Drilling costs in the petroleum industry have continued to escalate over the past decade. This trend has increased operators' attempts to access the largest possible hydrocarbon resources with the lowest achievable costs in order to meet expected investment returns. To accomplish this, multiple well objectives are set prior to the start of drilling operations. Then, in many cases, a geosteering approach is implemented to help operators achieve these objectives. While the geosteering approach has a number of clear strengths and benefits, the efficiency of the current approach of using geosteering to optimize multiple well objectives is still questionable.

A comprehensive review of geosteering case histories discussed in SPE papers has been performed. Many of the field cases discussed in these papers include multiple well objectives. The listed objectives are often conflicting and expressed in different measures. However, none of the cases from the reviewed literature have presented or discussed a systematic approach for dealing with multiple objectives in geosteering contexts.

Although many will argue that the petroleum industry has adopted best-in-class technologies to support faster and better decisions, making real-time well placement decisions to meet all objectives is no simple task. It is impossible to optimize conflicting objectives at the same time without trading off the achievement of one objective against another. Without a well-structured approach, decision makers are likely to make judgments about the relative importance of each objective based on previous experience or on approximate methods. Research shows that such decision-making approaches are unlikely to identify optimal courses of action.

In this paper, we develop and illustrate a consistent multi-criteria decision-making process adapted to operational geosteering decisions. Using this process, we demonstrate the impact of different criteria, and combinations of criteria, on the resulting well trajectories and well final placements. We present a case study that applies multi-criteria decision-making (MCDM) methodologies to geosteering operations. The proposed method can assist the geosteering teams (GST) in their analysis and evaluation of multiple criteria for making better and more informed decisions.

We believe that the method developed and presented in this paper will provide a consistent and transparent guideline for making geosteering decisions using multiple objectives. Employing this approach can assist operators in optimizing well placement while balancing trade-offs among objectives according to the organizations' strategic and operational preferences.

You can access this article if you purchase or spend a download.