High efficiency synchronous rigs
Technical Specifications — SJ High Efficiency Synchronous Rigs
XJ Series Self-Propelled Workover Rigs — Dual-Engine Synchronous Models
SJ Petroleum Machinery has developed a series of workover rigs with maximum static load ranging from 300 to 2,250 kN and installed power ranging from 235 to 1,300 HP, including XJ150, XJ250, XJ350, XJ450, XJ550, XJ650, XJ1000 and XJ1200 models.
| Model | Workover Depth (2-7/8″ DP, m) | Nominal Hook Load (kN) | Max Static Load (kN) | Drawworks HP | Power Configuration |
|---|---|---|---|---|---|
| XJ250 | 2,000 | 400 | 675 | 250hp | Single engine standard |
| XJ350 | 3,200 | 600 | 900 | 350hp | Single engine standard |
| XJ450 | 4,500 | 800 | 1,125 | 450hp | Single engine standard |
| XJ550 | 5,800 | 1,000 | 1,350 | 550hp | Single engine standard |
| XJ650 | 7,000 | 1,200 | 1,470 | 650hp | Dual-engine optional |
| XJ1000 | 8,000 | 1,500 | 1,800 | 750hp | Dual-engine standard |
| XJ1200 | 9,000 | 1,800 | 2,250 | 1,000hp | Dual-engine standard |
Technical data source: SJ Petroleum Machinery Series of Self-propelled Workover Rigs product catalog. Dual-engine models feature emergency power switching capability and load-balanced parallel operation.
XJ1000 — Dual-Engine Synchronous Workover Rig (Detailed)
The XJ1000 is a key model in SJ's synchronous rig lineup. The XJ1000 workover rig, with 1,800 kN of maximum static hook load, is a self-propelled workover equipment with dual engines, primarily used for medium and deep well workover, oil testing, fishing, and pumping operations. The dual-engine configuration gives operators the flexibility to run on one engine for lighter operations or both engines together for peak demand.
Key XJ1000 technical specifications:
| Parameter | Specification |
|---|---|
| Workover Depth (2-7/8″ DP) | 8,000 m |
| Max Static Hook Load | 1,800 kN |
| Power System | Dual-engine parallel with paralleling gearbox |
| Mobility | Self-propelled, 14×8 drive type |
| Wireline Diameter | φ29 mm |
| Traveling System | 5×6 |
| Mast Clearance Height | 38 m |
| Substructure Floor Height | 6 m |
*Technical data source: SJ Petroleum Machinery Series of Self-propelled Workover Rigs catalog and XJ1000 product documentation.*
BigEasy Series — Trailer-Mounted AC-VFD Synchronous Rigs
SJ offers BigEasy rigs in BE770 and BE550 models — new conceptual AC VFD drilling rigs jointly developed with LOADMASTER, featuring special module, trailer-mounted structure and fast transportation without a crane.
| Parameter | BE550 (ZJ40D) | BE770 (ZJ50D) |
|---|---|---|
| Drilling Depth (4½″ DP) | 4,000 m / 13,200 ft | 5,000 m / 16,400 ft |
| Max Hook Load | 2,450 kN / 550,000 lb | 3,430 kN / 770,000 lb |
| Drive System | AC-VFD electric, dual-motor capable | AC-VFD electric, dual-motor capable |
| Structure | Full trailer-mounted modules | Full trailer-mounted modules |
| Installation | Six trailers, no crane required | Six trailers, no crane required |
| Mast Type | Three-section telescoping, hydraulic raise | Three-section telescoping, hydraulic raise |
| Substructure Type | Parallelogram design, folding transport | Parallelogram design, folding transport |
| Drawworks Position | High-mounted for AC drive | High-mounted for AC drive |
| Control | Integrated instrumentation in driller's cabin | Integrated instrumentation in driller's cabin |
ZJ Series Land Drilling Rigs — AC-VFD Synchronous Drive
| Model | Drilling Depth (m) | Max Hook Load (kN) | Drawworks Power (kW/hp) | Drive System |
|---|---|---|---|---|
| ZJ30 | 3,000 | 1,700 | 600 / 800 | AC-VFD or AC-SCR-DC |
| ZJ40 | 4,000 | 2,250 | 800 / 1,100 | AC-VFD or AC-SCR-DC |
| ZJ50 | 5,000 | 3,150 | 1,100 / 1,470 | AC-VFD or AC-SCR-DC |
| ZJ70 | 7,000 | 4,500 | 1,470 / 2,000 | AC-VFD with dual-motor drawworks |
| ZJ90 | 9,000 | 5,850 | 2,200 / 3,000 | AC-VFD with quad-motor drawworks |
*ZJ70 and ZJ90 models feature multi-motor synchronous drive with master-slave control architecture.*
ZJ90DB — Ultra-Deep Well Synchronous Rig
The ZJ90DB is SJ's most advanced high efficiency synchronous rig, proven in ultra-deep well applications including 23 wells drilled in Northwest China reaching 9,270 m depth. Six of these rigs have been exported to Kuwait for Middle Eastern operations — the first large-scale batch export of Chinese super deep well drilling rigs to the Middle Eastern high-end market.
The ZJ90DB features a fully digital AC-VFD synchronous control system with advanced motor load sharing:
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Dual-engine AC-VFD synchronous drive (quad-motor optional)
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PLC-based master-slave control architecture
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Regenerative braking with energy recovery
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Integrated HMI control panel in driller's cabin
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Designed for 50°C desert operation with sandstorm protection
Synchronous Drive System Specifications
| Parameter | Specification |
|---|---|
| Control Architecture | Master-slave with load balancing |
| Master Mode | Speed control (closed-loop vector) |
| Slave Mode | Torque control (torque following) |
| Power Equalization | Open-loop vector for mud pumps; closed-loop for drawworks |
| Communication Method | High-speed fieldbus between drives |
| Single/Dual Operation | Switchable; engines can run individually or together |
| Emergency Power Switching | Automatic transfer on engine failure |
Synchronous Driveline Configurations
| Configuration | Application | Power Source | Control Method |
|---|---|---|---|
| Dual-engine diesel-mechanical | Workover rigs (XJ1000, XJ1200) | Two diesel engines driving single transmission | Mechanical coupling with overrunning clutches |
| Dual-motor AC-VFD | Drilling rig drawworks (ZJ70, ZJ90) | Two AC motors driving single gearbox | Master-slave speed/torque control |
| Dual-motor mud pump drive | Drilling fluid circulation | Two motors driving pump shaft | Open-loop vector with load sharing |
| Four-motor AC-VFD | Ultra-deep well drawworks (ZJ90DB) | Four AC motors driving synchronized gear train | Distributed master-slave with load averaging |
*[Product images: SJ's XJ1000 dual-engine workover rig — dual-engine configuration for medium and deep well workover operations]*
Product Types — SJ High Efficiency Synchronous Rig Configurations
SJ offers five primary configurations of high efficiency synchronous rigs, each tailored to specific operational requirements:
Type 1: XJ Series Dual-Engine Workover Rigs (Most Common)
Self-propelled workover rigs with dual-engine parallel configuration. Engines can run singly or together with automatic power switching on failure. Available from XJ650 (optional dual-engine) through XJ1200 (standard dual-engine).
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Best for: Workover and well servicing where uptime and power flexibility are critical
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Depth range: 7,000–9,000 m workover depth
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Key advantage: Continuous operation when one engine is down
Type 2: BigEasy Trailer-Mounted AC-VFD Synchronous Rigs
Trailer-mounted AC-VFD drilling rigs with AC-VFD synchronous drive and advanced load sharing. Fully mobile, no crane required for installation.
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Best for: Remote operations, areas without heavy crane support
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Depth range: 4,000–5,000 m drilling depth
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Key advantage: Fast mobilization with synchronous drive reliability
Type 3: ZJ Series AC-VFD Synchronous Drilling Rigs (Standard Land Configuration)
Full-scale land drilling rigs with AC-VFD drive and master-slave motor control. Available from ZJ30 through ZJ90, with dual or quad-motor drawworks configurations.
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Best for: Conventional land drilling operations requiring maximum uptime
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Depth range: 3,000–9,000 m drilling depth
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Key advantage: Distributed load balancing across multiple motors
Type 4: ZJ90DB Ultra-Deep Well Synchronous Rig
The highest-capacity synchronous rig in SJ's lineup. Quad-motor drawworks with master-slave load balancing, designed for 9,000-meter drilling in extreme conditions.
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Best for: Ultra-deep HPHT drilling, Middle Eastern desert operations
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Depth range: 9,000 m (field-proven to 9,270 m)
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Key advantage: Continuous power across all depth ranges
Type 5: Diesel-Electric Hybrid Synchronous Workover Rig
Hybrid configuration combining diesel engines for power generation with AC-VFD electric motors for drawworks and rotary table. Dual diesel generators feed dual AC motors through master-slave controllers.
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Best for: Remote areas requiring independent power with electric drive benefits
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Depth range: 4,000–7,000 m (customizable)
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Key advantage: Fuel flexibility + electric drive precision
*[Product images: SJ's ZJ90DB synchronous drilling rig in Kuwait — 6-rig batch export for Middle Eastern ultra-deep well operations]*
Applications — Where SJ High Efficiency Synchronous Rigs Deliver Maximum Value
| Application | Why Synchronous Drive Matters | Recommended Configuration |
|---|---|---|
| Remote basin drilling | Long supply lines for replacement parts — dual engines keep the rig running while waiting for repairs | Type 1 (XJ series dual-engine) or Type 2 (BigEasy) |
| Deep and ultra-deep well drilling | High power demands require distributed motor loads — multi-motor synchronous drive prevents overloading | Type 3 (ZJ series multi-motor) or Type 4 (ZJ90DB) |
| Continuous workover operations | Production downtime is expensive — dual-engine configuration eliminates single-point engine failure risk | Type 1 (XJ1000, XJ1200 dual-engine) |
| Unconventional / pad drilling | Frequent rig moves and high-power requirements demand both mobility and power flexibility | Type 2 (BigEasy) or Type 3 with fast-moving modules |
| HPHT exploration | Load fluctuations require real-time power balancing — master-slave control responds instantly | Type 4 (ZJ90DB) |
| Desert ultra-deep drilling | Extreme heat and sand demand reliability — dual/quad-motor configurations provide redundancy | Type 4 (ZJ90DB with desert package) |
| Remote workover campaigns | No local maintenance facilities — two engines mean one can fail without stopping the job | Type 1 (XJ series) |
ZJ90DB in the Middle East — Field Validation
In 2025, SJ completed a six-rig batch export of ZJ90DB ultra-deep well synchronous drilling rigs to Kuwait — the first large-scale batch export of Chinese super deep well drilling rigs to the Middle Eastern high-end market. These rigs are now operating in Kuwait's northern oilfields, proving the reliability of SJ's synchronous drive technology in the world's most demanding desert conditions, with documented drilling to 9,270 meters.
*[Product images: SJ's ZJ90DB synchronous rig in Kuwait — field-proven in 50°C desert operations with dual/quad-motor drive]*
[Product images: SJ's high efficiency synchronous workover rig in field operation — dual-engine configuration for continuous uptime]
Why Choose SJ for Your High Efficiency Synchronous Rig?
1. Sinopec-Grade Quality — Built by a National Oil Company
As a Sinopec subsidiary, SJ operates under the quality protocols that govern one of the world's largest integrated energy companies. Our dual-engine synchronous rigs meet the exacting standards demanded by Saudi Aramco, Kuwait Oil Company (KOC), and ADNOC. Our parent company's 80-rig MENA land fleet demonstrates consistent reliability — most fitted with SJ equipment.
2. Field-Proven Dual-Engine Synchronous Technology
SJ's dual-engine synchronous rigs have been field-proven across thousands of wells in China's major oilfields and internationally. The XJ1000 dual-engine workover rig is a standard offering in our product line, with documented performance in medium and deep well workover, oil testing, fishing, and pumping operations.
3. API-Certified and Third-Party Verified
All SJ synchronous rigs are designed and manufactured in compliance with API Spec Q1, 4F, 7K, 8C, 6A, and 16C, with full third-party inspection available through any accredited agency. Our manufacturing process is open to customer supervision, and we provide complete traceability documentation for every certified component.
4. Complete One-Stop Synchronous Rig Supplier
SJ manufactures every component of the synchronous rig — both engines, the paralleling gearbox, the AC-VFD drives, the drawworks, the mast, the mud pumps, the solid control system — under one roof. You're not assembling parts from multiple vendors and hoping they integrate. One supplier, one warranty, one team that knows the entire system.
5. 50,000 m² Assembly Yard with Full Factory Acceptance Testing
Our rig assembly yard covers 50,000 square meters with 24 rigging-up positions and two offshore rig commissioning sites (four rig positions), where we can perform 750-ton load tests and assemble or commission 12 drilling or workover rigs simultaneously. Before any synchronous rig leaves our facility, it undergoes full factory acceptance testing with customer-witnessed verification available.
6. Global After-Sales Support
SJ maintains regional support infrastructure across the Middle East and other key markets. For the six-rig ZJ90DB batch export to Kuwait, SJ provided comprehensive field support. Our 24/7 remote support desk and field service teams are available for commissioning, operator training, preventive maintenance, and emergency service.
7. 70+ Years of Manufacturing Heritage
From our founding in 1941 to the present day, SJ has delivered more drilling rigs to more oilfields than any other Chinese manufacturer. Our Technical Center employs 314 engineers and researchers dedicated to product development across three research institutes, and we are authorized to operate a post-doctoral research station.
8. Competitive Pricing — The Chinese Manufacturing Advantage
SJ's high efficiency synchronous rigs are priced 30–50% below comparable Western brands for equivalent API-certified specifications, due to our vertically integrated manufacturing and efficient production systems. Lower price does not mean lower quality — we build to Sinopec-grade standards and API certifications.
Frequently Asked Questions (FAQ)
Q1: What is a high efficiency synchronous rig in drilling applications?
A high efficiency synchronous rig uses multiple synchronized power sources — typically two diesel engines or two AC electric motors — operating in parallel through a control system that balances load distribution and provides redundancy. The two power sources can run individually or together. This configuration keeps the rig operating if one engine fails and provides maximum torque and hook load when both run simultaneously.
Q2: What is the difference between a dual-engine workover rig and a single-engine rig?
A single-engine rig stops completely if that engine requires maintenance or fails. A dual-engine rig with synchronous drive continues operating on the remaining engine at reduced capacity — keeping the drill string moving, keeping the pumps running, and maintaining well control while repairs are arranged. In the XJ1000 dual-engine workover rig, for example, the two engines are interlocked through a paralleling system that allows automatic emergency power switching and seamless changeover between single-engine and dual-engine operation.
Q3: How does master-slave motor control work on SJ's synchronous rigs?
In a dual-motor drawworks configuration, one motor runs in speed control mode as the "master," while the second motor runs in torque control mode as the "slave" following the master's torque output. This ensures balanced load sharing between both motors. ABB frequency converters with master-slave communication capability are widely used to construct variable frequency speed-control synchronization systems for dual and multi-motor applications. For mud pumps driven by two motors, open-loop vector control with master-slave architecture is used for power equalization.
Q4: What is the advantage of AC-VFD drive over DC drive in synchronous rigs?
AC-VFD (variable frequency drive) systems offer: higher motor efficiency, regenerative braking capability that recovers energy during lowering operations, precise speed and torque control through master-slave architectures, reduced maintenance compared to DC motors with commutators, and direct integration with PLC-based control systems. DC drive systems (AC-SCR-DC) remain a reliable and simpler option for many applications — SJ offers both, depending on customer preference.
Q5: What drilling depths can SJ synchronous rigs handle?
SJ synchronous rigs cover the full depth range:
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XJ series dual-engine workover rigs: 7,000–9,000 m workover depth
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BigEasy series: 4,000–5,000 m drilling depth
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ZJ series: 3,000–9,000 m drilling depth
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ZJ90DB: 9,000 m (field-proven to 9,270 m)
Q6: Are SJ synchronous rigs available in trailer-mounted configurations for remote operations?
Yes. The BigEasy series (BE770 and BE550) are new conceptual AC VFD drilling rigs jointly developed by SJ and LOADMASTER, featuring special module, trailer-mounted structure and fast transportation without a crane. The entire rig installs on location using only six trailers, with modules positioned by the same tractors that transported them. The AC-VFD synchronous drive architecture provides the same power redundancy and load-balancing benefits as larger land rigs.
Q7: What is SJ's track record with dual-engine synchronous rigs?
SJ has manufactured dual-engine workover rigs for decades. The XJ1000 model — a self-propelled workover equipment with dual engines, primarily used for medium and deep well workover, oil testing, fishing, and pumping operations — is a standard offering in our product line. The XJ series covers workover rigs with maximum static load from 300 to 2,250 kN and installed power from 235 to 1,300 HP.
Q8: How does the emergency power switching work on SJ dual-engine rigs?
When one engine requires maintenance or fails, the paralleling system automatically transfers load to the remaining engine. Power devices can be configured to work together or individually, with paralleling boxes distributing input from multiple power sources to the rig's rotating systems. The transfer occurs without stopping the rig, though operations continue at reduced capacity until the second engine is restored.
