Glossary
ACIDIZING: Involves using specially formulated acid blends to dissolve portions of the rock in the producing formation. Acidizing may also be used to clean out other unwanted materials and debris in order to maximize production.
ANNULUS: Downhole space between drillstring or casing and borehole wall, or between production tubing and casing, or between surface casing and production tubing and casing.
BLOWOUT: Uncontrolled gas and/or oil pressure and eruption from a well.
BLOWOUT PREVENTOR: A safety device installed immediately above the casing or in the drillstem that can close the borehole in an emergency.
CASING: Steel pipe used in wells to seal the borehole from formation fluids and reinforce the walls of the borehole.
CASING COMPLETION: Completing a well by installing casing within the borehole.
CASING HANGER: Device used to support or suspend the casing within the wellbore, usually consisting of mechanical teeth to keep the pipe from slipping.
CEMENTING: Securing the well casing in place and excluding excess fluids from the wellbore by forcing cement slurry down through the casing and out up the annulus. A bond between the pipe and the formation is made after the cement sets.
COGENERATION: Simultaneous generation of electricity and process steam or heat from a single fuel. A cogeneration plant is usually coal or gas-fired.
COIL TUBING: Coil tubing is a continuous, jointless, high-pressure-rated hollow steel cylinder. Production tubing traditionally was made up of jointed sections of pipe, similar to the string of pipe used for drilling, but coil tubing is now used in this application. It is transported to the wellsite on a reel holding up to 7,000 metres. Special equipment is used to inject the tubing through the wellhead into the wellbore. This method is considerably quicker and more efficient than joining sections of pipe. Coil tubing has also proved useful in other applications such as well stimulation and under-balanced drilling.
COIL TUBING DRILLING: A continuous piece of tubing is used to deploy a drilling device, usually a positive displacement motor, to the drill target. Hydraulic power to turn the drill bit is provided by surface pumps.
COIL TUBING UNIT: The coil tubing unit is a self-contained, easily transported, hydraulically powered workover unit that injects and retrieves a continuous string of tubing into a larger string of tubing or casing. The system can be used on land or offshore and does not require a separate workover rig. The unit can be used on live wells and allows continuous injection of fluids or nitrogen while continuing to move the pipe.
COMPRESSOR STATION: Used to propel natural gas through pipelines at a speed of about 40 km per hour. It takes approximately four and half days for natural gas to travel from Alberta to Ontario. The gas is compressed up to 100 times atmospheric pressure in the transmission pipelines. Pressures are typically much lower in gathering and distribution systems.
CORE ANALYSIS: Analysis of rock samples which are cut downhole and brought to the surface for examination to determine characteristics such as porosity and permeability.
CORING BIT: A specialized drilling bit for cutting and removing rock samples from the bottom of a well.
CRUDE OIL: Unrefined petroleum, i.e., oil as it comes from the well.
DAY RATE CONTRACT: A well drilling contract which specifies paying the drilling contractor on the basis of days required to achieve the well completion.
DEEP WELL: A well that is generally more than 3,000 metres deep and requires several months to drill.
DEHYDRATOR: While natural gas leaving the separator no longer contains free liquids, the gas may contain significant amounts of water vapor at high pressure. If not removed, it can cause serious problems by forming gas hydrates - an ice-like sludge. In this case a dehydrator may be used to separate the water vapor from the gas.
DEVELOPMENT DRILLING: Drilling wells in a resource area already proven to be productive.
DIAMOND BIT: Drilling bit with industrial diamonds set in cutting surfaces.
DIRECTIONAL (HORIZONTAL) DRILLING: By slanting or curving wells, it is possible to reach reservoirs under lakes or other environmentally sensitive areas. By turning a full 90 degrees, wells can bore horizontally into formations, greatly increasing productivity by exposing a larger area of the hydrocarbon bearing rock to the well bore.
DOWNHOLE MOTORS: Specifically designed motors which rotate the bit by using energy from the circulation of the drilling fluid. Downhole motors are particularly useful for drilling horizontal wells because they can turn small-radius corners.
DRILL COLLAR: Heavy tubular connector between drillpipe and drilling bit.
DRILL STRING: The string of tools that are used to drill a well, i.e., the kelly, drillpipe, drill collars, stabilizers and drilling bit.
DRILL BIT: A cutting or grinding tool or head attached to the tip of the drill string.
DRILLING FLUIDS OR MUD: Drilling fluids or muds have become more sophisticated to improve performance and reduce environmental impacts. The mud is typically a mixture of water (or sometimes diesel fuel, mineral oil or other fluids) and various minerals and chemicals, with the precise mixture determined by the depth of the hole and type of rock being drilled. The flow of mud, down the drill pipe and up the surrounding space, cools and lubricates the bit and removes the rock cuttings. The weight of the mud column, which can be considerable at a depth of several thousand metres, offsets the pressure of underground reservoirs and prevents uncontrolled release of oil or gas from the well. Drillers can control the weight by altering the compression of the mud.
DRILLING RIG: A sophisticated combination of machinery and controls. The key functions are lifting and lowering pipe, rotating the drill bit, circulating fluid to remove rock cuttings, and controlling the pressure in the hole. The principal components of a rotary rig are the derrick, the drawworks, the engines, the mud system, and the drillstring. The derrick is the structure placed over the well. The drawworks is the hoisting equipment. The engines drive the mud pumps and drawworks and provide power for miscellaneous equipment. The mud system is comprised of the mud pumps, the mud tanks, the mud flow lines and the circulating hose. The drill string is the entire rotating assembly and consists of the kelly, drill pipe, drill collars and drill bit. Rigs are described as "singles", "doubles" or "triples" depending on how many nine-metre (30-foot) sections of pipe can be lifted and stacked in the derrick. Generally, the taller the derrick, the deeper the rig can drill.
FLOWLINES AND GATHERING SYSTEMS: These are relatively small pipelines, two to twenty-four inches, or fifty to six hundred millimetres, in diameter, which link producing wells, processing facilities and transmission pipelines. They are part of the upstream producing sector. Crude oil can be stored in tanks near the wellhead and trucked to the nearest pipeline terminal, but pipelines are the only means by which natural gas can be transported economically overland. About 60 per cent of the gathering lines in Alberta carry natural gas and NGLs.
HYDRAULIC FRACTURING: Often known as "fracing", this process involves pumping a fluid into the well at very high pressure to create cracks in the reservoir rock. Sand or other material may be used as the "proppant" to prop open the gaps created by fracing.
GAS-OIL RATIO: Measurement of the volume of gas produced with oil.
GAS PROCESSING: Primary purposes are the recovery of gas liquids, water & solids.
HORIZONTAL DRILLING: See Directional Drilling.
HUFF AND PUFF: Cyclic steam/hot water injection into a well in order to stimulate oil production.
INDEPENDENT PRODUCER: A producer of petroleum without vertical integration of operations.
KELLY: Square or hexagonal hollow shaft of which one end engages the drilling table and the other end engages the drillpipe.
KICK: Pressure surge in the well.
LAG TIME: The amount of time it takes for cuttings to circulate from the bottom of the hole to the surface.
LIQUIFIED NATURAL GAS: Gas (mainly methane) that has been liquefied in a refrigeration and pressure process.
LIQUIFIED PETROLEUM GAS: Lighter hydrocarbons (mainly propane and butane) that have been liquefied by special processes.
LOGGING: Involves using instruments to determine what type of rock is being encountered and whether it is likely to contain oil, gas or water. Various types of logging can measure and record the natural or induced radioactive properties of the rock, or the way formations respond to electric current, or how fast sound waves travel through the rock, or porosity & permeability.
MEASUREMENT WHILE DRILLING (MWD): Used to assist in horizontal drilling. Computerized devices are placed in the drill string just above the bit. These devices are called MWD tools. MWD tools monitor the drill string's orientation and transmit this information in sonar-like pulses through the drilling fluid to the surface, allowing the driller to navigate the bit very precisely. A MWD system usually consists of three fully integrated assemblies: a pulser, a battery power pack and a sensor system.
MIGRATION: Movement of hydrocarbons in the ground; primary migration is from source bed or rock to permeable rock.
MUD: See Drilling Fluids
MUD LOG/MUD LOGGING: Analysis of cuttings brought to the surface in circulating drilling fluid.
MUD SYSTEM: Equipment comprising drilling fluid storage and circulating system components.
MULTI-ZONE COMPLETION: Completing a well in which provision is made for producing formation fluids from more than one formation or formation zone.
NATURAL GAS: The gaseous forms of petroleum such as mixtures of hydrocarbon gases and vapors.
OVERBURDEN: Earth material overlying a mineral or other useful material deposit.
PERFORATE/PERFORATING: Making holes through the casing opposite the producing formation to allow flow into the well.
PERFORATING GUN/TOOL: After the production tubing is in place, the casing must be perforated to allow a flow of hydrocarbons from the producing rock strata into the well. This is done by lowering a device called a perforating gun to the depth of the producing formation. An electrical pulse sent from the surface detonates shaped explosive charges in the gun to create perforations through the production casing.
PERMANENT WELL COMPLETION: Completing a well in which the tubing is run and the wellhead is assembled only once in the life of the well.
PETROLEUM: Generic name of hydrocarbons, including oil, crude oil, natural gas, natural gas liquids and their refined products.
PROVED RESERVE: Petroleum that has been discovered and determined to be recoverable, but is not yet produced.
RESIDUE GAS: Gas remaining after natural gas is processed and liquids are removed.
ROTARY DRILLING: Making a hole in the earth by rotating an entire drill string into the earth; the tip of the drill string may be any kind of drilling bit.
ROTARY TABLE: Turning section of the derrick floor, transfers engine power into turning motion to rotate drill string.
ROYALTY: A share of production from a property without bearing the expense of finding or producing the petroleum.
SCREEN-OUT: Well congested with sand which has fallen out of produced fluids in the well.
SEDIMENTARY ROCK: Rock formed by successive layers of materials, which are compacted by layers of subsequent deposits.
SEISMIC SURVEYS: Seismic surveys involve crews of between 35 and 200 workers, averaging about 50 persons per survey. These crews place geophones or "jugs" in carefully surveyed lines or grid patterns. The geophones are similar to microphones. They pick up the low-frequency sound waves that are generated by explosives or mechanical vibrators and then reflected by underground rock strata. Sophisticated computer programs are used to process and interpret the digitally recorded data from the survey. Because sound waves travel at different speeds through different kinds of rock, geophysicists can produce quite detailed "maps" of the geography thousands of metres below the surface.
SEISMIC (3D): Three-dimensional seismic is more commonly used in existing production areas. Geophones are laid out in a grid pattern for 3D. Although more expensive, 3D saves on other costs because companies can identify the best "targets" for drilling and production-enhancement programs.
SEPARATORS: Well fluids are a complex mixture of liquid hydrocarbons, gas, water, and some impurities. The water and impurities must be removed before the hydrocarbons are stored, transported, and sold. Liquid hydrocarbons and objectionable impurities must also be removed from natural gas before gas goes to a sales line. A separator is a piece of equipment used to separate wellstream gas from free liquids. The size of the separator depends on the rate of natural gas flow and/or liquids going into the vessel.
SLANT DRILLING: Slant drilling involves drilling a straight hole at a predetermined angle from the surface. It is an ideal option for reaching target zones which are at relatively shallow depths. This may be required to consolidate difficult terrain conditions such as drilling under bodies of water, population centres or environmentally protected areas.
SOUR GAS: Natural gas containing relatively large amounts of sulfur/sulfur compounds. Sour gas is commonly found in deep, hot, high pressure natural gas deposits, such as those in the eastern slopes and foothills of the Rocky Mountains in Alberta and northeastern British Columbia.
SUCKER ROD: A series of steel rods connecting the pump inside well tubing down-hole to the pumping jack on the surface.
SURFACE EQUIPMENT: Lease equipment used to produce hydrocarbons and clean them in the field.
SURFACE RIGHT: Ownership of a property tract with or without concurrent ownership.
SWABBING: Cleaning out a well with a special tool connected to a wireline.
SWEET GAS: Natural gas containing little sulfur/sulfur compounds.
TANK BATTERY: Field equipment comprising oil and gas separating components, treating equipment, and storage facilities.
TOOL PUSHER (RIG MANAGER): Typically lives on site, works closely with company representative and crew for on-site decisions.
TOP DRIVES: Are electric or hydraulic motors that move up and down the derrick at the top of the drill string, rotating the drill bit. These take the place of the conventional rotary table at the base of the derrick. Top drives facilitate directional and horizontal drilling.
TRANSMISSION PIPELINES: Transmission lines are generally large-diameter pipelines carrying oil and gas between producing and consuming regions. Some of the pipe is a metre or more in diameter (up to 52 inches or 1,320 millimetres).
TURNKEY CONTRACT: A well drilling contract which specifies paying the drilling contractor on the basis of completing drilling and preparing a well for production.
UNDERBALANCED DRILLING: This is where nitrogen is used as part of the drilling fluid. This is called underbalanced drilling because the weight of the drilling fluid is less than the reservoir pressure. This method avoids a common problem of conventional drilling, where the mud can penetrate into surrounding rock formations and block the channels that allow hydrocarbons to flow into the well bore. Mud penetration can reduce productivity and even cause some reserves to be overlooked entirely.
VERTICAL INTEGRATION: Business operations designed to participate in successive operations of an industry, e.g., an oil company that produces, refines transports and markets products.
VISCOSITY: The ability of a liquid to flow.
WASH TANK: A settling vessel in which an oil and water emulsion can separate.
WELL LOG: Geological, formation attribute, and hydrocarbon potential data obtained with special tools and techniques used downhole.
WELL STIMULATION: Treatments on a well or formation to obtain improved production, e.g., hydraulic fracturing, acidizing or sand control.
WELLHEAD: Casing attachment to the blowout preventer or the production Christmas tree, bolted or welded to conductor pipe or surface casing.
WELLSITE TRAILER: Usually skid-mounted, modern wellsite trailers are used to provide wellsite accommodation for geologists and engineers. These 12'x56' units include two rooms with queen size beds, complete ensuite baths, geologist lab, separate working facilities and virtually every modern convenience you will require. Some wellsite trailers are smaller "wheeled" units that are used on shorter term, shallow wells.
WET/RICH GAS: Natural gas containing significantly large amounts of associated petroleum liquids.
WILDCAT WELL: An exploratory well drilled in an unproven resource area.
WIRELINE LOGGING: Logging or measuring downhole formation attributes using special tools or equipment lowered into the borehole on a wireline (slender steel cable).