Offset Fracture Events Made Simple: An Operator's Collaborative Approachto Observe Parent Child Interactions,Measure Frac Hit Severity and TestMitigation Strategies

摘要

It has long been postulated that complicated problems can usually be solved with simple solutions.While thisis not always the case,one might,at least,ask for a simple framework to guide a team through a technicallydifficult issue.When one private oil & gas operator was faced with the common industry challenge ofParent/Child well interactions in an unconventional,dry-gas shale,a collaborative team applied a simpleworkflow in the form of the scientific method.The iterative workflow provided a simple approach to utilizecommon data,clearly calculate economic risk and ultimately reveal major performance indicators of offsetwell development.The study area focuses on the northeast region of Pennsylvania,specifically in the dry gas window ofthe 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 andstarted offsetting older appraisal wells.The impact from these offset events were varied ranging fromparents and children losing reserves to parents and children gaining reserves.However,value loss was morecommon.As this risk grew,management charged the technical team and service partners with the goal ofempirically 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,measurethe impact to reserves and experiment with mitigation techniques.To date,the team has cataloged > 70offset events,classified over 350 frac hits and tested one mitigation technique.In addition to an offset fracworkflow,this paper will highlight statistical correlations of high value variables and detail an economicMonte Carlo Simulator to quantify the risk of a parent/child event.