In deep shale oil and gas and ultra deep well fracturing operations, a working pressure of 20000psi (approximately 138MPa) is already the top pressure level in the industry. Under such working conditions, ordinary steel wire reinforced structures are prone to interlayer delamination or even rupture under high voltage pulses due to their strong rigidity and concentrated interlayer stress. The high-strength and ultra flexible steel wire winding structure is an enhanced solution for this extreme working condition - it uses the dual properties of "strength" and "flexibility" of high-strength and ultra flexible steel wire to bear an ultimate pressure of 20000psi, uses a multi-layer alternating winding mechanical skeleton to ensure pulse fatigue life, and uses UPE lining to resist strong acid and proppant erosion, becoming a reliable channel for "pressure bearing without bursting and pulse non fatigue" in deep well fracturing operations.
1、 20000 psi pressure positioning and enhancement layer design logic
20000psi (approximately 138MPa) is in the highest pressure range in the standard system of fracturing hoses. According to API Spec. 7K FSL0 standard, the validation pressure for this grade of product is 30000 psi (1.5 times the working pressure), and the burst pressure reaches 40000 psi (approximately 276 MPa). This three-level safety gradient of "work pressure verification pressure explosion pressure" provides sufficient safety redundancy for the frequent occurrence of pressure transients and overpressure impacts in deep well fracturing.
High strength and ultra flexible steel wire is the core material foundation for achieving this pressure level. Compared with traditional high carbon steel wire, ultra flexible steel wire has better flexibility at the same tensile strength (usually ≥ 2000MPa), and can maintain uniform tension distribution in multi-layer winding structures, avoiding steel wire fracture caused by local stress concentration. A high-strength ultra flexible steel wire or steel wire rope wrapped in 4 to 10 layers is used as the pressure bearing skeleton, and an "interlocking" structure is formed by alternately winding adjacent layers in a spiral direction, so that the reinforcement layer can deform synergistically instead of sliding between layers when subjected to an internal pressure of 20000psi. The inner steel wire provides radial support at a higher angle to resist tube swelling; The outer steel wire carries axial loads at a lower angle to prevent excessive elongation of the hose under pulse pressure.
For more stringent working conditions, some products will increase the number of reinforcement layers to 12, further distributing the stress of each layer, while ensuring safety factors and extending the pulse fatigue life.
2、 The synergy between UPE lining and ultra strong ultra flexible steel wire: "dual resistance" protection system
The reliability of 20000psi fracturing hoses not only depends on the ultimate pressure bearing capacity of the reinforcement layer, but also requires the long-term stability of the inner lining layer in strong acid and high abrasion media. The UPE (ultra-high molecular weight polyethylene) lining and high-strength ultra flexible steel wire reinforcement layer together form a dual protection of "acid resistance+pressure resistance".
The chemical inertness of UPE lining gives it natural resistance to 28% hydrochloric acid, hydrofluoric acid, and acid fracturing fluids, making it safe to transport acid based fracturing fluids without pressure. Its molecular weight is as high as several million, and through the "slip rearrangement" mechanism, the impact kinetic energy of abrasive particles is converted into intermolecular frictional heat energy. It can achieve continuous wear resistance for 8000 hours under high-pressure sand acid fluid conditions. An anti-seepage layer is installed outside the inner lining layer to further prevent strong acidic media from seeping out and corroding at the joint, thereby extending the service life of the hose in acidic well conditions.
The full diameter equal flow design is another core feature of this structural scheme. The inner wall of the 2 to 6-inch inner diameter series products has no steps or necking, and the flow resistance of fracturing fluid and proppant is extremely low when passing through, avoiding proppant accumulation and energy loss caused by necking in traditional rigid manifolds. Taking the 2-inch specification of 20000psi level as an example, the minimum bending radius is controlled at around 1200mm, which takes into account the flexibility requirements of ultra-high pressure bearing and on-site pipe layout of fracturing truck groups.
3、 Adaptation and on-site verification of deep well fracturing scenarios
The 20000psi high strength ultra flexible wire fracturing hose has been verified in China's deep shale gas and Tarim Basin ultra deep well operations. In projects such as Tarim Oilfield and Tuha Oilfield, this product can achieve a single well fracturing fluid delivery capacity of over 8000 cubic meters per day, with installation efficiency increased by 200% compared to the rigid steel pipe scheme, and comprehensive cost reduced by 70%. The product complies with API Spec. 7K FSL0 standard and has obtained ABS classification society certification. Each hose is equipped with a unique traceability code to achieve full lifecycle quality monitoring.
In terms of temperature adaptation range, this series of hoses maintains stable performance within the temperature range of -29 ℃ to+100 ℃, and can adapt to temperature differences from severe winter in the northwest to high-temperature reflux in the formation. The end adopts an integral union or integral flange configuration, which is combined with a hammering union to achieve quick connection and disassembly of the fracturing manifold, further reducing the auxiliary time of the operation. The actual application data of shale gas fields in North America shows that the average service life of the hose in a single well has exceeded 1200 hours, with a 40% reduction in replacement times compared to similar products, providing key equipment support for the efficient development of unconventional oil and gas in deep layers.
In summary, the acid fracturing hose with high-strength and ultra flexible steel wire winding and pressure bearing 20000psi perfectly meets the systematic requirements of "ultra-high pressure, strong corrosion, and continuous operation" in deep shale gas fracturing with its multi-layered alternating winding "strong+flexible" load-bearing skeleton, acid resistant and wear-resistant "dual resistance" barrier with UPE lining, and API 7K FSL0 certification and full bore design for operational efficiency. From 40000 psi blasting redundancy to 8000 hours of wear resistance verification, from full bore flow guarantee of 2 inches to 6 inches to batch application of 138 MPa working pressure, behind every pressure pulse and every meter of formation transformation, there is a safety line constructed by the collaboration of high-strength ultra flexible steel wire and UPE material.
在线留言