient development of different tight gas reservoirs in Sulige area.