Development and Field Testing of a New Low Toxicity Polymer Crosslinking System

Abstract

Development and Field Testing of a New Low Toxicity Polymer Crosslinking System P.D. Moffitt; P.D. Moffitt Phillips Petroleum Co. Search for other works by this author on: This Site Google Scholar A. Moradi-Araghi; A. Moradi-Araghi Phillips Petroleum Co. Search for other works by this author on: This Site Google Scholar I. Ahmed; I. Ahmed Phillips Petroleum Co. Search for other works by this author on: This Site Google Scholar V.R. Janway; V.R. Janway Phillips Petroleum Co. Search for other works by this author on: This Site Google Scholar G.R. Young G.R. Young Western Atlas E&P Services Search for other works by this author on: This Site Google Scholar Paper presented at the Permian Basin Oil and Gas Recovery Conference, Midland, Texas, March 1996. Paper Number: SPE-35173-MS https://doi.org/10.2118/35173-MS Published: March 27 1996 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Get Permissions Search Site Citation Moffitt, P.D., Moradi-Araghi, A., Ahmed, I., Janway, V.R., and G.R. Young. "Development and Field Testing of a New Low Toxicity Polymer Crosslinking System." Paper presented at the Permian Basin Oil and Gas Recovery Conference, Midland, Texas, March 1996. doi: https://doi.org/10.2118/35173-MS Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll ProceedingsSociety of Petroleum Engineers (SPE)SPE Permian Basin Oil and Gas Recovery Conference Search Advanced Search AbstractA low toxicity polymer crosslinking system has been developed which is tolerant of high brine salinity and hardness and has worked well in two field applications. The system involves the gelation of polyacrylamide with zirconium lactate; this is a lower toxicity system than the commonly used chromium gelling systems. Microgels prepared with the new polyacrylamide/zirconium system have been tested in two different field applications:an injection well test in a large waterflood unit in northeastern Oklahoma, the North Burbank Unit, andan injection well and a production well test in a waterflood unit in northern Texas, the C.B. Long Unit.In the injection well test in the North Burbank Unit, 69,000 barrels of polyacrylamide/zirconium gel were injected into an injection well. Pressure falloff tests before and after polymer gelant injection showed a reduction in fluid mobility by a factor of 5 to 6 as a result of the crosslinked polymer treatment. In the C.B. Long Unit, an injection well was treated with 65,500 barrels of microgel and injection profile surveys before and after the treatment showed a diversion of 55 percent of the injected fluid to a low permeability zone. Several offset producing wells responded to the polyacrylamide/zirconium treatment and incremental oil production has been in the range of 15 to 20 BOPD. The production well treatment in the C.B. Long Unit resulted in a reduction of the producing water-oil ratio.This low toxicity polymer crosslinking system has been developed for in-depth diversion of injection fluid in a variety of applications. The polymer gelant uses a fairly low concentration of polymer and zirconium crosslinker so large volume treatments are economical. The polymer system is also tolerant to hard brines and low pH environments.IntroductionPolymer and gelled polymer solutions have been used since the 1960's to improve waterflood sweep efficiency and to increase the macroscopic displacement efficiency of water displacing oil. Some gelled polymer solutions used for these purposes, however, had drawbacks associated with their use. These drawbacks included a requirement for fresh or softened water and/or the use of chromium (+6), a carcinogen, as a crosslinker. This paper reports on the development of a low toxicity, polymer crosslinking system which is tolerant to high salinity and hardness in the water used as the polymer solvent. The newly developed polymer crosslinking system is also effective at low polymer concentrations which makes large volume treatments economical.Zirconium (IV) Lactate as a Low Toxicity CrosslinkerDue to concerns over the environmental effects of chromium crosslinkers, zirconium (IV) and titanium (IV) complexes were evaluated as alternative crosslinkers for gelation of polyacrylamide. Extensive tests showed that polyacrylamide when crosslinked with zirconium and titanium produced stable gels in high salinity brines. Water analyses for two of the produced brines used in this study are shown in Table 1. Although a number of titanium and zirconium crosslinkers were identified which can produce stable gels in high salinity brines, our discussion in this paper will be limited to the data presented in Table 2 and references 1 through 3 show that zirconium (IV) lactate is a low toxicity compound which is a mild eye irritant and slight skin irritant to animals1–3. Keywords: field testing, lactate, upstream oil & gas, polymer, low toxicity polymer, microgel, polymer concentration, injection well, zirconium, polyacrylamide Subjects: Improved and Enhanced Recovery, Waterflooding This content is only available via PDF. Copyright 1996, Society of Petroleum Engineers Inc. You can access this article if you purchase or spend a download.