Top Drive System: Driving Efficiency into Drilling Process

There has been consistent research and development over the years in areas of oil and gas production, especially in the drilling sector. The focus has been on enhancing efficiency and to drive more profits from operations. An important result of these efforts was the substitution of the rotary table and the introduction of the top drive system on the drilling rigs. Delivering high-performance in drilling processes, top drive system has enabled operators to reduce the downtime and increase the efficiency of drilling rigs.

In this article, let us talk about the top drive manufacturers around the world, and how operators have benefitted from this system!

Never-ending Opportunities for Top Drive Manufacturers

In recent times, the top drive system has seen a major transformation with the incorporation of more powerful motors into the system, capable of delivering output torque of around 90,000 ft-lb. Top drive manufacturers have also boosted the load ratings of the top drive system so as to enhance rig floor safety and to enable running of larger casing strings. In fact, a lot of modifications in the top drive system have bolstered the overall performance of drilling rigs and opened up huge business opportunities.

Let us look at some of the global top drive manufacturers, who are providing innovative top drive system to the drilling industry:

• Aker Solutions: Established in 1841, Aker Solutions is a Norway-based leading provider of the top drive system to the industry. Aker’s expertise in areas such as subsea drilling, decommissioning, and others. The company envisions to be “a leader in forging a sustainable future for our industry and the world it serves.”
• Bentec GMBH: Widely recognised as an industry expert in oilfield equipment, Bentec Gmbh is a German manufacturer and supplier of rigs and other equipment used in the upstream sector. Bentec’s Top Drive TD-500-HT is highly regarded for reducing downtime and maintenance cost.
• National Oilwell Varco: Established in the year 1841, National Oilwell Varco (NOV) is a leading provider of oilfield equipment and services to the upstream oil and gas industry. NOV’s released the TDS-11SH top drive in 2012, which deploys two permanent magnet motors to provide 1,100 HPs power and can hoist 500 tons, all the while delivering 51,000 ft-b of continuous torque at a rate of 110 RPM.

Difference between Top Drive Oil Rig & Kelly Drilling Rig

Both the Top Drive Oil Rig and Kelly Drilling Rig have been in wide usage in drilling operations across the globe. While each of these systems has its own pros and cons, it totally depends on companies about deploying which system for operations. In case of top drive systems, the advantages are seen in safer, faster, and more efficient usage, and in their capability to drive 2-3 joints of drill pipe at once. Top Drive system is also seen as a solution to the loss of rig time due to the stuck pipe. Rigs with top drive system carry out the process of reaming, which is to rotate the pipe while tripping pipe into or out of the hole. This helps in cutting down on the problems associated with the stuck pipe. Reaming is an extremely important process in a process like directional drilling, where larger portions of the pipe come into contact with the wellbore. Stuck pipe is a common problem associated with directional drilling.

However, all the advantages of the top drive system make it an expensive resource. Typical top drive system needs an investment of around $1-1.3 million with about 3 weeks of installation time. Even during installation, a bigger problem is carrying out extensive derrick modifications so as to be able to retrofit the rig with the top drive system. Most manufacturers have to spend most of the installation time on adding derrick extensions and support bracing, typically 2-3 weeks, which adds a cost of upto $250,000 to the installation cost. A rig downtime of almost three weeks and the additional cost associated with Derrick modifications have pushed drilling contractors to delay the installation of top drives on rigs. That is why the top drive system are rarely installed on smaller rigs. Additionally, in order for the top drive system to handle 2-3 joints of drill pipe at once necessitates a taller derrick than most derricks on a conventional kelly drive rigs. Typical top drive systems see an addition of approximately 24 ft to the traveling assembly. This has inspired the development of shorter top drives.

Benefits of Top Drive Drilling

The addition of top drive in drilling rigs is referred as to one of the most significant advancements in drilling technology. The conventional rotary drilling rigs were substituted by Top Drive Systems which constantly drill faster and safer, and as is discussed above, with way fewer scenarios of stuck drill pipe. However, one of the most significant advantages of drilling with a Top Drive system is that it enables operators to explore areas and formations otherwise inaccessible with conventional rotary drilling. The result of this is visible in the dramatic increase in production rates from particular fields, where drill rigs with Top Drive system were used.

If the benefits of the top drive system had to be listed out, it’d look like the following:

• With top drive system drilling with 90-ft stands, the number of connections is slashed. And since the number of connections is less, crew safety automatically improves.
• Top drive system also improves safety enabling the operators to quickly control the kicks while the drill pipe is tripped out of the hole. With top drive, the driller can easily set the slips and come down with the assembly to screw into the pipe. The driller can, then, use remotely operated valves to close the well.
• As discussed above, reaming while tripping in the hole allows operators to eliminate bridges and tight spots. In the case of a rotary table, a lot of time is wasted in picking up the swivel and kelly, and is, therefore, sometimes neglected.
• The process of Directional drilling has seen significant improvement due to the top drive system, with a huge reduction in downhole motor orientation activities.

Delivering Excellence in Operations

The wide array of advantages offered by top drive system has made them an indispensable part of both exploration and production of wells. The improvements in speed, safety, performance, and production have made them a preferred choice of most of the operators and contractors in the world. Currently, approximately 92% of all mobile offshore drilling rigs have a top drive system installed. Even onshore contractors and operators are now rapidly retrofitting Top Drives system on land rigs. With more research and investment into Top Drive Drilling Systems, the efficiency of drilling operations is bound to increase in the near future!