Application of nitrogen foam in selective water plugging of offshore high water content oil field

Since foreign cooperative offshore oilfields pursue the quickest oil production rate for the purpose of profitability maximization, irrational extraction can hardly be avoided, and the W oilfield in Indonesia was extracted so. W oilfield is a sandstone edge-bottom aqueous lamellar oil reservoir with sufficient edge-bottom water. It was developed by virtue of natural energy. Its average water cut reached 70% after putting into operation for 2 years. There were totally 190 production wells, 33 of which were closed for water logging. Water cut of production wells was between 97%~99%, and some mature water control techniques were not used due to small platform space. To solve these problems, a set of selective water control techniques with nitrogen foam suitable for ultra-high water cut reservoirs after multiple technique optimization researches. This technique was implemented for 32 wells onsite and achieved a success rate of 78.1%. Besides, the operation success rate of application in reservoir wells with characteristics of positive rhythm was 88%, and oil of 116 513 m3 was increased accumulatively.