1 TCF Prospect
turns out to be only
169 BCF & 3.6 MMBO reserves*
by Owen Hopkins

In 1984, I was working on retainer to Winston Sexton, an independent geologist in Corpus Christi, and as I remember the story, a Houston geologist Bill Audas wanted $25,000 in exchange for his acreage on a small Cib haz/Camerina 12,000’ prospect on the south side of Lafayette, Louisiana (Figure A) that Bill had not been able to sell. Since I had previously worked 5 years with Chevron in Lafayette, Win gave me the brochure to review it to see if we could turn it.

While I was reviewing the acreage, the Davis Oil #1 Bayou Tortue blew out (Figure B) while drilling about 1 mile east of our acreage at 16,421 feet at an estimated rate of 20-40 MMCFD. This was very exciting—it was a blowtorch going straight up–and I flew to Lafayette to see for myself. The main roads were blocked, but I managed to go a back way around them later that night and walked into a nearby field. I could easily read a book with the light and the ground was rumbling constantly. Well, this was my show (Figure B) that I needed for our prospect! But what sand was it in?

A critical well to address this sand issue for the prospect was the 1957 Monsanto #1 Girouard that had a 430’ Bol Mex III sand (Figure C), wet and upthrown, to a regional fault one mile northeast of our acreage. This well convinced me that we had a good, deep sand and that this was the primary objective of our prospect. The nearest well control to the west was 10 miles away in the tremendous discoveries of Bol Mex III productive sands in Judice and Maurice Fields (Figure D) on the west side of Lafayette.

To display the stratigraphic, regional control, I decided to make a map showing the major structural features of the area. While I had worked for Chevron, I had mapped South Bosco, North Ossun and Duson Fields, and so I decided to make a Frio map that showed the Nodosaria and Nonion Struma sand embayment areas and then to isopach the deeper Bol Mex sands to generate a Bol Mex Embayment map (Figure E). I interpreted a Bol Mex shelf edge going from North Ossun Field to the St. Martinville salt dome. The Bol Mex north of this line was generally less than 100 feet thick and south of the line I had only one point of control in the prospect area—430 feet of sand in the Monsanto #1 Giraud (Figure C) and several Bol Mex fields just west of Lafayette over 10 miles away with sand sections as thick as 700 feet. (Figure D)

Structurally, we knew from shallower horizons that there were large, major east/west faults traversing this area; and we needed seismic to confirm the deep subsurface picture since there was very little well control below 14,000’. The only strike seismic line that was available was a 1950’s vintage line that was not usable at these depths. Win told me that he had found a lot of oil on old lines and that I should “look at it again for any hints at all that we could get off of it because it was better to make an interpretation rather than to say the line was no good.” Brewer and Associates in Houston suggested having the line reprocessed. They sent the line to India to be hand digitized and then had it reprocessed in Houston. Working with this line, our consulting geophysicist, Tony Hauglum, could make the case for the east dip I needed to separate us from the Davis structure but only at about 16,000’.

Davis finally controlled the blowout, and we knew their discovery sand was the Bol Mex II at 15,000 feet. (Figure F) The seismic line showed a separate Bol Mex III structure to the west of the Davis well. We now had a defined, large Bol Mex III prospect and were able to lease 2200 acres.

After some trouble selling the prospect, Mesa Petroleum eventually bought it. They shot four seismic lines. Mesa returned the prospect to us, as required in the terms of the trade, when they decided not to drill.

That was discouraging, but now I had four brand new seismic lines to work. Using the new seismic control, I revised my maps and now I had a better defined, larger downthrown closure at 16,000 feet separated from the Davis Bol Mex II closure. It was bigger and better and exciting. I thought there could be 1 TCF of gas from not only the Bol Mex III (Figure I), but also the deeper Bol Mex 4 sand. The most important map was on what I called CP3 (Figure G)—This correlation point was above the second pipe point. Most wells TD here so this was a good mapping horizon. I essentially projected this structure down to 15,000’ and 16,000’ using the regional seismic lines we had and the new Mesa lines.

It was somewhat difficult for me to get Louisiana production and completion data while I was based out of Corpus Christi. One of the assistants in the Lafayette Conservation Commission (similar to the Railroad Commission) office told me one time to “get on your jet and fly over here and get it yourself!”

This was a large prospect with many structure maps, isopach maps, marked logs, fault plane maps and it all needed drafted with many colors on each map—and this was long before we had computers. We used Chase Grigsby (draftsman now at CC Log Library). Chase air brushed many, many maps for the multiple brochures we needed—he did these at his home. (remember, you could only do one color at a time and wait for it to dry before adding more colors) He had maps laid out all over his house! Ask him about it sometime.

It was so large that I could only show the prospect 2 times per day. And we showed this prospect to many, many companies and were turned down. We traveled to Houston, Austin, San Antonio, Dallas, Oklahoma City, New Orleans, Lafayette and more.

Here are some of the reasons for not taking this prospect in 1985:

Why didn’t Mesa Petroleum want to drill it?
Why didn’t Davis get this acreage/prospect before a Texas company did?
“Owen, don’t you know there are no sands east of the Wall Fault?”
“Owen, you have been in Texas too long”.
Too expensive – $4,500,000 dry hole cost (cost $25 MM today)

I just could not sell it, not because of the geology–the problem was the trade. We had 2,200 acres and Sexton wanted $1,000/acre and delivering 72% leases with a 25% back-in after payout—and this was late 1985 with an AFE of $4.5million! Many companies said they wanted the deal if only Win Sexton would back off on some of the terms. Win’s idea has always been “the lower the risk, the tougher the trade,” and he was not going to GIVE the prospect away.

But finally we found a company that believed in the prospect—the largest oil company in the world—Exxon! They had a “Quick Hit” team in New Orleans that was autonomous from the Exxon Corporation and had the authority to make decisions and commit the company to deals without all the red tape and normal big company stuff. A few days after we showed Exxon the prospect, they took it all — on Sexton’s terms.

The Broussard Field wells completed in the Bol Mex III Sand were:

Lessons Learned:
Don’t give up.
Don’t be discouraged by others.
Believe in yourself.
Believe in your own work.

But that’s not the end of the story.

An obvious place to extend exploration in this trend would be to the west of our wells—we knew we had east dip and we did put a prospect together west of our discovery wells and we needed 800-1,000 acres (Figure I). But that was tricky–it was very complex land situation with subdivision leasing and town lots and was going to very expensive for the acquisition. So Win contacted a friend of his who owned a car dealership in Jackson, Mississippi. We showed the Pillette Prospect to him and he took on the financing of the leasing.

So a prospect in Lafayette, conceived in Corpus Christi was financed from Jackson.

We put the package (Figure J) together and went on the road. Our Pillette Prospect sold relatively quickly—we sold it to Davis Oil in 1987. They wanted it because it was adjacent to a block they had and they paid Win’s terms that included $1000/acre for 850 acres. We thought we hit a home run until we saw where they staked a well—upthrown to the producing regional fault on the acreage block they leased. I did all I could to convince them that this was a downthrown play just like their Bol Mex II discovery and our Bol Mex III discovery several miles to the east and they needed to drill on the block they bought from us. But they proceeded to drill a deep dry hole (Figure J) and all the acreage fell apart.

The lesson learned here:
Have a working interest in your prospects so you can have more control.

And the story continues in 1998:

13 years later Newfield drilled two very (Figure J) spectacular wells–the Newfield#1 Garber tested 17.8 MMCFD in the same Bol Mex III sands as the ones we drilled in 1986—on the acreage we had for our Pillette Prospect!

The story continues in 2003: drilling 2 more wells on acreage we had in the Pillette prospect in 1987.

This prospect was too big for any one company. It had very complex land issues inside a city—we had one company decline the Pillette prospect because it was to close to a church.

Owen Hopkins
December 2010

*This verifies my old rule:
“Small prospects result in smaller reserves”
Always think big, then if you are wrong, you still have something to be proud of.

Figure A. Index Map

Figure B. Davis Oil #1 Bayou Tortue-Bol Mex II discovery well

Figure C. Monsanto #1 Girouard

Figure D. Judice and Maurice Fields – Bol Mex III Sands

Figure E. Embayment Map for Bol Mex sands with thicknesses annotated

Figure F. Bol Mex II Structure Map

Figure G. Cameron #1 St. Julien

Figure H. Exxon #1 Garber

Figure I. Bol Mex III Regional Structure Map

Figure J. 1987 Pillette Prospect Bol Mex III Map
Newfield wells drilled in 1998-2003