CATEGORIZED | 2009, May/June

New-Concept land rig design based on parallel operations

Posted on 17 May 2009

Driven by ‘crisis,’ rig design is based on parallel operations, aims to change drilling process

By Frank Springett, National Oilwell Varco

The drilling industry hasn’t seen paradigm shifts in surface equipment in recent years. Driving up to a land rig today can be virtually the same experience it was 30 years ago. However, downhole technologies have made significant advancements in directional drilling, which allows for more wells on a single site.

As an industry, we have often focused our discussion on the subject of automation and, in practice, we have applied some remote control and increasing levels of automation. These efforts have provided for incremental improvements through corner-cutting and a small amount of overlapping once-linear activities, improving drilling efficiency on the rig floor and safety benefits. But they have not accomplished great gains in the time needed to drill wells.

Manufacturing facilities found themselves in the same efficiencies dialogue that the drilling industry is experiencing, and they responded by questioning the entire operation, not just individual processes. By addressing the operation and not just the highly technical processes that resulted in a quality, cost-effective product, these facilities have optimized automation to a degree that makes their product available at the speed, quality and cost that the market demands.

National Oilwell Varco (NOV) has applied lessons learned from the massive market ramp-up of the last few years, as well as from working with operators, and developed an answer for the cost-cutting needs of this downturn to address lower-cost wells.

The company revisited and questioned the traditional land rig design and came up with a safe, productive, reliable, efficient drilling solution, or the SPRED Rig.

It is a new conceptual design that could potentially reduce the time to drill a well by a factor of three to four. By looking at the drilling process and how to nearly eliminate flat time on batch well applications, it is possible to change the way wells are drilled.

THE ORANGE STORY

While NOV’s ultimate success hinges on providing equipment solutions to the industry’s drilling and production challenges, it is fundamentally an equipment provider with core competencies based in manufacturing. In 2001, after the Varco/Tuboscope merger, one of Varco’s higher-cost facilities in Orange, Calif., was under pressure to provide lower-cost solutions.

The plant specialized in manufacturing top drives, Iron Roughnecks, drawworks and pipe-handling equipment. Despite the highly automated facility with its autonomous multi-robot-operated warehouse and large selection of cell-based, automated CNC machining centers, it was one of the more expensive drilling equipment manufacturing facilities in the company.

Crisis stimulates innovation and therefore change, and the Orange facility had to change something. They had very limited capital for upgrades but needed to improve the productivity, quality and cost of their processes in order to reduce the risk of closure. But if the facility already had some of the best equipment and the best automated machines, how could they increase capacity and drive down cost with limited capital? The answer – process.

A detailed work flow analysis was performed at the Orange plant. It was determined that cellular and quick response manufacturing (QRM) techniques could drastically reduce the time and cost to manufacture the finished product. This analysis and improvement continues to match the optimum output from the investment in the plant and improve the reaction to variables, which always occur.

To ramp up production, one mainshaft CNC machine was purchased, with no additional roofline added. The plant increased its best year of production from 86 top drives per year to 2008’s peak at over 300 top drives, and from nine Iron Roughnecks per year to nine Iron Roughnecks a week.

Reorganizing machines was necessary but easy compared with reorganizing people. Ultimately, the Orange plant also had to overhaul its manufacturing ideology, train its people to multitask and perform as teams. Buy-in and support from top management down to each shop hand and all suppliers was key. It was a complete culture change made possible because of the pressure created by other potential plants worldwide.

In a sense, there was a perfect storm of the right equipment, right people and immediate crisis that enabled the facility to go from one of the most expensive facilities to one of the best-performing, lowest-cost drilling
equipment facilities in the company.

The Orange facility accomplished this turnaround in a relatively short amount of time by applying existing technology to the process and leveraged a crisis to change the culture to make great gains.

MANUFACTURING PROCESS

By addressing process, the Orange facility witnessed a four-fold improvement in efficiency. No major additional capital or space, just re-organizing the work flow. When looking at the drilling process today, it is a fair estimate that 30-40% of the time on site is spent actually progressing the hole in the ground. The remaining time is spent performing actions such as tripping in and out of the hole, running casing, cementing, etc. Today (as it always has been), all steps in the drilling process are done in series with one multipurpose drilling rig.

If the conventional drilling rig were applied to a manufacturing facility, the product efficiency would cripple its ability to ship any quality products in a timely manner. It would be like having one multipurpose machine that had a CNC machining center, an automated welding machine inside an oven for heat treating, located in a blast and painting booth enclosed in one unit. Sound ridiculous?

With a single station, the value of flow-through would be lost. Manufacturing plants have independent, function-specific tools working simultaneously, which is much more efficient because operations are performed in parallel. The challenging question is, could that be the case on a drilling rig?

THE SPRED RIG

The inspiration behind the SPRED Rig is the story of the Orange. The crisis driving its design is the economic viability of unconventional assets. It has applied existing technology but changed the drilling process to enable a three- to four-time reduction in the time needed to drill batch wells. How is that possible?

Today’s conventional drilling rigs have a single well center where it performs all functions in series. Flat time can include tripping the bit in and out of the hole, running casing, cementing, etc. The SPRED Rig has multiple well centers with movable function-specific tools that travel from well center to well center to perform specific operations. The modules, as shown in the accompanying illustrations, are as follows:

  • DrillCell – A drilling module used to drill ahead and contains existing technology such as a TDS-10R top drive and ST80 roughneck.
  • TripCell – A tripping module used to trip pipe in and out of the hole, as well as run casing. The unit contains a CRT350 casing running tool and ST80 roughneck.
  • CementCell – A simple stab used to tie into the casing to enable pumping cement in the hole. It can be independently deployed or in conjunction with the tripping machine.

There is a whole host of potential modules, such as completions, coiled tubing or any other module that could contribute to the drilling process.

To drill a well, the drilling module (DrillCell) is used to drill the first section. Once complete, the drilling module is moved to the next well to begin drilling a new hole. The tripping module (TripCell) then moves to the first hole and is used to trip out the drill pipe and run casing. It is then moved, and a cementing module (CementCell) is moved in its place to cement in the casing. The second well is being drilled concurrent to these tripping and cementing operations. This nearly eliminates the flat time associated with operations not directly involved in making new hole.

The rig’s primary use is for sites where multiple wells can be drilled. This has become more common as major advancements have been made in horizontal drilling.

WHY NOW?

In order for a step-change like this rig design to occur, there has to be a crisis. Here, that crisis was driven by a major oil and gas operator. As an industry innovator, they pushed the limits of existing technology, setting the stretch goal of reducing the cost of wells in order to make unconventional oil plays economical. Because a high quantity of wells are required for unconventionals, the customer set a target to reduce total drilling costs by a factor of three. Without this “crisis,” the completely different perspective to the drilling process would have never occurred.

A detailed analysis was performed of the work flow for specific wells to determine where time could be removed from the process to increase efficiency – the same issue that NOV faced in its Orange plant. From that analysis, the initial concept was born, a “lean” type drilling rig that was large and not very mobile but was intended to go out to a field and corridor and drill for many years.The initial design was based heavily on new conceptual machines from new pipe handling to top drives to roughnecks and slips. While the time studies indicated the efficiencies were possible, the newness of all the components incorporated risks beyond the main concept of process improvement.

After speaking to several key innovators in the industry, a complete redesign was conducted. The intent was to utilize as much existing equipment and technology as possible, and to redesign the package so that it would be much more mobile. The result is a rig with the same transport module dimensions as NOV’s Rapid Rig (10 ft x 10 ft x 55 ft), utilizing much of the same drilling equipment. The design intent was to minimize as much risk in the development and implementation as possible by using 90% existing equipment and systems, and rearrange them to optimize the drilling process.

WHERE TO FROM HERE?

How many times do we hear “the time of easy oil is over?” If that is the case, then what is the typical industry response? Usually the response is an innovative step-change that dramatically enhances the way we do business. This industry can be brilliant when it has to be, and the economics driving the search for difficult oil demand that our processes evolve to meet this challenge.

If the cost of drilling pad-type wells can be drastically reduced, then reservoirs that were not economically viable become possible. The difficult oil is plentiful, but it can’t make money with the existing cost of drilling wells and the current price of oil. The SPRED Rig is not the traditional approach that answers the modern drilling rig efficiency challenge with an incremental change. It rethinks the way we drill wells, maintaining that reduced operational cost is the success variable.

With a design driven by crisis, the rig is based on a concept of parallel operations that has already shown success in the manufacturing industry. The core technology exists, and the concept is not that great a leap technically, but procedurally it requires a culture change.

Are we, as an industry, ready to take the next big step and rethink the core of how wells are drilled? Are we ready to use our current crisis to change our culture and serial process mind set? The answers to these questions are ultimately up to us.

SPRED, SPRED Rig, DrillCell, TripCell and CementCell are trademarked terms of National Oilwell Varco.

This article was put together with the review and input from Jeremy Ogg of NOV, Ian Davidson of Shell and David Reid of NOV, and the graphic work of Dean Bennett and Jorge Perez with NOV, thank you.

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  1. Rig concept aims to revolutionize batch drilling | Drilling Contractor Says:

    [...] this is a higher-cost rig, the time savings it provides will ultimately provide net savings. A detailed article about the SPRED Rig was published in the May/June 2009 issue of Drilling Contractor. Share [...]

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