Edwin E. Sticker
Office of Geology
Jackson, Miss.
The Jurassic Haynesville formation of Mississippi and Alabama has historically been just another stratigraphic unit to be penetrated before the underlying Smackover-Norphlet potential could be evaluated.
But with recent production tests at rates in excess of 3,000 b/d of oil and individual wells that have produced more than 3 million bbl of oil equivalent, assuming a 6 Mcf/bbl ratio, many operators have reclassified the objective status of the Haynesville from secondary to primary.
STRATIGRAPHY, STRUCTURE
In the study area, the Haynesville reservoir rocks consist of relatively high porosity and permeability sandstones with interbedded lenticular shales and carbonates.
Incorporating studies done independently by both the author and others, it appears that the Haynesville reservoir unit was deposited in a near-shore alluvial-deltaic environment. 1 2
In Mississippi, which has the most widespread distribution of this unit, thicknesses in excess of 1,000 ft have been encountered. Figs. 1 and 2 show the location and stratigraphic relationship of the Haynesville reservoir sands respectively in the following four fields:
Tallahala Creek (including East Tallahala Creek), Smith County, Miss.
Shongelo Creek, Smith County, Miss.
Bay Springs, Jasper County, Miss.
North Frisco City, Monroe County, Ala.
It should be noted that these sand bodies are not continuous, particularly from Mississippi into Alabama.
Although all four of the previously mentioned fields are associated with anticlinal features, each exhibits a different trapping style at the Haynesnville level. These structural-stratigraphic styles are characterized as a simple anticline, a complexly faulted anticline, a saltbreached anticline, and a depositional termination.
SIMPLE ANTICLINE
Since its discovery in 1965 Bay Springs field has produced almost 32 million bbl of oil and 18 bcf of gas from a Haynesville zone known as the Bay Springs sand .3
Some geologists, including the author, either have correlated or do correlate the Bay Springs sand as part of the Cotton Valley group, but regional correlations integrated with lithologic comparisons have led the author to conclude that it is a Haynesville unit.
The structure at Bay Springs field is a simple anticline formed by upward movement of the underlying Louann salt (Fig. 3).
The Bay Springs sand, averaging about 500 ft in thickness, is draped over the structure, allowing the accumulation of a hydrocarbon column in excess of 100 ft (Fig. 4). Several individual wells have produced over 2 million barrels of oil equivalent from the Bay Springs sand, and one has produced more than 3 million BOE.
COMPLEXLY FAULTED
ANTICLINE
At the Haynesville level the structure at Tallahala Creek field is a steeply dipping anticline transacted by two major down-to-the-north fault systems (Fig. 5).
The Mary James sand, a name given to the field's Haynesville producing sand, is present over the entire structure but becomes thinner with diminishing porosity and permeability on the southern flank (Fig. 6).
The sand has yielded over 5 million bbl of oil and 12 bcf of gas thus far, the majority of which has come from the northern and western flanks of the structure.
The Lower Cretaceous Sligo formation and Jurassic Cotton Valley and Smackover formations have also contributed significantly to the cumulative production of the field.
SALT-BREACHED ANTICLINE
Shongelo Creek field is located on the northeast flank of a northwest-southeast trending anticline (Fig. 7).
The structure is pierced by the underlying Louann salt which forms a diapir that extends upward into the Lower Cretaceous strata. The Haynesville producing zone, a series of three different sands encased in a calcareous shale, is trapped as the sands are truncated updip and juxtaposed against the salt face (Fig. 8).
Although the Haynesville only produced just over 1 million BOE prior to abandonment, significant development potential appears to exist on the northeast flank of the structure.
DEPOSITIONAL TERMINATION
One of the most significant Gulf Coast discoveries in 1991 was North Frisco City field.
The discovery well, the Torch 1 Paramount-Sigler 25-6, encountered approximately 100 ft of net oil column in the Haynesville Frisco City sand. The well was completed at a rate of 832 b/d of oil and 1.03 MMcfd of gas, although several subsequent development wells have been tested at rates in excess of 3,000 b/d.
North Frisco City field is on an anticline created and cored by a Paleozoic basement secture (Fig. 9). The overlying Jurassic Norphlet, Smackover, Buckner, and Lower Haynesville formations lap onto the flanks of the Pateozoic structure and pinch out.
Hydrocarbons generated within the Smackover thus migrate upward into the Frisco City sand, since the Buckner evaporites are not positioned to provide a vertical seal (Fig. 10).
North Frisco City field was originally estimated to contain approximately 8 million bbl of recoverable oil (primary), but a subsequent reservoir study indicates that a pressure maintenance program could possibly more than double this amount.
PROJECTIONS
Without question the Haynesville play is here to stay.
Sure, as with most other plays, it will probably cool off, but only until another multimillion barrel oil field is discovered.
For the near future the primary area of Haynesville activity in Mississippi and Alabama will continue to be in southwestern Alabama. Eventually this play will probably be extended into a portion of the Florida panhandle.
Other promising areas for Haynesville hydrocarbon accumulations are southeastern Newton, northeastern Jasper, and northwestern Clarke counties, Miss. These traps would be the depositional termination type, as the Haynesville sands pinch out on the flanks of Paleozoic highs in areas where the Lower Smackover is in sufficient proximity to source the reservoirs.
Haynesville potential of the salt-breached anticline variety also exists in areas of Smith and Scott counties, Miss., particularly on the downthrown flanks.
REFERENCES
- Aultman, W.L., The Subsurface Bay Springs Sand, GCAGS Transactions, Vol. 25, 1975, pp. 217-229.
- Stephenson, M., Cov J., and Jones-Fuentes, P., How 3D seismic-CAEX combination affected development of N. Frisco City, field in Alabama, OGJ, Oct. 26, 1992, pp. 127-130.
- Mississippi Oil & Gas 1992 annual production report, Mississippi State Oil & Gas Board.
- Southeastern Oil Review, Vol. 56, No. 6, May, 3. 1993, p. 1.
