Rotary Drilling Rigs

Rotary Drilling Rigs

updated July 5, 2004

Geolog Training Department 2004 à Rotary Drilling Rigs

A rotary drilling rig is a set of equipments, devices, tools ena bling the Oil Company to drill a well in the Lithosphere, at the specific location indicated by the Exploration (Geophysics Dept.). This well will be on-land if located on the ground and off-shore if located in the sea and obviously, the equipments (rigs) used will be different.

This presentation will help you to understand : n n n

what are the various types of drilling rigs what are the main standard components of a drilling rig what is the people working usually on a drilling rig

Geolog Training Department 2004 à Rotary Drilling Rigs

Various types of Rigs

Drill ship

Semisubmersible

Jackup

Submersible

Geolog Training Department 2004 à Rotary Drilling Rigs

Land

Various types of Rigs ON LAND RIGS OFF SHORE RIGS : • Bottom supported units : Jackup – Submersibles Surface BOP

• Floating units : Drill ships – Semi-submersibles Sub sea BOP Sub sea BOP

Geolog Training Department 2004 à Rotary Drilling Rigs

Submersible

This is a particular type of floating vessel, usually used as a mobile offshore drilling unit (MODU), that is supported primarily on large pontoon -like structures submerged below the sea surface. The operating decks are elevated 100 or more feet (30 m) above t he pontoons on large steel columns. Once on the desired location, this type of structure is slowly flooded until it rests on the seafloor. After the well is completed, the water is pumped out of the buoyancy tanks, the vessel re-floats and can be towed to the next location. Submersibles operate in shallow water, since they must rest on t he seafloor (maximum 90m).

Geolog Training Department 2004 à Rotary Drilling Rigs

Jack-Up A self-contained combination of drilling rig and floating barge, fitted with three long support legs that can be raised or lowered independently of each other. The jack-up is towed onto location with its legs up and the barge section floating on the water. Upon arrival at the drilling location, the legs are jacked down onto the seafloor and the entire barge and drilling structure are slowly raised above the water to a predetermined height above the water, so that waves, tide and currents, act only on the legs and not the bulky barge and drilling package. Jack-up operate in shallow water like submersibles.

Geolog Training Department 2004 à Rotary Drilling Rigs

Jack-Up

Geolog Training Department 2004 à Rotary Drilling Rigs

Jack-Up

Geolog Training Department 2004 à Rotary Drilling Rigs

Semi-Submersible This is a floating vessel supported by large pontoon-like structures submerged below the sea surface. The operating decks are elevated 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, minimizing the loading from waves and wind. Semi-submersibles can operate in a wide range of water depths, including deep ultra deep and stormy waters. They are usually anchored with six to twelve anchors, computer-controlled to maintain the exact position of the semi-submersible.

Geolog Training Department 2004 à Rotary Drilling Rigs

Semi-Submersible

Geolog Training Department 2004 à Rotary Drilling Rigs

Semi-Submersible

Geolog Training Department 2004 à Rotary Drilling Rigs

Semi-Submersible

Geolog Training Department 2004 à Rotary Drilling Rigs

Semi-Submersible

Geolog Training Department 2004 à Rotary Drilling Rigs

Drill Ship

Is a special ship built to host a standard drilling rig. Drill ships are the most mobile of all the mobile drilling units and are used in remote waters. They can operate in very deep water but they are very susceptible to wave motion and are not suitable to operate in heavy seas. They are not anchored to the sea bed but dynamically positioned with a series of lateral propellers activated by computers reading the position through three satellites.

Geolog Training Department 2004 à Rotary Drilling Rigs

Drill Ship

Geolog Training Department 2004 à Rotary Drilling Rigs

Standard Components

• POWER SYSTEM • HOISTING SYSTEM • ROTATING SYSTEM • CIRCULATING SYSTEM • SAFETY SYSTEM

Geolog Training Department 2004 à Rotary Drilling Rigs

Power System The power system of a rig is usually a series of big diesel-electric engines. These engines drive generators to produce electric power. Cables transmit electric power to the various motors to drive all the rig components.

Geolog Training Department 2004 à Rotary Drilling Rigs

Hoisting System

It consists of the:

DERRICK CABLE CROWN BLOCK TRAVELLING BLOCK HOOK DRAW--WORKS (OR HOIST) DRAW

Geolog Training Department 2004 à Rotary Drilling Rigs

Derrick or Mast The structure used to support the crown block and the travelling block. Derricks are usually pyramidal in shape, and offer a good strength-to-weight ratio. The derrick must be tall enough to allow crew members to manipulate stands of drill pipes measuring 28.5 m. A standard derrick has four legs standing at the corners of the rig substructure. A big derrick has to be mounted piece by piece. Small derricks are raised with the drawworks and cable.

Geolog Training Department 2004 à Rotary Drilling Rigs

Cable

Is a wire rope used to support all the drilling equipment which has to be run inside the hole. The cable is rolled on the drawworks located on the rig floor and passes through the sheaves (or pulleys) of the crown block at the top of the derrick and runs downward to another set of sheaves fixed in the travelling block.

Geolog Training Department 2004 à Rotary Drilling Rigs

Crown Block

The fixed set of pulleys also called sheaves, located at the top of the derrick, over which the cable is threaded. The cable passes several times (8, 10 or 12) between the crown block and the travelling block. In this way is possible to use a single cable to support heavy loads.

Geolog Training Department 2004 à Rotary Drilling Rigs

Travelling Block

The set of sheaves that move up and down in the derrick. The wire rope threaded through them is threaded (or "reeved") back to the stationary crown block. On the base of the travelling block is attached the hook.

Geolog Training Department 2004 à Rotary Drilling Rigs

Hook The hook is used to handle all the equipment which will be run inside the hole.

Geolog Training Department 2004 à Rotary Drilling Rigs

Draw-Works

The machine (winch-like) on the rig floor, consisting of a large-diameter steel spool, brakes, a power source and assorted auxiliary devices. The cable is run downward from the crown block and wrapped around the draw-works spool. The primary function of the drawworks is to reel out and reel in the cable, causing the vertical (up & down) movement of the travelling block, hanged to the crown block.

Geolog Training Department 2004 à Rotary Drilling Rigs

Rotating System

It consists of the:

TOP DRIVE ROTARY TABLE AND KELLY SYSTEM DOWN HOLE MOTORS OR TURBINES

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Top Drive This device consists of one or more motors (electric or hydraulic) that rotates a drive shaft. The drive shaft is attached to the top of the drill-string which will rotate as well. The topdrive is suspended from the hook, so the rotary mechanism is free to travel up and down the derrick. It enables the drilling to be done with three pipes (one stand) instead of a single pipe. It also enables the driller to quickly engage the pumps or the rotary while tripping pipe.

Geolog Training Department 2004 à Rotary Drilling Rigs

Top Drive

Geolog Training Department 2004 à Rotary Drilling Rigs

Top Drive

Geolog Training Department 2004 à Rotary Drilling Rigs

Rotary Table & Kelly The kelly is a long square or hexagonal steel pipe with a hole drilled through the middle and is used to transmit rotary motion from the rotary table and kelly bushing to the entire drill-string and bit. It allows also the drill-string to be lowered or raised while rotating. The kelly goes through the kelly bushing, which is driven by the rotary table. The kelly bushing has an inside profile matching the kelly's outside profile (either square or hexagonal), but with slightly larger dimensions so that the kelly can freely move up and down inside.

Geolog Training Department 2004 à Rotary Drilling Rigs

Rotary Table & Kelly

Geolog Training Department 2004 à Rotary Drilling Rigs

Down Hole Motors & Turbines

A downhole motor / turbine is a strong pipe containing a special device that uses the hydraulic impact of the mud to rotate the shaft or the blades. The motor is attached to the bottom of the drill string and the bit is screwed to the bottom of the motor. In this way it is possible to drill, rotating only the bit, without rotating the entire drill string (sliding). They are used specially in directional drilling.

Geolog Training Department 2004 à Rotary Drilling Rigs

Circulating System

It consists of the :

MUD PITS MUD PUMPS FLOW LINE (MUD RETURN LINE) SHALE SHAKERS

Geolog Training Department 2004 à Rotary Drilling Rigs

Mud Pits

Large rectangular tanks that contain drilling fluid (mud) on the rig. They are connected each other and to the mud pumps, making the active mud system. Depending on their main purpose they can be called: SETTLING PIT: permits to separate the fine sediments (specially sand) from the mud per decantation MIXING PIT: where is possible to prepare the new mud SLUG PIT: where is stored mud with different characteristics (density) RESERVE PIT: where the mud is stored to be used in emergency situations SUCTION PIT: connected directly to the pumps TRIP TANK: small cylindrical tank used during a trip (pulling out of the hole the drill string)

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Mud Pits

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Mud Pits Trip tank

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Mud Pumps

Large pumps used to circulate the mud on a drilling rig. A typical mud pump is a piston pump whose pistons travel in replaceable liners. In base of the diameter of these liners changes the volume pumped for each pump stroke. They pick up the mud from the suction pit and force the mud into and down the drill string and to the bit. At the bit the mud jets out from the bit nozzles to move cuttings away from the bit and also to cool the bit. The mud then moves back up into the annulus to the surface and r eaches again the suction pit.

Geolog Training Department 2004 à Rotary Drilling Rigs

Mud Pumps

Geolog Training Department 2004 à Rotary Drilling Rigs

Mud Return Line – Flow Line

Since the mud picks up cutting produced by the bit, it carries t hem as it returns to the surface. The mud and the cuttings return to the surface in the space between the outside of the drill string and the inside of the hole. This space is the ANNULUS. At the surface, the mud and cuttings leave the well through a side outlet with a pipe on it: this pipe is the FLOW LINE. At the end of the flow line, mud and cutting fall onto vibrating screens (or sieves) called the SHALE SHAKERS.

Geolog Training Department 2004 à Rotary Drilling Rigs

Mud Return Line – Flow Line

Geolog Training Department 2004 à Rotary Drilling Rigs

Shale Shakers

While drilling, it indispensable to remove the cuttings from the mud. For this purpose, the mud coming out the Flow line falls on the Shale shakers acting as vibrating screens. The liquid phase of the mud and the solids smaller than the wire mesh pass through the screen (and go back to the pits) while larger solids are retained on the screen, fall out of the screen and are discarded.

Geolog Training Department 2004 à Rotary Drilling Rigs

Shale Shakers

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Safety System

It consists of the:

BOP stack (Blow out preventers) Choke manifold

Geolog Training Department 2004 à Rotary Drilling Rigs

Blow Out Preventers - BOPs

It consists of a series of large valves at the top of the well that can be closed in case of emergency : Blow Out which means the well is in eruption and cannot be controlled in another way than to be shut-in. Those valves are usually operated remotely via hydraulic actuators.

Geolog Training Department 2004 à Rotary Drilling Rigs

Blow Out Preventers - BOPs BOPs come in a variety of styles, sizes and pressure ratings. Some can effectively close over an open well bore, some are designed to seal around tubular components in the well (drill pipe, casing or tubing) and others are fitted with hardened steel shearing surfaces that can actually cut off the drill pipe. Since BOPs are critically important to the safety of the people and of the entire drilling operation, they are inspected, tested and refurbished at regular intervals determined by a combination of risk assessment, local practice, well type and legal requirements.

Geolog Training Department 2004 à Rotary Drilling Rigs

Annular Preventer

This huge valve is designed to form a seal in the annular space between the pipes and the casing and if no pipe is present, on the casing itself. They rate from 3,000 to 15,000 psi.

Geolog Training Department 2004 à Rotary Drilling Rigs

Rams Stack

Below the annular BOP, are additional rams : Shear ram : will cut off the drill pipes and close the well in case of eruption through the drill pipes. Pipe rams : will seal around the drill pipes. Blind rams : will seal the well without drill pipes.

Geolog Training Department 2004 à Rotary Drilling Rigs

Rams Stack

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Choke Manifold

This is an arrangement of piping and valves designed to control, distribute and monitor the fluid flow when the well is shut-in (BOP are closed). In this case the annular mud will flow through a variable diameter choke in order to hamper the uncontrolled eruption. In this way it will be possible to weight up the mud and to neutralize the influx of fluid from the formation. Like the BOP, the choke manifold has a fundamental importance for the safety.

Geolog Training Department 2004 à Rotary Drilling Rigs

Choke Manifold

Geolog Training Department 2004 à Rotary Drilling Rigs

People working on the rig

Company man (drilling engineer) : The representative of the Oil Company or Operator on a drilling location. For land operations, the company man is responsible for operational issues on the location, including the safety and efficiency of the project. Even administrative managers are expected to respond to the direction of the company man when they are on the rig site. Offshore, depending on the regulatory requirements, there might be an offshore installation manager, who supervises the company man on safety and vessel integrity issues, but not on operational issues. Well site Geologist : He belongs to the Oil Company and is responsible of all geological issues and decide circulating for bottom-up, coring, logging and testing.

Geolog Training Department 2004 à Rotary Drilling Rigs

People working on the rig

Tool pusher : He is the responsible of the drilling rig belonging to the drilling contractor. The tool pusher is usually a senior, experienced individual who has worked his way up through the ranks of the drilling crew positions. His job is largely administrative, including ensuring that the rig has sufficient materials, spare parts and skilled personnel to ensure efficient operations. The tool pusher also serves as a trusted advisor to many personnel on the rig site, including the operator's representative, the company man.

Geolog Training Department 2004 à Rotary Drilling Rigs

People working on the rig

from TOTAL

Geolog Training Department 2004 à Rotary Drilling Rigs

People working on the rig

The Mud Engineer is responsible of the drilling fluid (mud). He tests it continuously and prescribes necessary treatments to ensure the recommended properties. He also works closely with the rig's derrick man, who is in charge of the treatment. The Directional Engineer is responsible of the correct trajectory of the well in case of directional well (inclination and azimuth). He will consider parameters as rotary speed, weight on bit, down hole motors and will monitor the trajectory according to the deviation surveys.

Geolog Training Department 2004 à Rotary Drilling Rigs

People working on the rig

MWD – LWD Operators : He is in charge to collect and analyze data coming from MWD or LWD tools. MWD (Measurement While Drilling) is a special tool that allows t o measure different parameters (mainly deviation) while drilling. Those me asurements are made down hole, stored in solid-state memory for some time and later transmitted to the surface. Data transmission methods vary from company to company, but usually involve digitally encoding data and transmitting to the surface as pressure pulses in the mud system. LWD (Logging While Drilling) measures formation parameters like resistivity, porosity, sonic velocity, gamma ray.

Geolog Training Department 2004 à Rotary Drilling Rigs

People working on the rig

Driller : He is the supervisor of the rig crew. The driller is responsible for the efficient operation as well as the safety of the crew and normally has many years of experience. The driller drives the rig : he operates the pumps, draw works and rotary table via the driller console, a control room of gauges, control levers, rheostats, and other pneumatic, hydraulic and electronic instrumentation. The driller also operates the draw works brake using a long-handled lever.

Geolog Training Department 2004 à Rotary Drilling Rigs

People working on the rig

Drilling Crew : Personnel who operates the drilling rig and reports to the driller. The crew consists of motor man, roustabouts, roughnecks, floor hands, lead tong operators, derrick men, and assistant drillers. Since drilling rigs operate 24 hours a day, there are at least two crews (twelve hour work shifts called tours, more common when operating offshore), or three crews (eight hour tours, more common onshore).

Geolog Training Department 2004 à Rotary Drilling Rigs

People working on the rig

Geolog Training Department 2004 à Rotary Drilling Rigs

The End...

Geolog Training Department 2004 à Rotary Drilling Rigs