Study On Water Shut-off Technology Applied In Fractured Carbonate Reservoir Of Жанажол Oil Field

Since the main reason of the production decline in fractured carbonate reservoir is the water production caused by fractures, the water production must be controlled in the oil well to improve its recovery.Жанажолoilfield is a complicated fractured carbonate reservoir with serious water production and bad mechanical water shut-off effects. Due to the geological characteristics and water production mechanisms, the study on chemical water shut-off technology is of great importance to this oilfield. According to the analysis of its geologic characteristics and water production mechanisms, chemical water shut off method fitting this field was proposed, that is using precipitation type water shut-off agent for double-fluids method to form a barrier to plug bottom water and injecting YG103 gel type water shut off agent to plug injection water or edge water. Based on the study of operating fluids plugging bottom water, and injection water or edge water, the optimum fluids formation adapted in this field were obtained, i.e. operating fluids formulation for bottom water barrier is 15% CaCl2 plus 25% Na2O·mSiO2, and formulation for injection water or edge water is 0.5% YG100 plus 1.5% YG103. The fracture visual simulation experiments displayed the bottom water, edge water and injection water plugging process, and the recovery increments calculated by graph analysis system further proves the sound effects obtained by these water shut off methods and the selected plugging agents. Both single fracture and parallel fractures flow experiments indicates that YG103 gel agent has better injectivity, sealing property and resistance to washing, and can preferentially plug wide fractures, for which it fits to the plug of the injection water or edge water.