Development of Low Force Shear Blades for High Strength Coiled Tubing

2021 ◽  
Author(s):  
Scott Sherman
Keyword(s):  
Yield Strength ◽  
Shear Force ◽  
Yield Criterion ◽  
High Strength ◽  
Pressure Control ◽  
Maximum Pressure ◽  
Control Equipment ◽  
Coiled Tubing ◽  
Von Mises ◽  
Minimum Yield

Abstract As coiled tubing grades have evolved over the past 20 years from 70 grade with a minimum yield strength of 483 MPa (70,000 psi) to 140 grade with a minimum yield strength of 965 MPa (140,000 psi) and wall thicknesses have increased, the resulting force required to shear coil has more than doubled. Most coiled tubing units have a maximum pressure of 20.7 MPa (3000 psi) available for the blow out preventers (BOP) hydraulic circuits. There was an industry need to develop a shear blade for BOPs that could cut high strength coiled tubing using legacy pressure control equipment already in use. Additionally, the new shear blades must create a fish that can be easily retrieved from a wellbore. Shear strength is estimated using the maximum distortion criterion (von Mises yield criterion) as follows:Shear strength/Yield strength=1√3=.577 Since the maximum distortion criterion is merely an approximation and unique blade geometries are difficult to take into consideration using the above calculation, a considerable amount of hands on lab testing was required to design and optimize an elegant shear blade for cutting high strength coiled tubing with minimal hydraulic forces. The paper will share the iterative process as novel shear blades were developed that significantly reduced shear forces. Multiple piercing tip geometries were tested, including embodiments with several piercing tips. Success criteria was reduced shear force, acceptable fish profile on the lower piece of coiled tubing, and no damage to the blades after use. The embodiment that showed the most promise, based on lab testing was further optimized to improve its performance over multiple cuts. The result was a novel shear blade that is able to cut high strength coiled tubing with 50% of the normal shear force. As the industry continues to push the limits of coiled tubing with extended reach applications thought impossible only a few years ago, higher strength coiled tubing with increased wall thicknesses will continue to evolve. The new shear blade geometry developed in this project ensures that not only can the latest grades of coiled tubing be sheared in legacy pressure control equipment, but also future grades of coiled tubing that are in development.

Low-Force Shear Blades Developed for High-Strength Coiled Tubing

2021 ◽  
Vol 73 (06) ◽  
pp. 42-43
Author(s):  
Chris Carpenter
Keyword(s):  
Shear Force ◽  
High Strength ◽  
Pressure Control ◽  
Hydraulic Pressure ◽  
Closing Time ◽  
Similar System ◽  
Well Control ◽  
Control Equipment ◽  
Coiled Tubing ◽  
Wellbore Pressure

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 204403, “Development of Low-Force Shear Blades for High-Strength Coiled Tubing,” by Scott Sherman, Nexus Energy Technologies, prepared for the 2021 SPE/ICoTA Virtual Well Intervention Conference, 22–25 March. The paper has not been peer reviewed. As coiled tubing (CT) grades have evolved during the past 20 years and wall thicknesses have increased, the resulting force required to shear coil has more than doubled. An industry need existed to develop a shear blade for blowout preventers (BOPs) that could cut high-strength CT using legacy pressure-control equipment already in use. The paper describes the iterative process of development of a novel shear blade able to cut high-strength CT with 50% of the normal shear force. Objective The objective of the work detailed in the complete paper was to develop a novel CT-shearing system capable of cutting high-strength heavy-wall CT with reduced hydraulic pressures. Considering that CT will continue to evolve in terms of yield strength, the goal of the study was to future-proof BOPs wherever possible to protect customers from the liability of obsolete equipment. The authors write that, ultimately, BOPs will need to cut 175-grade CT strings with a 7-mm wall thickness with 103 MPa of wellbore pressure and less than 17.2 MPa hydraulic pressure. Development Process Initially, the following five options were considered: - Larger-diameter cylinders. This seemingly simple option, which would generate more shear force, was ruled out because the implementation would not be backward-compatible with existing well-control equipment and the larger cylinder volume would result in slower cycle times. - Boosted actuators. These could double shear force while maintaining piston diameter. While this solution is simple, theoretically, these actuators require twice as much hydraulic fluid from the accumulator to function. This results in a closing time that is nearly double that of a nonboosted actuator. - Pressure-balanced actuators. With this option, hydraulic forces would not need to overcome the forces related to wellbore pressure in addition to providing sufficient force to shear CT. These actuators do increase the amount of shear force available to cut CT when used on high-pressure wells. However, they increase complexity, cost, and weight and could result in trapped wellbore fluids within the actuator that could lead to corrosion-related issues. - Increasing hydraulic pressure to a given set of rams using a pressure multiplier for the shear rams or a similar system. This solution was deemed unsuitable because the hydraulics of most BOPs are designed for 150% of their rated pressure. Doubling the hydraulic pressure available to the BOP could damage the hydraulic cylinders and associated actuators, resulting in a catastrophic well-control situation. - Modifying shear blade geometry to reduce the shear force needed to cut CT using existing equipment. This was selected as the most-logical approach because the modified shear blades could be retrofitted into existing BOPs. Furthermore, this solution would not require modification to existing wellsite equipment such as accumulator skids and would not increase the weight or size of the BOP stack.

DOGAL LAD

Alloy Digest ◽  
2011 ◽  
Vol 60 (10) ◽  
Keyword(s):  
Yield Strength ◽  
Physical Properties ◽  
Surface Treatment ◽  
Tensile Properties ◽  
High Strength ◽  
Heat Treating ◽  
Minimum Yield

Abstract Dogal 300 LAD, 340 LAD, 380 LAD, 420 LAD, 460 LAD and 500 LAD are high-strength low alloyed steels intended for pressing. The designation in the name is the guaranteed minimum yield strength. Dogal steels can be zinc coated. This datasheet provides information on composition, physical properties, and tensile properties. It also includes information on surface qualities as well as forming, heat treating, joining, and surface treatment. Filing Code: CS-167. Producer or source: SSAB Swedish Steel Inc..

STRENX 700

Alloy Digest ◽  
2017 ◽  
Vol 66 (2) ◽  
Keyword(s):  
Fracture Toughness ◽  
Yield Strength ◽  
Physical Properties ◽  
Structural Steel ◽  
Tensile Properties ◽  
High Strength ◽  
Load Bearing ◽  
Minimum Yield

Abstract Strenx 700 is a high-strength structural steel with a minimum yield strength of 650–700 MPa (94–102 ksi) depending on thickness. Strenx 700 meets the requirements of EN 10 025-6 for the S690 grade and thicknesses. Typical applications include demanding load-bearing structures. This datasheet provides information on composition, physical properties, and tensile properties as well as fracture toughness. It also includes information on surface qualities as well as forming, machining, and joining. Filing Code: SA-779. Producer or source: SSAB Swedish Steel Inc..

DILLIMAX 690

Alloy Digest ◽  
2012 ◽  
Vol 61 (5) ◽  
Keyword(s):  
Fracture Toughness ◽  
Yield Strength ◽  
Physical Properties ◽  
Structural Steel ◽  
Tensile Properties ◽  
High Strength ◽  
Heat Treating ◽  
Fine Grained ◽  
Minimum Yield

Abstract Dillimax 550 is a high-strength quenched and tempered, fine-grained structural steel with a minimum yield strength of 690 MPa (100 ksi). Plate is delivered in three qualities: basic, tough, and extra tough. This datasheet provides information on composition, physical properties, and tensile properties as well as fracture toughness. It also includes information on forming, heat treating, and joining. Filing Code: SA-652. Producer or source: Dillinger Hütte GTS.

DILLIMAX 500

Alloy Digest ◽  
2012 ◽  
Vol 61 (3) ◽  
Keyword(s):  
Fracture Toughness ◽  
Yield Strength ◽  
Physical Properties ◽  
Structural Steel ◽  
Tensile Properties ◽  
High Strength ◽  
Heat Treating ◽  
Fine Grained ◽  
High Toughness ◽  
Minimum Yield

Abstract Dillimax 500 is a high-strength quenched and tempered, fine-grained structural steel with a minimum yield strength of 500 MPa (72 ksi). Plate is delivered in three qualities: basic, high toughness, and extra tough. This datasheet provides information on composition, physical properties, and tensile properties as well as fracture toughness. It also includes information on surface qualities as well as forming, heat treating, and joining. Filing Code: SA-645. Producer or source: Dillinger Hütte GTS.

SUMITOMO SMC276-110

Alloy Digest ◽  
2017 ◽  
Vol 66 (6) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Yield Strength ◽  
Physical Properties ◽  
Tensile Properties ◽  
Nickel Alloy ◽  
High Strength ◽  
Heat Treating ◽  
Sour Service ◽  
Minimum Yield

Abstract Sumitomo SMC276-110 (minimum yield strength of 110 ksi, or 758 MPa) is an austenitic high-strength nickel alloy for use in oil country tubular goods as a material suitable for severe sour service. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming and heat treating. Filing Code: Ni-730. Producer or source: Nippon Steel and Sumitomo Metal Corporation.

STRENX 100

Alloy Digest ◽  
2019 ◽  
Vol 68 (2) ◽  
Keyword(s):  
Yield Strength ◽  
Physical Properties ◽  
Structural Steel ◽  
Tensile Properties ◽  
High Performance ◽  
High Strength ◽  
Minimum Yield

Abstract Strenx 100 is a high-strength, high-performance structural steel with a minimum yield strength of 690 MPa (100 ksi). It meets the requirements of ASTM A514 Grade S. Strenx 100 is a US Customary steel similar to Strenx 700 (Alloy Digest SA-779, February 2017). This datasheet provides information on composition, physical properties, and tensile properties. Filing Code: SA-838. Producer or source: SSAB Swedish Steel Inc..

MECASTEEL 145

Alloy Digest ◽  
2014 ◽  
Vol 63 (2) ◽  
Keyword(s):  
Fracture Toughness ◽  
Yield Strength ◽  
Tensile Properties ◽  
High Strength ◽  
Hydraulic Systems ◽  
Minimum Yield

Abstract Mecasteel 145 (minimum yield strength 145 ksi) is a high-strength prehardened steel that can be used in substitution for conventional steels, such as AISI 4330, in the manufacture of massive steel components such as machines, hydraulic systems, and pumps. This datasheet provides information on composition and tensile properties as well as fracture toughness. It also includes information on forming. Filing Code: SA-691. Producer or source: Industeel USA, LLC. Revised as Alloy Digest SA-703, July 2014.

BETHSTAR 60

Alloy Digest ◽  
1986 ◽  
Vol 35 (8) ◽  
Keyword(s):  
Fracture Toughness ◽  
Yield Strength ◽  
Steel Plate ◽  
High Stress ◽  
High Strength ◽  
Heat Treating ◽  
Low Carbon ◽  
Bethlehem Steel Corporation ◽  
Low Sulfur ◽  
Minimum Yield

Abstract BethStar 60 steel plate is a high-strength product with a 60,000 psi minimum yield strength. It contains low carbon and low sulfur and has outstanding toughness, weldability and formability. It provides the design engineer with a an economical high-strength low-alloy (HSLA) grade that can be fabricated readily. Applications include weight-sensitive components subject to high stress such as frames for large off-highway haulers. This datasheet provides information on composition, physical properties, microstructure, elasticity, and tensile properties as well as fracture toughness. It also includes information on forming, heat treating, and joining. Filing Code: SA-421. Producer or source: Bethlehem Steel Corporation.

SPARTAN II

Alloy Digest ◽  
2016 ◽  
Vol 65 (1) ◽  
Keyword(s):  
Yield Strength ◽  
Physical Properties ◽  
Tensile Properties ◽  
High Strength ◽  
Low Carbon ◽  
Copper Precipitation ◽  
High Toughness ◽  
The Family ◽  
Alloy Steels ◽  
Minimum Yield

Abstract SPARTAN II (HSLA-100) is one of the family of Spartan high strength (>690 MPa, or >100 ksi, minimum yield strength), high toughness, improved weldability steels, which are alternatives to traditional quenched and tempered alloy steels. The Spartan family of steels are low carbon, copper precipitation hardened steels. Spartan II has improved yield strength compared to Spartan I. This datasheet provides information on composition, physical properties, microstructure, tensile properties. It also includes information on forming and joining. Filing Code: SA-738. Producer or source: ArcelorMittal USA.

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