General Field Information |
| Produces Oil: No Produces Gas: Yes |
| Geologic Province: |
Sedgwick Basin (Merriam, 1963) |
| Exploration Method: |
Subsurface geology |
| Surface Formation: |
Tertiary Ogallala Group |
| Oldest Formation Penetrated: |
Simpson Sand (Ordovician) |
| Drilling Casing Practices: |
All wells were drilled with rotary tools and chemical or starch mud systems. No apparent surface hole problems exist in the area. An average of 305' of surface pipe was run. A typical well was drilled to a total depth of around 2700' in the Wabaunsee Group. Wellsite geological supervision was present on most tests and the productivity of the reservoir was usually sampled by drillstem test, particularly in the early wells. Production casing was set through the pay section into the Wabaunsee and cemented back up above the Onaga Shale using from 75 to 200 sacks of cement with the average well using about 175 sacks. The wells were, in general, perforated through casing and, in general, tubing was run, the well swabbed in, and allowed to produce naturally. Five of the wells drilled before 1986 required acid treatment to clean up perforations, and one well was given a light foam frac after it would not flow during production testing. One operator used a perforating gun built into the tubing string to perforate the casing. Using this process, the tubing was not loaded with fluid, resulting in an under-balanced condition that allowed the formation gas to flow back immediately, without swabbing. |
| Electric Logging Practices: |
Gamma Ray with Compensated Neutron-Density Log, and Caliper Gamma Ray with SP and Dual Induction Laterolog |
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| Depth Top: |
2525 feet |
| Geological Age: |
The Indian Cave Sandstone occurs within the Towle Shale member of the Onaga Shale formation, Admire Group, Lower Wolfcampian Series, Permian Series. The Towle Shale lies with apparent conformity on the Brownville Limestone of Pennsylvanian Age except where the Indian Cave cuts or scours into the underlying beds (Zeller, et al., 1968). |
| Depositional Environment: |
Generally appears to represent two depositional facies: 1) Deltaplain is characterized on electric logs by an abrupt base, a blocky to serrate middle and commonly abrupt upper curves reflecting erosion, sand fill with possible brief abandonment and re-occupation at final abandonment; 2) Delta fringe is characterized by a transitional base, a serrate to blocky middle and transitional upper curves representing progradation alternation of pro-delta delta front interdistributary facies (Fisher, et al., 1976). |
| Formation Lithology: |
The Indian Cave Sandstone in the Komarek Field consists of a light colored greenish-gray quartz sandstone containing abundant muscovite mica flakes, and occasional glauconite pellets. The sand is fine grained (1/8 1/4 mm) fairly well-sorted, and is generally sub-rounded. The sandstone unit, as a whole, tends to have numerous very thin 1/8" shale partings consisting of dark brown to black thinly bedded shale. Associated with the dark shale partings are occasional streaks and nodules of pyrite. The presence of abundant mica and shale in the formation sometimes gives rise to high radioactivity on gamma ray logs, which makes the zone appear shalier in some intervals than is actually the case. |
| Formation Geometry: |
The Indian Cave Sandstone in the Komarek Field consists of a general section of sandstone lying between 8 and 40 feet below the top of the Onaga Shale. For purposes of mapping areal extent, the sandstone was divided arbitrarily into upper and lower sands by considering all sands occurring 25' or deeper in the section as lower sand. Isopach maps of these sands yield a pattern of bifurcating lobate sand distribution apparently originating from the northeast and spreading and terminating to the south and west. Marginal dry holes on all sides of the reservoir have either very little or no sand or contain a very shaly non-reservoir siltstone. |
| Trap Type: |
Structural / Stratigraphic |
