Rig Floor Equipment

Eight diverse equipment advances are presented in the Rig Floor Equipment segment: a self-elevating drilling system, a dual wireline drilling riser tensioner, a compact snubbing unit, a new well-test separator, a three-deck shale shaker, a double-hinged, stabberless single joint elevator, a low-noise motor and advanced software offerings.

Lightweight dual-wireline drilling riser tensioner  

Over the course of a decade, the drilling industry has ventured away from the use of wireline riser tensioners due to the increased sizes of the deepwater designs. The latest 250,000-lb tensioners typically weigh 77 kips and use a 27⁄8-in.-diameter wire rope. These designs result in sheave sizes of 98–104 in. and require several rig crew members to accomplish termination and “cutting and slipping,” resulting in extended downtime to complete. Additionally, the variable deckload capacity suffers, resulting in decreased load capacities that reduce the number of riser joints available for deepwater drilling.

DTI has mitigated this problem with a new design using dual wirelines in place of the single-wire arrangement, Fig. 1. The goal was to reduce the size of the tensioner to a manageable level while not jeopardizing the integrity of the tensioner’s capacity.

Fig. 1. Single-wireline vs. dual-wireline tensioner.

In comparison to other 250,000-lb systems, DTI’s unit weighs about 42 kips and is shorter in height by more than 6 ft. It uses two wires in tandem to support the load, thus reducing the wire diameter to 2 in., compared with 2⅞ in. on a single-wire design. These features make the unit comparable to an existing 160,000-lb tensioner in size and wire rope diameter. On a 12-tensioner comparison, the dual-wire design saves more than 350 tons of variable deck load capacity.

DTI’s design allows a 120,000-lb tensioner to be constructed to the same size and weight as an existing 80,000-lb unit utilizing the same wire diameter. The compact design fits within the same envelope, thus requiring limited rig modifications to incorporate an upgrade. The extra weight savings and size can be transferred into the rig design, resulting in extra room for the drilling equipment or reducing the footprint of the structure needed to support the tensioner equipment. 

The dual-wireline tensioners have a single sheave machined with dual grooves to support parallel lines that share the tension loading. A special tri-plate arranged at the terminating ends of the two wires maintains equilibrium between the lines to avoid eccentric fatiguing of the wire. Each sheave keeps the same ratio of wire diameter to sheave diameter as its native single-wire version, assuring a maximum lifecycle fatigue of the wire rope.

In addition to the load sharing of the wirelines, DTI says safety factors driving the tensioner design allow for one line to support the entire load. In the event of a wireline break, the second line could safely accommodate the load to allow time to shut down the tensioner without having to deal with a runaway situation. A safety valve is still incorporated as the primary means to avoid catastrophic failure.

DTI’s tensioners are rated as true-sized units. A 250,000-lb unit will provide 250 kips at the null point position instead of the typical maximum bottom-out position. Each tensioner is made as a left- or right-hand unit, and they can be mounted together in pairs for a tighter footprint.

One benefit to going with a smaller and lighter system, the company says, is taking full advantage of the rising price of steel. Aside from the price-per-pound savings, machining costs and labor costs are also scaled back. DTI says it found a 32% reduction in price on major components like the sheaves and housings, with the company passing on the savings to the customer. With the advantages of these savings, DTI says it is also able to incorporate built-in upgrades like a ton mileage monitoring system for wireline fatigue measurement and laser cladding overlay on the cylinder rods for extended rod life.

Water-cooled drilling motor 

After nearly two years of development, GE Transportation has introduced its Water Jacket AC drilling motor (GE1150W), a completely enclosed, flameproof, water-cooled AC machine, Fig. 1. The GE1150W motor is expected to be available commercially beginning in June 2010. 

Fig. 1. With a continuous rating of 1,150 hp, GE Transportation’s water-cooled Water Jacket AC drilling motor is designed for drawworks, rotary tables and top-drive drilling systems.

Key performance highlights include operation at a continuous rating of 1,150 hp, or an intermittent rating of 1,400 hp, with torques of 7,550 and 9,200 lb/ft, respectively. Pending certifications for the motor include IECEx, ATEX Ex-d, American Bureau of Shipping, and Det Norske Veritas. 

The motor is designed to drive drawworks, rotary tables and top drives with the capability for use within a wide range of offshore and onshore drilling rigs. The motor can be mounted in a vertical or horizontal configuration. The compact motor maintains the existing footprint of GE’s already in-market selection of drilling motors, and it is dimensionally interchangeable with the GEB20/22 and GE752 series drilling motors. Since there are no external fans or blowers required to cool the motor, the water-cooled drilling motor can be used where noise reduction is a concern.

Self-elevating drilling system  

Integrated Drilling Equipment’s (IDE’s) patent-pending Self-Elevating Drilling System (SEDS) is a self-erecting box-on-box-style substructure with a bootstrap-style vertically erecting mast that is assembled 12 ft from grade, Fig. 1. The mast is vertically extended with the drawworks, and the substructure is raised with hydraulic cylinders.

Fig. 1. Self-Elevating Drilling System.

Self-erecting mast. The IDE-3000 SEDS mast is a freestanding 152-ft clear-height bootstrap mast with 1.5 million lb of static hook load strung on 12 lines and a 25-ft leg spread. The five-piece mast consists of a base section, a crown/upper section and three intermediate sections that can be assembled and raised without crane assistance. The bottom and crown sections are pinned to floor pedestals at ground level and erected hydraulically. Subsequent sections are added and scoped with the traveling block. Each base section is complete with 42-in. handrails and 6-in. toe plates that are designed to facilitate inspection of the latching system during the mast extension and vertical erection procedure.

The crown assembly consists of a seven-sheave main cluster with seven 60-in.-diameter sheaves grooved for 1⅝-in. wireline, one 72-in. fastline sheave assembly with a sheave-grooved 1⅝-in. sheave, 42-in.-high handrails and bumper blocks. The crown assembly frame will have pad-eyes for a block suspension line complete with a certified wire rope and shackle assembly.

The racking board will have a capacity of 25,000 ft of 5½-in. drill pipe including eight stands of 10-in. drill collars and eight stands of 8-in. drill collars. The platform includes a folding diving board, an access catwalk, a pullback winch and a fold-up floor slab on the driller’s side. The racking board is adjustable from 85 ft to 92 ft above the drill floor and includes 84-in.-high handrails and an escape platform.

Self-erecting substructure. The SEDS self-erecting box-on-box-style substructure includes a drill floor and sub base with nominal dimensions of 45 ft x 45 ft that is extended and retracted with eight hydraulic rams. The substructure is designed to a rated capacity of 1.5 million-lb casing and 1.0 million-lb setback simultaneously. The drill floor rotary area and the setback area are supplied with a zero-discharge recovery system.

The SEDS is designed to allow installation of the mast, drill floor sections, drawworks, setback and rotary section on the assembled drill floor while the substructure is in the lowest position, 12 ft from grade.

When the drill floor sections are in place and secured, eight hydraulic rams extend the floor and strong-backs vertically to allow another box section to be inserted. This process is repeated twice to reach the required floor height and clearance.

The 36-ft drill floor with 32-ft clear height is supplied with 42-in. hinged handrails and 6-in. toe plate and a sliding gate at the V-door. The independent rotary system is designed into the center drill floor section, and the drill floor is checker plated with 3⁄8-in. plate around the rotary table and drill floor. The setback area is equipped with two layers of 3-in. hardwood.

The drill floor sections are mounted and pinned on top of two perpendicular strong-back beam boxes and are comprised of a setback section, a rotary section and a drawworks section, each 15 ft wide x 45 ft long.

The two strong-back sections are designed to transport on the base box sections and are 10 ft wide x 45 ft long, complete with rolling tailboard-type hitches at each end and with pad-eyes for securing the strong-backs to the drill floor sections and the jacking box pedestals. Each of the upper, center and lower intermediated box sections are 8 ft tall x 10 ft wide x 45 ft long.

The two base box sections are 6 ft tall x 10 ft wide x 45 ft long and are equipped with a diesel-powered hydraulic unit incorporating a valve manifold system and eight hydraulic cylinders to facilitate structure extension and retraction. The lower box skids are provided with ½-in. plating (mud bottom) and drains.

One set of hydraulic make-up and break-out catheads is integrated into the floor section, and one mousehole and a range-2 scabbard is included. One set of 50-ton BOP trolley beams is integrated into the drill floor boxes, complete with a hydraulic hoist and gear-driven trolley system.

Small-footprint shale shaker  

When space is at a premium, the small footprint of M-I Swaco’s MD-3 shale shaker provides effective solids control options and the ability to adapt quickly to changing drilling conditions in a compact, high-performance unit, Fig. 1. The shaker’s footprint matches the M-I Swaco BEM-650 shaker to simplify retrofitting.

Fig. 1. M-I Swaco’s three-deck MD-3 shale shaker can be configured to process high volumes of fluid or to recover loss-prevention material.

The MD-3 shaker comes standard with many features typically considered special-order, including the fume-extraction hood that reduces operator exposure to vapors associated with drilling fluids and prevents fluids from splashing outside the shaker boundaries. It has a unique feeder assembly that presents fluid to the scalping screens as a uniform, low-impact curtain. The feeder can be easily configured into a variety of connection points for installation with limited space.

It can be configured to process high volumes of fluid or to recover loss-prevention material (LPM). It is available configured to operate with international power supplies (230, 400, 460, 575 and 690 volts) while meeting regional hazardous-area specifications (UL, CE, ATEX and NORSOK).

The shaker has three decks of automated, effective solids control, which translates to lower waste volumes as a result of drier cuttings. Higher feed rates increase project upside and reduce downtime for shaker repairs. The standard configuration has one scalping deck and two primary decks. Screens are held in place by pneumatic actuators and are replaced by deactivating the pneumatic pressure and removing the lightweight composite screens.

The MD-3 shaker was chosen for an operator in South Louisiana who faced a difficult 20-in. top-hole section that consisted mainly of gumbo and sand formations, and a 14¾-in. intermediate section. The shaker processed a maximum of 840 gal/min. while equipped with urethane screens on the scalping deck and HC-84 mesh (API-60) screens on the two primary decks. The MD-3 shaker averaged 700 gal/min. during the 20-in. interval, a rate higher than the combined processing rate of the three rig-owned shakers.

Trailer- and truck-mounted snubbing unit  

A new generation of snubbing equipment has been manufactured by MTech Industries in Canada and distributed exclusively by its subsidiary Mitey Titan. The compact snubbing unit can be mounted in various configurations including with a 1-ton truck, a small trailer, or skid-mounted.  If mounted on a body-load truck, the hydraulics can be run from the truck’s main engine.  In the trailer-mounted (Fig. 1) or skid-mounted configuration, a hydraulic power unit is supplied in the package. The compact snubbing jack design comes with hydraulic speed cushions on both sides and has a snubbing capacity of up to 85,000 lb. The lift capacity of this equipment can be up to 125,000 lb.

Fig. 1. Mitey Titan’s compact snubbing unit is shown here in the trailer configuration, which can be pulled by a 1-ton pickup truck. The flat deck includes a fluid containment system to minimize uncontrolled spills. The snubbing unit comes with a choice of annular BOP with adaptor spool or an RS stripping head and hanger flange combination. The operator controls can be set up on the truck deck, rig floor or other safe location.

The snubbing unit utilizes two-legged hydraulic jack cylinders outfitted with a stationary plate, a snub plate and a traveler plate. Depending on the application, two sets of bidirectional slips or any combination of wedge-style slips can be mounted as stationary and traveler slips. The complete jack assembly comes with a choice of annular BOP with an adapter spool or an RS stripping head and hanger flange combination, or both. With the RS-100 head option, the maximum surface pressure is 1,200 psi. The maximum surface pressure that can be serviced with the dual-RS head is 1,800 psi. Using an annular BOP, the surface pressure that can be serviced can be increased to 3,000 psi. 

The stroke, overall width and height can be customized to meet application requirements. The minimum overall width of the unit with bidirectional hydraulic slips is about 28 in. with an overall height of about 3 ft. The compact snubbing unit fits through most rig floors.  

The custom-designed cradle is used to mount the complete jack assembly on the deck or skid base for traveling. Swivel hoist rings with a tie-in connection between the traveler plate and the snub plate are utilized to lift the unit from a deck.

The jack is equipped with a snub plate to give rigidity to the jack design, allowing stationary slips to swing out of the way when a change of RS seals is required. This allows RS seals to be changed while the unit is still in service, reducing maintenance and increasing productivity.

The head is designed for a higher load capacity on top of the traveler plate. A custom-built flat deck with fluid containment is installed to minimize uncontrolled spills. Anti-skid coating is installed on the deck to further ensure safety. The portable operator console can be set up on the truck deck, rig floor or any safe location. Advanced hydraulics are utilized to control the jack, two to three sets of slips, the annular BOP and the single-gate BOP.

Software enables control of eight independent operations from one integrated drilling machine  

National Oilwell Varco (NOV) has new software that converts eight independently controlled machines into one integrated drilling machine with synchronization of the operation controlled by one joystick that regulates the speed of the sequence. NOV’s Multi-Machine Control (MMC) software package can be installed with the company’s Cyberbase system or a similar integrated control system for automatic control of the complete trip in/out sequence, Fig. 1.

Fig. 1. National Oilwell Varco’s Multi-Machine Control (MMC) converts eight independently controlled machines into one integrated drilling machine with synchronized operation that is joystick controlled.

A single operator running a Cyberbase system outfitted with MMC can control the synchronic speed of eight machines using one joystick, on top of normal controls.  When the operator increases the speed using the joystick, operations of the following machines are also increased: column racker and fingerboard, pipe chute, lower guide arm, drill floor guide arm, V-door machine, top-drive dolly, slips, elevator and iron roughneck.  The operator doesn’t instruct each individual machine to perform single actions; he instructs the entire machine suite to perform a sequence of actions that add up to an entire task.

MMC allows continuous and consistent operations so the speed of tripping is increased while the risk of damage to machines is decreased. This system requires fewer workers on the drill floor, which results in safer and more efficient operations overall.

MMC software currently is being utilized on a sixth-generation ultra-deepwater semisubmersible. In this case, the pipe setback was moved to a separate level from the rig floor, and the operator commands when to have the pipe delivered to him. The driller’s responsibility is to set the rate at which he wants the pipe tripped in/out of the hole to maximize efficiency and safety. 

Stabberless elevators reduce safety incidents  

Traditional methods, equipment and safety measures have often failed to eliminate accidents, injuries and near misses while picking up single joints of drill pipe. Drilling operations, particularly in the North Sea, have recorded a significant number of serious incidents with conventional single-joint elevators that have resulted in dropped objects and near misses.

A review of 30 of these incidents in the industry showed that similar faults occurred with the single-pin type of elevator, most resulting in dropped objects, according to Weatherford. The root causes of the lifting incidents include a variety of both operational and equipment failures, such as incorrect latching, safety pin problems, incorrect selection of blocks and hinge pin failures, said the company. 

A recent effort was initiated between Weatherford and a major oil company to develop tools and methods that incorporate several key features to enhance safety and operational efficiency during the lifting of single joints of drill pipe. This collaboration resulted in a fundamental redesign and development of a new product, Weatherford’s Stabberless  Single-Joint Elevator for drill pipe and tubing, Fig. 1.

Fig. 1. Pins on each side of Weatherford’s double-hinged Stabberless Single-Joint Elevator enables left- or right-handed use. The size-specific body design eliminates incorrectly sized inserts from being used.

Specific features improve operational safety and efficiency. For example, the elevator’s size-specific body design eliminates variable-sized inserts, removing the potential of incorrectly sized inserts being used for lifting and the resultant safety hazards.

The size of the elevator is hard-stamped on the tool body, simplifying identification and reducing potential for errors that may result in dropped objects.

The locking pins and related design elements are engineered to provide several advantages. A pin on each side enables left- or right-handed use and can always be unlatched from the topside of horizontal pipe. Pins cannot be removed; there is no requirement for secondary retention devices such as chains. The positive latch mechanism confirms that the pins are locked, ensuring safety.  The stabberless elevator is double-hinged for easy installation and removal from joints and is substantially lighter than variable-sized elevators, which should improve operational efficiency.

The collaborating North Sea operator is now eliminating the use of single-pin-type, single-joint elevators from its drilling operations and standardizing this new product.

Real-time drilling data within a 3D geological model  

With a properly designed well information system, operators can improve the drilling process through seamless planning, scheduling, tracking and measuring of performance. The addition of affordable 3D visualization software enables operators to further leverage their investment in 3D seismic data.

During 2009, Petron Industries Inc. added 3D visualization software to its easy-to-use RigFocus package. The software integrates structural seismic information with downhole data, allowing users to visualize real-time directional drilling and rock property data within a 3D geological model. The high-impact visual interface, launched from the Petron DrilNET Secure Portal website, is available both at the rigsite and remotely, enabling efficient operation from any location. Newly introduced 3D capability is applicable to directional drilling, geosteering, offset well comparison, anti-collision, seismic interpretation adjustment and real-time operation/collaboration center environments. Immediate graphic replication of the real formation allows the user to make decisions “on the fly.”

The RigFocus application software was first introduced in 2008. All data is presented in familiar formats with pre-designed displays. No special computer skills are required. Additional integrated features include both audible and visible alarm capabilities, precise time- and depth-based data, charting of selectable parameters and flexible printing options. Users can access and browse numerical well data through a data pop-up window. Data export is available as log ASCII standard (LAS) and comma-separated value (CSV) in time- and depth-based format.

Fig. 1. 3D visualization from RigFocus.

New to the RigFocus software is 3D visualization of wellbores complete with 3D strip charts, offset wells, and pre-drill plan versus as-drilled information, among other features.  Petron’s RigBrain information manager, the powerhouse behind RigFocus, was also introduced in 2008 and is used to import directional surveys via Wellsite Information Transfer Specification (WITS). The 3D model is automatically updated in real time. The pre-drill plan can be imported in seconds, allowing the user to visualize and measure deviation from plan.

Any number of traces can be plotted in highly configurable 3D strip charts; the software offers configurable measured depth labels, casing shoe location and animated drill bit location with real-time drilling parameters.