Following the mobilization of the KCA Deutag T-48 drilling rig to the Tsiengui area in late 2005, the first well that was drilled was a Tsiengui water disposal well, TST-W1, immediately to the south of the Tsiengui field. This well reached a total depth of 1,660 metres confirming the structural interpretation of the southern end of the Tsiengui field. Wireline logging indicated the existence of over 60 metres of excellent quality reservoir sands in the Gamba Sandstone formation, which were completed in the water zone for future disposal of produced water from Tsiengui.
Since January 2006, three horizontal development wells have been successfully drilled and completed on the Tsiengui field. All three wells were drilled from the same surface location known as Pad C, in the northeastern part of the field. No production figures for these three wells are available at this time as they are in the pre-production phase of operations. The rig has moved on to a different surface location, called Pad B, and has begun drilling the fourth horizontal well of 2006.
The first development well, TST-5, was spudded in mid-January and drilled towards the north-central area of the field to a total measured depth of 2,368 metres. This includes over 500 metres of completed horizontal drain entirely within the main Gamba Sandstone reservoir.
TST-6 spudded one month later and was drilled to a measured depth of 2,706 metres. The well targeted and reached the eastern edge of the Tsiengui field, having drilled a horizontal drain length of 844 metres, a record for the Company. The last 500 metres of horizontal drain in the well were completed for future production. Drilling results demonstrated the reservoir potential of both the oil bearing Gamba and Dentale Sandstone formations, and also demonstrated Tsiengui to be structurally higher in the central part of the field than previously interpreted. With the entire 844 metre drain length being oil bearing from both zones, the decision was taken to exclude the Dentale zone from completion of this well for production engineering reasons. The implications of these drilling results are positive for two reasons: (i) in general the Dentale Sandstone is an excellent reservoir, and (ii) the eastern boundary of the field at TST-6 was encountered further eastwards than expected. The precise impact of the TST-6 well results on the potential for increased overall field reserves is still being evaluated.
Drilling operations on TST-7 commenced on 18th March. The well was designed to drill a long horizontal drain towards the centre of the field, entirely within the Dentale Sandstone reservoir and to test the production potential entirely within the Dentale zone for the first time at Tsiengui. The drilling results produced a horizontal drain of over 650 metres in length, entirely within the oil bearing Dentale Sandstone. Logging results of the drain section show excellent reservoir properties, similar to that at Obangue to the south of Tsiengui. The conclusions from TST-6 and TST-7 suggest that the possible future potential of the Dentale reservoir at Tsiengui may, in general, exceed previous expectations. The rig was released from TST-7 on 13th April.
The next well being drilled (TST-8) is a Gamba Sandstone horizontal drain located in the northeastern part of the field. The rig has been relocated to Pad B and drilling operations on TST-8 commenced on 21st April.
Export pipeline and facilities
Construction of the Company's wholly-owned and operated export pipeline continues to be on schedule, with the commissioning of the pipeline and pump station expected in July. Approximately 23 kilometres (km), or 70%, of the 33 km 10-inch crude oil export pipeline is completed. Equipment for the two (2) re-heating and re-pumping stations is in country and initial construction of both stations is underway. Completion of the pipeline is scheduled for June 2006 and subsequent commissioning of the pipeline is planned to coincide with the completion of the Tsiengui Central Production Facility ("CPF") and the Coucal Export Pump Station. Approximately 65% of CPF equipment and 75% of the Coucal Export Pump Station equipment is in country. Construction is ongoing on both these projects with completion and commissioning scheduled for July 2006.
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