Open Hole DST
Inflate
Open hole inflate tests utilize a pair of interval spaced packers which are inflated using annular fluid to isolate the formation of interest. This type of testing is adaptable to a wide range of conditions. Inflate testing is the most time and cost effective method that can be used to isolate multiple formations since multiple zones can be analyzed during a single run in the hole.
Compression
Open hole compression, or conventional drillstem test uses a compression set packer set above the formation, with tail pipe below the packers to the bottom of the hole. Placing weight on the tool string opens the hydraulic valve allowing the formation to flow into the tool and rise to the surface. The formation is flowed for a specified time period, after which weight is removed from the tool string closing the hydraulic valve for a specified shut-in period. Measuring flows and shut-ins with this procedure can be performed as many times as are deemed necessary.