Drilling horizontally and hydraulic fracturing is proving to be the well type of choice for low and ultra- low permeability shale. However, due to the extreme complexities encountered, determining the specifics of a completion and hydraulic fracture design that will result in the highest economic return on investment is problematic. The subject of this paper are results from detailed evaluations performed by experienced engineers with reservoir knowledge for the purpose of evaluating completion effectiveness and improving economics for shale and other low permeability formations.
Detailed engineering evaluations were performed to estimate reservoir and frac characteristics for a multi-well Utica pad. These evaluations consisted of (1) performing production history matching on all production phases with a numeric reservoir simulator, (2) estimating conditions within the fracture over time as the wells are produced and (3) calibration of a 3-D frac model by frac pressure matching. The methods used to perform these evaluations are not new, however they currently are underutilized by the industry today
The evaluations performed indicate that completion, frac design, operational and production issues can all significantly influence multi-fractured horizontal well production and economics. In addition the findings show that in many cases the hydraulic fractures are not very effective1-9 . This ineffectiveness is due to the stranding of large portions of the propped fracture area which consequently do not contribute to well performance. This condition results in loss of productivity, recovery and return on investment. Experience shows that improvements to the frac treatment design can mitigate some of this inefficiency and improve the economics of multi-fractured horizontal completions.