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A mud tank is an open-top container, typically made of square steel tube and steel plate, to store drilling fluid on a drilling rig. They are also called mud pits, as they were once simple pits in the earth.
Mud tanks are divided into square tanks and cone-shaped tanks according to the shape difference of the tank bottom.
The body of the tank is made by welding the steel plate and section, using the smooth cone-shape structure or the corrugated structure. The mud tank surface and passages are made of slip resistant steel plate and expanded steel plate. The mud tanks are made of the side steel pipe, all of the structure can be folded without barrier and pegged reliably. The surface of the tank is equipped with a water pipeline for cleaning the surface and equipment on the tank, it uses soaked zinc processing for the expanded steel plate. The ladder is made of channel steel to take responsibility the body, the foot board is made of expanded steel plate. The two-sided guard rails are installed on the safe suspension hook. The mud tank is designed to be in a standard shanty to prevent the sand and the rain. The pipeline is installed in the tank to preserve the warm air.
The tanks are generally open-top and have walkways on top to allow a worker to traverse and inspect the level of fluids in the tanks. The walkways also allow access to other equipment that is mounted on the top. Recently, offshore drilling rigs have closed-in tanks for safety. The mud tank plays a critical role in mechanically removing destructive solids and sediment from costly land and offshore drilling systems.
A tank is sectioned off into different compartments. A compartment may include a settling tank, sometimes called a sand trap, to allow sand and other solids in the drilling fluid to precipitate before it flows into the next compartment. Other compartments may have agitators on the top, which have long impellers below inserting into the tank and stirring the fluids to prevent its contents from precipitating. And mud guns are often equipped at the corners of the tanks' top, spraying high-pressed mud to prevent the drilling fluids in the corner of the compartment from precipitating, typically for the square tanks.
The piping linking the mud tanks/pits with the mud pumps is called the suction line. This may be gravity fed or charged by centrifugal pumps to provide additional volumetric efficiency to the mud pumps.
Mud tanks play an important role in a solids control system. It is the base of solids control equipment, and also the carrier of drilling fluids. Solids control equipment that are all mounted on the top of mud tanks include the following:
Drilling fluids flow into the shale shaker directly after it returns to the surface of the well, and the solids that are removed by the screen would be discharged out of the tank, and the drilling fluids with smaller solids would flow through the screen into mud tank for further purification. A centrifugal pump sucks the shaker-treated fluids up to the desilter or mud cleaner for further purification. And vertical slurry pump is used to pump the drilling fluids up to the centrifuge, and a mud pump would pump the drilling fluids from mud tank into the borehole after it is treated by centrifuge and the circulation system continues.
The number of the mud tanks that are needed on the drilling rig depends on the depth of the well, and also the mud demands of drilling. Normally the shale shaker and vacuum degasser and desander are mounted together on the same mud tank as the first tank at the oilfield, while desilter and centrifuge on the second tank. Also, the drilling rig has other different tanks such as a reserve tank, emergency tank, etc.
Mud tanks are an important part in the solids control system. Based on functions, mud tanks include metering tanks, circulating tanks, chemical tanks, aggravating tanks, precipitating tanks, storing tanks, etc. [1] [2]
An oil well is a drillhole boring in Earth that is designed to bring petroleum oil hydrocarbons to the surface. Usually some natural gas is released as associated petroleum gas along with the oil. A well that is designed to produce only gas may be termed a gas well. Wells are created by drilling down into an oil or gas reserve and if necessary equipped with extraction devices such as pumpjacks. Creating the wells can be an expensive process, costing at least hundreds of thousands of dollars, and costing much more when in difficult-to-access locations, e.g., offshore. The process of modern drilling for wells first started in the 19th century but was made more efficient with advances to oil drilling rigs and technology during the 20th century.
A mud engineer works on an oil well or gas well drilling rig, and is responsible for ensuring the properties of the drilling fluid, also known as drilling mud, are within designed specifications.
In geotechnical engineering, drilling fluid, also known as drilling mud, is used to aid the drilling of boreholes into the earth. Used while drilling oil and natural gas wells and on exploration drilling rigs, drilling fluids are also used for much simpler boreholes, such as water wells.
Mud logging is the creation of a detailed record of a borehole by examining the cuttings of rock brought to the surface by the circulating drilling medium. Mud logging is usually performed by a third-party mud logging company. This provides well owners and producers with information about the lithology and fluid content of the borehole while drilling. Historically it is the earliest type of well log. Under some circumstances compressed air is employed as a circulating fluid, rather than mud. Although most commonly used in petroleum exploration, mud logging is also sometimes used when drilling water wells and in other mineral exploration, where drilling fluid is the circulating medium used to lift cuttings out of the hole. In hydrocarbon exploration, hydrocarbon surface gas detectors record the level of natural gas brought up in the mud. A mobile laboratory is situated by the mud logging company near the drilling rig or on deck of an offshore drilling rig, or on a drill ship.
A derrickhand or derrickman is the person who sits atop the derrick on a drilling rig. Though the exact duties vary from rig to rig, they almost always report directly to the driller. Their job is to guide the stands of the drill pipe into the fingers at the top of the derrick. Other duties might include monitoring pH and calcium levels, viscosity and the mud weight (density), adding chemicals and oil based fluids, and being responsible for the shale shakers and mud pump.
Shale shakers are components of drilling equipment used in many industries, such as coal cleaning, mining, oil and gas drilling.They are the first phase of a solids control system on a drilling rig, and are used to remove large solids (cuttings) from the drilling fluid ("mud").
A coal preparation plant is a facility that washes coal of soil and rock, crushes it into graded sized chunks (sorting), stockpiles grades preparing it for transport to market, and more often than not, also loads coal into rail cars, barges, or ships.
In the oil industry, mud weight is the density of the drilling fluid and is normally measured in pounds per gallon (lb/gal) (ppg) or pound cubic feet (pcf). In the field it is measured using a mud scale or mud balance. Mud can weigh up to 22 or 23 ppg. A gallon of water typically weighs 8.33 pounds.
A mud pump, is a reciprocating piston/plunger pump designed to circulate drilling fluid under high pressure down the drill string and back up the annulus. A mud pump is an important part of the equipment used for oil well drilling.
Desanders and desilters are solid control equipment with a set of hydrocyclones that separate sand and silt from the drilling fluids in drilling rigs. Desanders are installed on top of the mud tank following the shale shaker and the degasser, but before the desilter. The desander removes the abrasive solids from the drilling fluids which cannot be removed by shakers. Normally, the solid diameters for desanders to separate would be 45~74μm, and 15~44μm for desilters.
Squeeze job, or squeeze cementing is a term often used in the oilfield to describe the process of injecting cement slurry into a zone, generally for pressure-isolation purposes.
Oil well cementing equipment are essential for oil and gas exploration and are required oilfield equipment when drilling a well.
Effective solids control can be attributed to the overall performance of all the components of the mud systems. Conditioning the drilling fluid with the goal of dramatically lowering maintenance cost, avoiding excessive chemical treatment and maintaining mud systems volume will decrease the chance of equipment failure, unnecessary high mud costs, hole and drilling problems.
Mud Gas Separator is commonly called a gas-buster or poor boy degasser. It captures and separates the large volumes of free gas within the drilling fluid. If there is a "kick" situation, this vessel separates the mud and the gas by allowing it to flow over baffle plates. The gas then is forced to flow through a line, venting to a flare. A "kick" situation happens when the annular hydrostatic pressure in a drilling well temporarily falls below that of the formation, or pore, pressure in a permeable section downhole, and before control of the situation is lost.
A degasser is a device used in the upstream oil industry to remove dissolved and entrained gases from a liquid. In drilling it is used to remove gasses from drilling fluid which could otherwise form bubbles. In a produced water treatment plant it is part of the process to clean produced water prior to disposal.
Solids control is a process used in drilling rigs which use drilling fluid. It involves separating the "cuttings" from the fluid, allowing it to be recirculated or discharged to the environment.
A mud gun is designed for use in a solids control system of a drilling rig. It is a tool which is mainly used for mixing drilling mud in the circulatory system and to prevent the mud from precipitating. The structure of equipment is simple offering flexible operation and easy use. A mud gun is commonly used to guard against precipitates in a solids control system. The mud gun is installed in a mud tank.
A centrifugal water–oil separator, centrifugal oil–water separator or centrifugal liquid–liquid separator is a device designed to separate oil and water by centrifugation. It generally contains a cylindrical container that rotates inside a larger stationary container. The denser liquid, usually water, accumulates at the periphery of the rotating container and is collected from the side of the device, whereas the less dense liquid, usually oil, accumulates at the rotation axis and is collected from the center.
A conical plate centrifuge is a type of centrifuge that has a series of conical discs which provides a parallel configuration of centrifugation spaces.