A Pragmatic Approach to Casing Deformation Remediation for Post Stimulation Wellbore Access Assurance Utilizing an Iterative Approach

Lateral wellbore sections below moderate to severely deformed regions are often abandoned as uncertainty of actual final recovery and variance associated with cost of intervention can ascend at a rapid rate. This is of particular importance when encountering instances of bedding plane slippage affecting the build section or liner top of the well; effectively restricting access to the entire wellbore and rendering the stimulated zones inaccessible. In this scenario, limited options for removal of temporary obstructions such as composite frac plugs are available and conventional bypassing options carry additional inherent operational risks when deployed. The objective of this paper is to explore consistently successful methodologies for removal of casing impediments introduced during the process of multi-stage hydraulic fracturing (MSHF) in unconventional plays. This work intends to identify practical and repeatable methods for regaining access to sections of the wellbore below the deformed area with consistent results and a low variance of outcomes. The solutions presented are summarized from a comprehensive review of operations performed on twenty wells wherein the nature of the deformations examined are principally tectonic factors such as natural fractures, fault slip and bedding-parallel slippage Type III (Casero & Rylance, 2020) in the Montney formation of the Western Canadian Sedimentary Basin (WCSB), though other deformation root-causes were present. However, this study focuses on remedial solutions post-event rather than exploring causation or event mitigation, as other works have, and this paper is thereby agnostic to root-cause factors present in the underlying sample cases. Here we explore an iterative approach to remediation through which each deformation is measured and examined for severity then opened via a downhole machining process subject to the restraint of induced casing breach and additional contextual considerations are applied in selecting final methodologies for implementation. Access to the toe of the well is then able to be confirmed utilizing a risk-adjusted procedure selected using real-time assessment. Through evidence-based process refinements, the required steps are able to be quantified, normalized and optimized to a near 100% success rate. The findings presented in this case history review serve as a demonstration that economic and measurable solutions to wellbore recovery following a MSHF induced deformation event can be obtained from the perspective of service providers and well operators with the ultimate objective of reestablishing flow assurance from the toe of the well in the fewest steps possible.