Design Configuration for Autonomous Inflow Control Valve Technology for Newly Drilled Well in a Mature Field in Malaysia – Model vs Reality

Abstract

Design of an ICD (Inflow Control Device) completion is initially determined based on the static and dynamic models prepared during pre-drilling stage of the well. However, actual well properties available post-drilled are quite different from the pre-drilled properties, and the completion must be optimized. The objective of this study is to address the challenges on pre- and post-completion designs which was conducted for a gas and water control application in redevelopment phase infill well in a mature field in Malaysia. All types of ICD completions are designed based on the static simulation for selected time steps of a dynamic simulation. The autonomous inflow control valve (AICV) is an advanced ICD that can also choke/close unwanted gas and water. The number of AICVs are determined based on the initial maximum oil production rate, despite permeability and gas/water saturation. Therefore, several sensitivities were conducted to determine optimum production rate with an AICV completion. The compartmentalization and distribution of AICVs mainly depended on the well constraints. Although, the required number of AICV are same for the post drill completion, packers and AICV joint placement were adjusted based on the drilling log data. Drilling logs indicated that permeabilities of the post-drilling were about 1/10 of the expected permeabilities of the model and high permeability zones were concentrated to localized zones compared to distributed high permeability in the model. Localized high permeable zones create challenging situations to place the required number of AICV joints in respective compartments due to length constraints. The completion design was re-optimized based on the new permeability profile and new constraints. Packers were placed in low permeability zones to maximize the effect of zonal isolation. Additional packers were installed to delay the gas transport to oil producing compartments in case of a gas breakthrough in neighboring compartment. The number of AICV joints utilized in the well was lower compared to the originally predicted number of joints due to shorter TD of the well. For the well, the number of AICV joints utilized was 38 out of 45 joints. The well started production with desired oil rate at 1500 BOPD with minimal gas and water production with productivity index (PI) 2x better than expected.