I am a recent member of this group but I am activitly engaged in Oil and Gas Exploration in the Gulf Coast of Texas. As such I have access to the Drilling Info service in Texas that has an enormous amount of information on permits, drilling wells and production history. I do not have access to the same service in Oklahoma.
Since I have a small mineral interest in Grady County and there is a well in the section next to where I own an interest and other wells permitted neaby I was interested in seeing what a Woodford shale well might produce over the short term and the long term. Having no direct access (except the OCC website which seems a little hard to manage much less download in the first place) I looked at the Barnett shale play just across the river in North Texas and the Eagleford shale play in far South Texas. The Barnett play has some age (10+ years) on it and the Eagleford is much younger. Both these plays are in what is known as "tight reservoirs" which is the same type reseervoir that the Woodford Shale is classified as. The advances in drilling techniques, especially the horiaontal aspect, and the improvement in fracturing techniques has opened up many areas besides Oklahoma to production out of shale reservoirs.
What i have found out is a generalization and will not reflect exactly in the performance of a given well that anybody has a royalty interest in. Since my conslusions are from "out of State", if anyone has some direct information on the decline rate of a given Woodford shale well or wells please chime in.
Looking at the above mentioned reservoirs I find that the declline rate of gas produced declines about 50 to 80% in the first two to three years of initial production and then levels out and can produce for another 10 to 15 years. The oil production seems to decline faster and can be 80 to 90% down in the same two or three year period. I had no break out of condensate with the gas to look at. There will be wells in the Woodford that have more oil with the gas produced and some with less and wells that produce gas only.
Again, I have no direct info on the Woodford except for initial tests. The play in Grady is somewhat new and a better view of the production would be to look in the eastern part of the play that has a longer history if anyone has access to this kind of information. A production result from a 5 or 10 year history in the Woodford shale would be most useful.
I am posting this to demonstrate what happens in the real world of tight shale reservoirs as opposed to what someone may hope happens. The initial tests in a given well may look very promising and that well may live up to the initial results. But overall, the decline curves are a historical fact and, in general, a decline will take place at some rate in any well.
The upside of this is the number of wells that can be drilled in a 640 acre unit. In the Counties north of Grady the spacing may be as small as 80 acres which could put 8 wells into the 640 acre unit. All the wells in the unit would not give exactly the same results as to initial production or decline rates. Some would be better than others. With the forced pooling in Oklahoma all royalty interest owners in that 640 would share in every well drilled there. The operator of that unit would decide how many wells to drill in the unit and when. The royalty owner has no part of this decision by the operator.
Hi Don,
Thanks for all the info! Question: Who sets the spacing within a 640 acre unit? In the units in the Woodford that I have interest in the spacing is 640 acres. Can that change later down the road? Thanks again.
Yes it can change and it is up to the operator with permission from the State. With some companies considering 80 acre spacing as the final optimum spacing in the Woodford to drain a given 640, some 640 acre units will have more wells in them than other 640 acre units in the long run. This "infill drilling’ cam take place over months or years depending on the performance of the wells, the price of the oil ond gas and the finiancial health of the operator.
Go to Cimarex.com
Click on PRESENTATIONS
For example, page 15 of the following presentation shows a typical decline curve:
http://phx.corporate-ir.net/External.File?item=UGFyZW50SUQ9NDM3Mzc4fENoaWxkSUQ9NDU4MDkzfFR5cGU9MQ==&t=1
Great info JW, now with some of the presentation I can draw some broad conclusions. The "core" of the CanaWoodford seems to reach a thickness of about 300 feet in Northwestern Canadian County. This thickest area may cover only about 1/2 of a township (+/- 18 square miles). With the drilling that Cimerax has done I don't doubt the accuracy of the maps presentated.
The "core" area seems to be located at a depth of 12,000 to 13,000 feet with thickness of the Woodford in that depth range being 200 to 300 feet. The decline curve shown was based on a well giving up 6.5 to 8.5 Bcfe total and have a life of 10 years or more. The greatest production will happen in the first two years as the actual production out of the Barnett and Eagleford shales confirm.
My small interest being in central Grady indicated the same depth range of 12,000 to 13,000 feet. Now only if another "core" area of the thickness of 200 to 300 feet could be located there I might be able to see some good production associated with that royalty interest.
The maps Cimerax presented were based on a lot of well information in the "core" area. As they move away from the heavier drilled areas into the lesser drilled areas, maps such as were presentated get more unreliable. Any conclusion drawn in the lesser drilled areas can be wrong and probably is when all of the drilling has taken place and the well data is worked into the "final" maps.
MIchael, do you have info on activity in Reeves county TX Or a way for me to obtain info? thanks Phyllis
Phyllis-
I have access to Drilling Info in Texas. What type activity do you want to know? Permits, leasing, production?
Reeves is a big county. If you could give me an Abstract number or something to get me to the area you a interested in, I can find some things out, maybe not everything but items like I mentioned above. Again, try and pinpoint your location you are interested in and what kind of activity. I pulled up Reeves County and there is activity all over the county.
Shot a lot of seismic data over Reeves 45 years ago.
PHYLLIS TIMS said:
MIchael, do you have info on activity in Reeves county TX Or a way for me to obtain info? thanks Phyllis
SEC 30 BLOCK 54 T4 T&P RR CO. SURVEY SEC38 BLOCK 54 T4 T&PRR CO. SURVEY ANY DRILLING ACTIVITY OR PERMITS Thanks again
Phyllis-
I don't see anything in the last year. Drilling Info was having trouble taking the location information as you gave it to me. Check that again and make sure it was correct.
PHYLLIS TIMS said:
SEC 30 BLOCK 54 T4 T&P RR CO. SURVEY SEC38 BLOCK 54 T4 T&PRR CO. SURVEY ANY DRILLING ACTIVITY OR PERMITS Thanks again
I do think the description is correct. If not our lease is bogus. :) It is about 15 miles north of Pecos
Don,
Look on OCC site at sec15 13n10w. this is an infill test done by cimarex with 5 wells. As they state in the presentations infill is going to be 8 wells. Cimarex also doing 8 well project in sec 25 14n 11w blaine county.
I believe Devon and Cimarex are working well together and trying to get as much of the fairway HBP as possible.
Do not think Continental Resources is with the two above as they are protesting the application cimarex has on sec 35 11n 9w but cannot find out why the protest.
Interesting info Patrick.
Infill drilling in the Woodford is a given with the amount of hydrocarbons available to be recovered there. Some companies want a more robust return for their investment, some companies want the term of production stretched out longer. If, and this is only an if, a company drills eight successful wells in a 640 section over 2 years, the "flush" (i.e. maximum flow rates) of those 8 wells might be 4 years. Rapidly declining flows on all wells after that. The company that takes the longer view of drilling the eight wells in the section could take as long as 8 years to drill the eight wells to drain the 640 section. The cash flow is stretched out much longer and may be of more long term benefit to the company than a quicker return of drilling the 8 wells in two years.
The companies that drill the 8 wells quickly will force a company in the adjacent sections to act more quickly in drilling their infill wells to keep from losing product to the more rapidly drilled wells in the sections next to them. Worst case scenerio: The sections north, east, south and west of a given section have 8 wells each. That section with only one well in it, holding it for several years HBP, might not get the expected total reserves out of it because of possible draining by the adjacent 32 wells.
Lots of possible arguments about these sorts of things, probably to be settled in court. The starting of the 1280 acre units in the woodford will make this situation worse in terms of conflict between various companies.
Don,
That is so right. I think the 1280 is going to bring on the progression of a 8k to 9k lateral running the length of two sections. What do you think? I think that cimarex may already be doing one down in Grady some where in the 10n 8w area. That will be interesting to see returns on that kinda of drainage. What do you think about the woodford being source rock for all or most of the formations above?
Don Underwood said:
Interesting info Patrick.
Infill drilling in the Woodford is a given with the amount of hydrocarbons available to be recovered there. Some companies want a more robust return for their investment, some companies want the term of production stretched out longer. If, and this is only an if, a company drills eight successful wells in a 640 section over 2 years, the "flush" (i.e. maximum flow rates) of those 8 wells might be 4 years. Rapidly declining flows on all wells after that. The company that takes the longer view of drilling the eight wells in the section could take as long as 8 years to drill the eight wells to drain the 640 section. The cash flow is stretched out much longer and may be of more long term benefit to the company than a quicker return of drilling the 8 wells in two years.
The companies that drill the 8 wells quickly will force a company in the adjacent sections to act more quickly in drilling their infill wells to keep from losing product to the more rapidly drilled wells in the sections next to them. Worst case scenerio: The sections north, east, south and west of a given section have 8 wells each. That section with only one well in it, holding it for several years HBP, might not get the expected total reserves out of it because of possible draining by the adjacent 32 wells.
Lots of possible arguments about these sorts of things, probably to be settled in court. The starting of the 1280 acre units in the woodford will make this situation worse in terms of conflict between various companies.
That the Woodford is the source for many of the formations that are above it. That was one of the givens when I took a degree in Geology at OU. I have spent most of my career in Geophysics since then but have to integrate both in my exploration activities.
I think there are already a few 8K laterals north of Grady. The companies will be jumping all over themselves to get these 1280s approved. More lease to hold easier. Some companies are "booking" reserves under their leases without having drilled wells on them. Nice little slight of hand to make the company seem worth more than their "proved reserves" says they are worth. Mother Nature is a very fickle beast. Surprises galore. What you think you have, you find out by the drill bit that you really had nothing at all. So long rosy finiances.
I saw on interesting engineering comment on these web sites a few week ago that indicated that the best production came out of the first 1000 feet of a 3000 foot lateral. If there is any truth to that, what about an 8000 foot lateral? Sort of knowing the rocks, I think the first 1000 feet may still hold the better production.
Don I am glad I get to talk to a rock Guy! Have you heard anything about the Barnett extension into the Hardeman basin? I also see the Atoka formation is showing good results in Jackson county OK.
No, have not heard anything about that but it would not surprise me. All of this shale gas and oil production across the U.S. west of the Rocky Mountians should not surprise any Geologist since the shales are generally viewed as the source for most oil and gas, not all, but most in the Sedementairy Basins here in the U.S.
The Sixty four $ Trillion dollar question is whether the powers that be will let it be developed.
amen to that Don! Is it true that from, lets say, the Cherokee platform southwest was once a river delta, like the Mississippi at
Don Underwood said:
No, have not heard anything about that but it would not surprise me. All of this shale gas and oil production across the U.S. west of the Rocky Mountians should not surprise any Geologist since the shales are generally viewed as the source for most oil and gas, not all, but most in the Sedementairy Basins here in the U.S.
The Sixty four $ Trillion dollar question is whether the powers that be will let it be developed.
The stratagraphic differences from area to area contain everything possible in a depositional sequence. From river deltas to beaches to tubrodite deposits to deep water limestone sequences. Since the Cherokee platform was a higher area, the southwest flow of the various rivers off it could form delta sequences to the southwest of it. If it was high enough and large enough, it could have rivers depositing delta sequences to the south and east also.
The advent of 3D seismic data will let an interpreter tear apart the depositional sequences that the 3D covers. However the collection of this type data is very expensive and it is usually limited to specific oil and gas targets to maximize the results from drilling there such as the Woodford shale in Central Ok.
Don I hope I am not bothering you with these questions? I am very fascinated with O&G geology. That and I want to know what is under my feet when I am negotiating