Water Drive Gas Reservoir Dynamic Characteristics And Analysis Methods For Research

At present, most gas reservoirs are water-drive gas reservoirs of varying degrees in China's natural gas resources. In our country, water-drive gas reservoirs accounted for 65% in developed gas reservoirs. For water-drive gas reservoirs, water encroachment is not only a displacing force, but also a negative factor in reservoir development. Water encroachment will seriously affect the development and production of gas reservoirs, reducing the production of gas well and lower the recovery of gas reservoirs. Therefore, the researches of dynamic analysis method have important theoretical and practical significance for the reasonable and efficient development of water-drive gas reservoirs. This paper discusses the factors that affect the water encroachment of water-drive gas reservoirs based on the percolation mechanism and water blocked mechanism. Combining the theory with case analysis, the advantagges and disadvantages and the applicability conditions of each traditional early identification method of water encroachment are studied. Two models of using the non-stabilized well test material for the early identification of water encroachment are focused on. It provides more effective options for the early identification of water encroachment of water-drive gas reservoirs. The water encroachment dynamic performance is analyzed on the basis of the identification of water encroachment. The aquifer energy and the water influx which are two important parameters of the water encroachment dynamic performance are studied. Especially, the improved aquifer influence function model is established. The linprog function in Matlab software can be used to solve the improved aquifer influence function easily. At last, the parameters which reflect the aquifer behavior and the water encroachment dynamic performance of water-drive gas reservoirs can be determined. Considering the influence of water encroachment on gas reservoirs, the dynamic reserves of water-drive gas reservoirs is evaluated according to the water encroachment dynamic performance. The application conditions of a variety of methods for dynamic reserves evaluation and the accuracy of evaluation results are analyzed. At the same time, the theory and method of using the water-drive curve of water-drive gas reservoirs to evaluate the dynamic reserves are consummated. It enriches the method for the dynamic reserves evaluation of water-drive gas reservoirs. Finally, the reasons and the critical conditions of closed in production of flooded gas well and the critical conditions of revivification of flooded gas well are discussed. The unloading and revivification technology of flooded gas well is evaluated and optimized after summing up the characteristics and applicability of correlated technologies. It can make the revivification of flooded gas well and the development of water-drive gas reservoirs better.The research work in this paper enrich the research content of gas reservoir engineering method of water-drive gas reservoirs. It has a positive significance for the reasonable and efficient development of water-drive gas reservoirs.