Air core drilling

Air core drilling and related methods use hardened steel or tungstun blades to bore a hole into unconsolidated ground. The drill bit has three blades arranged around the bit head, which cut the unconsolidated ground. The rods are hollow and contain an inner tube which sits inside the hollow outer rod barrel. The drill cuttings are removed by injection of compressed air into the hole via the annular area between the innertube and the drill rod. The cuttings are then blown back to surface up the inner tube where they pass through the sample separating system and are collected if needed. Drilling continues with the addition of rods to the top of the drill string. Air core drilling can occasionally produce small chunks of cored rock.

This method of drilling is used to drill the weathered regolith, as the drill rig and steel or tungsten blades cannot penetrate fresh rock. Where possible, air core drilling is preferred over RAB drilling as it provides a more representative sample. Air core drilling can achieve depths approaching 300 metres in good conditions. As the cuttings are removed inside the rods and are less prone to contamination compared to conventional drilling where the cuttings pass to the surface via outside return between the outside of the drill rod and the walls of the hole. This method is more costly and slower than RAB.

Cable tool drilling

SpeedStar cable tool drilling rig, Ballston Spa, New York

Cable tool rigs are a traditional way of drilling water wheel. The majority of large diameter water supply wells, especially deep wells completed in bedrock aquifers, were completed using this drilling method. Although this drilling method has largely been supplanted in recent years by other, faster drilling techniques, it is still the most practicable drilling method for large diameter, deep bedrock wells, and in widespread use for small rural water supply wells. The impact of the drill bit fractures the rock and in many shale rock situations increases the water flow into a well over rotary.

Also known as ballistic well drilling and sometimes called “spudders”, these rigs raise and drop a drill string with a heavy carbide tipped drilling bit that chisels through the rock by finely pulverizing the subsurface materials. The drill string is composed of the upper drill rods, a set of “jars” (inter-locking “sliders” that help transmit additional energy to the drill bit and assist in removing the bit if it is stuck) and the drill bit. During the drilling process, the drill string is periodically removed from the borehole and a bailer is lowered to collect the drill cuttings (rock fragments, soil, etc.). The bailer is a bucket-like tool with a trapdoor in the base. If the borehole is dry, water is added so that the drill cuttings will flow into the bailer. When lifted, the trapdoor closes and the cuttings are then raised and removed. Since the drill string must be raised and lowered to advance the boring, the casing (larger diameter outer piping) is typically used to hold back upper soil materials and stabilize the borehole.

Cable tool rigs are simpler and cheaper than similarly sized rotary rigs, although loud and very slow to operate. The world record cable tool well was drilled in New York to a depth of almost 12,000 feet (3,700 m). The common Bucyrus Erie 22 can drill down to about 1,100 feet (340 m). Since cable tool drilling does not use air to eject the drilling chips like a rotary, instead using a cable strung bailer, technically there is no limitation on depth.

Cable tool rigs now are nearly obsolete in the United States. They are mostly used in Africa or Third-World countries. Being slow, cable tool rig drilling means increased wages for drillers. In the United States drilling wages would average around US$200 per day per man, while in Africa it is only US$6 per day per man, so a slow drilling machine can still be used in undeveloped countries with depressed wages. A cable tool rig can drill 25 feet (7.6 m) to 60 feet (18 m) of hard rock a day. A newer rotary drillcat top head rig equipped with down-the-hole (DTH) hammer can drill 500 feet (150 m) or more per day, depending on size and formation hardness.

Downstream Oil Jobs

The downstream oil sector of the oil and natural gas industry is the retail or consumer sector of the industry. When anyone talks about the downstream sector of this industry they may be referring to the many products that are produced based on materials from oil refineries, which can include an extensive list of chemical compounds, and elements, which are created from the crude oil, and natural gas from the earth.
Some jobs that are associated with this sector of the industry include chemical engineers that take the raw materials from the refineries and turn them into many thousands of other products by utilizing products, formulas and equipment specially designed for this purpose. The plastics industry is entirely dependent on the oil and natural gas industry for the chemicals and raw products used in creating the many compounds of plastic articles. When consumers pick up and buy a product made from plastic, they may not always realize that the plastic in the article is entirely dependent on crude oil for its composition.
Oil refinery jobs and the marketing representatives associated with the industry, are all in the downstream sector. Gas distribution utilities, oil product wholesalers, service stations and petrochemical companies are all part of the downstream sector. This sector of the industry is responsible for a considerable portion of the oil industry’s’ profits every year and the personnel involved in this sector are valued employees. Petroleum oil wholesalers need truck drivers to deliver their oil products all over the country while larger wholesalers may be in need of oil tanker captains and crew on a regular basis.
Oil refineries are in constant need of trained and experienced workers who can use their expertise to help turn the base crude oil into any number of useable products which the refinery then sells to other manufacturers to make more products. There are several types of refinery jobs including entry-level positions and degreed positions.
Engineering technicians are always in high demand in oil refining facilities. Whether mechanical, chemical, or petroleum engineers, personnel who work within the degreed areas of the refinery are responsible for the more technical aspects of the day-to-day refinement duties. Petroleum engineers require many years of specialized training and can expect to earn $95,000 to $150,000 annually.Mechanical engineers with five or more years of experience routinely make $65,000 annually, while chemical engineers can make anywhere from $60,000 to $90,000 depending on a variety of factors.