1. Applications
Powered by hydraulic pressure, the PDM drives the downhole drilling assembly in rotation, enabling operations such as drilling, milling, and sidetracking.
2. Structure
The PDM primarily consists of a top sub, bypass valve, stator, rotor, coupling, water passage sub, bearing assembly, drive shaft, and bottom sub.
3. Operating Principle
The PDM converts the energy of high-pressure fluid into mechanical energy via the interaction of the rotor and stator. High-pressure fluid enters the sealed chambers formed between the rotor and stator. The pressure differential causes the rotor to turn along the spiral channel of the stator. The rotor rotates eccentrically around the stator’s axis, while simultaneously spinning clockwise on its own axis, driving the drill bit rotation.
4. Technical Specifications
Applicable standard: SY/T 5383 Positive Displacement Motor
Specification model
examples:
- 9LZ95×7.0 : Outside diameter 95 mm, 9/10 lobe ratio hydraulic motor, bit nozzle pressure drop 7 MPa.
- 5LZ165×7.0Ⅱ : Outside diameter 165 mm, 5/6 lobe ratio hydraulic motor, bit nozzle pressure drop 7.0 MPa, second design modification of straight-body PDM.
- 5LZ197×7.0-SWFG : Outside diameter 197 mm, 5/6 lobe ratio hydraulic motor, double-bent housing with stabilizer, hollow rotor with flow diversion, maximum operating temperature 150°C, bit nozzle pressure drop 7.0 MPa.
5. Operating Procedure
(1) Assemble the BHA.
(2) Run slowly to 3–5 m above target depth, start pumps to circulate and clean the well. A running speed of 30 m/min is recommended. Fill the drill string with clean circulation fluid every 500 m of run-in.
(3) Slow lowering, then commence drilling. Weight on bit (WOB): 5–15 kN. Flow rate: 500–600 L/min.
(4) Pull out of hole (POOH).
6. Precautions
(1) Ensure the surface PDM is securely fixed during surface testing.
(2) Circulation fluid must be clean.
(3) Return fluid must be screened and desanded.
(4) The wellhead must be equipped with a self-sealing device to prevent small objects from falling into the well.
(5) Perform thorough well cleaning before changing singles and after completing drilling.
7. Maintenance and Storage
(1) After use, disassemble, clean, and inspect the tool. Replace any damaged parts. Apply lubricating oil to all components during reassembly.
(2) When cleaning the stator rubber lining, do not use steam to prevent rubber aging.
(3) Store the tool in a well-ventilated warehouse. Maintain a temperature between 10°C and 25°C, with humidity not exceeding 85%. Avoid direct sunlight and rain.
Contact: Jessie Zhou
Mobile/Whatsapp: +0086-18109206861
Email: energy@landrilltools.com
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Company Name: Xi'an Landrill Oil Tools Co., Ltd.
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Country: China
Website: https://www.landrilloiltools.com/
