Laboratory Studies and Field Evaluation of a New Gelant for High-Temperature Profile Modification

Abstract

ABSTRACT This paper reports the laboratory development and initial field testing of FLOPERM™ 325, a novel gelant for high temperature profile modification. The new gelant is a synthetic, thermosetting material which can be used at concentrations of about 1-2% in injection brines. Its gelation rate can be controlled over the range of several hours to about 10 days at temperatures of up to 221°F (105°C), permitting emplacement at varying distances from the injector wellbore. In sandpack testing to simulate gelant performance under reservoir conditions, the new system reduced permeability to brine by more than 90% while retaining most of the original permeability to oil. Moreover, in parallel sandpack tests the gelant selectively reduced permeability in the zone with higher initial permeability. Emplaced gels have retained functional stability in sandpacks for more than ten months at 197°F (92°C). An injector well test of the gelant was performed at ARCO's Nelson Minnelusa Unit ((197°F (92°C), in Campbell County, Wyoming)) in March, 1984. A 2000-bbl solution was emplaced in the formation over a two-and-one-half day period. Injection profiles showed diversion of injection brines from a water channel to the oil payzone. Enhanced oil recovery and decreased water cut were observed within several months of the treatment and are continuing.