Sonangol

Fresh oil discovery strengthens Angola’s hydrocarbon arsenal

Exploration & Production

Angola’s state-owned oil company Sonangol has found more offshore black gold, augmenting the African country’s oil reserves.  

Sonangol
Courtesy of Sonangol

The National Agency of Petroleum, Gas and Biofuels (ANPG), alongside Sonangol Exploration and Production, as operator, and the partners of the contractor group of Block 3/05, have revealed the completion of drilling operations at the PAC 416 well in the southwest compartment of the Pacassa field in Block 3/05 within the Lower Congo Basin.

The main objective of the well was to develop the oil potential of the southwestern compartment of the Pacassa field. The PAC 416 well reached a total measured depth of 5,381 meters and a vertical depth of 3,600 meters, traversing two productive intervals in the Pacassa and Buffalo reservoirs, with characteristics favorable to hydrocarbon production.

According to the operator, the results confirmed a liquid oil column of approximately 100 meters in good-quality reservoirs, reinforcing the productive potential of the Pacassa field. The completion of PAC 416 is perceived to constitute a significant milestone in Block 3/05’s redevelopment program, contributing to strengthening production capacity and extending the productive life of its assets.

Given Sonangol’s strategy of sustainably increasing operated production, the program foresees the drilling of three wells during 2026, with the purpose of maximizing the exploitation of the existing oil potential in Block 3/05, contributing to the increase in national production.

The contractor group for Block 3/05 consists of Sonangol E&P with a 36% operated participating interest, Afentra (30%), Maurel & Prom (20%), Etu Energias (10%), and Nis-Naftgas (4%). Afentra has reported that the Pacassa SW well has reached a total measured depth (MD) of 5,381 meters and encountered a significant oil-bearing reservoir section in the fractured Albian Pinda carbonate formation.

The company emphasizes that the evaluation of wireline logging data and oil shows has identified a gross hydrocarbon-bearing interval of 217 meters, containing an estimated 136 meters of net oil pay, characterized by good quality and fractured reservoir intervals. Initial pressure indications suggest limited pressure depletion, confirming communication with the main Pacassa field.

The firm elaborated: “The drilling results are consistent with the company’s pre-drill geological model and support the previously announced development potential of the wider Pacassa SW structure.

“Based on the initial evaluation, the results continue to support management’s previously announced view that the Pacassa SW area has the potential to contain up to 70 mmbo of gross recoverable resources (net 23 mmbo), subject to completion of the ongoing technical evaluation and reserves and resources assessment.”

The well will now be completed as an oil production well and connected to the Pacassa production infrastructure. Completion operations are now underway, after which the rig will be mobilized to the next well location. Following the connection of the well to the production system, the first oil from the well is anticipated to be delivered in Q3 2026.


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“Sustainable production rates will be established following well clean-up and flow-back operations. Our current analysis of the well data suggests that a Pacassa SW injection well is unlikely to be required at this time, a final decision will be made ahead of the completion of the current rig operations,” explained Afentra.

Regarding the Impala redevelopment, the Impala-1 well, which had remained shut in since 2017, has been returned to production as part of the light well intervention (LWI) program. During production testing, the well achieved gross flow rates of up to about 4,700 bopd and has been producing at around 3,000 bopd, with production intentionally constrained to manage water cut and longer-term reservoir performance.

The company underlines that production was re-established via a slickline intervention that identified and removed a shallow wellbore obstruction after acid stimulation undertaken during an earlier LWI program proved unsuccessful. The firm notes that the well intervention also provided valuable reservoir pressure and well productivity data, which supports the expected production estimates for the planned Impala-2 development well.

Afentra points out that the operator’s preparation for the well continues, with drilling expected to begin upon completion of the Pacassa SW operations, subject to a final decision by the joint venture partners on the requirement for a Pacassa SW injection well. The Impala-2 well is expected to take approximately 80 days, with results expected at the end of Q4 2026.

The results from well intervention, together with the reservoir pressure data acquired during testing, have reduced subsurface uncertainty and have been incorporated into the final well planning for Impala-2. The well is expected to target an initial production rate of approximately 4,000 bopd and, if successful, would represent the start of the next phase in the redevelopment of the Impala field.

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