In 2013, NAE (New Age Ethiopia) required well testing data to determine the fiscal viability of one of their exploration well sites in Ethiopia (El Kuran 3).
After examining the option of performing DST’s (Drillstem Tests) in Ethiopia, factoring in that the equipment would have to be imported into the country, NAE initially decided to forgo DST’s and run MDT tests (Modular Formation Dynamics Tester) instead. However, after running the MDT’s NAE discovered that the limited data derived from the smaller test volumes and minimal reservoir fluid samples was insufficient to make an informed decision. Essentially, the MDT tests failed to deliver the required data to allow for an informed decision on whether to complete the well, and DST’s were deemed necessary.
Using Northstar’s industry leading ability to mobilize quicker than any other DST providers-via our “Self-Sufficient Mobile Setup” – DST equipment was delivered to crating within 3 days, expedited to Ethiopia, and as a result NAE was able to rapidly perform DST’s on El Kuran 3.
At El Kuran 3, Northstar ran two successful drill stem tests (Standard Bottom Hole Compression) for NAE. hydrocarbons were found on both tests, the results yielded definitive data and assisted the operator in its decision to declare a discovery and suspend the well for future operations. Thankfully, this decision was able to be made at the cheapest point possible for NAE due to the fact that open-hole DST data is acquired prior to running casing.
Where MDT tests measure formation pressure as well as limited info on fluid type and/or gas presence, DST’s provide extensive flow data whereas the reservoir contents can enter the drill string and move unobstructed to surface, at which time flow rates & samples can be taken. A reservoir also has the ability during a DST to improve its flow rate and provide more representative fluid samples as it flows into the drill string, and if required, artificial stimulation & lift can be utilized during a DST if the reservoir cannot flow naturally. For the downhole shut-in’s, the data is more accurate than during an MDT test since they are performed after the reservoir has purged itself of drilling fluid invasion and/or supercharging, and the reservoir has had an opportunity to clean itself up during the flow periods. DST’s also allow a much larger sample to be taken by trapping all recovered reservoir fluid in the drill string, as well as inside the Northstar Bottom-hole Sampler.
At the conclusion of each DST, Northstar provides a comprehensive DST report including the downhole pressure data during each of the events (flow’s & shut-in’s), virgin & final shut-in reservoir build-up data, flow rates, observations during the test, and volume & type of recovered fluid. Additional analysis such as horner & derivative plots, permeability calculations, skin damage, and much more reservoir data are provided either live using Northstar’s exclusive surface read-out technology; NorthstarLive, or once the downhole pressure gauges are recovered on surface.
Acquiring all of this quantitative & qualitative data while the well is still in the drilling stage can be an essential key in determining if a well has commercial appeal, and reducing both the finding & abandonment costs. Operators that utilize DST’s in their program also benefit from a more focused & cost efficient completions program when DST data compliments the log data & drilling shows.
By performing open-hole DST’s, Northstar saved NAE extensive time and money with the abandonment process. While MDT data is limited and often ineffective, DST’s will prove without a doubt, whether a reservoir is viable or not. “The MDT test just didn’t give us the quality of data to make a proper analysis of the reservoir, therefore the DST’s were required”, says Phil Arundel, Executive Vice President of New Age Ethiopia. “Once the DST data was in-hand, it was clear to us which direction we needed to go”.
You can only get so much data from a MDT log, but DST data will prove your reserve.