Improved Tooling Meets Holemaking Challenges in Growing Fracking Market - Tools improve penetration rate for large diameter deep hole drilling of fracking components
October 02, 2018
Chris & Paul Best
Allied Machine & Engineering
Hydraulic fracking has existed since the late 1800’s and continues today to be a major topic in the US energy sector. Fracking recovers gas and oil from shale rock by drilling down into the earth and injecting a mixture of water, sand, and chemicals into the rock at high pressure. This extraction technique creates cracks in the deep-rock formations through which natural gas and petroleum can freely flow out to the head of the well.
One component used in fracking is the fluid end block, which regulates the solution as it is pumped aggressively into the wellbore. The fluid end block industry has historically experienced highs and lows that reflect the overall state of the worldwide oil and gas market. After experiencing a decline in the past few years, the industry is now making a comeback. There has been a marked increase in the demand for fluid end blocks, based on the stabilization of crude oil prices.
Manufacturers work to supply fracking components
Fluid end blocks are made from solid blocks of steel, or stainless steel, and are usually about 3 feet tall, 4 feet wide and 2-3 feet thick. They are high-wear consumables that typically last no more than a few days. Most modern pumps are designed so these components can be replaced quickly to reduce downtime.
Fluid end blocks, also known as frack blocks, require huge amounts of machining – milling, drilling, and threading – to give them the complex contours, numerous channels, and finish required to pump the solution at extreme pressures. Typically, 3 to 5 holes are drilled through the block and then 3 to 5 additional crossholes are drilled to intersect. Each hole is usually about 3 to 4 inches in diameter, though some can measure up to 8 inches. To meet aggressive production goals, it is extremely important to manufacturers that their holemaking tools enable fast drilling of these large diameter (up to 8 inches) holes.
Interrupted cuts and material variance present major machining challenges during the hole-drilling process, creating serious issues with chip formation and tool life, and resulting in lost profits.
Interrupted cuts are inherent to fluid end block manufacturing since the cross-holes are drilled perpendicular to existing holes. Because of the resulting shape of the intersecting holes, the outside edges of the drill will continue to be engaged in the cut, while the inside edge will not. This can destabilize the drill, which can destroy the tool and damage the integrity of the fracking block. In some cases, drills can be used to repair the fracking blocks by re-machining them, but this can slow production time.
Material variances can also be a huge issue. Since fluid end blocks are a consumable item, operators are looking to purchase them as economically as possible. To keep costs low, fracking block manufacturers tend to use material that has not been heat-treated, which leads to significant variations that affect the quality of hole-drilling during machining. One block may work well with a particular drill, while the next may be so hard it cannot be drilled at the same feed and speed, while another may be so soft that ideal chip formation is impossible. This variation in chip formation is perhaps the most significant challenge facing fluid end block manufacturers.
Manufacturers look to respond to market trends
As manufacturers of fracking equipment anticipate a rebirth in demand, they are experimenting with exotic materials to get better wear from consumable components like fluid end blocks. While frack blocks may have lasted just a few days historically, manufacturers are looking to extend their life to a week or more by changing the material composition to stainless steels and other more wear-resistant steels.
New tools in demand
Tools needed to bore the large diameter deep holes found in the frack blocks have been changing in response to these market trends. For example, Allied Machine & Engineering, which has been supplying tools needed for machining fluid end blocks for over a decade, developed a next generation tool that provided a 20 percent improvement in the penetration rate for drilling into a modified AISI 4340 alloy steel material compared to a competitor’s product. The improved penetration rates were accomplished while consuming less power on the machine on which the blocks are being processed.
The newest tools are nearly 30 percent faster than their predecessors, which can result in significant savings for manufacturers in this industry. One customer estimates that drilling 1 inch per minute faster results in 17 minutes per block in saved drill time. With 5 to 6 blocks manufactured per day on each of 4 machines, the time savings add up quickly, reducing overall costs. They estimate about $20,000-25,000 savings in time, as well as better hole quality, and less downtime due to better chip formation.
Manufacturers of these components are demanding improved tooling solutions in order to stay competitive. That’s where industrial tooling manufacturers are rising to the challenge – using innovation and design to respond to manufacturers’ increasing demands to reduce cost and time in their processes. These next generation tools are being engineered to handle material inconsistencies, interrupted cuts, and machine limitations, while increasing penetration rates.