Optimization of supercharged gathering scheme for YQ2 Wellblock by multi-level fuzzy evaluation

Abstract

With the continuous development of YQ2 Wellblock, it is estimated that there will be about 65.42% of gas wells whose wellhead pressure cannot reach the required inlet pressure within two years, and then, the wellblock cannot be maintained at stable production. Thus, it is urgent to conduct the research on optimization of supercharged gathering scheme. Herein, 5 supercharged gathering schemes were developed based on the different locations and quantity of supercharging equipment, which were determined according to the Benedict-Webb-Rubin-Starling(BWRS) Equation and the Fourth Order Runge-Kutta Method, through the analysis on change laws of oil/casing pressure in 309 wells and the prediction of supercharging time. Then, comparison was made among the 5 supercharged gathering schemes through fuzzy evaluation using the two primary evaluation indicators of technical economy and safety, refining the seven secondary evaluation indicators, such as the wellhead abandonment pressure, pressure loss of pipeline network and total investment,and determining their weights with the Analytic Hierarchy Process(AHP) method. Finally, it was determined to adopt the scheme of centralized supercharging at the terminal station + regional supercharging at 12 stations. In general, the research results are of great significance to the efficient development of gas field, cost reducing and benefit increasing, effective reduction of wellhead abandonment pressure, and the maximization of effectiveness of supercharging equipment for stable production.

Keywords

• abandonment pressure
• supercharging time
• supercharging scheme
• analytic hierarchy process(ahp)
• fuzzy evaluation