Reinjection of Large Volumes of Produced Water in Secondary Operations

Abstract

Abstract A study was made of the operating performance histories of a pressure-maintenance and four waterflood projects in the Permian Basin area, where large volumes of produced water have been reinjected into the producing formations. The projects reviewed include a wide range of characteristics: open and closed water systems, volumes of reinjected water froth 2,200 to 12,500 B/D, sand and limestone formations, depths of 1.300 to 6,750 ft. average permeabilities from 17 to 275 md, bare and protected facilities, and 10- to 50-year project life. Each project exhibited performance data which indicated that reinjection of large volumes of produced water provides a good source of injection fluid, results in practical and prudent salt water disposal and, in many cases, results in conservation of fresh water for future domestic needs. Introduction The increasing difficulty of finding adequate new oil reserves has caused almost every field in West Texas to be reviewed for possible secondary recovery applications. Because most secondary recovery processes use water, the availability and prudent utilization of water are very important to all oil operators. Standard Oil Co. of Texas' production operations in West Texas include numerous water floods, and several of these projects are reviewed and discussed in this paper. The case histories presented cover handling and reinjecting large volumes of produced water. The fields presented, as shown in Fig. 1. include SACROC unit, Howard-Glasscock, North Ward-Estes. Keystone-Colby sand, and South Ward. The combined cumulative primary and waterflood recovery of these fields to Jan., 1965. is 878.8 million bbl. Pertinent reservoir and waterflood data for the Standard of Texas' projects in each field are shown in Tables 1 and 2. Equipment used and materials for construction in each injection system are shown in Table 3. Waterflood performance histories are shown in Figs. 2 through 7. Schematic flow diagrams of the injection systems are shown in Figs. 9 through 13. SACROC Unit History and Development The Canyon Reef reservoir of the Kelly-Snyder field in Scurry County was discovered in Nov., 1948. The field now encompasses some 50,000 productive acres and 1,321 wells. Cumulative field recovery to Jan., 1965, is 322.4 million bbl. The reef, a limestone formation, is a low mound-type structure varying In thickness from 0 to 800 ft. The field was essentially developed by 1951; and, after extensive negotiations, the field was unitized with a unit manager and three segments, each operated by a working-interest owner effective March, 1953. Standard of Texas was designated unit operator on May 1, 1962. JPT P. 781ˆ