snubbing unit vs workover rig free sample

The rig assist unit was installed on top of the rig’s Bops. A landing joint was lowered into the stack and screwed into the tubing hanger. The snubbing Bops were tested using the rig pump to 35mpa

The stack was equalized using the snubbing unit equalize line to well bore pressure. The hanger hold-down screws were backed out and the tubing hanger staged out using the snubbing units annular and stripping rams

Once the lift force from the well overcame the weight of the string, the snubbing unit took over pipe movement. The tubing connections were still staged out and the pipe continued to be racked in the derrick

The joint was gently snubbed up until the fill/flow sub was above the snubbing unit annular element. The operator continued to raise the tubing until the lower connection of the 3m pup joint engaged the bottom side of the stripping rams. The rams were locked and the chamber between the stripping rams and annular was re-equalized

BHA: Bottom hole assembly. Describes the production or workover tools used for completion or workover operations. (i.e. packers, bridge plugs, fishing tools, etc).

BOP stack: A series of blow out preventers stacked together using an equalizing and bleed of spool. Stack normally consists of an annular; equalize spool and a set of stripping rams. In snubbing operations the BOP stack is considered a secondary BOP. When working in conjunction with a workover, service or drilling rig the rig supplies the primary BOP’s.

Counter Balance Winches: A winch that can hydraulically counter balance the weight it is picking up. This gives the winch the ability to automatically feed off should the load placed upon it become greater than the actual weight being held via the hydraulics. Typically the snubbing unit will have two of these winches.

Equalize line: High pressure line pipe, chick sans (swivels) and valves for use during a snubbing operation to equalize or bleed off pressures within different chambers in a snubbing BOP stack.

Equalize spool: A ported spool for use in a snubbing operations allowing the operator the ability to equalize or bleed off certain sections of the BOP stack.

Gas well snubbing: Workover or completion work on a gas well which is either live or underbalanced with a rig assist or self-contained snubbing unit. Many gas well formations are fluid sensitive making a snubbing operation ideal for maximum production of the well. Eliminates the need for expensive kill fluids.

Guide Tube: Any arrangement of support system that prevents columnar buckling of the pipe being snubbed. Typical arrangements can be telescopic or static depending on the design of the snubbing unit structure.

Hydraulic Workover Unit: A unit that competes directly with conventional work over rigs. By utilizing hydraulic cylinders instead of a traditional draw-works arrangement, the unit maintains a small footprint allowing rig up in tight areas such as on offshore platforms.

Live well completions: A well condition where tubulars and tools are pulled or inserted into a well with the use of a rig assist snubbing unit or self-contained snubbing unit. The well has surface pressure from the down hole formations. Wells can be either gas or oil.

Live well workovers: Describes the condition of a gas or oil well is in when tubulars are snubbed in or out of well. There is pressure at surface in these wells making them ideal candidates for snubbing operations.

Lower snubbing basket: The work floor area which allows access to the snubbing crew to the BOP stack components and stationary snubbing and heavy slips.

Passive Rotary: A turn-table integrally mounted in the snubbing unit traveling plate which allows the rotation of the string with the slips closed on the pipe in either the snub mode or pipe heavy mode. This rotary must be driven with an external force be it by hand or with a power swivel rigged above the unit.

Pipe Heavy: In regards to snubbing, this is a pipe condition in which the tubing has sufficient string weight to overcome the forces acting on its cross-sectional area. Once the weight is sufficient, it overcomes the force applied by the pressure in the well and will fall under its own weight into the well.

Pipe Light:  In regards to snubbing, this term describes the condition when the well bore forces acting on the cross-sectional area of the pipe being snubbed are greater than string weight; if tubing is not controlled, the snubbing unit will eject itself from the well.

Power-Pack: This is the prime mover that provides the force needed to turn hydraulic pumps which allow the operation of the snubbing jack and BOP systems. Diesel engines are the most common form, although electric drives are also utilized in special circumstances.

Powered Rotary: A turn-table integrally mounted in the snubbing unit traveling plate which allows the rotation of the string with the slips closed on the pipe in either the snub mode or pipe heavy mode. This rotary is driven with hydraulic motors, allowing the unit to perform string rotation without external support equipment.

Rig assist snubbing: A mobile snubbing unit, either truck-mounted or skid-mounted, that works in conjunction with a workover, service or drilling rig for workover or completions work on a live well or underbalanced well. Unit is capable of running or pulling tubulars and tools under pressure.

Scalloped spool: A spacer spool modified for snubbing to allow well bore pressures to equalize or bleed off around the tubing hanger when landing or pulling the hanger.

Self contained snubbing:A snubbing unit which stands alone by itself with no need of a service, workover or drilling rig. A self-contained unit is capable of workover or completion work on a live well or underbalanced well or indirect.

Snubbing: A procedure in which tubing is run or pulled from a well, which is in an underbalanced or live well condition. Snubbing units have specialized pressure control devices which permit them to deliver drilling, completion and workover services while there is pressure in the wellbore. Snubbing units eliminate the need to neutralize well pressure prior to servicing and therefore avoid the formation damage which neutralizing pressure can have on a well’s ability to produce.

Snubbing Assistant: This person’s position is primarily focused on taking direction from the snubbing operator, and entails routine maintenance, pipe handling and power tong operation.

Snubbing jack: The structure of the unit designed to withstand engineered ratings for both the pipe weight and the force applied by the unit’s hydraulic cylinders. The hydraulically operated equipment which enables crews to work on underbalanced or live well.

Snubbing Operator:Equivalent to a driller position, the snubbing operator physically operates the snubbing unit and takes direction from the snubbing supervisor. The operator is responsible for managing the daily activities of the rest of the snubbing crew, and ensuring that the equipment is functioning as designed.

Snubbing slips: A set of hydraulically actuated slips which can be run either inverted or right side up to control the movements of pipe in conjunction with a snubbing jack to insert or extract tubulars under live well or underbalanced conditions.

Snubbing Supervisor:Equivalent to a rig manager or tool push, the snubbing supervisor is responsible for all aspects of the snubbing unit and its operations. He/she is the direct liaison to the oil company representative he/she is working for. All members of the snubbing crew are subordinate to the snubbing supervisor. Typically the supervisor will have in excess of 10 years’ experience in snubbing operations.

Snubbing unit: A hydraulically actuated unit with slips, BOP stack and hydraulic jack for inserting or pulling tubing and BHA’s from underbalanced or live well conditions.

Stand alone snubbing (see self contained unit): Use of a snubbing unit by itself without the aid of a service, workover or drilling rig. Unit is capable of workover or completion work on a live well or underbalanced well.

Stationary snubbing slips: A set of snubbing slips that are typically mounted on top of a BOP stack which will hold pipe that is in a pipe light or neutral state.

Stripping: : During snubbing operations this is the procedure where you move pipe through a closed preventer (pipe rams or annular) on a live or underbalanced well containing pressure from the well bore with a closed preventer.

Stripping on: : The procedure in which a snubbing unit is rigged onto a service, workover or drilling rig, which is holding the pipe heavy tubing string with their tubing slips and not with a tubing hanger landed.

Stripping Ram: A hydraulically operated ram style BOP used during snubbing and stripping operations. Typically the ram front insert is a sacrificial material that is easily replaced for extended stripping. Materials for the inserts can be custom ordered for the application at hand.

TEP: A type of tubing plug developed for snubbing to control well bore pressures inside the tubing. Only viable for snubbing in operations. The plug is a machined collar with a removable disc and “o” ring. Once the tubing string has been snubbed in, the disc can be knocked out by equalizing the tubing string and flowing the casing. Once an overbalanced condition has been achieved inside the tubing string, the disc will fall out. Disc may also be removed by sand line or wire line tapping down on the disc once tubing string has been equalized with casing pressures.

Traveling plate: The plate which connects the rods from the hydraulic cylinders together on a snubbing unit where the traveling and heavy slips are attached. There are many cylinder configurations and stroke lengths possible depending on job requirements.

Traveling snubbing slips: A set of slips mounted upside down on a snubbing jacks traveling plate, which controls the movement of tubing in or out of a well. Slips will hold tubing only when tubing is in the pipe light state.

Underbalanced:A term to describe the pressure conditions in a well. Formation pressure is greater than the hydrostatic pressure of fluid, mud, etc… exerted on the formation causing pressure to migrate to surface in a well. A well in an underbalanced state is a prime candidate for snubbing.

Underbalanced completions: The condition of a well when completion services such as snubbing are performed. Formation pressure is greater than the hydrostatic pressure inside the well bore causing pressure to be at surface in the well. Underbalanced completions are prime candidates for snubbing. Typically wells have been perforated before snubbing unit arrives and the unit snubs in a production string to allow the well to be produced.

Underbalanced drilling: This term describes the condition of the well when drilling operations are ongoing. Snubbing units are used to snub out drill strings, i.e. bit changes and then snub in the drill string again or run productions strings.

Underbalanced workovers: The well is live with pressure to surface when workover operations are performed. Rig assist snubbing or self-contained snubbing units are used for the running or pulling of tubulars and BHA’s. Typically the snubbing unit pulls pipe from the well, the original zone is worked over, abandoned, or a new zone perforated and the snubbing unit snubs the production string back into the well.

Well control:In regards to snubbing, well control is the operation of containing well bore pressure with the use of a blowout preventer stack and tubing pressure by the use of a plugging system.

Snubbing units have evolved into one of the most capable and efficient well servicing tools in the oil & gas industry. In the 1920"s, the need for a rig to work with pressures at surface drove the invention of the snubbing unit. The first snubbing unit was primarily designed to work in well control situations to "snub" drill pipe and or casing into, or out of, a well bore when conventional well killing methods could not be used. The first snubbing unit relied on the draw works of the companion rig to supply its" power. A series of sheaves, cables and counter weights were rigged up so that as the rig"s traveling blocks hoisted up, the snubbing unit would snub in the hole. Conversely, when the traveling blocks on the rig were lowered, the snubbing unit would snub out of the hole. As you can imagine, this required close communication with several different contractors in order to perform the work safely and efficiently.

One of the main components of a snubbing unit is the slip. Stationary and travelling slips are operated in sequence to grip the pipe as it is snubbed into the well. Typically, a minimum of four slip bowls are used in snubbing operations. Two slip bowls are designated for "pipe light" operations. Pipe light is when the well bore forces are greater than the tubular weight in the well bore. The other two slip bowls are designated for "pipe heavy" operations. Pipe heavy occurs when either enough pipe has been snubbed into the well bore and fluid weight inside of the pipe is greater than the snub forces acting against the pipe in the well bore.

While snubbing into the hole, there is a transition point the tubular goes through from being pipe light, to pipe heavy. This transition is an equilibrium typically referred to as the "balance point". The balance point occurs when there is enough pipe weight in the wellbore to equal the snub forces generated against the pipe. In certain instances, thousands of feet of pipe can be moved with minimal effort since the pipe weight is at an equal state with the snub forces. Snubbing contractors calculate this snub force and add in a friction factor from the BOP and wall contact on either a casing or tubing string. If done correctly, the snubbing contractor can predict when this balance point will take place and can properly prepare for it.

Modern snubbing units are powered by sophisticated hydraulic systems. These hydraulic units typically supply all power required by the components of a snubbing operation. With a better understanding of hydraulics and modern advances, companies have been able to harness this hydraulic energy to develop precision controlled snubbing units. These units move tubulars into and out of a well bore by use of a "multi cylinder jack"; a snubbing jack comes in many sizes depending on the task at hand. They are usually denoted in size by the snubbing unit description (i.e. 460K, 340K, 200K, etc). The 460K snubbing unit has the ability to lift 460,000 LBS and a snubbing capacity of 230,000 LBS. Most snubbing units can typically snub half of their lift rating. Assume you had a well with 10,000 PSI at surface and wished to snub in a string of 2 3/8" tubing. The snubbing contractor can calculate the snub force, add in their respective friction calculations and project the snub force to overcome will be approximately 51,000 LBS. This would put a 120K snubbing unit to close to its maximum capacity of 60,000 LBS snub loading. The safest bet would be a 150K or 235K snubbing unit.

Well control is taken very seriously by snubbing contractors. The BOP is the only barrier between the well bore and personnel. Depending upon well conditions, pressures and work performed, the BOP stack configuration varies greatly; there can be a minimum of three BOP"s and in some cases, up to ten. All of this is determined in the pre-job phase of the operation.

Pipe handling is performed by the snubbing units "gin pole" and "pipe winches". The gin pole is typically telescoped out in excess of 40ft above the snubbing unit. With the use of dual tubing winches, multiple joints of pipe can be handled simultaneously, speeding up the operation.

The snubbing "basket" is the platform where the snubbing personnel work. The basket contains all of the necessary hydraulic controls to operate all the features of the snubbing unit, as well as a large bank of BOP"s and hydraulic valve controls.

Today"s snubbing units can be employed to provide a wide range of services. In essence, a snubbing unit is a hydraulic rig that can do everything a rig can do, plus it can perform under pressure in an under balanced live well state. This is especially critical to the operators in the Haynesville Shale, which is known for HPHT wells. With the use of the snubbing units" hydraulic rotary, the unit can be employed for fishing, milling, drilling, side tracking or any task needed to remove bridge plugs, cement or deepen wells.

The industry has become more aware of damages caused by heavy kill weight fluids and mud. This has helped make snubbing units more popular in a completion and workover role, versus its" traditional use as a well control response tool. With the advances in drilling technologies in the unconventional shale market, the benefits of snubbing units have become very apparent. These types of completions often have laterals extending out thousands of feet. With costly stimulations used to help extract the gas more efficiently, operators often times do not wish to turn around and load the well with heavy fluids to complete the well dead.

Coiled tubing has its limitations in reach, due to wall to wall mechanical friction in horizontal wells. Often times the coiled tubing units cannot reach TD or supply the needed weight on bit to mill up composite plugs typically used in completions.

Another clear advantage to using a snubbing unit is its" small footprint, which is critical on the tight locations in the unconventional shale"s. Moreover, the small size and ease of mobilizing is especially useful and cost effective with offshore wells.

In conclusion, with the snubbing unit"s size, ability to handle pressure, rotary capabilities, rigidity of jointed tubing and minimal wall contact, snubbing units have become the chosen resource for these types of completions.

Pipe light(figure 1) describes the condition of the well which well head pressure and buoyancy acting upward against a cross sectional area of pipe is greater than weight of the string. If the light pipe condition is happened and the string is not controlled by the snubbing unit, the string will be pushed out of the well.

When workover the well under pressure with either a rig or a hydraulic workover (Figure 2), there is a risk of pipe light so it is imperative to know which condition of the well will be pipe light.

After knowing the concept of light pipe, we will apply it to determine how many feet of tubular required snubbing into the well before the weight will overcome the surface pressure plus buoyancy force.

When Petronas Carigali, the national oil company of Malaysia, planned the development of its platform EWDP-A offshore Sabah, they did so on the basis of using coiled tubing for any thru-tubing workover operations which were needed while the drilling rig was still in place. In this way the drilling rig could be fully utilized for drilling operations, thus maximizing the efficiency of, and minimizing the total time for, the development. Well EW 117 was completed on this platform as a level 6 Multilateral in July 2000 with dual 3-1/2" tubing strings accessing two laterals with measured depths of 14,910ft. and 15,236ft., respectively. The clean-out and perforation operations commenced with coiled tubing with the rig assisting. However, due to a combination of the tortuosity and the lengthy horizontal sections of the laterals, it was not possible to reach bottom with coiled tubing because of the high frictional forces encountered.

After consideration of several alternatives a feasibility study was undertaken to explore the possibility of using a Hydraulic Workover (Snubbing) unit to perform the -thru-tubing operations concurrent with the continuing drilling activity. The study concluded that, with some custom designed handling equipment, a special tapered workstring and strict adherence to a permissible concurrent activity matrix, this approach was indeed feasible. The operation was performed in February 2001 and the well made available for production by the beginning of March. Throughout the workover operation the drilling rig sequence remained in accordance with plans, apart from a period of 14 hours downtime while moving the Snubbing unit into its working location.

This paper will review the problem encountered, the motive forces applicable, the feasibility study and the resultant custom designed equipment and workover operation. It will discuss on the integrated team approach and detailed planning, in which active participation from Petronas Carigali, the drilling contractor and several service companies resulted in a successful operation.

Drilling Operations. Drilling operations will be carried out using electrical rig for well. Drilling unit for drilling of oil and gas wells consists of a derrick at the top of which is mounted a crown block and a hoisting block with a hook. From the swivel is suspended a Kelly stem which passes through a square or hexagonal Kelly bush which fits into the rotary table. The rotary table receives the power to drive it from an electric motor. The electric motor rotates the rotary table, through which passes the Kelly bush, and the rotations are transmitted to the bit as the drilling progresses, the drill pipes in singles are added to continue the drilling process. At the end of the bit life, the drill pipes are pulled out in stands and stacked on the derrick platform. A stand normally has 3 single drill pipes. After changing the bit, the drill string is run back into the hole and further drilling is continued. This process continues till the target depth is reached. During the course of drilling, cuttings are generated due to crushing action of the bit. These cuttings are removed by flushing the well with duplex/triplex mud pumps. The mud from the pump discharge through the rotary hose connected to stationary part of the swivel, the drill string and bit nozzles. The mud coming out of the bit nozzles pushes the cuttings up hole and transports them to the surface through the annular space between the drill string and the hole. The mud not only carries away crushed rock from the bottom of the hole but it also cools the bit as it gets heated due to friction with formation while rotating. The mud also helps in balancing subsurface formation pressures and by forming a cake on the walls of the well also diminishes the possibility of crumbling or caving of the well bore. At the surface, the mud coming out from well along with the cuttings falls in a trough, passes through the solids control equipment"s i.e. shale shaker, de-sander/ de-silter and mud cleaner. These equipment"s remove the solids of different sizes, which get mixed with the mud during the course of drilling. The cleaned mudflows back to the suction tanks to be again pumped into the well. The drilling mud/fluid circulation is thus continuous cyclic operation. The most suitable clay for mud preparation is bentonite, which is capable of forming highly dispersed colloidal solutions. Various other chemicals are also used in mud preparation as per requirements dictated by the temperature/pressure conditions of the wells. The mud i...SaveCopy

The global hydraulic workover unit (HWU) market size was USD 8.11 billion in 2020. The market is anticipated to grow from USD 8.59 billion in 2021 to USD 13.21 billion in 2028 at a CAGR of 6.4% in the 2021-2028 period. The global impact of COVID-19 has been unrivaled and staggering, with it witnessing a negative demand across all regions amid the pandemic. Based on our analysis, the global hydraulic workover unit (HWU) market exhibited a decline of -14.5% in 2020 compared to the average year-on-year growth during 2017-2019. The growth during the forecast period is attributable to this market"s demand and growth, returning to pre-pandemic levels once the epidemic is over.

The COVID-19 pandemic initiated by the spread of the novel coronavirus has had a damaging impact on the global industrial landscape. This industry faced significant losses and have had to reduce operations due to the imposition of rigorous lockdowns to contain the spread of the COVID-19 virus. Consequently, the outbreak of the virus has transformed the demand for HWUs.

As the hydraulic workover unit industry is majorly dependent on oil and gas activities, the decline in oil prices in a long time has significantly impacted the investment in the instrument. The imposition of lockdowns in various countries and the shutting down businesses except for essential services with minimal workforce affected the energy demand. This factor has directly impacted work in the well interventions sector.

In July 2019, Kuwait signed a USD 600 billion offshore exploration contract with Halliburton. The contract aimed to drill six exploration wells in the next two to three years, which is anticipated to increase around 100,000 b/d in the forecast period. The United Arab Emirates invested approximately 31,000 square kilometers of acreage for offshore oil gas production, majorly in the Abu Dhabi and Ras Al Khaima regions. In January 2020, Russia announced a significant investment of around USD 300 billion for new offshore oil and gas projects.

The world is likely to derive massive oil and gas from offshore production. The more arduous production conditions in offshore locations increase the investment in more complex and newer technologies like hydraulic workover units. The onerous requirement for offshore with ease of operations is the primary market driver during the projected period.

There is a substantial increase in demand for developing a safe, versatile, and cost-effective tool for workover and well intervention operations due to the increasing number of mature oil fields. This factor bolsters the demand for HWUs globally. This equipment can be efficiently used with low setup times and are more cost-effective. Earlier workover rigs were used for similar operations, which took a lot of time and effort to be set up and used. Further, the wells had to be killed before operations, However, with newer technologies, HWUs with snubbing capabilities have made snubbing capabilities possible with newer technologies.

In 2021, MEIL, India started manufacturing a new type of HWUs with indigenous know-how, especially for the local market. The increasing demand for more effortless functioning, avoiding well-killing, secure and cost-effective well intervention units is an important trend for the hydraulic workover unit market.

A mature oil and gas field is past peak production. These oilfields account for a majority of the world"s crude oil production. With enhanced technological approaches like enhanced oil recovery (EOR), the recovery of mature oil fields has seen a tremendous increase. Increasing recovery from mature fields has necessitated prolonging the well and improving production using well interventions and workover.

With the deterioration in oil reserves, companies have increased their focus on inventing equipment required to access remaining reserves on mature wells. The prime focus is to improve recovery and prolong life. But the amplified water cut with constrained topside facilities, growing flow assurance problems, rising operating costs, and integrity issues because of the maturing facilities have made brownfield operationally and economically impractical. The increasing requirement for workover services is anticipated to bolster the market growth.

The growing population explosion and urbanization has resulted in a spike in energy requirement from the various end-user sector. As renewable energy is still in an early adoption stage of its product life cycle, the majority of power generation is handled by hydrocarbons. Due to inadequate development of other energy sources, the growing global oil and gas demand enhances well drilling and maintenance. The increase in crude oil and shale gas production capacities and an increasing number of brownfields is expected to enhance the well workover and intervention demand, fueling the market growth.

The primary factor restraining the hydraulic workover unit market growth is the consumer shift towards clean fuels. The increasing requirement of the renewable energy sector will undoubtedly decrease the investment being made in the oil and gas energy sector, which will harm the well intervention sector. The increasing proportion of power generation using renewable energy can hinder the principal investments being made for oil and gas. Also, the necessity to reduce carbon emissions has powered the acceptance of renewable energy, with government incentives being granted worldwide. Further, the developing competence of renewables for power generation with durable benefits can result in increased adoption over conventional fuels.

The services carried out by hydraulic workover units are completions, plug & abandonment, ESP completion, sand screen installations, well deepening, fishing/clean-outs, casing repairs, etc. Workover segment includes operations over dead-wells, while snubbing involves installing or removing pipes in or out of live wells. The increasing demand for dead wells" services due to the high number of brownfields is critical for the workover segment. The workover segment involves a broader range of services, making the segment significant.

The snubbing market segment is gaining traction due to increased demand for performing operations of live-wells and avoiding well killing. The rising popularity of snubbing services is anticipated to propel the snubbing segment of the market.

Due to the high oil production from the onshore segment and the larger number of onshore oil rigs, the segment dominates the market. Moreover, most of the onshore oil rigs are mature and drive significant demand for the market.

The North American region holds a significant share in the market due to the high adoption of workover and snubbing services, coupled with demand for ease and efficiency of operations and technological advancement. Also, the rising proportion of mature oilfields in the region drives the market. Additionally, the government norms to reduce emissions led to companies finding it unviable to increase exploration and an increased necessity to prolong existing oil wells and drive the region"s market.

The competitive landscape for the hydraulic workover unit study shows that very few current companies have invested widely in research and development. The market has seen substantial recent technological advancements to keep pace with the best manufacturers. Considering all the scenarios, Balance Point Control and Halliburton are the major companies that have invested in developing HWUs. They are anticipated to continue being the key players in the future.

April 2021- Megha Engineering and Infrastructures Limited (MEIL) started manufacturing advanced hydraulic technology rigs with indigenous knowledge for the oil and gas sector. The development of HWUs commenced in the Kalol oil field near Ahmedabad, Gujarat. This manufacturing project was taken up to support the Government of India"s "Make in India" initiative.

July 2021-In its quarterly results, Norwegian Energy Company ASA announced that the Noble Sam Turner drilling program began a well workover and maintenance campaign in spring 2021 and completed three well workovers, which contributed to almost 2000 bpd bringing positive results on operating performance during the second quarter. The use of HWUs significantly contributed to the success of the campaign.

The global hydraulic workover unit market research report highlights the leading regions worldwide to understand the user better. Also, it provides insights into the latest market trends and analyzes technologies deployed rapidly with market statistics. The report highlights some of the growth-stimulating factors and restraints, helping the reader gain in-depth knowledge about the industry.

The global hydraulic workover unit market size is predicted to grow at a 3.84% CAGR in the forecast period (2020- 2027), states the current Market Research Future (MRFR) report. A hydraulic workover unit is the perfect well intervention solution for re-entry operations, well interventions, and well maintenance. This unit uses hydraulic cylinders for lifting the tubular or out of the well. The hydraulic cylinders enable complete control over tubular movements and helps in eliminating the need for a huge mast construction that is present on conventional drilling rigs.

According to the MRFR report, there are numerous factors that are propelling the global hydraulic workover unit market share. Some of these entail technological advances in oil and gas well production, increasing offshore production post decline in oil prices, the burgeoning need for hydraulic workover units in the offshore oil and gas industry, the rising electricity demand, increasing focus on offshore exploration, the production of E&P of oil and gas, the rising efforts by upstream companies to improve the production from the mature fields, and the increasing oil and gas production. The additional factors adding to the global hydraulic workover unit market value includes the growing development of natural gas resources, the rising focus on mature oil and gas fields with the implementation of digital technologies which are the latest hydraulic workover unit market trends, rising energy demand in developing economies, increasing number of exploration activities, well drilling activities, and hydraulic fracturing, growing demand for snubbing services, and rising number of mature oil and gas fields.

On the contrary, stringent environmental regulations, lack of skilled workforce, problems related to the use of hydraulic workover unit like long rig-up time, and problems in transport for its heavy weight may impede the global hydraulic workover unit market revenue over the forecast period.

The oil and gas sector unfortunately has faced the brunt of the ongoing COVID-19 crisis which in turn has impacted the hydraulic workover unit market. Owing to the present scenario, several oil and gas companies across regions were compelled to shut down their services and producing assets as countries practiced complete or partial lockdown strategy for dealing with the pandemic. Across the region, companies has either delayed or suspended the key oil and gas projects. Besides, the crisis has also impacted the rig count for oil and gas, well drilling and production activities, and also crude oil prices. All these factors have negatively impacted the global hydraulic workover unit market growth.

The MRFR report highlights an inclusive analysis of the global hydraulic workover unit industry based on application, installation, service, and capacity.

By capacity, the global hydraulic workover unit market is segmented into above 150 tonnes, 50 to 150 tonnes, and up to 50 tonnes. Of these, the above 150 tonnes capacity segment will lead the market over the forecast period.

By service, the global hydraulic workover unit market is segmented into snubbing and workover. Of these, the workover service segment will dominate the market over the forecast period.

By installation, the global hydraulic workover unit market is segmented into trail mount and skid mount. Of these, the trail mount installation segment will spearhead the market over the forecast period.

By application, the global hydraulic worker unit market is segmented into offshore and onshore. Of these, the onshore application segment will have the lions share in the market over the forecast period.

Geographically, the global hydraulic workover unit market is bifurcated into Europe, North America, South America, the Asia Pacific, & the Middle East and Africa (MEA). Of these, North America will have the lions share in the market over the forecast period. Per capita consumption, production, and exploration of oil and gas, advances in upstream operations, high production of crude oil produced from tight oil resources in the US, the rise in the production and extraction of oil and gas increases the need for hydraulic workover units to perform routine well maintenance for offshore installations, inland waters, and land, increase in the need for cost-efficient method to repair leading to the installation of hydraulic workover units, the growth in unconventional resources in Canada and the US, and the demand for intervention operations in the maturing offshore fields in the Gulf of Mexico and other onshore fields in the US are adding to the global hydraulic workover unit market growth in the region.

In Europe, the global hydraulic workover unit market is predicted to hold the second-largest share over the forecast period for technological advances and increasing exploration and production of oil and gas.

In the APAC region, the global hydraulic workover unit market is predicted to have admirable growth over the forecast period. Rise in demand for energy in emerging economies of India and China are adding to the global hydraulic workover unit market growth in the region.

In the MEA and South America, the global hydraulic workover unit market is predicted to have sound growth over the forecast period. The presence of large untapped energy reserves is adding to the global hydraulic workover unit market growth in the region.

The prominent players profiled in the global hydraulic workover unit market report include ZYT Petroleum Equipment Co., Ltd (China), Uzma Berhad (Malaysia), PT Elnusa Tbk (Indonesia), Canadian Energy Equipment Manufacturing FZE (UAE), Velesto Energy (Malaysia), Superior Energy Services (US), Basic Energy Services (US), High Arctic Energy Services Inc. (Canada), Precision Drilling Corporation (Canada), Cudd Energy Services (US), Archer (Norway), National Oilwell Varco (US), and Halliburton (US), among others.

The global hydraulic workover unit market is fragmented and also competitive with the presence of many domestic as well as international industry players. They have incorporated assorted strategies to stay at the forefront and also cater to the surging needs of the customers, including collaborations, partnerships, contracts, geographic expansions, new product launches, joint ventures, and more. Additionally, these players are also making heavy investments in research and development activities for strengthening their portfolios and also creating a hold in the market.

United States of AmericaUnited KingdomAfghanistanÅland IslandsAlbaniaAlgeriaAmerican SamoaAndorraAngolaAnguillaAntigua and BarbudaArgentinaArmeniaArubaAustraliaAustriaAzerbaijanBahamasBahrainBangladeshBarbadosBelgiumBelizeBeninBermudaBhutanBoliviaBonaire, Sint Eustatius and SabaBosnia and HerzegovinaBotswanaBrazilBritish Indian Ocean TerritoryBritish Virgin IslandsBruneiBulgariaBurkina FasoBurundiCambodiaCameroonCanadaCanary IslandsCape VerdeCayman IslandsCentral African RepublicChadChileChinaChristmas IslandCocos (Keeling) IslandsColombiaComorosCongoCook IslandsCosta RicaCroatiaCubaCuraçaoCyprusCzech RepublicDemocratic Republic of the CongoDenmarkDjiboutiDominicaDominican RepublicEcuadorEgyptEl SalvadorEquatorial GuineaEritreaEstoniaEthiopiaFalkland Islands (Malvinas)Faroe IslandsFederated States of MicronesiaFijiFinlandFranceFrench GuianaFrench PolynesiaGabonGambiaGeorgiaGermanyGhanaGibraltarGreeceGreenlandGrenadaGuadeloupeGuamGuatemalaGuernseyGuineaGuinea-BissauGuyanaHaitiHondurasHong KongHungaryIcelandIndiaIndonesiaIranIraqIrelandIsle of ManIsraelItalyJamaicaJapanJerseyJordanKazakhstanKenyaKiribatiKuwaitKyrgyzstanLaoLatviaLesothoLiberiaLibyaLiechtensteinLuxembourgMacaoMacedoniaMadagascarMalawiMalaysiaMaldivesMaliMaltaMarshall IslandsMartiniqueMauritaniaMauritiusMayotteMexicoMoldovaMonacoMongoliaMontenegroMontserratMoroccoMozambiqueMyanmarNamibiaNepalNetherlandsNew CaledoniaNew ZealandNicaraguaNigerNiueNorfolk IslandNorth KoreaNorthern Mariana IslandsNorwayOmanPakistanPalauPanamaPapua New GuineaParaguayPeruPhilippinesPitcairnPolandPortugalPuerto RicoQatarRéunionRomaniaRwandaSaint BarthélemySaint HelenaSaint Kitts and NevisSaint LuciaSaint Martin (French part)Saint Pierre and MiquelonSaint Vincent and the GrenadinesSamoaSan MarinoSao Tome and PrincipeSaudi ArabiaSenegalSerbiaSeychellesSierra LeoneSingaporeSint Maarten (Dutch part)SlovakiaSloveniaSolomon IslandsSomaliaSouth AfricaSouth Georgia and the South Sandwich IslandsSouth KoreaSouth SudanSpainSri LankaSudanSurinameSvalbard and Jan MayenSwazilandSwedenSwitzerlandSyriaTaiwanTajikistanTanzaniaThailandTimor LesteTogoTokelauTongaTrinidad and TobagoTunisiaTurkeyTurkmenistanTurks and Caicos IslandsTuvaluUgandaUkraineUnited Arab EmiratesUruguayUS Virgin IslandsUzbekistanVanuatuVatican CityVenezuelaVietnamWallis and FutunaWestern SaharaYemenZambiaZimbabwe

This website is using a security service to protect itself from online attacks. The action you just performed triggered the security solution. There are several actions that could trigger this block including submitting a certain word or phrase, a SQL command or malformed data.

The claimed invention relates generally to well drilling and servicing equipment, and more specifically to portable rigs for handling pipe strings when making up and disconnecting long strings of pipe used in a bore hole during operations that are carried out in the exploration and production of petroleum and other fluids and minerals from substantial depths below the earth"s surface.

When such service operations become necessary, a portable installation called a workover rig is brought to the well site and set up. Generally, these rigs consist of a derrick or mast which supports pulleys or block and tackle arrangements that are operable to pull the pipe string from the well. These prior art workover rigs are usually heavy and difficult to erect and further often have the limited operational capability of only being able to hoist or pull pipe from a well without the capability of snubbing or pushing pipe back into the well. Since these conventional workover rigs cannot develop a downward force to push a string of pipe into the well, in such operations the well must necessarily always be under control or "dead", as is known in the art. This may require a preparatory operation of injecting a suitable substance such as mud or "kill" fluid into the well to maintain sufficient column weight of fluid to resist the pressure within the well which is tending to force the tubing out. However, it is usually desirable to carry out the workover operations without resorting to the injection of "kill" fluid into the well since the well may be lost if the formation is damaged because of the presence of the workover "kill" fluid. In such "killing" workover operations, there is a very high risk that the productivity of the subsurface formation may decline so severely after killing the well that the well must be abandoned.

An overriding concern in the construction of workover rigs is to get the necessary equipment into and out of the well as rapidly and safely as is economically possible. This concern has led to the development of a portable well service rig having a transportable mast or derrick. Before the invention of the first portable well service unit, it was necessary to leave the drilling derrick in place over the well for use in future well service operations. The portable well service rig eliminated the need for a permanent derrick and thus materially reduced overall well service costs. The early portable rigs, however, were unloaded in a heap and later sorted out, and then assembled without any definite plans therefore consuming a substantial amount of time in rigging up. Even when unitized and transported on pallets, a significant amount of time was required for transporting, rigging up and dismantling the palletized equipment. In the palletized approach, the field assembly and erection of the mast, mast support structure and reeving of the hoist cable caused expensive but unavoidable delays. Therefore recent improvements to conventional portable workover rigs have focused on changes which simplify the operations of transporting, rigging up and dismantling.

One of the problems associated with the development of the portable workover rig is that of providing sufficient working space below the mast floor while limiting the mast and its supporting base to dimensions which permit its transportation across public highways. A working space must be provided below the mast floor in order that the mast can be supported vertically above and engage well head equipment which may extend as much as eight to ten feet above the elevation of the rig platform deck. The minimum height of the mast is determined primarily by the length of the sections of pipe string added to or removed from the pipe already in the well bore. However, if the mast is so high that its length and height clearance when in a horizontal position on the workover rig exceeds the limits allowed by the state, the mast must be at least partially disassembled or must be telescoped. Most wells have tubing sections which are in the range of thirty-six to forty feet long, so that the construction of a transportable mast assembly having a stroke for accomodating the removal or insertion of such tubing sections poses no problem insofar as complying with state highway regulations.

As mentioned above, the conventional practice has been to provide a mast having telescoping sections or having sections which must be separately assembled and erected on site. To provide ample clearance for the well head equipment, the mast floor has been elevated above the ground level by placing it on a mast substructure carried by the rig base platform. This substructure is normally fabricated of heavy structural steel in a massive weldment which must be separately transported. The loads it must bear are greater than those born by the mast, since the substructure must support not only the weight of the derrick with its pipe string load, but other loads, such as the rotary table and draw works as well. However, the length and height of the separate mast support base when combined with the reclining mast may in some cases exceed highway limits, so that separate transportation, field assembly and erection are required. Most conventional rigs provide separate support base and mast sections which may be unbolted and separately transported to provide the short lengths allowed for highway travel. However, additional rigging up and tear down time is required for such arrangements.

Other important considerations involved in the construction of portable workover rigs are the strength and stability of the mast. The mast must be constructed to safely carry all loads which will ever be used in the well over which it is placed. This is the collapse resistance caused by vertical loading, or the dead load capacity of the mast. The largest dead load which will be imposed on the derrick will normally be the heaviest string of production tubing run in the well. However, this heaviest string of tubing will not be the greatest strain placed on the mast. The maximum vertical load which will ever be imposed on the mast will probably be the result of pulling on equipment, such as drill pipe or casing, that has become stuck in the hole. Therefore it must be considered that, sometime during the useful life of the mast, severe vertical strain will be placed on it because the equipment has become stuck in the hole. Therefore the mast and its intermediate support platform must be constructed to withstand and react loads which will exceed the capacity of the hoist line which will be used on the rig.

The mast must be also designed to withstand the maximum wind loads to which it will be subjected. The horizontal force of the wind acting on the mast and production tubing is usually counteracted by using from one to three guy wires along each leg of the mast which are attached to "dead man" anchors located some distance from the mast. A "dead man" anchor is made from a short length of large pipe, a concrete block, or a short section of timber, which is buried in the ground to provide an anchor for the guy wire. A substantial amount of time and labor is expended in setting up the "dead man" support lines. Additionally, when carrying out workover operations off shore, there is no practical way to anchor the guy lines. A suitable structural alternative for the guy wire supports is necessary for reacting the wind loads, and the snubbing forces must also be reacted in order to drive production tubing into an offshore well against the downhole pressures which may be encountered. Therefore there is a continuing interest in improving the design of support substructure for free-standing masts which do not require guy wires for support.

As a result of the many improvements to portable workover rigs, such vehicles now transport practically all the necessary servicing equipment directly to the field locations and when servicing has been completed, remove the necessary equipment to another well in need of service in the same field or in a different field miles away. Thus the equipment necessary to service a number of wells each having different service requirements has been greatly reduced, and consequently the labor and cost, as well as the amount of equipment has correspondingly dropped. However, there still remains considerable interest in the provision of more efficient and simplified machines in order that the job of well servicing in general may be carried out efficiently and at reasonable cost.

It is, therefore, the principal object of the present invention to provide an improved general purpose workover rig having a unitized configuration which is transportable across public highways and which can be easily rigged up and dismantled in the field.

Still another object of the invention is the provision of a workover rig having a mast, a mast support substructure, and draw works in which the static load of the draw works is supported by a portable base platform member rather than by being supported by the intermediate mast support substructure.

Another object of the invention is the provision of an erectable mast support substructure which cooperates with a portable base platform for stabilizing a free-standing mast erected on the support substructure and reacting vertically directed snubbing forces without the use of dead man anchor lines.

Yet another object of the invention is the provision of a workover rig having draw works carried by a portable platform and a mast and mast support substructure which are separately movable from a reclining transport position to an erect operating position wherein erection and retraction of the mast and mast support assembly can be carried out without disturbing cable reeving on the mast or on the draw works.

An important object of the present invention is the provision of draw works for a workover rig which can be carried in a reclining position on a portable rig platform and which is operably connected to develop driving forces required for either hoisting or snubbing operations.

Still another object of the invention is the provision of a portable workover rig having a mast and mast support substructure which are separately movable from a reclining transport position over a portable base platform to an erect workover position overlying well head equipment lying either above or below the elevation of the portable base platform.

Yet another object of the invention is the provision of a base support substructure for an erectable mast and a carriage assembly for moving the base support substructure from a reclining transport position over a portable base platform to an erect workover position, the carriage assembly cooperatively coupled to the base platform for stabilizing the erectable mast in free-standing relation on the mast support substructure and for transmitting mast load reaction forces through the portable base platform.

Another object of the invention is the provision of a workover rig having an erectable mast supported on a cantilever support substructure which is movable from a reclining transport position overlying a portable base platform to an elevated position of use wherein the cantilever support base is extended beyond the portable base platform for carrying out workover operations.

A related object is the provision of a bolster assembly for attachment to the vertically adjustable stack assembly for providing lateral support for a length of pipe string extending between the mast and the well head equipment to prevent buckling of the length of pipe string when it is undergoing compression loading during either snubbing or drilling operations.

The foregoing objects are achieved by a workover rig which is mounted on a portable base platform such as a skid or the bed of a trailer vehicle, and which features a collapsible mast assembly which is movable from a reclining transport position to an erect elevated position of use. The mast assembly is supported for freestanding operation by a carriage assembly including a cantilever substructure support base mounted on the rig support platform for pivotable movement from the reclining transport position to an elevated position of use. The carriage assembly includes lift arms coupled in parallel relation intermediate the cantilever support structure and the rig support platform, thereby defining a parallelogram throughout the range of movement of the mast support assembly for maintaining the cantilever support base in parallel alignment with the base platform. According to this arrangement, the mast and the carriage assembly are separately collapsible for transport in a low profile, reclining position over the base platform to comply with the length and height limitations established for public highways. The mast and the carriage assembly are separately erectable to an elevated operating position overlying well head equipment which may be disposed at an elevation either above or below the elevation of the portable base platform. The mast is connected in hinged engagement with the carriage assembly, and both the carriage assembly and the mast are separately driven from the transport position to the erect operating position by linear hydraulic actuators. The linear hydraulic actuators in combination with the carriage assembly serve to stabilize the mast for free-standing operation and transmit mast load reaction forces through the portable base platform. An important feature of this arrangement is the cantilever support substructure which is extended to an elevated operating position beyond the portable base platform for carrying out workover operations adjacent elevated well head equipment. A further advantage of this arrangement is that the mast, mast support substructure, and draw works can be carried in a collapsed, low profile transport position and both erection and retraction of the mast and mast support assembly can be carried out without disturbing the cable reeving on the mast and draw works.

According to an important aspect of the invention, the workover rig is provided with a mast, a mast support substructure, and draw works in which the static load of the draw works is supported by a portable base platform member rather than being supported by the intermediate mast support substructure. In this arrangement, the draw works includes a linear hydraulic actuator having rod and housing elements in which one of the elements is anchored to the base platform with the other element being mounted for movement along the base platform through a stroke pathway which extends transversely with respect to the mast. The traveling sheaves are cooperatively reeved with hoist and snub cables for developing driving forces required for either hoisting or snubbing operations. The advantage of this arrangement is that the intermediate mast support substructure must support only the mast in an erect operating position with the substantial weight of the draw works being supported by the portable base platform. This arrangement permits the mast support substructure to be easily movable from the reclining, low profile transport position to the elevated workover position without the burden of the draw works. Hoisting and snubbing operations are carried out by the draw works which includes a linear hydraulic actuator carried on the base platform, a load engaging traveling block supported for vertical movement along the mast by hoist and snub cables, and by traveling sheaves carried by the actuator through a stroke pathway which is oriented transversely with respect to the mast. In this arrangement the load engaging traveling block is driven upwardly or downwardly along the mast in response to extension and retraction of the rod and housing elements of the hydraulic actuator.

In yet another important embodiment of the invention, a vertically adjustable stack assembly is provided for accomodating the existing elevation of well head flange connections. The vertically adjustable stack assembly includes an adjustable support column assembly anchoring the rig platform to the well head casing, and an adjustable support column assembly interposed between the well head casing and the mast for transferring the weight of the mast from the intermediate mast support structure to the well casing. The vertically adjustable stack assembly simultaneously anchors the portable base platform to the well head casing, thereby stabilizing the mast support substructure, while relieving the burden of the mast from the intermediate mast support substructure. This arrangement helps stabilize the mast for free-standing operation on the mast support substructure and for transmitting mast load reaction forces through the portable base platform, thereby eliminating the need of dead man anchor lines which would otherwise be required for stabilizing the mast and for reacting dynamic mast loads.

According to another important embodiment of the invention, a bolster assembly is attached to the adjustable stack connector assembly for providing lateral support to a length of pipe string extending between the mast and the well head flange. In a preferred embodiment, the bolster assembly includes a number of bolster plates each having central openings for receiving the length of pipe string with link elements interconnected in a scissors arrangement on opposite sides of the bolster plates for permitting accordion-like movement of the bolster plates relative to each other in parallel, stacked relation and with their central openings concentrically aligned. The bolster plates are fastened to the adjustable stack connector and provide lateral support to the length of pipe string extending between the mast and well head equipment to prevent buckling of the length of the pipe string when it is undergoing compression loading during either snubbing or drilling operations.

Finally, the portable workover rig of the invention is adapted to perform drilling operations by the combination of a vertically yieldable stab assembly which interconnects a powered drill sub with a traveling block for permitting vertical displacement of the powered drill sub during make-up and break-out operations while simultaneously reacting torque forces which arise in response to rotary forces applied to the drill string. The vertically yieldable stab assembly includes upstanding stab receptacles anchored to the top side of the traveling block and stab elements downwardly depending from the under side of the powered drill assembly for engagement with the stab receptacles. Each stab element is supported for vertical reciprocal movement between retracted and extended positions, and each stab element is yieldably biased to the fully extended position, thereby permitting vertical displacement of the power sub relative to the traveling block during the make-up and break-out operations while reacting torque forces which are produced by operation of the powered drill sub.

FIG. 3 is a top plan view of the workover rig of FIG. 1 with the mast and carriage assembly removed which illustrates the layout of the draw works and related equipment on the deck of a portable rig support platform;

FIG. 7 is a side elevational view of a skid mounted workover rig having draw works and an erectable mast constructed according to the teachings of the present invention;

FIG. 10 is a perspective view which illustrates the arrangement of sheaves and reeving of cables for conducting snubbing operations on the workover rig shown in FIG. 1;

FIG. 11 is a perspective view which illustrates the arrangement of sheaves and reeving of cables for conducting hoist operations on the workover rig shown in FIG. 1;

FIG. 16 is a front elevation view of the completed vertically adjustable stack assembly shown interconnecting the mast support substructure and the rig support platform with the flanged connector of a well head assembly;

Referring now to the drawings, and more particularly to FIGS. 1-4, a workover rig 10 is shown having a transportable mast assembly 12 and draw works 14 supported on a portable trailer platform 16. The trailer platform 16 includes the usual longitudinal side frame rails 18, 20 which supports forward and rear decks 22, 24, respectively. The side rails 18, 20 are interconnected by the usual structural members, including a tailboard 26. The trailer platform 16 includes a fifth wheel connection 28 for attachment to a tractor, and rear wheels 30 supported by shock assemblies and leaf springs in the usual manner. Outrigger jacks or props 32 support the side frame rails 18, 20 to prevent tilting or overturning of the rig during operation and also for maintaining the orientation of the trailer platform 16 once it has been set up. The jacks 32 are preferably hydraulically actuated and are controlled from a central station so that the trailer platform 16 can be aligned in parallel with the ground or inclined in a tilted position for workover of slant wells. Each jack 32 is equipped with a stabilizer pad 34 for engaging a mud sill (not shown) so that the trailer load can be more evenly distributed. Slung underneath the side frame rails 18, 20 are tool boxes 36 and a spare tire 38. Anchored top side on the forward deck 22 is power unit 40 which develops the main hydraulic power for the draw works 14 and includes hydraulic pumps driven by a diesel engine. The power unit is coupled to a hydraulic reservoir 42 so that as the required pressure in the system exceeds predetermined levels, one or another pump automatically unloads into the reservoir 42 and all engine horse power is then diverted for driving the alternate pump(s). Immediately forward of the