The Flank Shallow Piercement Plays of Mississippi
WARNER, JOHN, and JACK MOODY, Office of Geology, Jackson, MS
The search for production on the flanks of the piercement salt domes extends from the East Texas basin to the Mississippi Interior Salt basin. The combination of fundamental subsurface geology, modern seismic, and deeper drilling have resulted in several field discoveries in Mississippi. Existing subsurface and production information suggests the flanks of the domes are structurally and stratigraphically complicated, but the potential rewards warrant the necessary effort. A brief review of the existing flank productive fields illustrates the complexities and similarities of the flank dome-related fields.
The first such field in Mississippi was Shell's Camp Shelby field on the flank of the Cypress Creek salt dome in Perry County. In 1972, Shell drilled through a 2775-ft salt overhang and established production in the Tertiary Clayton and the Lower Cretaceous Paluxy Formations. Of the five wells drilled, three produced and one of the dry holes was used as a saltwater disposal well. The wells were drilled to an average depth of 15,400 ft. In addition to the productive zones, excellent shows were encountered in the Hosston Formation (flowed 169 bbl of oil/day). As of January 1990, the three producing wells drilled in the Camp Shelby field have produced 555,360 bbl of oil and 293,483 mcfg of gas.
Since this discovery, several more domes have proven productive. Enserch developed West Raymond field on the southwestern flanks of the Oakley salt dome in Hinds County, Mississippi. After their 1985 discovery in the Lower Cretaceous Rodessa, they drilled 13 wells. Enserch established production in the Lower Cretaceous Mooringsport, Pine Island, and Rodessa formations. As of August 1990, this field has yielded 1,474,869 bbl of oil and 1,004,911 mcfg of gas.
In 1986, Sun Oil drilled a discovery well on the southern flank of Dont dome in Covington County, Mississippi. The well was a dual completion from the Lower Cretaceous Rodessa and Sligo formations and tested 468 bbl of oil/day and 3710 mcf of gas/day. Sun has since drilled two more producing wells in the Leaf River field. Oryx (formerly Sun) then moved over to the Centerville salt dome in Jones County, Mississippi, and drilled a discovery well in 1989. Production is from a series of sands in the Lower Cretaceous Hosston Formation on the flank of the dome.
These examples show that production is present on the flanks of Mississippi piercement domes. With the use of subsurface well information and today's advanced seismic, the complex structure and stratigraphy associated with the shallow piercement salt domes can be deciphered. The flanks of these domes can produce fields with steeply dipping beds, thick potential reservoir sands, and multiple pay zones. This equates to large per-well reserve potential under relatively small acreage. What can be learned from the fields already discovered will surely aid in future efforts to explore and develop other dome-related fields.
AAPG Search and Discovery Article #91006 © 1991 GCAGS and GC-SEPM Meeting, Houston, Texas, October 16-18, 1991 (2009)