Analysis of Production and Well Test Data from Barnett Shale Wells Operated by Mitchell Energy Corporation. Topical Report, March-August 1991.

摘要

The report presents the results of production data and well test analyses on wells operated by Mitchell Energy Corporation that are completed in the Barnett Shale of the Fort Worth Basin. The study consisted of two parts: production data analysis for six wells and pressure buildup analysis on seven wells, including five pre-fracture and two post-fracture tests. The objectives of the study were to determine reservoir quality and to estimate stimulation effectiveness in the Barnett Shale. Good matches of the production data were achieved for all six wells studied, but the results seemed unreasonable; i.e., small drainage areas and short fracture half-lengths. The pre-fracture well tests were difficult to interpret due to wellbore storage distortion problems. The two post-fracture tests provided much better quality data and yielded longer estimates for fracture half-length than those obtained from production data analysis. There appears to be two closely-related explanations for these results. First, the values of net pay being used in the Barnett are too large. While there may be 150 to 200 ft of gas-filled porosity in the Barnett, well performance suggests a much smaller portion is responsible for most of the well productivity. Second, the authors expect that the Barnett may be described best by a multilayered reservoir model, where most of the permeability is confined to thin, higher permeability layer(s) whose productivity may be enhanced by natural fractures, while most of the gas is stored in thicker, lower permeability layer(s). They are currently working to apply this type of reservoir description to the Barnett Shale (specifically, using Mitchell's Stella Young 4 well); these results will be the subject of a subsequent, followup report to the work.