Production Response to Polymer Treatment
Three injection wells were treated with polymer-gel during 1996. The SU 10-28 was treated in March, the SU 3-21 was treated in June and the SU 15-21 was treated in August (see figure 1 for well locations). No increase of oil production has been observed after 12 months from any producing well at the Sooner Unit following polymer-gel treatments. Total fluid production has decreased from wells which offset polymer treatments but the oil cut has remained the same. The most notable change in waterflood operations is greater injection pressures at the treated wells. Wellhead pressures vary up to over 1200 psi when attempts are made to establish injection at pre-treatment rates which were at less than 100 psi wellhead pressure.
Production has been closely monitored at each well with frequent tank testing. The completion of the SU 21-16-9 well in September 1995, has had a dramatic impact on production from the Sooner Unit and it is necessary to compare production with and without the SU 21-16-9 to assess any impact on production resulting from the polymer-gel treatments. Figure 5 is a plot of total monthly production from the Sooner Unit since January 1995. Monthly oil, oil cut and water injection are shown. Two time lines are drawn to indicate the completion of the SU 21-16-9 and commencement of polymer-gel treatments. Completion of the SU 21-16-9 resulted in an increase in oil production from 8800 bbl per month to over 12,000 bbl per month. Production decline since April 1996, is mostly the result of water breakthrough at the SU 21-16-9 well. Figure 6 is a plot of total Unit production as a function of total cumulative oil produced. Figure 7 is a plot of total Unit production as a function of cumulative water injected. Figure 8 is a plot of Unit production with time, less allocated production from the SU 21-16-9 well. Trends are drawn through the monthly oil and oil cut prior to the commencement of polymer-gel treatments in March 1996. Figure 8 shows there has been no improvement in monthly oil production after polymer-gel treatments in the last 12 months. Figure 9 is a plot of Unit production less that allocated to the SU 21-16-9 well as a function of cumulative oil (minus that attributed to the SU 21-16-9). Trends are drawn for the monthly oil and oil cut. Figure 10 is a plot of Unit production less that allocated to the SU 21-16-9 well as a function of total water injection. Water production from the other wells is also shown. While there is no apparent change in the oil production trend, water production has decreased from about 1300 bwpd to 930 bwpd. Total water injection has been reduced from 2700 bwpd in March 1996, to 2300 bwpd in January 1997.
