Gel Polymer Treatments in Kansas Arbuckle Wells

Rodney R. Reynolds
Director of the North Midcontinent Region for the Petroleum Technology Transfer Council and
Petroleum Engineer with the Tertiary Oil Recovery Project
University of Kansas

Bottom Line
Recent success in applying gel polymer treatments in Kansas Arbuckle producing wells has created a “boom” of activity. All of the approximately 300 wells treated since 2001 have responded favorably to the treatments to one degree or another. All of the wells have responded with significant reduction in water production and many have also responded with an increase in oil production. In many instances these treatments are paying out in weeks to months. Even though the mechanisms of why these treatments have been so successful are not well understood and is still being studied, it has not slowed down operator’s enthusiasm in applying this technology.

Introduction
In the Arbuckle formation in Kansas, water production can be excessive due to channeling in this water-drive reservoir. High water production restricts oil production and increases operating costs, often leading to leases and/or wells becoming prematurely uneconomic to produce. Gel polymer treatments have a long history in the mid-continent for blocking these channels. Recent treatments in Kansas Arbuckle producing wells are proving to be more effective in controlling water production and increasing oil production than past treatments.

Overview
Comparing recent treatments to earlier ones indicate several differences. The majority of the recent successful treatments are using the MARCIT^SM technology where the polymer and crosslinker are mixed on the surface as opposed to previous systems that mixed chemicals in the reservoir and much larger volumes of gel are being used. Recent treatment volumes range from 1,500 to 5,000 barrels versus the few hundred barrels historically used. MARCIT^SM is the acronym for MARathon Conformance Improvement Treatment. This polymer gel system was developed in the mid-1980s by Marathon Oil Company and licensed to various service companies in the early 1990s. The MARCIT^SM technology consists of mixing dry polymer, Cr(III)carboxylate/acrylamide in water and crosslinking it with chromium triacetate at the surface. Gel Technologies Corporation and TIORCO (The Improved Oil Recovery Company), Inc. are the two service companies applying the MARCIT^SM technology in Kansas.

In January 2003 another service company (Polymer Services, LLC) started conducting treatments using a Chevron/Phillips Chemical Company technology referred to as the PROD^SM system. This system also uses the chromium III crosslinking system with chromium propionate as the crosslinker and is applied similarly as the MARCIT^SM system. Forty-two producing oil wells were treated with this system from January through July of 2003.

Since 2001, over 30 operators have treated approximately 300 central Kansas Arbuckle producing wells with MARCIT^SM and PROD^SM gel polymer systems. To one degree or another, the wells have successfully responded to the treatments. For some wells, oil production has increased from approximately 5 BOPD to over 200 BOPD for several days after the treatments (+/- 14 days) and has stabilized at between 10 and 30 BOPD for six months or longer. For the same wells, water production has dropped from over 1500 BWPD in many cases to between 100 and 200 BWPD and has remained at the lower volumes for a year or longer. Other wells have not responded as favorably, but have still seen an increase in oil production and a decrease in water production. In some cases no significant oil benefits are seen, but water production is still reduced. Operators indicate that the $20,000 to $50,000 gel treatments in most instances pay out in weeks to months.