FLUID DRILLING METHODS WE OFFER
1) Direct Rotary Mud
The borehole is drilled by rotating either a drag or a tricone rotary drill bit. The drill cuttings are removed by means of either air circulation (air compressor) or direct mud flow (mud pumps). The returning materials and their medium move between the annulus of borehole and the drill string to the surface. Samples can be taken using this method as desired. Boreholes at diameters from 6” – 24”
2) Reverse Rotary Circulation System
The drilling fluid flows from the mud pit down the borehole outside the drill rods, then passes upward through the bit into the drill rods after entraining the cuttings. Drilling fluid can be mixed when gravel and boulders are encountered by means of the mudpit. This method has been used specifically for clients who want minimal formation damage when drilling well completion zones 8” to 24”.
AIR DRILLING METHODS WE OFFER
1 A) Air Drilling (Direct Rotary)
Cuttings are lifted by air up the borehole between the pipe and borehole and loosely collect on the surface. The firm has normally done these types of holes for shallow water quantity 6” and up, testing in coal seams in southern Saskatchewan.
B) Down Hole Hammer
The cuttings are removed in the same manner as Direct Rotary Air. The different is the pneumatically operated drill located at the bottom of the drill string. The unique shape of the button bit on the bottom of the hammer allows the rock to be chipped, as the tool strikes the rock rapidly. The cuttings are then carried to the surface with the uphole velocity of air often helped by “foam or stiff foam.” The company has been very actively involved in recent years with this method ranging in boreholes of 6” to 17 ½”.
C) Reverse Circulation (Inverse) with Down Hole Hammer (CSR)
The air passed from the annular space between the dual wall pipes to a cross-over channel into the interchange sub situated on the top of the hammer. This permits cutting samples to be caught at given depths of 6” to 10” as required through the cycle sampler.
D) Reverse Circulation with Drag or Rock bit (CSR)
This is primarily used in the overburden where the sample collected for a given interval is accurately collected from the sampler (eg. coals, speckled shales, tills, etc.) 6 ¾” – 9 7/8”. This method has been also used when bulk sampling kimberlite (diamond exploration) The large 8” dual wall drill string can handle large diameter holes of up to 24” and beyond.
E) Drill through Casing Hammer
The driver unit is mounted in the mast of the Drilltech D50 Crawler Drill. The drill pipe and casing are preassembled as a single unit. A bit that fits inside the casing is installed on the bottom of the drill string, making it possible to drill and drive casing simultaneously. The cuttings are returned between the casing and the drill string though the swivel located below the hammer unit. Samples can be obtained at various depths as required by means of a hose attachment on the swivel unit. The company has used this method for many years in the Key Lake area to rid itself of serious overburden problems associated with drilling dry sands and boulders at overburden bedrock contacts. This type of air drilling is excellent for marginal shallow well fields, up to 20” in diameter.
2) Hard Rock and Glacial Coring
We have experience in many feet of HQ coring in both Key Lake and for the Nipawin Hydo Project. Shelby tube and split spoon sampling along with standard penetration tests are some other facets of our special sampling techniques.