DST is the drill stem test. Normally during the exploration drilling, you need to know how much you can produce from well (reservoir section). So that you can decide whether to drill additional well to appraise or abandon (as dry hole). RFT is called Repeated Formation Tester, it is for generic term for Baker Hughes tool. In Schlumberger tool, it is called MDT (Modular Dynamic Tester). It is usually during all kind of drilling operations (Exploration, appraisal, development/ producing). You need to know the sample of your oil and gas you want to produce. What RFT did is it got probes to take fluid samples from reservoir section drillstem test 1. n. [Drilling] ID: 1373 A procedure to determine the productive capacity, pressure, permeability or extent (or a combination of these) of a hydrocarbon reservoir. While several different proprietary hardware sets are available to accomplish this, the common idea is to isolate the zone of interest with temporary packers. Next, one or more valves are opened to produce the reservoir fluids through the drillpipe and allow the well to flow for a time. Finally, the operator kills the well, closes the valves, removes the packers and trips the tools out of the hole. Depending on the requirements and goals for the test, it may be of short (one hour or less) or long (several days or weeks) duration and there might be more than one flow period and pressure buildup period. [url=http://www.glossary.oilfield.slb.com/Display.cfm?Term=drillstem%20test]Oilfield Glossary: Term 'drillstem test'[/url]
