Control technology for bottom water coning in horizontal well of offshore oilfield

The methods for controlling bottom water coning in horizontal well of offshore oilfield are presented.The technologies of selective plugging agent and selective injection as well as over-displacement to restrain bottom water from coning were applied in C4 Well.The formation conditions of Weizhou 11-4 Oilfield make it practical to employ cheap gel plugging agent with various gelling time and gelling strength.The selective injection was made according to the advantage of differences between formation permeability and phase permeability.The plugging agent preferably entered high-permeability formations,and water-based plugging agent preferably entered water-producing formations.The over-displacement method is to push plugging agent to oil-water interface by working fluids with the same viscosity as the plugging agent and provide good leaving recovery channels for oil.Field tests have proved that this technology has good results and validity.