Rachel North 14/15-2-Drilling

RNS Number : 3929X

Rockhopper Exploration plc

06 December 2010

 

Embargoed 0700hrs, 6 December 2010

Rockhopper Exploration plc

("Rockhopper")

Rachel North 14/15-2 - Drilling Update

Rockhopper Exploration plc (AIM: RKH), the North Falkland Basin oil and gas exploration company, notes the announcement by Desire Petroleum plc (the "Operator") regarding the 14/15-2 Rachel North well, in which Rockhopper holds a 7.5% working interest.

The Operator provided the following update on the latest logging results from the 14/15-2 Rachel North well which, following additional wireline data, will be plugged and abandoned with oil shows.

The results from the new logging data can be summarised as follows:

1. As announced on 3 December 2010 preliminary results from the interpretation of the initial log data indicated that the well had encountered a 349m gross interval of sands and shales with hydrocarbons, of which 57m was net pay in multiple zones.

2. However sampling of the main sand has shown that the hydrocarbons are residual and that the mobile fluid is water.

3. Analysis of the formation water recovered by sampling indicates much lower salinity than anticipated and when this value is incorporated into a revised log interpretation it is confirmed that the sands are water bearing.  The salinity impacts the resistivity of the formation water (Rw) which is used to calculate the saturation of hydrocarbons in sands.  Using industry standard procedures, the initial interpretation was based on a calculated Rw value from a clear water sand only 55m above the target sand, of the same stratigraphic age and depositional setting.  This calculated value was consistent with measurements from other wells in the basin.  Unexpectedly, the actual Rw value in the sample taken from the main sand turned out to be markedly different and the target sand is now interpreted to be water-bearing.

4. Formation pressures and sampling confirm the presence of good reservoir quality in the upper sands.

5. A deeper target is still interpreted to be oil bearing, but the interval is thin and reservoir quality is poor.

The wells drilled by Desire in the Rachel area have identified five fan systems of varying areal extent and reservoir properties. Good reservoir development has been recorded in a number of the fans. Some of the sands are of a similar age to the sands in Rockhopper's Sea Lion discovery. All of these fans will now be remapped incorporating the data from the wells to identify areas where better quality reservoir can be expected and stratigraphic traps developed. As these fans can only be mapped on 3D seismic, final mapping will therefore need to await the new 3D data acquisition, which is expected to commence shortly. 

The Operator will now proceed with collecting the final logging data prior to plugging and abandoning this well.  A full evaluation of all the data will then be undertaken. 

Enquiries:

Rockhopper Exploration plc

Sam Moody - Chief Executive

Tel. [phone] (via M: Communications)

M: Communications

Patrick d'Ancona or Ben Simons

Tel. [phone]

Canaccord Genuity Limited

Charles Berkeley / Henry Fitzgerald-O'Connor

Tel. [phone]

Notes to Editors

Rockhopper was established in February 2004 with a strategy to invest in and carry out an offshore oil exploration programme to the north of the Falkland Islands. The Company floated on AIM in August 2005 and holds a 100 per cent. interest in four offshore production licences: PL023, PL024, PL032 and PL033 which cover approximately 3,800 sq. km. Rockhopper has also farmed in (7.5% working interest) to licences PL003 and PL004, which are operated by Desire Petroleum. These licences have been granted by the Falkland Islands government.

An extensive work programme has been carried out over a number of years on the licences operated by Rockhopper. This has included 2D and 3D Seismic and Controlled Source Electromagnetic Mapping (CSEM). In February 2010, the Ocean Guardian drilling rig arrived in Falkland waters to carry out a multi-well drilling campaign. Rockhopper drilled an exploration well on its Sea Lion prospect during April and May 2010, the result of which was the first oil discovery and Contingent Oil Resource in the North Falkland Basin. The Sea Lion discovery was successfully tested during September 2010 and was the first oil to flow to surface in Falkland Islands waters. Rockhopper has contracted seismic vessels MV Polarcus Asima and Nadia to carry out a 3D seismic survey, beginning December 2010, over areas of licences PL024, PL032 and PL033 which were not previously defined by 3D, as well as adjacent areas.

Rockhopper Exploration plc www.rockhopperexploration.co.uk

Desire Petroleum plc's statement was approved by Dr Ian Duncan of Desire Petroleum plc, who is a Fellow of the Geological Society, Chartered Geologist, and a member of the American Association of Petroleum Geologists with over 35 years experience in petroleum exploration and management.

 

END

 

 

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