Reliance gas is good quality with low sulphur

Vol 6, PW 18 (06 Nov 02) Exploration & Production

OTHER KEY INFORMATION missing from the Reliance-Niko statements was the quality of the gas.

Again, we have details. "The gas is sweet, dry and dominantly (95%) methane," reveals a source.

"The other components are ethane, butane and propane." We also learn it has no carbon dioxide. Apparently, this is also a plus point because otherwise CO2 reacts with water to form acid and this means that special steel pipes will have to be laid unlike the usual gas transport pipes.

"It is good that the sulphur and CO2 are both low," says our technical expert. "As it is mostly methane, and shallow below sea-bed, it could well be biogenic, i.

e. produced by bacteria, rather than thermogenic which is the more common mechanism for generating gas and oil." He adds: "It does not sound unreasonable that Reliance has made a multi-TCF discovery, but given the water depth and the shallow depth to reservoir, plus the large area, the development costs will be critical in determining its commerciality." Another crucial question is whether the discoveries are "separate accumulations" or on the same structure.

"All the discoveries took place in the same structure," we learn. "The appraisal phase will take about two or three years."Since April this year the Transocean drillship Discoverer 534 has drilled four wells for Reliance on this block.

One well was capped and abandoned due to "cementation problems" in late September. Plans to drill a fifth well began but were aborted.

Drilling was in water depths of between 640 metres to 1,332 metres and most wells reached a target depth of about 2,400 metres. Block KG-DWN-98/3 measures 7,465-sq km.

Reliance's drilling locations are 150-km from shore.