• Appraisal program commences with Mukuyu-2 spud targeted for early Q3 2023
• Well services and long lead process tendering commenced
• Mukuyu-1 post well analysis of pressure data indicates potential for significant gas
columns in Pebbly Arkose and Upper Angwa
• Industry interest received to partner in project and forward work program
• 2D seismic acquisition planned to mature multiple leads in proven fairway
Mukuyu-2 appraisal well program commences with spud targeted for early Q3
Preparations have commenced for the Mukuyu appraisal program, with the first well,
Mukuyu-2, targeted to spud early Q3 CY2023. Mukuyu-2 will target multiple hydrocarbon (gas-condensate and potentially light oil) bearing intervals encountered in the Mukuyu-1/ST1 well in the Upper Angwa and Pebbly Arkose formations, as detailed in the ASX release on 23 January, with the aim of confirming a gascondensate discovery.
The well design for Mukuyu-2 will incorporate valuable experience gained from the drilling of
the successful Mukuyu-1/ST1 exploration well to improve drilling efficiency and lowering
operational risks. The appraisal well will also be designed to test the deeper potential in the remaining Upper Angwa formation, which was not encountered in the Mukuyu-1/ST1 campaign due to it being
thicker than pre-drill estimates. The Mukuyu-1/ST1 well encountered gas pay to total depth, interpreted from wireline logs and fluorescence in multiple reservoirs throughout the 900-metre interval penetrated.
This additional prospectivity in the Upper Angwa and the undrilled Lower Angwa target provides further up-side potential at Mukuyu-2.
The Mukuyu-2 well design will allow for flow testing to confirm reservoir deliverability and
connectivity following a successful discovery. The tendering process has commenced for minor additional long leads and well services and the completion of this process will help further refine the timing of the spud date for Mukuyu-2. Exalo Rig 202 remains warm stacked at the Mukuyu-1 wellsite, with planned upgrades and maintenance to commence in April following the end of the wet season and prior to
mobilisation to the Mukuyu-2 wellsite.
All permitting and approvals are in place for the drilling of Mukuyu-2 and the wellpad
construction will commence following the finalisation of well location and construction design.
On the back of positive results from Mukuyu-1/ST1, the Company has received interest from
industry partners to participate in the Cabora Bassa Project. The Company is considering
farming down an interest across the project area or on an individual licence basis to manage
forward exploration and appraisal work and future development programs.
Mukuyu-1 sidewall core analysis in progress
Analysis of the sidewall cores obtained from Mukuyu-1 is in progress, with both reservoir (on
suitable unfractured plugs) and source rock samples at various stages of evaluation.
Initial processing at the lab has shown strong fluorescence in side wall cores obtained from
approximately 2,407m Measured Depth in the upper Pebbly Arkose reservoir sections (example
shown in Figure 1). This subsequently increased the gross interval of observed fluorescence and hydrocarbon charge in the Pebbly Arkose and Upper Angwa to 1,500m and substantially expands the play
interval in the Cabora Bassa Basin. Fluorescence was not previously identified in the drill cuttings across the upper Pebbly Arkose interval, most likely due to the drilling fluid losses incurred across this zone and remedial action required to stabilise the fluid loss. Mud gas readings were not available for this interval due to a non-functioning gas chromatograph during drilling.
The sidewall core results will allow for better calibration of the wireline log data to refine the
log interpretation and net pay zones. Following the completion of routine core analysis (RCA),
further special core analysis (SCAL) will be undertaken on select plugs to determine saturation
data and electrical rock properties. Results from geochemical analysis of the source rock side wall cores and cuttings will enable further calibration of the basin model and hydrocarbon generation and migration history, which will enable the Company to better determine the likely liquid hydrocarbon migration
and entrapment locations across its wider exploration acreage.
Post Mukuyu-1/ST1 Well Analysis
Post well analysis has determined the presence of significant filter cake build-up on the
wellbore, as evidenced from recovered side wall cores (Figure 2) which impeded the ability to
acquire formation pressure pre-tests to confirm hydrocarbon gradients and the ability to
obtain fluid samples in reservoir zones interpreted to contain hydrocarbons based on wireline
However, some valid formation pressure pre-tests obtained in the upper Pebbly Arkose and
Upper Angwa reservoirs were considerably above hydrostatic pressure and potentially indicate
a significant gas column (assuming a normally pressure aquifer) in these formations.
Further analysis is being undertaken to assess the impact to the reservoir from the high mud
weight and drilling fluid composition. This analysis will determine whether any changes to the
drilling mud design and drilling fluid composition is required for future wells.
The presence of gas in Mukuyu-1 interpreted from wireline logs and elevated gas shows, along
with liquid hydrocarbons evidenced from strong fluorescence and visual inspection of source
rock side wall cores from multiple intervals, has validated the Company’s pre-drill basin
modelling of the presence of organic rich source and multiple phases of oil and gas generation
and hydrocarbon charged reservoirs at multiple horizons.
2D seismic acquisition planned to mature eastern leads to drillable prospects
The Company plans to acquire additional seismic in the eastern portion of EPO 1848 & 1849
to mature multiple leads (Mopane, Musuma, Machabel and Mahogany) along the proven
play on trend to the east of Mukuyu and additional leads along the highly prospective Basin
Margin play (Mimosa and Mukwa), as per Figure 3.
The leads all display seismic amplitude anomalies such as “flat spots” (often indicative of
hydrocarbon contacts) and velocity interval slowdowns (Figure 4), which correlate with the
hydrocarbon bearing intervals intersected in the Mukuyu-1/ST1 well.
The acquisition of modern 2D seismic will likely allow the Company to mature a number of
these leads, previously identified on reprocessed vintage seismic data, to drillable prospects,
providing additional running room and adding materially to the portfolio.
Seismic survey design and planning is well advanced and acquisition is anticipated to
commence in Q2 2023, incorporating the Company’s experience from the successful CB21
Seismic Survey acquisition.
Comments from Managing Director Scott Macmillan:
“Preparations for the Mukuyu-2 appraisal well have commenced, with drilling currently targeted
to commence in early Q3. We will take the learnings from the successful Mukuyu-1/ST1 well to optimise the well design for the drilling conditions encountered and the ability to evaluate multiple hydrocarbon bearing intervals.
“Post well analysis of Mukuyu-1 indicates potential for significant gas columns in the Pebbly
Arkose and Upper Angwa formations, based on significantly elevated pressures in interpreted gas
bearing sands above normal hydrostatic gradient. “Preliminary processing of the side wall cores obtained in the Mukuyu-1 well have also provided further encouragement for the Company.
“Additional fluorescence observed in the upper Pebbly Arkose reservoir sections has increased the
gross interval with hydrocarbon charge throughout the Pebbly Arkose and Upper Angwa to 1,500
metres and substantially expands the play interval in the Cabora Bassa Basin.
“Following success at Mukuyu-1/ST1, which confirmed a working hydrocarbon system in the
basin, we have received industry interest to participate in the Cabora Bassa Project and the
Company is considering a range of options to manage forward exploration, appraisal and
“We are also planning an infill 2D seismic survey in EPO 1848/49 to mature multiple leads into
drillable prospects along trend from Mukuyu, and the highly prospective Basin Margin play.
“I look forward to spending time on the ground in Zimbabwe early next month with the entire
Board as momentum builds towards the drilling of Mukuyu-2.
“Success at Mukuyu-2 and confirmation of a significant discovery will further unlock the value of
our material portfolio and basin master position in the Cabora Bassa Basin.”