Antelope South-1

[petrengr1]

Antelope South-1

Last year I got in trouble for being too optimistic about the expected success ratio of our exploration wells. I have not looked back to see exactly what I said but I believe I guessed between 85% and 95% successful. As it turns out I guessed too low as the success ratio so far has been 100%. Now I have a new guess for you on Antelope South-1. Yes, that’s right... I am guessing 100%.

Now why would I do that? Let’s look at http://tinyurl.com/palye9e slide 27 and see what Mr. Saxon Palmer had to say.
 
“We like that Antelope South partially underlies the Antelope field.

Seismically, it looks a lot like the Antelope field.

As you can see from the top insert this is an area where we have acquired substantial seismic data.

Based on our internal estimates, Antelope-South also has a mid-case estimate of 5.5 Tcfe.

The joint venture has now agreed on a site location for the well and will determine a spud date, pending venture approval.

This well will be drilled by Total as operator.”

And the slide itself says:

“107km seismic acquired in 2013-14

Large-scale, high-impact, low-risk exploration target supported by joint venture

Success at Antelope-South will result in a $65.4 million discovery bonus payment by Total to InterOil for every Tcfe above 1 Tcfe

InterOil is 75% carried by Total SA on first $60 million gross cost”

So it is next door to Antelope, looks like Antelope on seismic, partially underlies Antelope, is a large-scale, high-impact, low-risk exploration target.

We know Antelope Field contains gas. For that gas to get there it migrated from below Antelope South, so the Antelope South should also be full of gas.

Yep, it  looks like a sure thing.

If we find 5.5 Tcfe Total will have to pay IOC $294.3 plus we get our share for the LNG plant.

Have a good night/day!!

[ArtM72]

Are there telltale signs or rationale that dismisses the potential it might be flooded with water?

[jft310]

PET how does gas migrate .?.Would you guess it migrated before the faulting ?.That faulting now blocking connectivity ?.If it migrated after faulting then there is some type connectivity my non geologic mind concludes.
You do not think Ant and Ant S connect so the double faulting must have occurred after the migration??
Thanks for the geology lesson in advance .

[petrengr1]

PET how does gas migrate .?.Would you guess it migrated before the faulting ?.That faulting now blocking connectivity ?.If it migrated after faulting then there is some type connectivity my non geologic mind concludes. You do not think Ant and Ant S connect so the double faulting must have occurred after the migration?? Thanks for the geology lesson in advance .

JFT- You have to think long term. Millions of years. That is long term. All of these limestones and reefs were formed over the same time period and were all one connected body of limestone and reef is a shallow sea. The reefs formed on  top of the limestone in the most shallow water. Over millions of years the limestone and reefs were buried under a few thousand feet of sediments. The moving of the earth’s crust caused faults and fractures separating the limestone and reefs into different segments i.e. Elk/Antelope/Antelope South/Raptor/Whitetail/Mule Deer etc. All at different depths and the blocks were all pushed around with some forming traps with faults and anticlines. The gas migrated from deeper zones that were deposited millions of years before the limestone. All of these rocks are what we call sedimentary rock which means they were formed in water. So at one time all of the porosity in these rocks were filled with water. So we had all of these traps formed and they were full of water. As the gas formed in the lower sediments it started to rise because gas is lighter than water. The gas migrates through any kind of permeable path it can find. That may be faults, fractures, permeable sandstones or limestones. Over millions of years it probably even migrated through the shales which we consider to be impermeable in real time. As the gas migrates toward the surface it enters some of these traps formed by faults and anticlines. The traps are sealed by impermeable barriers so the gas accumulates in the top of the trap and displaces the water out leaving gas at the top and at some point below a gas/water contact.

If a very thick limestone zone has a fault through it with small movement that leaves the limestone in both blocks in contact it is “possible” that there could be pressure communication. I think that is the case between Elk and Antelope but even there GLJ says the blocks are not in communication because they have different gas/water contacts, pressure and I think slightly different gas composition.  Most of these prospects are separated by several faults and the depths are  different by hundreds to thousands of meters. The SPA says the hydrocarbons must be in contact. That is not possible where the different blocks are separated by hundreds to thousands of meters and they all have different pressures and gas/water contacts and different gas composition.

There may be some connectivity between the blocks over millions of years for gas migration but we have to deal with days and years and over that kind of time frame there is no connectivity.

[jft310]

Interesting geology lesson thanks . Just because they used to connect does not mean they communicate today .and no we do not have millions of years for them to re communicate .

[petrengr1]

Are there telltale signs or rationale that dismisses the potential it might be flooded with water?

If we have a trap, as we think we do based on the seismic, as the gas migrates in the water is displaced out.

[2126]

As usual, a great geology lesson put in straight-forward language by a consummate professional. Thanks again, Pet!

[petrengr1]

If Saxon Palmer likes the fact that Antelope South is partially under Antelope Field he must also like the fact that Mule Dear is partially under Antelope Field http://tinyurl.com/palye9e ; slide 26. It appears to me that since we have gas at Antelope and Raptor we have considerably de-risked White Tail and Mule Deer. These two smaller prospects are lying between two sleeping giants.
As far as Raptor is concerned this one seismic line make it look like they may have at least two separate reservoir traps. There could be more if there are some fault traps along the way and depending on how far down dip the gas column extends from Raptor-1.  The western end of Raptor could be another reservoir where the upper end of the formation is below White Tail and seals against the White Tail fault.

These Raptor wells are getting pretty deep. Raptor-1 was drilled to 4032 meters (13,329 feet) and the wells to the East will be deeper. On Dec. 3, 2014 the Company press release said:

 “The Company flared gas and condensate from the Raptor-1 well test. Raptor is only 12km west of Antelope and the deepest well drilled into the Kapau limestone reservoir, encountered at 3,800 meters. On November 14, 2014, the Company notified the Department of Petroleum and Energy (“DPE&rdquo of a discovery at Raptor-1.

Results from the testing program, including pressure measurements, support the presence of a multi-hundred meter hydrocarbon column in excess of the 200 meter gross gas interval already encountered by the well. Logs indicate a highly fractured reservoir system and mud loss during drilling supports the likely connectivity of the fracture network.”

We do not know what “multi-hundred meter” means so we do not know how far down dip the gas column goes. We could at least imply 200 meters plus multi-hundred meters would be more than 400 meters (1,312 feet) but I expect it to be more than that.

Some of these prospects may be difficult to drill if we have to drill through an upper over pressured gas zone to get to them. I guess that is a good problem to have. Too many over pressured gas zones.

[sageo]

If Saxon Palmer likes the fact that Antelope South is partially under Antelope Field he must also like the fact that Mule Dear is partially under Antelope Field http://tinyurl.com/palye9e ; slide 26. It appears to me that since we have gas at Antelope and Raptor we have considerably de-risked White Tail and Mule Deer. These two smaller prospects are lying between two sleeping giants.
As far as Raptor is concerned this one seismic line make it look like they may have at least two separate reservoir traps. There could be more if there are some fault traps along the way and depending on how far down dip the gas column extends from Raptor-1.  The western end of Raptor could be another reservoir where the upper end of the formation is below White Tail and seals against the White Tail fault.

These Raptor wells are getting pretty deep. Raptor-1 was drilled to 4032 meters (13,329 feet) and the wells to the East will be deeper. On Dec. 3, 2014 the Company press release said:

 “The Company flared gas and condensate from the Raptor-1 well test. Raptor is only 12km west of Antelope and the deepest well drilled into the Kapau limestone reservoir, encountered at 3,800 meters. On November 14, 2014, the Company notified the Department of Petroleum and Energy (“DPE&rdquo of a discovery at Raptor-1.

Results from the testing program, including pressure measurements, support the presence of a multi-hundred meter hydrocarbon column in excess of the 200 meter gross gas interval already encountered by the well. Logs indicate a highly fractured reservoir system and mud loss during drilling supports the likely connectivity of the fracture network.”

We do not know what “multi-hundred meter” means so we do not know how far down dip the gas column goes. We could at least imply 200 meters plus multi-hundred meters would be more than 400 meters (1,312 feet) but I expect it to be more than that.

Some of these prospects may be difficult to drill if we have to drill through an upper over pressured gas zone to get to them. I guess that is a good problem to have. Too many over pressured gas zones.

Pet - Many,many thanks for your additional comments on the Raptor discovery .

[petrengr1]

I know we are trying to finish the appraisal work at Antelope so we can get our big payday but it is also important to know how many trains PRL15 will support. If the JV partners are all as high on Antelope South as it appears they need to get this well drilled as soon as possible. If Antelope South does have 5.5 Tcfe and Antelope has 10+ Tcfe that would be enough gas for four trains. At the present they are still hung up talking about 7 Tcfe and a two train plant.

I see Antelope Deep is scheduled for 2nd half of 2015 (timing subject to JV approval), Concept
Selection by Midyear 2015 and FID in 2017.