Laboratory/Field Study of Oil-Soluble Resin-Diverting Agents in Prudhoe Bay, Alaska, Acidizing Operations

Abstract

Abstract Treatment of long intervals of varying permeabilities and thief zones requires fluid diversion control to assure well distributed fluid placement. Oil Soluble Resins (OSR) , when properIy appl i ed, ar e effective, readily removable diverting agents. Application of laboratory studies of 15 OSR products from 5 service companies combined with additional OSR field experiments at Prudhoe Bay ( PB) , br ought about the use of higher concentrations and larger size OSR particles and resulted in improved diversion during acid stimulation and scale inhibitor squeeze treatments. Successful OSR field applications depend both on selecting proper OSR particle size distributi ons and sufficient OSR concentrations for rapid bridging on pores and/or fractures being contacted. Tests of sand/gravel packs, confirmed that effective sealing was achieved when the median OSR size was equal to or greater than 1/3 of the calculated mean sand pore diameter. With fractured cor es, however, effective seal i ng by OSR concentrations up to 10 wt% required that 1020% of the OSR particles be as large or slightly larger than the fracture width. Smaller volumes of higher OSR concentrations were more effective in diversion than larger volumes of lower concentrations. Generally, a broad particle size distribution was desirable for sealing fractures whereas fine particle sizes were better for 350 md to 3500 md sandstone cores.