Reservoir Drive Matters

[haroco]

It's hard to get a straight answer to the size or drive question.

I have posted this information before but some of you might find it of interest.

Go to the 2009 GLJ report at http://tinyurl.com/lrjknkq 

GLJ thinks this is  not a water drive as described on page 27 of 51:

"If the Elk/Antelope structure was connected to this system, then an infinite-acting aquifer would be expected. However, as shown on Plot 1, the Elk/Antelope aquifer is approximately 460 psi higher in pressure, proving a disconnection. The over pressuring of this aquifer could be related to a sealed fault block or series of fault blocks being elevated during tectonic movement, which would result in a limited water drive, or a higher recharge area (approximately 500+ metres above sea level, which would be in the mountains to the north). This second option would require a regional, north-south oriented permeability barrier to the west of the structure. If this was the case, then a strong aquifer would exist."

Recovery factors  for the Low Estimate, Best Estimate and High Estimate are shown on page 31 of 51. TheLow Estimate was for a strong water drive with 80% water swept volume. The Best Estimate was for a weaker water drive with 50% water swept volume and the High Estimate was for 20% water swept volume or pretty much a depletion drive.

I do not know how this has changed over the years with the GLJ reports since this is the only one that has been published.

I am a believer in the depletion drive simply because the aquifer pressure is 460 psi higher than the regional aquifer. I do not buy the 500+ meters higher recharge area. I think there are too many faults and we are too far from the mountains for this to be the case. We will probably have some water drive due to the expansion of the "sealed up" and over pressured aquifer but this should be minimal since water is pretty much incompressible. If the aquifer is sealed up then the high case becomes the Best or most likely case. In  2009 the "marketable" P-50 gas was 9.08TCF plus 156.5 million barrels of condensate.

I'm onboard with Pet ... plus,plus the enity that would have the best info is XOM ... if they are afraid of water drive, why would they put a cap on their "additional stk payments" at 10 , i.e., no cap probably needed?   ... they probably wouldn't be bidding at all.   It was OSH that started the rumor to keep others from bidding against them !!!

At the end of 2015 GLJ had a Gross un-risked 2C resource level of 1,662.6 MMBOe which is equivalent to10.4 TCFe. The Gross un-risked 3C resource level was 2,022.4 MMBOe which is equivalent to 12.13 TCFe. So if we had a perfect depletion drive the recovery should be more than 12 TCFe.

[haroco]

It's hard to get a straight answer to the size or drive question.

I have posted this information before but some of you might find it of interest.

Go to the 2009 GLJ report at http://tinyurl.com/lrjknkq 

GLJ thinks this is  not a water drive as described on page 27 of 51:

"If the Elk/Antelope structure was connected to this system, then an infinite-acting aquifer would be expected. However, as shown on Plot 1, the Elk/Antelope aquifer is approximately 460 psi higher in pressure, proving a disconnection. The over pressuring of this aquifer could be related to a sealed fault block or series of fault blocks being elevated during tectonic movement, which would result in a limited water drive, or a higher recharge area (approximately 500+ metres above sea level, which would be in the mountains to the north). This second option would require a regional, north-south oriented permeability barrier to the west of the structure. If this was the case, then a strong aquifer would exist."

Recovery factors  for the Low Estimate, Best Estimate and High Estimate are shown on page 31 of 51. TheLow Estimate was for a strong water drive with 80% water swept volume. The Best Estimate was for a weaker water drive with 50% water swept volume and the High Estimate was for 20% water swept volume or pretty much a depletion drive.

I do not know how this has changed over the years with the GLJ reports since this is the only one that has been published.

I am a believer in the depletion drive simply because the aquifer pressure is 460 psi higher than the regional aquifer. I do not buy the 500+ meters higher recharge area. I think there are too many faults and we are too far from the mountains for this to be the case. We will probably have some water drive due to the expansion of the "sealed up" and over pressured aquifer but this should be minimal since water is pretty much incompressible. If the aquifer is sealed up then the high case becomes the Best or most likely case. In  2009 the "marketable" P-50 gas was 9.08TCF plus 156.5 million barrels of condensate.

I'm onboard with Pet ... plus,plus the enity that would have the best info is XOM ... if they are afraid of water drive, why would they put a cap on their "additional stk payments" at 10 , i.e., no cap probably needed?   ... they probably wouldn't be bidding at all.   It was OSH that started the rumor to keep others from bidding against them !!!

At the end of 2015 GLJ had a Gross un-risked 2C resource level of 1,662.6 MMBOe which is equivalent to10.4 TCFe. The Gross un-risked 3C resource level was 2,022.4 MMBOe which is equivalent to 12.13 TCFe. So if we had a perfect depletion drive the recovery should be more than 12 TCFe.

[petrengr1]

Pet - Based on this statement from GLJ, will Ant-7 likely provide essential information towards defining drive type?

"This second option would require a regional, north-south oriented permeability barrier to the west of the structure. If this was the case, then a strong aquifer would exist."

Li’oilady- I don’ think we will learn anything about the type of reservoir drive we have from Antelope-7. We have always known that we have a fault bounding the field on the west side. As I have said before I think we are too far from the mountains to the north and we probably have many permeability barriers (faults) between Antelope and the mountains, so I do not think the a higher recharge area is a viable reason to expect a strong water drive. I do not know anything about a regional fault to the west but I would think that if one exists that GLJ would know about it. I prefer the sealed fault block theory to explain the 460 psi over pressure that we have in the Antelope aquifer. That would give us a depletion drive instead of a strong water drive.

To change the subject a bit if you look at page 18 of Phil’s presentation you will see what he has to say about the drilling of Antelope-7. I have posted before that if we drill the well too far west we might have a dry hole. Phil’s theory would be to move the Antelope-7 far enough east to be sure we are going to hit the reservoir on the east side of the fault and then, soon after penetrating the top of the reservoir, drill a horizontal hole toward the west to see if we can locate the fault. This would allow us to find the fault without drilling through it which Phil says will give us drilling problems. Sounds like a good idea to me but since they have already built the location I doubt that they will change it at this late date.

[Putncalls]

Isn't the primary question a RF question rather than an accurate western fault location?

[petrengr1]

Isn't the primary question a RF question rather than an accurate western fault location?

I guess if proving the fault is further west will add 1- 3 TCF it is a pretty big deal.  And yes recovery factor is one of the primary questions and apparently there is a difference of opinion between the companies doing the appraisal work. I think GLJ has "all" of the data and I think their number looks like they believe we will have a high recovery factor similar to Arun, ~80 -90%. If that is true they obviously believe we will have a depletion drive.

[Putncalls]

GCA seems partial to water drive? XOM gets to pick the drive mechanism? I guess, better them than MH?

[sageo]

Pet - Based on this statement from GLJ, will Ant-7 likely provide essential information towards defining drive type?

"This second option would require a regional, north-south oriented permeability barrier to the west of the structure. If this was the case, then a strong aquifer would exist."

Li’oilady- I don’ think we will learn anything about the type of reservoir drive we have from Antelope-7. We have always known that we have a fault bounding the field on the west side. As I have said before I think we are too far from the mountains to the north and we probably have many permeability barriers (faults) between Antelope and the mountains, so I do not think the a higher recharge area is a viable reason to expect a strong water drive. I do not know anything about a regional fault to the west but I would think that if one exists that GLJ would know about it. I prefer the sealed fault block theory to explain the 460 psi over pressure that we have in the Antelope aquifer. That would give us a depletion drive instead of a strong water drive.

To change the subject a bit if you look at page 18 of Phil’s presentation you will see what he has to say about the drilling of Antelope-7. I have posted before that if we drill the well too far west we might have a dry hole. Phil’s theory would be to move the Antelope-7 far enough east to be sure we are going to hit the reservoir on the east side of the fault and then, soon after penetrating the top of the reservoir, drill a horizontal hole toward the west to see if we can locate the fault. This would allow us to find the fault without drilling through it which Phil says will give us drilling problems. Sounds like a good idea to me but since they have already built the location I doubt that they will change it at this late date.

Pet - I agree wholeheartedly with Phil's theory about moving the Ant 7 location to the east and you are 100% right about the possibility of a dry hole if we move too far to the west. In fact ,at the time I saw the map showing the site so far away from our other wells,I voiced some concern about it .[ My thoughts at the time were,"why would they run the risk of a dry hole by going this far to the west" ] . Now that we have more information about the crap that was going on,and their fear that a well closer to the other wells would be more likely to prove up more tcfs, I can better understand . What's that,someone might ask,why would they want the expense of a dry hole ? Well,if it saved them many millions later, they would darn sure consider just such a ruse .

Thanks for your "increasing" help !

[Putncalls]

A two digit TCFe number is now in XOM's AND OSH's best interest.

[Li'loilady]

Pet - Thanks for your response.

[Stavros]

Pet - Based on this statement from GLJ, will Ant-7 likely provide essential information towards defining drive type?

"This second option would require a regional, north-south oriented permeability barrier to the west of the structure. If this was the case, then a strong aquifer would exist."

Li’oilady- I don’ think we will learn anything about the type of reservoir drive we have from Antelope-7. We have always known that we have a fault bounding the field on the west side. As I have said before I think we are too far from the mountains to the north and we probably have many permeability barriers (faults) between Antelope and the mountains, so I do not think the a higher recharge area is a viable reason to expect a strong water drive. I do not know anything about a regional fault to the west but I would think that if one exists that GLJ would know about it. I prefer the sealed fault block theory to explain the 460 psi over pressure that we have in the Antelope aquifer. That would give us a depletion drive instead of a strong water drive.

To change the subject a bit if you look at page 18 of Phil’s presentation you will see what he has to say about the drilling of Antelope-7. I have posted before that if we drill the well too far west we might have a dry hole. Phil’s theory would be to move the Antelope-7 far enough east to be sure we are going to hit the reservoir on the east side of the fault and then, soon after penetrating the top of the reservoir, drill a horizontal hole toward the west to see if we can locate the fault. This would allow us to find the fault without drilling through it which Phil says will give us drilling problems. Sounds like a good idea to me but since they have already built the location I doubt that they will change it at this late date.

Perhaps they can drill A-7 at the currently contemplated location (where they already cleared trees and flattened the area) and then drill horizontally towards the East to find the fault if they miss the Reservoir.

This would be a less desirable option than your/Phil's option because it would not pinpoint the top of the Reservoir.

ADDED: As subsequently noted by Cyber, this is less desirable for IOC Shareholders