Research and application effect analysis on water-drive characteristic curve for water-drive gas reservoir.

Water/gas-yielding rules in the water-drive gas reservoir become complicated after water breakthrough, which results in the increasing difficulty of the water-drive gas reservoir development. At present, there is no mature and effective dynamic analysis method in developing the water-drive gas reservoir. Based on the gas-water two-phase flow law and the material balance equation, the water-drive characteristic curve of water-drive gas reservoir was developed in this paper, in which the cumulative gas production is in logarithmic relation with gas-water ratio, and in linear relation on semi-logarithmic coordinates. And the dynamic control reserve of gas well after water breakthrough can be inversely calculated by the slope of the line. By the application on a certain gas field, the research results were proved to be able to effectively predict the gas wells development performance and the dynamic control reserve variation during development. And it is of great significance to the development of water-drive gas reservoir.