Aminex has confirmed that the Ntorya-2 appraisal well drilled in the onshore Ruvuma Basin of Mtwara Licence has now been successfully tested and is being suspended for future production.
According to Aminex the well was perforated over a gross interval of 34 metres and underwent a testing programme for a period of 160 hours and flowed across a variety of choke sizes. Aminex adds that in order to preserve reservoir integrity and operate safely, it limited test flow rates with a 40/64” choke and the well flowed dry, high quality gas at average stable rate of 17 MMscfd (2,833 BOED).
Strong pressure build-up occurred in all instances during the well test.
Due to strong gas influxes encountered while drilling through the reservoir section, and in order to preserve the safety of the well operations, Aminex says it increased drilling mud weights in order to maintain well control and operate within safety parameters resulting in reservoir invasion which tempered overall test performance.
“Despite the measures we had to take to control the well during drilling, due to a large gas influx in the reservoir section, the Ntorya-2 test clearly supports our belief that there is a considerable gas basin to be exploited in our Ruvuma onshore acreage which we are looking forward to developing,” says Jay Bhattacherjee, CEO of Aminex.
“Ntorya-2, when taken together with the Ntorya-1 discovery well and the mapped seismic features, clearly indicates a gas volume of significant commercial interest. Flow rates were restricted for technical reasons; however, they fully meet the requirements for a declaration of commerciality and application for a development licence,” Neil Ritson, Solo’s Chairman commented.
According to wireline logs, Ntorya-2 encountered the equivalent reservoir section at approximately 74 metres higher than in the Ntorya-1 well. No formation water was produced during the test, leading Aminex to conclude that the Ntorya-1 and Ntorya-2 area contains a significant volume of gas in place.
Notably Ntorya-2 also encountered traces of oil in the gross reservoir interval and the Company says it is now updating its basin model to determine the optimal drilling depths for Ntorya-3 and for future development wells.
Post analysis, Aminex will be able to revise its interpretation of in-place volumes.
“The overall results of Ntorya-2 have substantially exceeded Aminex’s expectations and now we have the potential for a commercial development project in the Ruvuma Basin,” Bhattacherjee adds.
Aminex says it will now complete a full analysis of all technical data prior to applying for a 25-year development licence over the Ntorya appraisal area.
As earlier announced Ntorya-2 was drilled to a final total vertical depth of 2,795 metres. At 2,593 metres drilling depth, the well encountered a gross gas-bearing reservoir unit of approximately 51 metres.