Petroleum Technicians

Before petroleum technicians can begin work on an oil reservoir, prospective sites must first be sought by geological exploration teams. These crews perform seismic surveying, in which sound waves are created and their reflection from underground rocks recorded by seismographs, to help locate potential sources of oil. Other team members collect and examine geological data or test geological samples to determine petroleum and mineral content. They may also use surveying and mapping instruments and techniques to locate and map test holes or the results of seismic tests.

It is the drill bit, however, that ultimately proves whether or not there is oil. Drilling for oil is a highly skilled operation involving many kinds of technicians: rotary drillers, derrick operators, engine operators, and tool pushers.

In the most common type of drilling, a drill bit with metal or diamond teeth is suspended on a drilling string consisting of 30-foot pipes joined together. The bit is turned either by a rotary mechanism on the drill floor or, increasingly, by a downhole motor. As drilling progresses, the bit gets worn and has to be replaced. The entire drilling string, sometimes weighing more than 100 tons, must be hauled to the surface and dismantled section by section, and after the bit is replaced, the string is reassembled and run back down the well. Known as a "round trip," this operation can take the drilling crew most of a 12-hour shift in a deep well. Until recently, drill strings were mostly manually handled; however, mechanized drill rigs that handle pipe automatically have been introduced to improve safety and efficiency.

The driller directs the crew and is responsible for the machinery operation. The driller watches gauges and works throttles and levers to control the hoisting and rotation speed of the drill pipe and the amount of weight on the bit. Special care is needed as the bit nears oil and gas to avoid a "blow-out." Such "gushers" were common in the early days of the oil industry, but today's drilling technicians are trained to prevent them. Drillers also record the type and depth of strata penetrated each day and materials used.

Derrick operators are next in charge of the drilling crew. They work on a platform high up on the derrick and help handle the upper end of the drilling string during placement and removal. They also mix the special drilling "mud" that is pumped down through the pipe to lubricate and cool the bit as well as help control the flow of oil and gas when oil is struck.

Engine operators run engines to supply power for rotary drilling machinery and oversee their maintenance. They may help when the roughnecks (oilfield laborers) pull or add pipe sections.

Tool pushers are in charge of one or more drilling rigs. They oversee erection of the rig, the selection of drill bits, the operation of drilling machinery, and the mixing of drilling mud. They arrange for the delivery of tools, machinery, fuel, water, and other supplies to the drilling site.

One very specialized drilling position is the oil-well fishing-tool technician. These technicians analyze conditions at wells where some object, or "fish," has obstructed the borehole. They direct the work of removing the obstacle (lost equipment or broken drill pipes, for example), choosing from a variety of techniques.

During drilling, mud test technicians, also called mud loggers, use a microscope at a portable laboratory on-site to analyze drill cuttings carried out of the well by the circulating mud for traces of oil. After final depth is reached, technicians called well loggers lower measuring devices to the bottom of the well on cable called wireline. Wireline logs examine the electrical, acoustic, and radioactive properties of the rocks and provide information about rock type and porosity, and how much fluid (oil, gas, or water) it contains. These techniques, known as formation evaluation, help the operating company decide whether enough oil exists to warrant continued drilling.

The first well drilled is an exploration well. If oil is discovered, more wells, called appraisal wells, are drilled to establish the limits of the field. Then the field's economic worth and profit are evaluated. If it is judged economically worthwhile to develop the field, some of the appraisal wells may be used as production wells. The production phase of the operation deals with bringing the well fluids to the surface and preparing them for their trip through the pipeline to the refinery.

The first step is to complete the well—that is, to perform whatever operations are needed to start the well fluids flowing to the surface—and is performed by well-servicing technicians. These technicians use a variety of well-completion methods, determined by the oil reservoir's characteristics. Typical tasks include setting and cementing pipe (called production casing) so that the oil can come to the surface without leaking into the upper layers of rock. Well-servicing technicians may later perform maintenance work to improve or maintain the production from a formation already producing oil. These technicians bring in smaller rigs similar to drilling rigs for their work.

After the well has been completed, a structure consisting of control valves, pressure gauges, and chokes (called a Christmas tree because of the way its fittings branch out) is assembled at the top of the well to control the flow of oil and gas. Generally, production crews direct operations for several wells.

Well fluids are often a mixture of oil, gas, and water and must be separated and treated before going into the storage tanks. After separation, treaters apply heat, chemicals, electricity, or all three to remove contaminants. They also control well flow when the natural pressure is great enough to force oil from the well without pumping.

Pumpers operate, monitor, and maintain production facilities. They visually inspect well equipment to make sure it's functioning properly. They also detect and perform any routine maintenance needs. They adjust pumping cycle time to optimize production and measure the fluid levels in storage tanks, recording the information each day for entry on weekly gauge reports. Pumpers also advise oil haulers or purchasers when a tank is ready for sale.

Gaugers ensure that other company personnel and purchasers comply with the company's oil measurement and sale policy. They spot-check oil measurements and resolve any discrepancies. They also check pumpers' equipment for accuracy and arrange for the replacement of malfunctioning gauging equipment.

Once a field has been brought into production, good reservoir management is needed to ensure that as much oil as possible is recovered. Production engineering technicians work with the production engineers to plan field workovers and well stimulation techniques such as secondary and tertiary recovery (for example, injecting steam, water, or a special recovery fluid) to maximize field production. Reservoir engineering technicians provide technical assistance to reservoir engineers. They prepare spreadsheets for analyses required for economic evaluations and forecasts. They also gather production data and maintain well histories and decline curves on both company-operated and outside-operated wells.

The petroleum industry has a need for other kinds of technicians as well, including geological technicians, chemical technicians, and civil engineering technicians.