Maximizing Reserves Value Using Multilateral Wells - A Decision Support Tool and Key Applications

Abstract

As global energy market conditions demand more reliable energy sources, fields with lower productivity reservoirs struggle to provide cost-effective production options. Multilateral technology (MLT) has been used to improve per-well deliverability and economics, i.e., by increasing the drainage area with less surface footprint. The objective of this work is to review the state-of-the-art of selected completions to provide insights for adoption of MLT technologies including lessons learnt, experiences and some recommendations. Six globally selected demonstrative applications were reviewed to validate the technical assumptions for selecting a particular MLT concept. The first step was to review earlier applications in similar formations to identify the degree of success of these wells and to research possible better candidate reservoirs. Secondly, a screening tool analyzes specific reservoir production conditions where the application of MLT would be compelling. The research was focused on reservoirs with noticeable high-economic potential interest in the application of such technologies. We propose a workflow combining both technical and economic criteria to guide the selection of MLT vs single lateral wells, providing a cost-effective and lower risk decision support tool. We introduced a process to identify the MLT applicability window based on the Activation Index (AI) and the mother to Lateral cost ratio. Our proposed method is likely to be beneficial for operators which struggle to make smart decisions on MLT well concept selection. We show that MLT completions can reduce between 10 and 30% the D&C cost requirements while enhancing field development NPV in the range of 1-21%, and with the potential of promoting fields that were otherwise uneconomic. We discuss here the success factors to make this possible. In addition, one key advantage of MLT is the acceleration of production since multiple zones are available for production much earlier compared to the single zone wells. Furthermore, the implementation of MLT completions is enabling the recovery of reserves on fields where the surface space is constrained due to either a high number of wells or a geographic limitation or even a combination of both.