Waterfloods Project
A Waterflood located in Southern Oklahoma producing out of the Deese Sand formation was experiencing water quality and injectivity problems due to the deposition of calcium sulfate scale and oil coated iron sulfide particles plugging filters. The flood was comprised of eight producing wells and five injectors producing 2,500 BOPM and 4,650 BWPM.
The conventional treatment program consisted of continuous injection of scale inhibition and corrosion chemicals at the central injection station and monthly batch treatments of demulsifier. The 25 micron filters used for water filtration had to be replaced every three days. In addition to the chemical treatments, the operator had to acicdize the injectors annually to maintain injection pressures below 1400 psi.
In December 1991, Bio Tech designed and implemented a microbial treatment program at the Waterflood central injection station.
Bio Tech designed and implemented a treatment program to achieve the following goals:
1.) Eliminate chemical and acid treatments.
2.) Reduce the frequency of filter changes.
3.) Improve water quality and injectivity
Bio Tech treated the central injection station with Corroso-Bac microbes on a monthly basis. The results of this treatment have proved to be very dramatic. The water quality was greatly improved (See Water Quality Table). Filter changes were reduced from every 3 days to every 14 days.
Skin damage in the injection wells was reduced and water injectivity was greatly improved, as seen in the Hall Plot. The Operator’s treatment cost gas remained constant compared to the conventional chemical treatment program, while performance has been improved and environmental exposure has been eliminated.