Guys just to add some more discussion.CO2 contents have been...

Guys just to add some more discussion.

CO2 contents have been regionally much higher in the southern end of the Song Hong Basin. Gas and oil shows in the northern ends of the basin typically were low CO2 and even absent in some areas.

Ones to the south could have between 75 to 100% CO2.

The thoughts for sources of the CO2 are from the mantle, CO2 rich shales that have been cooked by an Tertiary intrusion extending N-NE through Vietnam and extending into China.

So where there was the well by Premier to the north that had 100% CO2 that was a fractured basement play. So faults extending to the basement probably meant that degassing of the mantle allowed significant amounts of CO2 to move up these large structures into overlying hydrocarbon traps.

Wells to the south of block 105 (couldn't find out exactly where, but would be on blocks 115 and 118), drilled by IPL 115A-1X and BP/Statoil 118-CV-1X reported high CO2 volumes.

These wells in the south are located proximal to the Tertiary basaltic intrusion that is thought to be high in CO2. It is also thought that these intrusions could have caused thermal metamorphism of calcareous shales located within lower Miocene which also contributed to CO2 production.

It is thought that the intra basin highs (Dongfang gas field) and the flanks of the Hong Song Basin are still very prospective for hydrocarbons.

So after a bit of reading I think that the Cuo Lo targets are far enough north to be away from the basalt intrusions to have caused significant thermal metamorphism of the calc shales.

I think the biggest risk is if the diapirs below our target zone have deep penetrative faults that extend into the basement. This would allow fluid/gas pathways for mantle CO2 degassing to move up these structures into potential traps.

Here are a few links for some papers/information on the Hong Song Basin if anyone is interested.

http://archives.datapages.com/data/bulletns/2004/09sep/1277/1277.HTM

http://www.searchanddiscovery.com/abstracts/pdf/2011/hedberg-beijing/abstracts/ndx_huang02.pdf

http://www.gaschem.com/evalu.html

http://www.offshore-mag.com/articles/print/volume-55/issue-2/news/general-interest/vietnam-geologic-reappraisal-reveals-potential-of-song-hong-blocks.html

http://archives.datapages.com/data/ipa/data/044/044001/511_ipa0440511.htm


Lastly, if anyone can find this article, that would a great source of information.

http://www.academia.edu/1204160/The_structure_and_formation_of_diapirs_in_the_Yinggehai-Song_Hong_Basin_South_China_Sea

Cheers