Canadian independent ReconAfrica has reported a successful flow of natural gas and “potential liquids” to surface from two separate zones in the Kavango West 1X (KW1X) discovery well in the onshore Kavango Basin in North east Namibia
The upper Huttenberg flowed natural gas and potential liquid content to surface, the same way the Upper Elandshoek flowed hydrocarbons to surface earlier
The company says that Vertical production testing at KW1X is now complete; and, Huttenberg formation has been prioritized for an open-hole horizontal production test, targeting up to 1,000 metres of horizontal section.
The uppermost zone of the Huttenberg formation flowed natural gas and potential liquid content to surface immediately upon perforation, ahead of any acid stimulation, and was flared through the relief flare stack. Flow rates were not measured from the Huttenberg due to equipment limitations, which has been rectified for the upcoming open hole horizontal production test by way of procuring the necessary equipment, which is currently being shipped to site, and by changing the surface operations service provider at site. Production samples, including both natural gas and potential liquid content have been collected in several IsoTubes with results of the compositional analysis expected in the coming weeks from samples sent to laboratories in the United States.
This test result completes vertical production testing operations at KW1X. Surface testing equipment associated with the vertical programme has been stood down and demobilized as the Company advances to Open-Hole Horizontal Production Test
Having flowed natural gas and potentially liquids to surface from two separate zones at KW1X, the next stage of success-based testing is to proceed with an open-hole horizontal production test in the uppermost zone of the Huttenberg formation, with an option for an additional horizontal test in the uppermost zone of the Elandshoek formation.
The Huttenberg formation was selected for the initial horizontal test based on:
Flow of natural gas and potential liquids to surface;
75 metres of pay identified from original well log analysis;
Presence of matrix porosity between large natural fractures;
Longer horizontal lateral section due to being approximately 600 metres shallower than the Elandshoek;
The Jarvie-1 rig is expected to drill up to 1,000 metres of horizontal section through the Huttenberg formation.
Brian Reinsborough, ReconAfrica’s President and CEO, says the company has a high level of confidence moving forward with an open-hole horizontal production test in the Huttenberg formation.
“ KW1X’s well results do not just validate a single structure; it also opens running room across the block. We have mapped 22 structures using existing seismic data and anticipate the inventory could grow with additional seismic coverage on PEL 73. Confirming the KW1X results with a flow rate test on a horizontal sidetrack as soon as possible will ultimately support resource and reserve bookings and a final investment decision on this emerging Damara Fold Belt Play.”
From Vertical to Horizontal: The Path Forward
ReconAfrica explains that the purpose of the vertical production testing programme was to determine which parts of the reservoir, if any, could flow hydrocarbons to surface.
“It was not to determine flow rate as cased vertical wells are not the optimized development design for this fractured reservoir. Phase one production testing achieved a critical milestone; the programme established two of the six zones of interest identified in the well contain hydrocarbons capable of flowing to surface. This does not preclude the other sections from flowing hydrocarbons via a more optimized horizontal open hole completion.
“The next step, an open-hole horizontal production test in the upper Huttenberg zone, is designed to establish a representative flow rate over a large, exposed reservoir section uninhibited by production casing, cement and perforations. An open-hole horizontal well is required to achieve maximum reservoir penetration and optimal fracture intersection, consistent with the natural fracture orientation observed in the reservoir. Horizontal development of the Damara Fold Belt structures is also expected to reduce surface land disturbance as well as the number of wells required per structure, resulting in lower field development costs and improved capital efficiency.
“Formation imaging log (FMI) analysis from wells drilled through the Otavi reservoir indicates fracture density ranging from 1.0 to 12.7 fractures per metre (P90–P10), with fracture orientation running parallel to the fold structure. The current well design contemplates a horizontal lateral of up to 1,000 metres to optimally intersect these natural fracture swarms. Completing the well open hole, without casing or cement, is intended to maximize flow from fractures. These fractures have inclinations of 50-90 degrees, with most fractures being vertical, to near vertical. The horizontal well will be drilled perpendicular to the fracture orientation. Open fractures in analogue carbonate fields enhance permeability and often link matrix porosity with the reservoirs”.
