Well-Data Files and the Computer, a Case History from Northern Rocky Mountains

Abstract

Computer processable well-data systems in the United States and Canada contain information from more than 700,000 wells. Ownership, location, well classification and status, drilling and completion activities, tests, depths to formation tops, core descriptions, shows, and other data are included. The use of computers to extract, analyze, and display this information is essential for economically efficient exploration where large amounts of data are available. Well-data files are used at various stages of the exploration process for basin evaluation, selection of prospective stratigraphic intervals, selection of areas for detailed study, and for building peripheral files containing proprietary, technical, and economic data. Use of the well-data file for regional evaluation is illustrated by a study of the gas potential in the northern Rocky Mountain region. A study of the Muddy play in the Powder River basin illustrates an application of computer processing of a large well-data file to aid play and prospect definition. Prior to the discovery of the Bell Creek field, data from the file revealed areas in Wyoming and southeasternmost Montana with abundant hydrocarbon shows in the Muddy formation. North Dakota, South Dakota, and the rest of Mon ana had Muddy shows. In the area of abundant shows geologic maps based on formation tops obtained from the file indicated trends on which subsequent drilling has discovered more than 250 million bbl of reserves. East and West Sandbar, Ute, and Whitetail fields are related to deposition around a pre-Muddy positive feature defined by Skull Creek structure and Muddy isopach residual maps. Recluse and Odekoven are related to a channel defined on a Muddy isopach residual map. No commercial production has been found in the no show area. At the time of discovery of Recluse and Bell Creek fields, information was available within the Rocky Mountain Well History Control System to suggest areas favorable for similar types of production from the Muddy. With addition of new well control and proprietary information the well-data file can aid in the planning of development drilling, analysis of completion practices, and reservoir evaluation. The proper application of the computer to well-data files will become increasingly important in the discovery of oil and gas during the 1970s.