Crux-2 ST1 Well Encounters More Gas than Expected
A gross gas column of 158 meters yielding a net gas pay zone of 102 meters, will in excess of pre-drill expectations, has been intersected in the Crux-2 ST1 well drilled by Nexus Energy. The well is located in AC/P23 in the Browse Basin offshore Western Australia.
The Crux-2 ST1 well has been drilled to a measured depth of 4,308 meters RT (measured below rotary table). Based on electric wireline longs, the well has encountered 85 meters (79 meters net) of high quality Triassic aged "A" sands which are the same sands intersected in the Crux-1 well.
The total gas column is significantly greater than pre-drill estimates due to the intersection of an additional 73 meters (22 meters net) of a younger formation with excellent reservoir properties. This gas bearing formation was not seen in the Crux-1 well.
These results confirm the extension of the high quality reservoir sands seen in the Crux-1 well to the northeastern part of the field (as predicted from the similarity in seismic character at the sidetrack location) and increases confidence in the resource volumes. It is expected that the core area of the Crux field will contain sufficient condensate volumes necessary to underpin the development of the Crux liquids project.
The Crux-2 ST1 well has achieved the pre-drill appraisal objective of intersecting greater than 70 meters of net gas sand in the Triassic aged gas sands, confirmed the continuity of the primary reservoir encountered in Crux-1 and established additional resource potential in younger aged reservoirs overlaying the structure to the north of Crux-1.
A further 25 meters of net gas pay is interpreted in the Triassic aged "B" sands below a 60 meter shale based on correlations with the Crux-1 well. This additional incremental pay can be accessed more cost effectively by deepening the well during the development phase when the well will need to be re-entered to run production tubing.
"We now look forward to progressing the Crux liquids project with renewed vigor. Our goal is to secure an investment decision for this significant project in early 2008 with a view to first production in 2010."
Nexus will update its condensate resources estimates for the "A" and "B" reservoirs in the core are of the Crux field incorporating the results to date with results of additional down hole gas sampling, which should be available during the coming weeks. Down hole gas samples recovered from the Crux-2 well indicate the liquids content of the gas in the Crux field is 30% higher than previously calculated from less accurate gas surface sampling recovered at Crux-1. A 10% increase has been assumed in the Nexus resource estimates for the field which were announced last month.
The additional volumes attributable to the younger gas sands which overlay the "A" sand at the Crux-2 ST1 location and the Jurassic aged Plover formation which was encountered in Crux-2, will be incorporated into field resource estimates when detailed remapping of the reservoirs has been completed.
The field is 100 kilometers northeast of the 100% Nexus-owned permit WA-377-P which contains the Echuca Shoals gas discovery, adjacent to Inpex's Ichthys gas field; currently being considered as a LNG project.
Early in 2006 Nexus sold the rights to the gas (excluding condensate) to Shell for US $40 million.
The gas sales agreement enables Nexus to undertake its condensate recycle project until December 31, 2020 at which time Shell will take ownership of the permit and will be able to extract the gas and any remaining condensate.
Nexus commenced appraisal of the field with the drilling of the Crux-2 well which confirmed a gross gas column of 70 meters with a net 26 meters of good quality sandstones in Jurassic aged Plover formation. The well did not intersect the required minimum thickness of reservoir sands necessary to support the proposed liquids project gas injection rate and a decision was made to side track the well.
The Crux-2 ST1 sidetrack location encountered gas sands the same as the reservoir sands encountered at the Crux-1 well. By sidetracking the Crux-2 well to a more optimal location the company plans to utilize the cased large-bore well as the first of up to six wells required for the potential recycle project.
Nexus recently announced a revised best estimate contingent resource for the field within the AC/P23 permit of 55 million barrels based on remapping of the field by Nexus post Crux-2 but before the Crux-2 ST1 results. A further revision of contingent resources which will incorporate the results of Crux-2 ST 1 will be announced in the near future.
Nexus has completed a basis for design for a gas recycling facility for the Crux liquids project with approximately 900MMscf/d of gas being produced through three production wells. Over 29,000stb/d of condensate could be stripped from the gas before re-injection into the reservoir through three injections wells. A 600MMscf/d scheme is also being considered which would allow 19,000stb/d to be stripped.
The wells are to be tied back to a floating production, storage and offloading facility (FPSO).
- Nexus Resumes Production at Longtom-4 Well in Gippsland Basin (Mar 12)
- Nexus Updates on Plans to Divest its Crux, Longtom Assets in Australia (Feb 21)
- Santos Suspends Production at Patricia-Baleen Gas Processing Plant (Jan 14)