Technical and reservoir overview
Renergen’s principal asset is Tetra4 which it acquired in December 2015 as Molopo South Africa Exploration and Production Proprietary. The company holds a 90% interest in the first and only onshore petroleum production right in South Africa, located in the Virginia area of the Free State and around 150km north of Bloemfontein. It also holds seven exploration rights across the area, with five located in the Virginia Project and the remaining two in the early stage Evander exploration project in Mpumalanga (Exhibit 3).
The region is known for the presence of gold, uranium and coal and in particular has been extensively mined for gold, which was discovered in the Welkom Goldfield in 1932. Gas was originally encountered in the Virginia Project area in a number of holes drilled as part of the gold mining process at Welkom, with 13 of these historical wells still blowing ie capable of producing, today. The gas is predominantly methane, but also has a high helium content of approximately 2%. The methane is believed to be biogenic in origin, while the helium is either mantle-derived or from the decay of radioactive minerals within the crust which moves up through large faults and mixes with the methane in the deep subsurface.
|
|
Source: Renergen/Deloitte CPR
|
The source of the gas is the Witwatersrand Supergroup, a very hard rock consisting of quartzites, lava, shales and conglomerates which is usually deeply buried at depths of around 1.8–2km. Outcrops do however occur in places and one of these covers a 60km stretch across the Tetra4 assets where the Witwatersrand sits at a depth of only 300m, making it more accessible at this location. The Witwatersand is overlain by the volcanic Ventersdorp Supergroup which contains major faults together with fractures and fissures that provide natural pathways for the gas to flow. A 1-2m thick Doleritic plate and the Karoo Supergroup deposited on top of the Ventersdorp post faulting both act as a seal.
Exhibit 4: Virginia Project – stratigraphic cross-section
|
Exhibit 5: Virginia Project – map with faults
|
|
|
Source: Renergen/Deloitte CPR
|
Source: Renergen/Deloitte CPR
|
Exhibit 4: Virginia Project – stratigraphic cross-section
|
|
Source: Renergen/Deloitte CPR
|
Exhibit 5: Virginia Project – map with faults
|
|
Source: Renergen/Deloitte CPR
|
The understanding of the geological structure in the Virginia Project is based on 3,000 logs and a lithological database gathered during the drilling of wells, the majority of which were drilled by miners. The structure is North-South trending and is characterised by the presence of faults created during the tectonically active Ventersdorp period. These faults act as conduits that facilitate gas flow and so are actively targeted when drilling for gas production purposes. Borehole data have been proven to be most effective in mapping these faults and fissures, as they are too small to be properly identified on seismic. Drilling at the Welkom Goldfield was historically designed to avoid faults, so that older wellbores were not optimally located for encountering gas. The faults tend to have a North-South orientation and are complemented by a series of dykes that run in an East–West direction. A dyke, in geological terms, is a sheet of rock that has formed in a fracture and in the case of the Virginia Project these dykes are almost vertical, creating unique continuous connections between the Witwatersrand and the Ventersdorp.
Methane isotope studies demonstrate that very little, if any, of the methane gas can be attributed to the Karoo coal beds or carbonaceous shales. This indicates that the methane is biogenic in origin and is therefore an ongoing renewable resource. The rate at which this is renewed, known as the recharge rate, is uncertain at this stage. However, this should not affect the Virginia Project since the planned development is not expected to deplete the volume in the reserves area.
Exhibit 6: Summary of Virginia Project wells drilled targeting gas
Year |
Well name |
Results |
2009 |
HADV1 |
Low gas rate |
2009 |
HADV2 |
Low gas rate |
2009 |
HDR1 |
Significant gas rate |
2010 |
HPAL1 |
No gas |
2010 |
HZON1 |
Significant gas rate |
2016 |
MDR1 |
Produced gas for short time |
2016 |
MDR4 |
Produced gas for short time |
2016 |
2057 |
Significant gas rate |
2016 |
MDR5 |
Significant gas rate |
Source: Edison Investment Research
Exploration drilling specifically targeting gas was first carried out in 2008 and 2010, when Molopo drilled five wells within the Virginia Project area, followed by a further four wells in 2015 and 2016. Of these, four wells (HDR1, HZON1, 2057 and MDR5) produced gas at significant rates, while two wells (HADV1 and HADV2) produced gas at low rates. HPAL1 did not encounter gas and MDR1 and MDR4 both produced gas initially but stopped after a short time, indicating that they encountered pockets of trapped gas, though not close enough to a fissure to sustain production.
All of these wells were drilled vertically and, with the exception of MDR5, without the benefit of a detailed study of the fault structure. Rates from the wells vary with for example, HDR1 originally produced at over 200mscfd and 2057 at up to 400mscfd, while some older wells produce closer to 30–40mscfd. Importantly, data from all wells have shown no decline in flow rates as a result of production. There is also scope for these rates to be higher in future inclined wells and for existing wells with the use of compressors. The low rate and low pressures in the wells means that friction between the gas and the wellbore restricts the flow. The use of compressors results in negative pressures at the wellhead which can increase flow from the well. In HDR1, the use of a compressor saw an increase in flow from 200mscfd to 250mscfd.
Recognising that the existing well design was sub-optimal in targeting gas bearing fractures, Tetra4 commissioned Shango Solutions to carry out a study in 2016 to investigate how to refine the company’s drilling model to increase the likelihood of intersecting the steeply dipping structures. The study recommended that future wells should be drilled at an angle of 55o and inclined to the southeast in order to ensure the intersection of steep E-W and westerly dipping N-S structures. The results of the study were available in time to change the surface location of the final 2016 well, MDR5. However, there was not enough time to complete the engineering required to change the design from vertical to inclined.
The company is targeting flow rates of 8-10mmscfd by 2022 and estimates that this will require a total of 66 producing wells (Edison’s assumptions are a little below these figures due to assumed funding constraints, see Exhibit 11 and Exhibit 12). There are 18 existing wells, of which 13 are considered suitable for use initially, with the remaining four either located too far from the planned pipeline location or with lower flow rates. The 13 suitable wells consist of nine historical wells originally drilled for gold mining purposes, together with four of the more recent wells targeting gas (HZON1, HDR1, MDR5 and 2057). The first inclined well is planned in May 2018 in order to prove the concept and, if successful, all subsequent wells will be drilled this way.
The company is currently assuming a well success rate of 60% in its planning, although this could increase with the refinement of the model as new well data are acquired. At present, Tetra4 has budgeted for 85 wells over the next three years (we assume 60 due to funding constraints).
Exhibit 7: Virginia Project Cluster 1 well locations and pipeline
|
|
|
Initial development will focus on the Cluster 1 area, which is designed to connect the high prospectivity areas in the north of the field with those in the south. Construction of the LNG plant commenced in Q417, with pipeline construction to follow in Q118 and first gas in Q119. The longest lead items, two gas liquefiers, were ordered in Q417.
Three independent reserves reports have been prepared on the Virginia Project, the first two from Venmyn Deloitte with effective dates of 31 May 2015 and 31 July 2016. Based on work carried out in the interim period, Deloitte was able to increase its 2P reserves estimate by 18% from 87.9bcf to 103.5bcf.
Exhibit 8: Reserves evolution (bcf) of Virginia Project (gross)
|
Natural Gas |
Helium |
Reserves |
1P |
2P |
3P |
1P |
2P |
3P |
Deloitte 2015 |
27.1 |
87.9 |
245 |
- |
- |
- |
Deloitte 2016 |
35.2 |
103.5 |
276.4 |
- |
- |
- |
MHA 2018 |
40.4 |
141.6 |
299.0 |
0.91 |
3.16 |
6.56 |
Contingent resources |
1C |
2C |
3C |
1C |
2C |
3C |
MHA 2018 |
286 |
548 |
847 |
9.09 |
17.2 |
25.9 |
Source: Venmyn Deloitte, MHA
In late 2017, Renergen engaged MHA to independently assess the Virginia Project. MHA estimated 2P gas reserves of 141.6bcf of natural gas (an increase of 57%), along with 2C contingent resources of 548 bcf and best estimate prospective resources of 1,278bcf. For the first time, MHA also assessed the helium reserves (these had not been considered in the previous Venmyn Deloitte reports), awarding 2P Helium resources of 3.16bcf.
Alongside its LNG facilities, Renergen plans to build a plant to extract and sell helium at 300kg/day by Q119 and has signed a gas sales agreement (GSA) with Linde Global Helium (Linde) for the purchase of helium gas.
Based on the historical analysis of both blowers and legacy 2009/10 wells, Renergen has known for some time that the gas produced from the Virginia Project contains a significant quantity of helium. However, historical helium concentration data has been inconsistent, mainly because helium can diffuse out of inappropriate containers, such as steel canisters, and gas analyses need to be carried out as soon as possible after collection.
Renergen has recently carried out fresh helium analyses of the wells it intends to use as producers (under strict sampling and testing criteria), returning results that range from a minimum of 1.4% to a maximum of over 10% for the 2057 well. MHA’s 2018 CPR has assumed a 3-4% concentration in the centre of the production licence and assigns 2P helium reserves of 3.16bcf on this basis (i.e. 2.23% helium). The gas composition is ideal for separating out helium as it contains no H2S, H2 or Neon and low levels of CO2.
Helium market and pricing
During 2017, Edison carried out an independent review of the global helium market, assessing the likely evolution of the supply demand balance, different pricing mechanisms and the overall competitive landscape. This report was published in December 2017.
Exhibit 9: Estimated global supply/demand forecast, mmcf/year
|
|
Source: JR Campbell & Associates report for BLM Office of Minerals Evaluation, public and private company data, Edison Investment Research, various
|
In conclusion, Edison estimated that, despite an opaque picture making forecasting difficult, we believe the balance is weighted towards a tightening market, at least in the next two to three years (Exhibit 9). This is being driven primarily by the imminent exhaustion of the US Bureau of Land Management (BLM) domestic storage as well as little new supply coming online to offset declines elsewhere.
The longer-term outlook is more balanced (assuming relatively conservative demand growth) with large additions from mega projects in Qatar and Russia planned from 2020 onwards. However, we consider there is significant risk of delays to these mega projects which would push the market into a substantial deficit on a longer-term basis.