Abstract
It has long been postulated that complicated problems can usually be solved with simple solutions. While this is not always the case, one might, at least, ask for a simple framework to guide a team through a technically difficult issue. When one private oil & gas operator was faced with the common industry challenge of Parent/Child well interactions in an unconventional, dry-gas shale, a collaborative team applied a simple workflow in the form of the scientific method. The iterative workflow provided a simple approach to utilize common data, clearly calculate economic risk and ultimately reveal major performance indicators of offset well development.
The study area focuses on the northeast region of Pennsylvania, specifically in the dry gas window of the Marcellus Shale. More specifically, five counties in Pennsylvania (Bradford, Sullivan, Susquehanna, Wyoming and Lycoming) are studied after the operating company moved into full time development and started offsetting older appraisal wells. The impact from these offset events were varied ranging from parents and children losing reserves to parents and children gaining reserves. However, value loss was more common. As this risk grew, management charged the technical team and service partners with the goal of empirically mitigating offset frac interference to 1) protect the Parent well's original completion and 2) maximize a Child well's completion effectiveness.
To accomplish these goals, the team employed the scientific method to observe offset events, measure the impact to reserves and experiment with mitigation techniques. To date, the team has cataloged > 70 offset events, classified over 350 frac hits and tested one mitigation technique. In addition to an offset frac workflow, this paper will highlight statistical correlations of high value variables and detail an economic Monte Carlo Simulator to quantify the risk of a parent/child event.
