Partial Monolayer Fracturing In The Three Bar Field

Prior to 1971, the Devonian formation of the Three Bar Field, Andrews County, Texas was hydraulically fractured with a variety of conventional techniques. These treatments gave fair after-frac results but sustained increases were small and sand backflow caused severe fill and pump problems. Much of the backflow material appeared to be finely crushed frac sand. Core studies and computerized treatment evaluation indicated 12-20 glass beads placed in a partial monolayer with a high viscosity fluid would yield better production increases, eliminate proppant crushing and minimized backflow problems. Since January, 1971, ten partial monolayer treatments have been performed in the Three Bar Field, which have resulted in more than two times the sustained production increase of conventional jobs and times the sustained production increase of conventional jobs and proppant backflow problems have been eliminated. In addition, no proppant screen-out problems were encountered. The partial monolayer frac technique appears to have particular application in hard rock formations where large fracture flow capacities are needed. Care should be taken in application and design of this technique to assure optimum results.