D4101 - Rat hole, seismic drilling, shot hole and directional drilling down to 200 feet, rig anchoring

Operational Details
Rat hole drilling is undertaken prior to the main drilling operations. Oil companies arrange for site survey access and gives the shot hole driller plans of where to shoot. The process include a truck mounted auger being used to drill 3 holes from 16 to 36 inches, and a conductor hole is drilled to a depth of 30 to 40 feet. The deepest hole becomes the pilot hole for the main drilling of a well. The 2 smaller holes are augured near the pilot hole. The smaller holes are also referred to as mouse holes, which are used to rest stands of pipe during the main drilling process.

Seismic drilling down to 200 feet is another shallow drilling service undertaken by a truck mounted drill that is used in providing test holes for exploration. As with others in this subcode, the drilling process is completed in a short period of time and no other services beyond the drilling is provided.

Rig anchoring is used to secure the drilling rig so that it is absolutely stationary. Anchoring services may also be used to secure flare stacks. Anchoring is completed, using truck mounted equipment that include a rotary bit that screws an augured piece of iron into the ground until a solid base is reached. The anchor bolts or screws are required to pass a pull test of 15,000 to 20,000 lbs on each leg. Safety cables then are run and fastened to the anchor and the drilling rig base. The fastening of the cables is usually undertaken by drilling rig crews. Shot hole drilling includes the drilling of a shallow hole, approximately 40 to 75 feet, for the purpose of holding explosive charges. This is undertaken by a small truck mounted driller. The explosive charges are set off by the exploration company or crew who then ensures the vibrations are recorded on a seismograph to aid in the exploration of oil and gas.

SIC Codes
000000343 - Rathole, seismic, shothole drilling
000000344 - Rig anchoring