Drilling Suspended on Block 16-1 in Cuu Long Basin
SOCO Vietnam says that the Te Giac Den exploration well on Block 16-1 in the Cuu Long Basin offshore Vietnam, drilled to evaluate the 'E' prospect, has been temporarily suspended at 4,625 meters after penetrating a gas and oil zone with pressure in excess of 12,000 psi, which is beyond the safe operating capacity of the drilling rig.
The well encountered hydrocarbons in two Oligocene clastic sequences, which were separated by a volcanic layer. Well logs over the upper sequence indicate approximately 30-meters of net pay. After drilling through the volcanics, the well encountered a lower clastic sequence with oil and gas shows. However, the mud weight required to control pressure and gas indicates downhole pressures at the upper limit of the safe operating capability of the drilling rig. Consequently, drilling had to be halted after only 22 meters of the sequence had been penetrated. High pressure and temperature also meant that the section could not be logged. The current seismic interpretation shows another 300-meters of sediment above Basement.
The well will be plugged back to isolate the lower higher pressure zone from the upper sequence. The upper Oligocene clastic sequence, which is also overpressured, will be tested using the Adriatic XI rig when suitable test equipment is available in Vietnam, which is expected to be in late August.
Going forward, the consortium expects to contract a 15,000 psi capability drilling rig either for a well re-entry or a new drill, dependent upon the timing of obtaining a suitable rig. If a larger rig can be contracted this year, it would also be used to drill the 'E' South prospect, similar to the 'E' prospect, but marginally deeper.
Ed Story, President and Chief Executive of SOCO, commented:
'The primary pre-drill risk of the 'E' prospect, that there would be insufficient seal to preserve the hydrocarbon charge and the reservoir at depth, has improved dramatically over this giant prospect covering some 30 square kilometers. Obviously the play works as we have already drilled potential pay equal to one third of our pre-drill estimate and we have more section to drill. We are anxious to return with suitable equipment as soon as it is available.'
Te Giac Hong exploration well - Block 16-1
The Te Giac Hong exploration well on Block 16-1 in the Cuu Long Basin offshore Vietnam drilled to evaluate the 'L' North prospect will be plugged and abandoned after reaching a total depth of 3,685 meters. The well tested the Lower Bach Ho 5.2 and the Oligocene C formations. The 5.2 sands were poorly developed and had no oil shows. There were sands with oil shows in the Oligocene C; however, log evaluation showed the sands to have poor permeability and they were not tested.
The Adriatic XI rig will immediately move to drill the Te Giac Lam 1X well to test the Miocene and Upper Oligocene at the 'O' prospect. The well will be deviated to test a deeper Oligocene stratigraphic trap, a new play in the basin, formed by the pinch out of the Oligocene against a Basement high.
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