Presentation on theme: "Environmental Drilling By: Josh Humphreys October 8,2006."— Presentation transcript:
Environmental Drilling By: Josh Humphreys October 8,2006
Why Do We Drill?? Environmental Site Characterization Ground Water Monitoring Exploration Petrochemical Exploration Water Well Drilling
Hand Drilling Methods Probing- Slender steel rod inches in diameter and 3-4 feet long. Used to locate shallow subsurface obstructions (Boulders, utility conduit, piping e.g.) When probe is advanced it forces the formation material out of its path by displacing the soil.
Hand Drilling Bits
Direct Push Boring Simple, efficient method of obtaining samples and installing wells. Can be accomplished with out the need of heavy equipment, fluids, and doesn’t produce drill cuttings. Well suited for shallow borings in soft materials. Generally small Truck or ATV mounted
Direct Push Boring Cont. Forced into the soil by direct application of weight of the machine, by the percussive effect of a hydraulic or mechanical hammer. Some may use a vibratory system to advance the drilling.
Auger Drilling Utilizes a spiral tool form to convey drilled borehole material to the surface. Auger Drilling doesn’t normally require the use of circulatory fluids, unless it is used to cope with blowing, heaving or running sands. Essentially a conveyor with a cutting bit at the bottom to disaggregate formation material, and be lifted to the surface, or forced into the borehole wall.
Auger Bit Types
Bucket Auger Utilize an auger bucket with cutting teeth attached to a square torque bar that passes through a drive mechanism. Generally advances 1 to 2 ft., is withdrawn, and contents are discarded in throw away pile. Depth capacity ft. Large diameter holes in. Commonly used to drill wells, caissons, and building footings.
Continuous-Flight Solid-Stem Augers Consists of a Plugged Tubluar steel centered shaft, around which a continuous steel strip in the form of a helix is welded. An individual auger section in known as a “flight”, and is normally 5 ft. long. Designed to connect to one another by way of safety pin or large bolt ‘u-pin” or “drive clip”. Torque is transmitted by the rig.
Continuous-Flight Solid-Stem Augers Cont. Drill cutter heads are attached to the bottom of the auger. Most of the cutter heads are field replaceable bit types. Bits are hardened or tungsten carbide steel teeth. Designed to cut 0.5 inches larger than the auger. WHY??? Most Successful in dry formations or cohesive materials- not frequently used for well installation.
Hollow Stem Augers Form of continuous-flight auger in which the helix is wound around, and welded to, a hollow center tube. When tubes are connected, the hollow stem auger will present a smooth, uniform bore throughout its length. Can be done with out drilling fluids. Most common drilling method for monitoring wells.
Vertical & Horizontal Drill Rigs
Rotary drilling rig Carry their own pumps and operating components. Power unit, rotation mechanism, feed or retract system, drum hoist, and other features.
Drilling Fluids Circulation medium can be liquid, water or drilling mud, or is can be a gas, such as air or foam with additives of various types. Media is forced down through the drill rod and out through the bit and back up between the borehole wall and drill rod. Cools and lubricates, stabilize the borehole and remove drill bit cuttings.
Wash Boring Simple, and almost obsolete method of advancing the borehole. Cut by chopping and twisting action of a bit, and disaggregated formation material is washed to the surface by fluid.
Sonic Drilling Utilizes high frequency vibration, aided by down pressure and rotation. Power for drilling is created by sine generator on top of drill mast, with rapidly rotating eccentric, counter balanced weights that are timed to direct 100% of the 0 and 180 degrees. Rotates at 3,000 to 10,800 r/min.
Sonic Drilling Cont. Developed in the 1970’s for use in mineral exploration, but ineffective. Later adapted to environmental exploration in the 1990’s and has been very effective. Drill in mostly unconsolidated formations is very rapid. Continuous sampling cuts down on costs. Can go up to 700 ft. can penetrate boulders, construction debris and bedrock to a point.