Hydraulic Fracturing - Fracture Flow Capacity vs Well Productivity

Abstract

Published in Petroleum Transactions, AIME, Volume 213, 1958, pages 91–95. Abstract In the past few years much consideration has been given to the evaluation of the effect of hydraulic fracturing on the productivity of wells. Generally, these studies included the evaluation of fracturing materials, fracture extension and formation damage due to the use of various fracturing fluids. Only little consideration has been given to the characteristics, and in particular the flow capacity, of the fracture itself and its effect on well productivity. This paper presents the results of laboratory investigations pointed toward the evaluation of the efficiency of various fractures with special emphasis on the flow capacity of these fractures. Data presented in this paper are the results of both an electrical model study and physical testing. Under consideration are (1) effect of overflush, (2) premature production of well after treatment,(3) "tailing-in" with coarse sand near the end of the treatment,(4) effect of propping agent size and concentration, (5) reduction in effective fracture permeability caused by formation caused by formation fines, silt and clays, and (6) effect of various fluids on formation strength and competency. The results of this investigation indicate that the flow capacity of a fracture is affected by any or all of the various parameters mentioned above. The authors believe that a better understanding and utilization of these factors should result in more efficient formation fracturing. Introduction Hydraulic fracturing has become almost a standard practice of many companies for stimulating production from old and new wells. Although most companies utilize this service, techniques of application vary widely between companies and areas. Probably too often when a well in an area responds favorably to a particular technique all future wells in the same area are treated in a similar manner. Possibly a modification of the technique would result in a further production increase. Variables, of which many are extremely difficult to evaluate from field results, hamper the selection of procedure changes.