Feasibility Study and Selection Process for ICD Applications in an Offshore Niger Delta Field

Abstract

Abstract Horizontal wells increase the reservoir-wellbore contact area, allowing the wells to produce at higher flow rates with smaller drawdowns which is especially important in oil reservoirs with a large gas cap or aquifer. Long wellbore lengths can lead to production challenges such as water or gas coning and cusping, an unwanted fluid breakthrough from high-permeability zones, and uneven inflow along the wellbore and nonuniform reservoir sweep. Inflow control devices (ICDs), based on well-established technology, have been used in hundreds of wells worldwide. Different ICD types and design methods are available and can be applied to mitigate some of the production challenges. The ICDs are installed as an integral part of the sand screens in the well completion hardware. They can be passive, where the ICD size and configuration does not change after it is run in the hole, or autonomous, where the ICD adapts to changes in downhole fluid-flow properties. However, the decision regarding the use of ICDs as well as the design criteria and selection has to be made prior to the well completion operation. This paper presents a feasibility study on an ICD application in an offshore Nigeria delta oil field with multiple hydrocarbon-bearing reservoirs. Most of the development wells in the field have horizontal openhole 1,000 to 3,000 ft drain sections completed with standalone screens. Strong aquifer and reservoir heterogeneity create production challenges associated with early water breakthrough and suboptimal reservoir sweep. This paper presents a detailed approach to ICD design, sensitivity analysis, and completion optimization, which is based on the coupling of a 3D reservoir model, segmented wellbore model, and ICD models. The proposed ICD completion design is evaluated and sensitized to subsurface reservoir uncertainties using volumetrics. The final decision process is presented to guide the selection and feasibility of an ICD application for two reservoirs.