Wahoo

[Spartina]

I Agree Sageo, your good work is much appreciated Pet. Thanks so much.

[kommonsents]

While way over my head, your post gives me a much better understanding of what may be going on at Wahoo. Thank you very much, Pet, for your expertise and time to provide some insight into things IOC.

A lot of us would be lost without you and others with expertise and experience. It is much appreciated.

[Putncalls]

Let me do an FDR on that if I may pet?
You invision 4 options for the drillers.
1 and 2 can salvage the well?
3 and 4 can test the well?

[petrengr1]

I guess there are many options:

1. They could abandon the well as it is.
2. They could set a packer inside the 7” casing (if they have set 7” casing) and test the open hole below the casing. This is not recommended as the sand or Talama volcanics zone may be unconsolidated sand and/or gravel. It would fill the hole and plug the down hole test tools.
3. They could run a liner and cement it in place at the present depth and test the zone giving them gas/problems now.
4. They can drill ahead through the present zone down to the top of the limestone (I have no idea how far that might be but it could be fairly close i.e. within a few hundred feet.) and then run the liner and test all of the upper zone.
5. They could drill all the way through the limestone zone before running the liner but I think they would risk getting in trouble if they lose circulation in a fractured or high permeability zone.
6. After setting a liner at the top of the limestone (if we ever find it) they could drill through the limestone safely with slim hole drilling equipment. In countries where they have the equipment this could even be done with coiled tubing.. Not an option in PNG, at least I have not heard of it being available.

[ArtM72]

Pet:

"6. PR says we have seen gas entering the well bore from permeable zones above the targeted reservoir. Comment: I think this is sandstones inter-bedded in the Orubadi shale (mudstone). Or it could be the Talama Volcanic Clastics zone".

The December 1993 paper by Buddin for SOPAC (Technical Report #183) shows (Figure 2) the Aure Beds lying under the Orubadi Beds. The Aure were reported to be of alluvial origin. If that were the case there would likely be a layered mix of clay, silt, sand and rock of varying thicknesses with a seemingly chaotic distribution.

Using Buddin's geologic theory the sand/rock strands running through the Aure could have a significant volume. (For the Creationists...think of the size of rock strewn rivers caused by water cascading from the mountains during Noah's flood :-) ) The gas and condensate would have been penetrating up from the underlying Moogli mudstone for around 3 million years. The tectonic "thrust of the Aure" would possibly be the source of the excess pressures.

A bit academic I suppose (serendipity?) but such a scenario could be winning if true and if IOC has hit a large, deep sand and gravel seam. Case, log, test and maybe it might be big enough to be an early producer.

A screwey dream??

[sageo]

I guess there are many options: 1. They could abandon the well as it is. 2. They could set a packer inside the 7” casing (if they have set 7” casing) and test the open hole below the casing. This is not recommended as the sand or Talama volcanics zone may be unconsolidated sand and/or gravel. It would fill the hole and plug the down hole test tools. 3. They could run a liner and cement it in place at the present depth and test the zone giving them gas/problems now. 4. They can drill ahead through the present zone down to the top of the limestone (I have no idea how far that might be but it could be fairly close i.e. within a few hundred feet.) and then run the liner and test all of the upper zone. 5. They could drill all the way through the limestone zone before running the liner but I think they would risk getting in trouble if they lose circulation in a fractured or high permeability zone. 6. After setting a liner at the top of the limestone (if we ever find it) they could drill through the limestone safely with slim hole drilling equipment. In countries where they have the equipment this could even be done with coiled tubing.. Not an option in PNG, at least I have not heard of it being available.

Pet - As always,thanks for your thoughts on our perplexing situation. Without a huge amount of thought,at this time I think I would choose #3. Expense wise and the good information we would probably be able to obtain, may be worth accomplishing at this stage of the game. If you disagree, I'm open to which option you think would be best.

[petrengr1]

A screwey dream?? Yes!

The high pressure may be caused by tectonic forces on a closed system. No connection to a regional aquifer etc. Such a reservoir could be large or small.

Or the high pressure could be due to a 6,000 foot gas column from about 6,000 feet to about 12,000 feet to the north, east and south. A fault is on the West.

[petrengr1]

I guess there are many options: 1. They could abandon the well as it is. 2. They could set a packer inside the 7” casing (if they have set 7” casing) and test the open hole below the casing. This is not recommended as the sand or Talama volcanics zone may be unconsolidated sand and/or gravel. It would fill the hole and plug the down hole test tools. 3. They could run a liner and cement it in place at the present depth and test the zone giving them gas/problems now. 4. They can drill ahead through the present zone down to the top of the limestone (I have no idea how far that might be but it could be fairly close i.e. within a few hundred feet.) and then run the liner and test all of the upper zone. 5. They could drill all the way through the limestone zone before running the liner but I think they would risk getting in trouble if they lose circulation in a fractured or high permeability zone. 6. After setting a liner at the top of the limestone (if we ever find it) they could drill through the limestone safely with slim hole drilling equipment. In countries where they have the equipment this could even be done with coiled tubing.. Not an option in PNG, at least I have not heard of it being available.

Pet - As always,thanks for your thoughts on our perplexing situation. Without a huge amount of thought,at this time I think I would choose #3. Expense wise and the good information we would probably be able to obtain, may be worth accomplishing at this stage of the game. If you disagree, I'm open to which option you think would be best.

I prefer #6. We can always come back and do #4 after completing #6. All done safely. Just takes time and money.

[sageo]

Pet: "6. PR says we have seen gas entering the well bore from permeable zones above the targeted reservoir. Comment: I think this is sandstones inter-bedded in the Orubadi shale (mudstone). Or it could be the Talama Volcanic Clastics zone". The December 1993 paper by Buddin for SOPAC (Technical Report #183) shows (Figure 2) the Aure Beds lying under the Orubadi Beds. The Aure were reported to be of alluvial origin. If that were the case there would likely be a layered mix of clay, silt, sand and rock of varying thicknesses with a seemingly chaotic distribution. Using Buddin's geologic theory the sand/rock strands running through the Aure could have a significant volume. (For the Creationists...think of the size of rock strewn rivers caused by water cascading from the mountains during Noah's flood :-) ) The gas and condensate would have been penetrating up from the underlying Moogli mudstone for around 3 million years. The tectonic "thrust of the Aure" would possibly be the source of the excess pressures. A bit academic I suppose (serendipity?) but such a scenario could be winning if true and if IOC has hit a large, deep sand and gravel seam. Case, log, test and maybe it might be big enough to be an early producer. A screwey dream??

Art - Your thinking is very interesting! I had read the Buddin paper some time back,and I was wondering at the time if the Aure fm. might be present in the Wahoo area. AS you say"a bit academic I suppose" about the tectonic"thrust of the Aure", but possible I believe.If my memory serves me right,some of the OSH wells in the highlands produce oil and/or ng from the Aure. ( keep thinking good thoughts about our possibilities !)