During the last decade, inflow control device (ICD) technology has rapidly developed and widely been used in horizontal wells due to its effectiveness in flux equalization and mitigation of unwanted fluid breakthrough. An ICD completion achieves flux equalization and manages water breakthrough by introducing an extra pressure drop in the ICD and redistributing the drawdown across the sandface between high and low permeable intervals of a horizontal well. This additional pressure loss in the ICD completion will cause reduction of effective productivity of the well, in other words it will require lower flowing bottom-hole pressure for a well with ICD completion to produce the same liquid rate compared to a well with a barefoot completion. The higher the pressure drop across the ICD completion, the better will be the equalization effect and water mitigation. Subsequently, the reservoir pressure has to be used wisely during field development as expensive pressure maintenance programs are utilized in many fields as part of the field development plans.
This study tries to answer an important question: What should the optimum pressure regulation in an ICD completion be to realize the benefits of ICD without excessive reduction of well productivity? The effect of ICD regulation on flux equalization and well productivity reduction for various cases of well productivity index (PI) and permeability variation were studied through numerous static near wellbore simulation runs. Dynamic reservoir simulation was conducted to verify the results from the static simulation and dependence of the degree of flux equalization along the horizontal section on water breakthrough deferment and the oil recovery factor.
An ICD design workflow is presented, which can be used to select an optimum ICD design, which maximizes the benefits of ICD with the least reduction in well productivity. A trade-off chart between well productivity and the degree of influx equalization has been built, which helps to determine the optimum pressure drop across an ICD completion in the presence of various levels of permeability variation along the wellbore. This approach can provide quick and simple calculation for the required ICD strength or number of ICD joints along the wellbore to maximize recovery of hydrocarbons. A real field case is used to illustrate the effectiveness of this workflow for optimum ICD design.