PSA signed with the Government of Tanzania and the Tanzania Petroleum Development Corporation in 2001, and embarked on a three-year period of construction.
At the same time, the Company signed an Operatorship Agreement with Songas for the operation of five existing gas wells, their associated flowlines and the soon to be constructed 70MMscfd gas processing facility on Songo Songo Island.
In 2003, we commenced the recruitment and training of our local workforce, with first gas being produced the following year.
In 2004, initial construction was largely concluded, enabling gas supply to Dar es Salaam and East Africa’s first large scale gas fired power generation at the Songas power generation plant at Ubungo.
As the economic, reliability and environmental benefits of using natural gas versus alternative fuels started to become widely understood in Tanzania, demand increased and we commenced a series of field development operations to increase production.
In 2007, we drilled SS-10 well onshore Songo Songo Island. This was followed in 2012 by the drilling of SS-11 onshore well, and subsequently the offshore SS-12 well in 2016. The newly drilled wells, and several workovers of existing wells, addressed reservoir pressure decline and demand increases, and eventually brought field production potential to approximately 180MMscfd.
In 2015-16, we undertook a major offshore field development program, working over three offshore wells and drilling the offshore SS-12 well. The workover program brought non-producing wells back into production to address declining reservoir pressure and ensure contractual obligations could continue to be met.
The SS-12 well was the first of the Songo Songo gas wells to be dedicated to supply gas to the newly completed TPDC gas processing plant on Songo Songo Island. Although production to the plant did not commence immediately, the well significantly increased production potential and eventually afforded some redundancy in both production and processing capacity.
In 2022, we added feed gas compression on the Songas gas processing plant via 3 x 35MMscfd reciprocating gas compressors, restoring plant production capacity to 105MMscfd. Later in 2022, we completed well workovers on onshore wells SS-3 and SS-10, and the side-track of SS-4.
In addition to drilling and workovers, in 2009 debottlenecking works were concluded enabling the Songas gas processing plant capacity to be increased, initially to 90MMscfd, and subsequently 110MMscfd.
By 2016 the Songo Songo gas field numbered 8-producable gas wells, with a combined production potential of c.180MMscfd.
Gas production however was only part of the sustainment of supply equation, and the in-place Songas processing facilities had to be developed to ensure the gas could be produced at the requisite specification.
In 2019, a feed gas refrigeration facility was installed on the Songas processing plant. The closed loop refrigeration system addressed declining reservoir pressure and the subsequent reduced effectiveness of the original Joules-Thomson cooling system, which combined to significantly reduce on-spec production potential. The system ensured the continued supply of the right quality of gas to our customers.
The program restored production potential from the field to approx. 155MMscfd via both gas processing plants.
Recognising the significant increase in demand, we continued to plan for further value realisation, with a 3D seismic program planned for 2023, which will help map out what the next development phase of the Songo Songo gas field will look like.