Well-Bore Notching and Hydraulic Fracturing

Abstract

Abstract Several advanced procedures for planning hydraulic fracturing treatmentswere introduced by research engineers during 1957 and 1958. Fracturing with thesingle-plane entry technique was one promising new concept. With this techniquethe well-bore is prepared at a selected point using a hydraulic or a mechanicalnotching tool. The well is then fractured with a treatment designed to generatea single, large-areal-extent fracture. A partial monolayer of large-sizepropping agent is distributed in the fracture to give high-flow capacity afterthe treatment. An experimental program was conducted in the Pincher Creek, Steelman and Pembina fields during 1959 and 1960 to evaluate single-plane-entryfracturing. It was found that the technique could not be indiscriminantlyapplied to every reservoir. Interference from natural vertical fracture systemswas a problem. However, when reservoir conditions were favorable, the resultsindicated that wells fractured with the single- plane entry technique havehigher and more sustained productivity than those fractured by conventionalmethods. Introduction Significant technological advances in the science of hydraulic fracturingwere made by research engineers during 1957 and 1958. These were received withconsiderable interest by the Canadian oil and gas industry. In particular, theconcept of a single, high-flow-capacity fracture held promise for many areas.An experimental program was carried out by The British American Oil Company Limited during 1959 and 1960 to evaluate some of the new fracturing theories.Fracturing with the single-plane entry technique was first attempted in Canadaat a gas well in the Pincher Creek field. Another proving ground for this type of fracturing were poor-productivitywells along the north side of the Steelman field. Rapid decline in productionrate after normal acid completion treatment was characteristic of wells in thisarea. Conventional sandfracturing had been tried with no success. In an effortto overcome the problem and work out a superior completion method, single-plane-entry fracturing treatments were performed on nine edge wellsduring the latter part of 1959 and in early 1960. An abrasive jetting tool anda mechanical under-reamer were evaluated as a means of notching the well-bore.Partial-monolayer and multilayer fracturing treatments were tried inconjunction with the single entry. Production data from these nine experimentalwells and from offsetting conventionally completed wells are compared toevaluate the usefulness of the single-plane entry technique and thepartial-monolayer propping theory.