A Method for Determining Reasonable Producing Pressure Drop of Gas Wells Considering Water Control Factors

Abstract

Reasonable production of gas wells is the key to achieve efficient and sustainable development of gas reservoirs. Most of the developed gas reservoirs produced formation water. Water invasion leads to the decline of gas well productivity and gas reservoir recovery, the increase of production management and environmental protection risk, and the reduction of gas field development benefits. It is difficult to eliminate the negative impact of water invasion in the later stage of gas reservoir development. Therefore, in the early stage of gas reservoir development, it is necessary to consider the water control factors to determine the reasonable production rate of gas wells. Taking the Carboniferous gas reservoirs in eastern Sichuan Basin as an example, this paper analyses the water production performance, flow conditions of different types of formation water and their influences on the development of gas reservoir. A method is established to determine the reasonable producing pressure drop for controlling pore water invasion and edge-water invasion, which can guide the reasonable production proration of gas wells. Typical gas reservoirs show that the water invasion performance is not only related to the geological factors, but also to the production factors. When the producing pressure drop of gas wells meets the requirements of water invasion control, the recovery of gas reservoir can be increased by 10%–20%.KeywordsGas wellReasonable producing pressure dropWater invasion controlPore waterEdge waterCarboniferous gas reservoir in eastern Sichuan