Well Samples: Sidewall Cores Small samples (1 x 2.5 inches) 30 samples per run Sampling based on logs Step 1: Gun in position Step 2: Shot fired Stabilizer Gun Body Core Barrels SLIDE 9 This slide explains what a sidewall core is The tool (pictured on the left) is part of the drill stem It has about 30 casings that can be fired into the formation The casing captures a small sample of rock The samples are retrieved at the end of a logging run This does not require very much extra rig time – so is relatively inexpensive The drawback is that the sample is small – we get the rock type but nothing about vertical variability, sedimentary structures, etc. Step 3: Core retrieved Courtesy of ExxonMobil L 3 - Types of Data