Replies to This Discussion

Permalink Reply by Big Little Oil on September 11, 2012 at 6:42

http://http://sonlite.dnr.state.la.us/sundown/cart_prod/cart_con_we...

Permalink Reply by Chip Sanches on September 12, 2012 at 2:20

Thanks B.L.O.  Looks like a vertical well and probably primarily a natural gas producer.  The SONLITE data doesn't seem to show any production data (yet).  Think I'm correct?  I appreciate your expertise.

Permalink Reply by obed w odom on September 12, 2012 at 3:32

Here is a link to the preliminary completion report for this well, filed with the LA DNR on Sept 7, 2012, but it shows no production data:

http://ucmwww.dnr.state.la.us/ucmsearch/UCMRedir.aspx?url=http%3a%2...

Permalink Reply by Big Little Oil on September 12, 2012 at 3:37

What formation is "Gray Sand"?

Permalink Reply by obed w odom on September 12, 2012 at 4:00

I had thought the Gray Sand was just below the Smackover, but I see the top of the Smackover is not listed in the preliminary completion report.

Permalink Reply by Big Little Oil on September 12, 2012 at 4:02

Also, what is the "Smackover C" sand that XTO keeps using in its well names?

Permalink Reply by obed w odom on September 12, 2012 at 6:24

I think the Smackover C is the lower part of the Upper Smackover and is probably very close to the Gray Sand. It seems that the Gray Sand is also considered part of the Smackover by some. Aubrey Sanders may be able to sort this out.

Permalink Reply by Chester Fairfield on September 13, 2012 at 2:19

The gray sand is not the same as the smackover.

 

The gray sand used to be considered to be part of the Smackover, but is now considered to be a lowstand fan deposit in the Buckner Formation.

Permalink Reply by obed w odom on September 13, 2012 at 8:15

I found this info online concerning the Gray Sand. It may be a little dated, but in 1980 it was apparently considered to be in the lower member (C zone?) of the Smackover formation:

Gulf Coast Association of Geological Societies Transactions
Vol. 30 ( 1980 ), Pages 177-182

A Petrographic, Stratigraphic, and Structural Study of the Smackover Gray Sand (Jurassic) in North Louisiana

Samuel A. Miciotto (1)

ABSTRACT

The Smackover Gray Sand is the target of intense exploration activity in the north Louisiana area. The gas-producing Gray Sand, a dark gray to black, very fine-grained sand, occurs as three sand tongues in the lower member of the Smackover Formation in the subsurface of Bossier, Webster, Claiborne, and Lincoln Parishes, Louisiana. The majority of Gray Sand wells have been drilled in Bossier and Webster Parishes. However, the most active exploration presently is to the east in Claiborne and Lincoln Parishes.

Samples of the Gray Sand are classified as subchertarenites because of their high percentage of quartz and the dominance of chert fragments over plagioclase. Additional mineral constituents include muscovite and biotite; oolites are also present. A flaser-bedded silty shale facies indicates deposition on a mid-tidal flat environment.

Smackover deposition during the Jurassic in the study area was located on the gently dipping slope between a broad coastal shelf to the north and a basin to the south. The Gray Sand was deposited over the Norphlet Formation and Louann Salt before flowage and swellng of the Louann Salt began. Uplift and swelling of the Louann Salt later in the Jurassic created growing anticlines; sediment slumped off the structural highs of the growing salt anticlines into basinal muds and silts. By superimposing the isopachous map of the Gray Sand interval over the structure map of the Gray Sand, it can be seen that the thickest Gray Sand intervals lie on the flanks of the anticlinal structures in South Sarepta, Ivan, and Cotton Valley fields. Absence of the Gray Sand between Ivan and Cotton Valley fields indicates a facies pinchout due to localized deposition of sand tongues on the structural highs.

The Gray Sand, because of its low porosity (7-10,%) and permeability (.5 Md.), must be stimulated to be productive.

Seismic exploration locates favorable structures for Gray Sand production in Lincoln Parish fields. The Smackover Gray Sand however continues to challenge exploration geologists because of the lateral pinch out of its sand tongues.