Natural and Induced Systems and Their Application to Petroleum Production

Abstract

Abstract The Morgantown Petroleum Research Laboratory, U.S. Bureau of Mines, is investigating the orientation of hydraulically induced fractures in petroleum reservoirs to help guide producers in better location and spacing of producers in better location and spacing of wells for more efficient fluid injection and petroleum production. The results of analyses petroleum production. The results of analyses of surface and subsurface information show a definite correlation between surface lineations and azimuths of hydraulically induced fractures. Joint systems determined from remote sensing imagery and/or surface surveys have been correlated with subsurface fracture orientations to depths of 3,000 feet and used to predict the bearing of hydraulically induced fractures in the Appalachian basin. Possible applications of fracture orientation Possible applications of fracture orientation prediction to petroleum production are also prediction to petroleum production are also discussed. Introduction One of the most important problems facing the domestic petroleum industry is the declining reserves to production ratio. Although additions to reserves through increased secondary recovery operations have nearly offset the decline in reserves added by drilling in recent years, there is a limit to the volume of crude oil that can be recovered through economic secondary means. A large fraction of our oil reserves, both primary and secondary, are contained in low permeability formations from which they cannot be economically produced by present techniques. Although the development of hydraulic fracturing has enabled the industry to develop a portion of these reserves, little is really known about the system of fractures created or the effect of natural fractures on fluid flow. Planes of weakness, which could be opened Planes of weakness, which could be opened during secondary recovery operations or hydraulic fracturing, do exist and have a preferred compass orientation. The effect preferred compass orientation. The effect of induced fractures on fluid movement in the reservoir must be known to attain maximum production efficiency. production efficiency. The Morgantown Petroleum Research Laboratory of the U.S. Bureau of Mines initiated a study in 1967 to investigate hydraulically induced and natural fracture systems and their effect on crude oil recovery. Results of these investigations will be used to locate wells in secondary recovery projects to obtain the highest injection rates and breakthrough sweep efficiencies possible and, in areas under primary recovery, to make maximum use of the primary recovery, to make maximum use of the drainage capabilities of the hydraulically induced fractures.