Waterflood operations were commenced on Sunray Mid-Continent Oil Company'ssolely owned Dora Roberts lease, located in the Howard Glassock field, Howard county, Texas, with the injection of water into a Yates sand 90 acre cooperative pilot water flood on Feb. 10, 1952. Production was boosted from 330to 3,281 bbl a day within 16 months after initial water injection. One year later the project attained a second peak production of 3,834 bbl a day. This represents a 1,062 per cent increase in production relative to the normal primary rate of production.

Today, after more than four years of operation, the production is still six times what it would have been under continuation of primary conditions. Cumulative totals indicate that up to July, 1956, 3,485,000 bbl of oil have been recovered through waterflood measures. One barrel of oil has been produced for every 3.78 bbl of water injected into the Yates sand. To date the waterflood operations have recovered an amount of oil equal to that obtained over the preceding 24-year primary period.

Total oil recovery from waterflood operations is expected to surpass 12,500bbl per acre.

Primary Development and Production History

The Yates Sand oil production from the Dora Roberts project, comprising 480leased acres, was obtained in March, 1928. Of 38 wells completed for production from the Yates sand found at about 1,400 ft, the same number of wells were still producing at the time water injection was commenced. Initial production of the wells ranged from 11 to 500 B/D natural.

Production has been obtained from three other formations all underlying the Yates sand formation. In addition to the Yates wells, a total of 49 wells were drilled and completed in the Seven Rivers sand reservoir found at about 1,800ft, the San Andres Lime reservoir found at about 2,600 ft, and the Clear Fork Lime reservoir found at about 3,000 ft.

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