Permian basin stratigraphy

It is very intertesting reading the current comments about the "layered cake" plays by Raphr, Jack, Page, and others. I have been on the Dawson Co forum for a year and I own some mineral interest on two farms my Granddad bought in the 1920's and on the farm near the Munger community, three "Triple D (Penn Reef) wells were drilled in the late 1950's and produced until about 10 years ago . Two of these wells were 8500 ft. and one was 12,500. I have a couple of questions which my 50 year old geology degree hasn't answered so I am open for your comments. Is the Penn Reef Pennsylvanian in age? Does the D part of Triple D indicate the "D" shelf of the Wolfcamp? Is the Cline shale the source rock for the Penn Reef? And why are 2 of these wells 8500 ft and one is 12,500 ft and all 3 are in a space of less that 1/2 mile? Our interest has been unleased since 2008 when the last well was plugged and reading all your comments keeps me hopeful so I will appreaciate you responces.

I think that the "Penn Reef" is the "Penn shale" that over lies the Horsehoe Atoll and that it is Pennsylvanian in age.

"Reef" seems to be related to the atoll in some way, related meaning on it or near it.

According to the RRC, the Penn Shale and the Cline are one and the same, at least in the lagoonal part of the atoll.

As far as the 12500 depth goes, I've got nothing.

You might go on the RRC Website and research other wells that are around yours and get a better idea of the formations and depths in your area.

Look for your County, and section number in the GIS Viewer. Click on "Identify wells." Check out a few of them around and see what comes up.

I'm just wildcatin' some thoughts for you. Hope it helps.

John, I'm no expert - just share with others some of what I've learned. Based on the Big Spring 1976 newspaper article I've copied and attached (which mentions the Triple D Penn. reef), and everything else I've learned, I doubt that Triple D refers to the Wolfcamp D. From the article, I'm thinking that perhaps Triple D in this case could have been the name of a ranch in the area? Maybe the article will help some.

Additionally, I've just looked at lots of area and stratigraphic maps from conference and corporate presentations, etc., and can't find the Penn reef mentioned in them per se. Maybe someone else has one that shows it?

2601-BigSpringnewspaper1976articleTripleDPennreef.pdf (251 KB)

Alrighty then! The “layered cake” analogy is a term I heard a VP in charge of E&P for a Mid-Cap Energy company use - and it helped me explain things about the potential of our mineral rights to my family in terms they can grasp. I recently came with my own improvement on the cake concept - certain formations (cake layers) are not as good as others (e.g., the layer of frosting is a really good formation like the Cline) and other formations like the Spraberry is a regular cake layer). Now think of it as a German Chocolate Cake. The frosting has coconut shavings in it. The coconut in the frosting is like a layer that is not so hot - it doesn’t hold as much oil, etc. but it is still in the frosting and it has some coconut oil in it - a little different, but not too bad. How does this analogy work for ya?

Yes, the Penn Reef is Pennsylvanian in age. It’s a carbonate/limestone/dolomite. Dolomite is a type of limestone which is more durable due to having magnesium in it in higher concentrations than LS.

Those well depths were very, very deep for that time and era. I can only surmise those wells were drilled by a large oil company. Without seeing the boring logs and geophysical info they were working off of - the reasons are various for why things were that way. I can’t answer your question about sources w/ out looking at my lithologic cheat sheet at the office. It is old though. I think the wells are deep wells were for exploration purposes and they were logging things for mapping - the wells may have been secondary. Most producing wells from that area and time are much shallower. Sorry to hear they are plugged. But there may be a silver lining - it is cheaper and faster to re-enter a abandoned well generally speaking. So you know your abandoned wells are on the radar screens. You should have the boring logs, well construction, geophysical data, and well development forms - if you don’t, get them. Read up on the Horseshoe Atoll, and on Residual Oil Zones (ROZ). If you’re due North of Lamesa and to the east there is a oil field in the Spraberry that is flying under the radar called the Powe oil field. That’s mentioned in dockets on the RRC website.

Thanks a lot for the come-back Paige and G T. Those articles in the Big Spring paper were interesting as the wells mentioned would be very close to our stuff. We are about 10 miles NW of Lamesa , Block M Sec 77 which is about 2 miles from the old Munger school. The J.A. Richardson #3 (ID# 12761) made over 2800 barrels in 2003 but was shut down for maint. in Jan 2004 and nearly 5 years later the operator still held the well in "inventory" so I filed a complaint against the operator with TTRC which ordered the operator to plug and abandon which was done in Oct 2008. I have seen the Penn Reef mentioned a few times through the years but not recently. During the last few years wells completed near us were Fusselman,Marholl,Siluro Devonian,San Andres, Canyon Reef, and Mungerville Penn which is the first mention of "Penn" I have seen in along time. We (12 siblings and first cousins) also have a few mineral acres about 3 miles NE of Lamesa not far from some Powe activity but neither of our places are leased at present. I'm 76 and kind of in a hurry so I just say bring it on. Thanks, John

Thanks Ralpr for you comments. I think Willow Creek Resources drilled those wells as their name is on the 1956 oil lease. You mentioned the possibility of a re-enter project and there is an operator in the area doing just that and they were interested in our stuff until they discovered that the previous operator was forced by TTRC to plug so they were very hesitant to enter the old well, in other words, the hole could be full of junk iron.

Sure. I guess that outfit had some major funding at the time then.

Sorry to hear about the fears with the abandoned wells - hopefully there is some geophysical method (magnetic anomalies?) to determine if there is junk in the well borings. There should be an individual’s name on the well abandonment form who you could ask about it. I’d talk to the person and not the company.


Whe n looking at recent drilling permits they just say Wolfcamp. Does that mean the target could be Wolfcamp A,B,C, or D? Any or all?

Any/All - they want to keep things as cloaked as possible for proprietary reasons. But with the estimated depth and/or lateral targets one might be able to infer the potential target. If it’s horizontal - it would be very interesting to see which direction it is slated for.



I guess the next obvious question would be, What would the direction of the lateral indicate?

Well, it may indicate the predominant fractures direction - the horizontal leg may be almost perpendicular to the fractures to capture the most BOE. Also, if you know that - it might be a way to estimate a ballpark figure on HZ wells for starters anyways - but that depends on the number of wells per well pad/nest. At any rate - it’s a back of the envelope estimate. Hopefully way off and on the low side. E .g., 320 Acres and well spacing approved is for 160-Acres per well - but based on where the fractures are - there may be leeway for more well/s, especially if the horizontal leg is 7,000 feet and you have 640- Acres plus sharing proceed from the wells.