Upstream
The Songo Songo gas field
Orca operates the Songo Songo natural gas field, an asset that has supplied >500 Bcf of gas to Tanzania since first production in 2004. The field sits astride the western shore of Songo Songo Island, stretching into the Indian Ocean towards mainland Tanzania.
Managing a maturing field, the Company’s sub-surface team has built an array of reservoir and well data, and static and dynamic models. These are being constantly updated, tested and adjusted to underpin gas production and develop the field efficiently.
Songas plant
The field comprises eight gas wells, with four offshore in shallow water, and four onshore.
Throughout the course of the past six years the Company has embarked on a staged well-workover, side-track and drilling program to restore production and ensure a safe operating environment.
More than $100 million was spent through this program, with all wells now completed with 13% chrome production tubing.
Gas wells
Seven of the eight gas wells are tied into the Songas gas processing facility, also operated by Orca and with a nameplate capacity of 110mmscfd. Two of the seven wells are also tied into, with dual flow capability, the National Natural Gas Infrastructure (NNGI) gas processing facility, with a name plate capacity of 140mmscfd. Also on Songo Songo Island, this plant is operated by GASCO, a subsidiary of the Tanzania Petroleum Development Corporation.
The final, eighth, gas well, is tied in only to the NNGI facility. Current production averages around 97mmscfd through the Songas facility and 30mmscfd through the NNGI.
Processing coordination
Having wells tied into two processing facilities on Songo Songo Island presents Orca with a unique fall-back position should a shutdown occur or be induced for maintenance on the main Songas plant. This aids the Company and Tanzania to sustain gas processing and thus power generation when necessary.
To achieve this, a significant degree of cooperation and coordination is required between operators. Having the Songas plant operated entirely by the Company’s local Tanzanian staff helps this significantly. Recently, following limited sand production, and subsequent sanding modelling and forecasting, the Company has started to implement control measures to protect the facilities.
Investment in upgrades
The Songas owned, Orca operated, gas processing plant has achieved >99% up-time since production began in 2004, producing more than 500 Bcf of gas. Normal operations and maintenance is conducted solely by the Company’s local Tanzanian team, while specialists are often brought in for major upgrades and projects.
The Company has invested more than $50 million, carrying out a number of upgrades on the plant, installing refrigeration and compression systems to address declining field pressures, ensuring gas continues to be processed and exported within specifications.
Increase in demand
Compression was completed in March 2022, the system was expected to sustain existing gas demand until the end of the current license in 2026. However, an immediate and significant increase in demand (c.30%) has forced the Company to examine additional options to sustain production; these options are still being evaluated and would be subject to partner approvals. Additional demand will require additional field development, which is being evaluated.
