General Field Information |
| Produces Oil: Yes Produces Gas: Yes |
| Geologic Province: |
Upper Anadarko Basin |
| Exploration Method: |
Toronto Discovery Well |
| Surface Formation: |
Dune and fluvial sands of Cimarronian Stage-Permian System-Paleozoic with modern sand deposits of Cimarron River |
| Oldest Formation Penetrated: |
Viola-Ordovician |
| Drilling Casing Practices: |
In the redevelopment of the Snake Creek Field for the Toronto many of the wells were drilled into the Mississippian to evaluate the Marmaton and the Morrow. In most wells drillstem tests were taken in the Toronto, as well as the Marmaton when shows occurred. Drillstem tests were also taken in most wells that were drilled to the Morrow in the sandstone intervals. Approximately 15 separate full hole cores were taken in various wells in the Toronto. A few cores were also taken in the Marmaton and Morrow.
Standard stimulation and treatment has been the most successful method of completion. The Toronto in the Snake Creek usually requires a small mud cleanup acid treatment to clean damage and sometimes followed with a 3,000-gallon-15% acid treatment. Several wells flowed naturally, while others were put on the pump immediately. |
| Electric Logging Practices: |
Generally a comprehensive suite consisting of: Compensated Density, Neutron, Dual Induction, S.P., Gamma Ray, and Caliper was used for most logging programs. |
| Comments: |
Producing Formation(s): Toronto, Marmaton, Morrow
Other Shows: Slight shows in the samples and on gas detectors have been observed in the Elgin, Swope Mississippian-Chester.
Because the old Morrow production in this region has been well documented, and the Marmaton production is insignificant, this data record focuses on just the Toronto. |
| Discussion: |
Rine Drilling Company, et al. purchased the Snake Creek Field in 1979. At that time, there was only one active Marmaton oil well that had been drilled in 1963. The Morrow gas wells in existence since the 1950's were abandoned. The original intent was to redevelop the field for Morrow gas due the increase in gas prices and the number of separate sandstones within the Morrow interval. The first well drilled was the Barby 1-21, a successful Morrow Gas Producer. This well was drilled using the standard wellsite procedure in the area of sending the geologist out to observe samples from the base of the Kansas City through the Mississippian. Before drilling the Barby 2-21 we felt it necessary to send the wellsite geologist out earlier due recent developments in the region in the Elgin Sandstone, Lansing A & B Zones, and the Kansas City-Swope. Careful and alert wellsite technique by John Rose who noted shows in the Toronto actually led to the discovery of this pay zone in the Snake Creek Field. Subsequent drilling through 1984 has led to over 30 productive Toronto wells, at least 10 Morrow wells, and several Marmaton wells. Fourteen dry holes exist in approximate boundaries of the Snake Creek. Although many of them flowed on initial production, some of edge wells are, at best, marginal. Because of the Cimarron River, which runs through the field, development in an orderly pattern was somewhat effected. It should also be noted that although a comprehensive log program was used it is very difficult to detect the quality of the reservoir in most cases from the logs themselves. Drillstem testing and coring has helped greatly in the performance evaluation of the reservoir. In summary, the Toronto portion of the field has been a very economical play, and further proves or fortifies the need to have a thorough wellsite geologist on location and to begin this supervision shallow enough to observe formations with even a remote chance of producing. |
|
| Depth Top: |
4254 feet |
| Geological Age: |
Shawnee Group-Upper Pennsylvanian |
| Depositional Environment: |
The upper Toronto Limestone in this region was generally deposited as a lime mud, and possibly as an algal mound, in a shallow marine environment. In the Snake Creek Area there appears to have existed an anomalous flattening of the regional dip of the Anadarko Basin as defined by the producing wells in the field. This anomalous structure possibly accumulated larger amounts of various exo-skeletal life and algae along with possible winnowing of the fines at the center of a very slight buildup in the anomaly. Evidence of secondary solution and leaching is seen in cores, ranging from greater solution in the middle to very slight leaching in the edge wells. Following this process much calcite growth filled or partially destroyed void space after burial. |
| Formation Lithology: |
The Toronto is a tan-gray limestone with varying amounts of secondary dolomitization. Texture varies from very fine crystalline, micritic in nature, to a fine plus medium crystalline structure, sparitic in nature. Edge wells tend to be finer and less fossiliferous and consequently and ultimately less porous and permeable. Interior wells have increased textural size with a higher fossil content, consequently the zone contains greater leaching causing pinpoint, fossiliferous, and vuggy porosity with increased permeability. Various amounts of calcite growth occurred in leaching destroying some porosity. |
| Formation Geometry: |
Total zone thickness in upper Toronto Limestone member is 30'. The producing area is approximately 2 1/2 miles long on strike lying East-Northeast by West-Southwest, and approximately 1 1/2 miles wide on dip lying North Northwest by South-Southeast. |
| Trap Type: |
Structural-Stratigraphic |
