Results of a Large-Scale Refracture Stimulation Program, Kuparuk River Unit, Alaska

Abstract

ABSTRACT An aggressive hydraulic fracture stimulation program on previously fractured wells in the Kuparuk River Field has increased production by 50,000 BOPD. The Kuparuk River Field is the second largest producing field in the United States with sixty-five percent of the reserves contained in a 20–100 md permeability sandstone. This paper describes results of a series of design improvements in an ongoing refracture program of oil wells in this moderate permeability formation. Over 185 of the 380 production wells have been refractured during the past five years. Long term production data are presented comparing productivities after the initial stimulations carried out in the early 1980’s to the recent refracture stimulations. A twofold improvement in long term productivity is shown with changes in the treatment design: increased job size, different proppant types (ceramic vs. sand), proppant mesh sizes (10/14 and 12/18 vs. 20/40 and 16/20), and fluid types (gelled water vs. gelled diesel). The average productivity increase from 30 to 60 BOPD/net foot pay provided the economic justification for refracturing some wells a second time. Additionally, wells with high flow potential after initial stimulation have been refractured for substantial increases in oil rate.