What Does Starter Barrel Mean?
A starter barrel is a part of the drilling equipment used to drill the borehole for in-situ stress testing. In-situ stress testing is an important part of a geotechnical investigation carried out before commencing a trenchless construction project. Starter barrels are needed to begin drilling, as they center the hole. Once sufficient depth is attained, the starter barrel can be replaced with a regular bit and core barrel to drill to the desired depth and retrieve a core sample. Some starter barrels also have a steel ring that can retrieve the core.
Trenchlesspedia Explains Starter Barrel
The starter barrel is used to begin drilling a test borehole. Sometimes single-tube core barrels are also used as starter barrels for beginning a core operation. Once the starter barrel reaches a sufficient depth, the crew replaces it with a regular bit and core barrel to extend the hole to the desired depth. The core is then removed, and casing with stabilizers is inserted. In addition to the drill, a diamond bit, reamer and drill rods of appropriate length are necessary. A core breaker, core shovel and core puller are also parts of the drilling equipment apparatus.
Subsurface rock formations influence all operations throughout the course of the construction process. Knowledge about possible rock formations at the beginning of a project allows engineers to determine the in-situ stress of a rock formation. Based on these tests, engineers are able to determine the trenchless method most suitable and cost-effective for the project. It also helps them to prepare the right mix of drilling fluid to handle the formation.