(Maps and type logs for Bassfield and Oakvale Fields follow
this discussion.)
The Hosston Formation
is a thick sand and shale sequence of Lower Cretaceous Hauterivian -
Aptian age, and is correlated to be the eastern representative of the
Travis Peak Formation of Texas. It can reach a thickness in excess of
1,000 feet within the center of the Mississippi Interior Salt Basin. In
general terms, the Hosston depositional environment transitions from
fluvial, in east-central Mississippi, to fluvial deltaic in south-central
Mississippi, to marine in southwest Mississippi and the Florida Parishes
of Louisiana. Hydrocarbon production from the Hosston Formation was first
derived from oil reservoirs located within the updip fluvial sequence
(primarily because these reservoirs were located at shallower depths), but
the real Hosston Play in Mississippi was kicked off in the 1970's with the
discovery of multiple Hosston gas reservoirs within the fluvial deltaic
trend in Jeff Davis, Covington, Simpson, and Marion Counties, in
south-central Mississippi. This part of the Interior Salt Basin is
dominated by salt diapirs, residual salt swells, and interdomal
"turtleback" (sedimentary-cored) anticlines. In the 1950's and 1960's,
test wells had been drilled atop most of the turtleback anticlines but had
for the most part stopped at the top of the Lower Cretaceous (in those
days, the Upper Cretaceous Lower Tuscaloosa Formation was the principal
target of interest, and little was known about the deeper Lower Cretaceous
section). Few of the shallower UK tests were successful, and Hosston
completions made elsewhere in the Basin were unimpressive. In addition,
steep dips around most of the salt diapirs in the area frustrated attempts
to accurately test their narrow flanks. However, in 1974, the discovery of
large (>100 BCF) Hosston gas reserves at
Bassfield Field in Jeff
Davis County, atop a turtleback anticline, created huge momentum for
drilling most of the turtleback anticlines deeper. The upward spike in gas
prices that occurred later in that decade only further fueled the
expanding gas play. Other large fields such as
Oakvale, Greens
Creek, Grange, White Sands, and Holiday Creek -
to name a few - were quickly developed. The collapse of natural gas prices
in 1981-1982, which coincided with the maturation of the play and a
decrease in new field discoveries, caused the Hosston Gas Play in central
Mississippi to quickly fade. However, from time to time, the industry was
reminded of its potential, especially when large Hosston gas reserves were
serendipitously discovered at Poplarville by Exxon in the
mid-1980's. Exxon, in the course of drilling a deep Smackover test on the
west flank of the Wiggins Arch (in Pearl River County, Mississippi),
stumbled into overpressured gas reserves in over seven different Hosston
Sands. Although the deep Smackover objective was found to be nonporous at
that location, Exxon's subsequent plug back and completion in two Hosston
gas sands eventually led to the production of over 150 BCF of gas from
multiple gas reservoirs in the 15 years since that first Hosston
completion was made in the Poplarville Field area.

Most of the gas reserves
produced from the Hosston in south-central Mississippi have come from the
Harper Sand, a very clean and porous sand located in the upper
Hosston section. Although some lenticularity is observed throughout the
area, the Harper Sand is fairly well distributed and there are many
individual Harper Sand gas wells in the trend that have produced in excess
of 10 BCF. Also noteworthy is the Booth Sand, which ranks second in
total Hosston gas production but is notoriously "dirtier" than the Harper
Sand. Specifically, the Booth Sand typically contains much higher
concentrations of smectite and illite, and is much more sensitive to
drilling and completion fluid rheology. For this reason, many Hosston
Booth Sand gas completions - especially those made early on, in the
life of the trend - were plagued by high "skin" factors, inefficient
drainage, and low cumulative gas production. Other Hosston reservoirs of
lesser importance include the First and Fifth Hosston Sands and the
Diffrient Sand, which hosts a deep (and rare) Hosston oil
pool in the Holiday Creek Field in Jeff Davis County.

The trapping style for the
Hosston reservoirs in Mississippi ranges from simple anticlinal closures
to truncation against salt dome flanks to purely stratigraphic traps
formed where a lenticular Hosston Sand crosses a structural nose in a
perpendicular fashion.

In the last two years, a
renewed effort to recapture those gas reserves still left in those Hosston
reservoirs damaged by early drilling and completion methods - in
particular, the significant reserves remaining in the Booth Sand - led
several operators to attempt new and innovative completion techniques in
several existing fields. One of the most successful of the new approaches
is the practice of re-entering a Hosston gas well known to have suffered
serious formation damage and plugging back and sidetracking out of the
original wellbore above the sand; redrilling the sidetrack hole back to
just above the top of the sand; cementing a liner in place; and drilling
into the top of the sand with a CO2 foam system, and producing
the reservoir as an open-hole completion. This method effectively prevents
the exposure of the sensitive Hosston reservoir to water or water-based
drilling fluid, a precaution that appears to have paid off; several of
these new "water-free" recompletions have resulted in stabilized flow
rates in the 2,000 to 3,000 MCFGPD range, which is more impressive when
one recalls that in many of those (original) wellbores, production from
the same reservoirs had declined to non-commercial (<100 MCFGPD) rates.

Vision Exploration believes
that significant gas potential still exists in those deeper Hosston Sands
- below the Booth Sand - that were not reached by many of the older
Hosston wells drilled in the 1970's and 1980's. These deeper reservoirs
have been found to be productive on the flanks of many of the salt domes
that have been recently drilled in the Basin. If these deeper sands are
productive on the salt dome flanks, they should also be productive on many
of the adjacent turtleback and residual structures, because those
structures experienced structural growth in the Hosston at the same time
as their related diapirs. Vision Exploration has singled out several of
these targets for inclusion in its Exploration Program.




(Daily flow rates shown above are as reported by the Mississippi O&G
Board, June 2004.)

