Decision Support Tool Shows Multilaterals Can Maximize Reserves Value
Authors: Carpenter Chris 
Published: June 2023

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This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 211570, “Maximizing Reserves Value Using Multilateral Wells: A Decision Support Tool and Key Applications,” by Eglier Yanez, SPE, Luigi Saputelli, SPE, and Fahad Alhosani, SPE, ADNOC. The paper has not been peer reviewed.

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In the complete paper, the authors review advances in selected completions to provide insight into adoption of multilateral technology (MLT), including lessons learned and recommendations. Six demonstrative applications were reviewed to validate technical assumptions for selecting particular MLT concepts. The authors write that MLT completions can reduce between 10 and 30% of drilling and completion (D&C) cost requirements while enhancing field-development net present value (NPV) in the range of 1–21%, with the potential of promoting fields that were otherwise uneconomic. This synopsis is devoted to the authors’ proposed technoeconomic assessment of MLT.

Part 1: Economic Assessment of Dual and Trilateral Wells

A simplified performance assessment was conducted to determine the economic effect of adding multilateral wells into a particular development plan. In this case, the following four well configurations or well types were considered:

- Two single-lateral horizontal wells

- One dual-lateral well with independent access to each lateral

- Three single-lateral horizontal wells

- One trilateral well completed with single controlled, commingled completion

This analysis aims to produce insights from the following two comparison cases:

- Comparison 1: Two single horizontal wells vs. one dual-lateral well

- Comparison 2: Three single horizontal wells vs. one trilateral well

The well design assumed for the cases can be found in the appendix of the complete paper. The production and reserves drained are maintained the same for each of the laterals; thus, those are considered controlled variables.

To understand the effect of adding laterals to a motherbore, three cases have been selected for each of the previously mentioned well configurations by varying drilling depths for each typical cost environment to specify the areas with more potential for multilateral application and, conversely, the areas where single wells might appear to be more convenient. The analysis is broken down into onshore and offshore-shallow-water environments, where the main difference is the drilling cost per foot. The three cases are as follows:

- Short-footage well: Motherbore depth of 5,000 ft and lateral length of 4,000 ft

- Medium-footage well: Motherbore depth of 7,000 ft and lateral length of 8,000 ft

- Long-footage well: Motherbore depth of 9,000 ft and lateral length of 12,000 ft

The well costs considered for the study can be seen in Tables B-1 and B-2 of the appendix. In this simplified example, the capital costs included are limited to well-construction costs.

Every lateral has a post-stimulation initial rate of 800 STB/D, which is expected to accumulate approximately 1.5 million STB on a 20-year horizon (Fig. 1). One should assume that, in this case, the equivalent rate of the dual-lateral well is exactly double of the one horizontal well and that of a three-lateral well is triple of one horizontal well.