Drilling in agricultural areas requires a strong blend of safe and efficient operations. The right tools and materials go a long way toward your success. Mud tanks are an essential part of any large drilling project, and equally important is the condition of the mud.
In this article, we will talk about mud tanks, drilling mud, and how float level transmitters ensure the right consistency for the job.
A mud tank is a large, rectangular container made of square-shaped steel tubing and plates that holds drilling mud (also called drilling fluid) on drilling platforms. In addition to storing mud, the tank is used for mixing and treating the mud and removing rocks and other unwanted materials from a drilling platform.
The tank is often open-topped with walkways for workers to inspect the mixture and operate other drilling platform equipment. Inside, the tank is composed of sections to help separate rocks and sediment and aid with agitation.
A mud tank can be a portable or permanent installation on or near a drilling platform. The quantity and size will depend on the drilling depth, the application, and the drilling method.
There are two basic types of tanks on a job: an active tank and a reserve tank. The active tank holds the mud used for most drilling while aiding with mixing chemicals or additives before usage. The reserve tank is set aside to store excess mud or other types of mud to aid with the project.
Drilling mud is a mud-like mixture pumped down the drilling pipe and through the drill bit to help lubricate and cool the bit. The mud also rises back up the same drilling pipe, bringing with it loose rock cuttings from the drilling pipe.
The drilling mud comes in three versions: water-based, oil-based, or synthetic-based:
Water-based drilling mud is made from either freshwater or seawater and often contains clay (bentonite) for ideal viscosity. It is also composed of special minerals like barite to make the column heavier for added borehole stability. Water-based muds are often used for less strenuous or less demanding drilling.
Oil-based mud often uses diesel oil or mineral oil, bentonite, brine, and barite to aid with viscosity and weight and other agents for lubricating properties. This mud is used for drilling work that puts more stress on the drill, such as deep drilling, horizontal drilling, and directional drilling.
Synthetic-based mud is an environmental alternative to oil. It uses highly refined compounds blended with similar additives as oil-based mud.
Unless the tanks are already installed or you use holes in the ground as mud tanks (called mud pits), the active and reserve tanks are transported from an outside location to your drilling platform. Bulk tanks may also be used to assist in pouring additives into the mud. In large jobs, these bulk tanks may have the additives already in them; otherwise, the additives come as dry sacks and stored in a safe house to be mixed in at the appropriate time.
The process starts by preparing the mud in the active tank with the needed ingredients. Then one or more mud pumps move the mud from the tank through pipes and into the interior of the drill bit, pushing cuttings away while you drill. The mud then travels up the pipe's interior sides and back to the surface into the original mud tank, carrying loose cuttings with it.
The returning mud is filtered using a desander and distiller or settling tanks to remove rocks and sediment. The mud is tested for volume to spot any inconsistencies. If any are found, more ingredients are added to retain previous levels. Then the entire process starts again.
Safe and economical drilling requires the right quantity and consistency of mud, so catching any volume changes is of paramount importance. Volume increases indicate changes in the ingredients such as water and oil levels. Volume decreases indicate loss of mud into the drilling pipe. Issues like these can damage your drill, rig, and the surrounding land area.
Level transmitters provide real-time readings of changes in volume. Today's transmitters come with varying technology for the job. Automation Products Group (APG) is a leader in the sensor market and offers a range of transmitter styles. One style of APG sensor, called a float level transmitter, has been a leader in the market for drilling platforms across North America, and it is a good example of how level transmitters work.
The continuous float level transmitter is used to measure a wide variety of liquids. In the case of drilling, it provides changes in volume to spot any loss of mud or increase in chemicals that can become hazardous during a drill.
There are two options of float level transmitters:
This option consists of a magnetic float that travels up and down a rod with a wire waveguide that aligns itself to surrounding magnetic fields. An electrical pulse aligns molecules in one direction. When the pulse meets the competing magnetic field from the float, the molecules shift into a different direction that causes a vibration back to the sensor called a strain pulse. By measuring the time delay of the first electrical pulse and the strain pulse, the float's position can be determined with high accuracy.
This type of transmitter can also house multiple floats to measure more than one ingredient, such as oil and water – a rather unique feature for a level transmitter.
This type of transmitter consists of a float with a magnet attached to a stem with a sensing rod. The rod contains closely spaced switches and sensors that are triggered as the float moves up and down the rod, charting divisions in the original voltage sent for an easy and reliable read on the foam's position.
Transmitters used for mud tanks must withstand significant pressures from rushing mud and internal turbulence in the tank. This is no place for the weak. APG sensors are no exception to this rule. The company's products are known for their durability, accuracy, and longevity, making them helpful in hazardous drilling locations.
