A Systematic Approach for Processing, Prioritising and Progressing Casing Deformation Understanding in Unconventional Reservoirs
Authors: Rylance M. , Montoza J. M. 
Published: January 2025

With unconventional reservoir developments, the industry has experienced an increasing frequency of casing deformation, particularly within the lateral sections. This can result in lost metreage, complex operations and in the worst case a complete loss of access to the lateral section itself. Still not very well understood, definitive root-causes are as yet somewhat uncertain and lack a predictability. This work provides a simple framework, that can be used to effectively begin the processing, prioritisation and progress casing deformation understanding in any particular new field, basin or play as required.

This paper outlines a detailed process, to gain an indication of root-causes and relationships underlying the occurrence of casing deformation. The approach is split into two distinct phases, reporting on the first phase here, which will concentrate on prioritising those characteristics that can be readily adjusted and as a result be most effective in reducing occurrence in the field. Integrated with this is the application of a means of determining both positive and negative relationships between individual well characteristics and the occurrence of the casing deformation itself. The approach makes use of such simplistic techniques as Machine-Learning, combined with conventional assessment and presentation approaches.

Using this process, the methodology is able to readily identify any apparent and obvious statistical relationships between the well construction and casing deformation, such as well trajectory, depth and areal location. While at the same time identifying those less obvious and more obscure trends which in themselves may be enlightening and offer a route to direct remediation. When applied to a new case, the well template, once established, can be augmented through additional phases; and additional well datasets as they become available over time. With each phase, the identification process is then cycled and those critical wellbore characteristics can be isolated, and consideration of possible remedial approaches made. In some cases, the identification of clear relationships may immediately point to adjustment in activities and engineering selection which can directly reduce the frequency of casing deformation occurrence. Even very simplistic insight, such as areal distribution means that areas for remediation trial may be targeted, scheduled and focussed. Underlying the general approach are the economic considerations; while understanding the problem is always interesting, it is a reduction/or elimination of the occurrence that contains the true value and this should be kept at the heart of all determination.

The phenomenon of casing deformation remains yet to be fully defined and comprehended. Multiple efforts are underway within the industry to improve this situation, and the process presented here offers a pragmatic, coherent and cost-effective means of obtaining an initial understanding in any particular field, basin or play. This method is flexible, adaptable and adjustable over time, and offers a unique approach to being able to track, investigate and support casing deformation identification / remediation in a timely and cost-effective fashion; while laying the groundwork for more conventional methods to be performed.