Drilling Riser for Offshore Rig

A drilling riser is a large pipe or duct used to encapsulate drilling equipment during underwater operations. These risers allow workers over the surface of the water to drill deep into the bottom of the sea. A drilling riser is commonly used to drill for oil under the sea, or just to explore the bottom of the sea and the ground below. After the tube has been placed in water, the drill itself drops down through the center of the duct to access the seabed.

Companies can choose between two basic types of drilling risers depending on the needs of each application. Marine punching risers are used with floating platforms or boats, and include an explosive preventer placed under the surface of the water. When working from a fixed oil platform, companies rely on tie-back drilling rigs. These systems include blowout preventer located at sea level, which protect workers and equipment from pressure variations or potential explosions.

A drilling riser can end at the bottom of the sea, or it may extend a little in the ground to prevent water infiltration. The tip itself and all the associated equipment pass through the upright and continue below the surface of the earth. Without these risers in place, the drill would be vulnerable to corrosion and damage caused by salty water. All cuts of rock and other debris would simply be released into the water, resulting in pollution that could have an impact on the quality of water and sea life. Drilling risers helps to contain drilling operations within the duct boundaries.

During sub-sea drilling, workers pump down drilling fluid down through the drill line into the cutting bit at the end. This spray fluid spray out of the bit to help reduce the heat generated by cutting through stone and hard ground. This fluid then carries rock and other debris back through the duct to the surface of the sea, where it can be harvested and treated by oil workers. The drilling riser should be slightly larger than the drill itself to make room for this fluid.

The use of puncture posts enables water drilling companies for long periods, with little risk of damage to the equipment. The tip can be left in place over time without being exposed to sea water, allowing workers to dig deeper than in previous years. Bringing waste and rocks to surface for disposal, the risers help to reduce water pollution and its effects.

Read More → Drilling Riser for Offshore Rig

What is Seismic Drilling

Seismic drilling, also known as drilling, is perforation conducted as part of a seismic survey of geological formation. In such studies, the team uses a series of controlled vibrations to generate a map of underground structures. This map can determine where deposited material is to be found and how accessible it will be drilling equipment. Seismic surveys are an important part of oil and gas, and are also used by researchers who want to map geological formations for scientific purposes.

In seismic drilling, a company uses a drill specially designed to dig a hole at the desired depth. Air and water cutters are both available for this purpose, and are often mounted on slides or mobile platforms. This allows the team to quickly move the drill between the positions, which may be critical on a large survey. The time it takes to establish a drilling platform and stabilize it can add considerably the overall time required for the survey, and as a result teams try to use mobile drills where it is possible to do so.

After sinking a hole, team members can mount explosives inside. These explosives cause ground vibrations when they go out. With the use of seismic equipment, the team can follow the movement and reflection of vibrations. This information can help build a map of underground features and formations. The seismic drilling team may include geologists, explosive experts, and other personnel with training in seismic surveys.

A permit is usually required for seismic drilling. The process can be disruptive and can cause problems for plants, animals, or residents in the region. Permission seekers must describe the area they want to work and what they will do there. While on the site, team members usually follow business protocols set to make the site as secure as possible. They also check waste material to keep the site clean and tidy.

If seismic drilling suggests that training is workable, the team can locate some locations for drilling wells. The company may sink some test wells to confirm the results before starting large-scale production on the site. This survey and exploration can be expensive, especially when companies believe that not all land sites will produce usable deposits. Some sites may not have any useful material, while other deposits may be visible on a seismic survey, but essentially unavailable due to their depth or configuration.

Read More → What is Seismic Drilling

Classification of BOP - Blowout Preventer

There are several types of BOPs, as they can be classified according to their scope, and their conformation.

Classification for use:

The first subdivision distinguishes the onshore (offshore) BOPs . The first ones are generally smaller and simpler, and are used exclusively in drilling rigs on the mainland. Submarines BOPs, on the other hand, are designed to operate in offshore fields, and therefore are used in oil platforms or drillships . They have a more advanced technology, especially for what concerns the control mode of the BOP itself having to be activated from remote locations, and are also more impressive, because of the presence of a frame (chassis) of support, and the different conformation of the wells submarines.

The split of a Blowout preventer stack: the upper one is an annular BOP, the lower one represents a BOP on a jaw.

Classification by constructive technology :

The classification as a function of their architecture, distinguishes between the so-called BOP - blowout preventer

The first ones consist of a rubber ring, perforated in the center and whose hole diameter is equal to that of the well. The ring is contained in a steel crankcase . Inside the crankcase , and under the rubber ring, a hydraulic piston is mounted , which when actuated compresses or decompresses the ring from bottom to top or from top to bottom. In this way the ring (also called anular ) is closed or opened.

The jaws BOPs are also made of a metal casing, in which there are two opposing jaws, and may differ in "Combi", that is, with jaws coupled to two to two in two arms, or "Quad", with four distinct arms.

In the case of BOP for Coiled Tubing of Quad type, we find the following rams: Top Blind Rams, which have the function of hermetically closing the shaft; Shear Rams or Cutter Rams, which have the task of cutting the coiled tubing that is well with blades, followed by the Rams Slip, which have the shape of wedges, which have the task of supporting the coiled tube section cut and left in well. Finally there are the Rams Pipe that must ensure hydraulic seal on the tube and prevent the shaft pressure from creating a Blowout.

Between the Cutters and the Slip there is a kill line, a point where fluid can be pumped to "kill" the well, that is to provide a hydrostatic to the latter, which avoids the blowout. The jaws are controlled by hydraulic pistons through which they can be closed or opened. The first jawbone BOP was invented in 1922.

Read More → Classification of BOP - Blowout Preventer

Intangible drilling costs - IDC

Costs to develop an oil well or gas for the elements that are not part of the final work well. Costs of intangible (IDC) including all expenses incurred by an incidental operator required the drilling and preparation of wells for oil and gas production, as the survey work, land clearing, drainage, wages, fuel, repairs, supplies and so on. In general, expenses are classified as IDC if they have no salvage value. Since IDC include all real and actual expenses, except for the drilling equipment, the word "immaterial" is something of a misnomer.

Our drillingknowledge blog calls - 'intangible drilling costs - IDC'

The IDC deduction was authorized in the United States since 1913 in order to attract investment capital for business at high risk for oil and gas exploration. If a taxpayer makes an election to IDC expenses, it shall be deducted the amount of the IDC in the tax period in which it was paid or incurred.

Read More → Intangible drilling costs - IDC

Drilling Rigs Type

There are many different types of drilling rigs. Which rig selected depends on the specific requirements of each drill site. Roll your mouse over each picture to see what kind of rig it is.Its a good for drilling knowledge

Land Based Drilling Rigs - The land-based drilling rig is the most common type used for exploration. This site is using a conventional, land-based drilling rig that is smaller and more efficient than those used in the past.

Slim Hole Drilling Rig - A conventional drill bore might be 18 inches in diameter; a slimhole bore can be as little as 6 inches. A slimhole well drilled to 14,760 feet may produce one-third the amount of rock cuttings generated by a standard well. The size of the drill site can be as much as 75 percent smaller, since slimhole equipment requires less space than conventional equipment. However, slimhole drilling is not technically feasible in all environments.

Coiled Tubing Drill Rig - Conventional wells are drilled using sections of rigid pipe to form the drill string. In some cases, coiled tubing technology can replace the typical drill string with a continuous length of pipe stored on a large spool. This approach has many benefits, including reduced drilling waste and minimized equipment footprints, so it is especially useful in environmentally sensitive areas. This technology is best suited to re-entering existing wells, and when multiple casing wells are unnecessary.

Jackup Drill Rigs – These rigs may be used in relatively shallow water -- less than 300 feet deep. A jackup rig is a floating barge containing the drilling structure that is outfitted with long support legs that can be raised or lowered independently of each other. The jackup, as it is known informally, is towed onto location with its legs up and the barge section floating on the water. Once at the drilling location, the legs are jacked down onto the seafloor, and then all three legs are jacked further down. Since the legs will not penetrate the seafloor, continued jacking down of the legs raises the jacking mechanism attached to the barge and drilling package, and slowly lifts the entire barge and drilling structure to a predetermined height above the water. These rigs are extremely strong, since they have to withstand ocean storms and high waves. These rigs are moved by simply by moving the legs up and down, which makes them cost-effective and easily shifted out of harm's way during storms.

Semi-Submersible Rigs – Drilling in water deeper than 300 feet demands some kind of floating platform to hold the rig. Semi-submersible rigs are floating vessels supported on large pontoon-like structures that are submerged below the sea surface. As with jackup rigs, the operating decks are elevated as much as 100 or more feet above the pontoons on large steel columns. This design has the advantage of submerging most of the area of components in contact with the sea and minimizing loading from waves and wind. Semisubmersibles can operate in a wide range of water depths, including deep water. Semi-submersibles can either be attached to the ocean bottom using strong chains and wire cables or may utilize dynamic positioning to remain stationary during drilling without anchors.

Drill Ship - For exploration targets farther offshore, specially designed rigs mounted on ships can drill a well in water depths up to 10,000 feet. These rigs float and can be attached to the ocean bottom using traditional mooring and anchoring systems, or utilize dynamic positioning to remain stationary during drilling without anchors.

Read More → Drilling Rigs Type