Offset rig specifications
Offset Rig Specifications — Complete Technical Tables
XJ Series Self-Propelled Workover Rigs — Offset Configurations
The XJ series covers maximum static load from 300 to 2,250kN and installed power from 235 to 1,300HP, including XJ150, XJ250, XJ350, XJ450, XJ550, XJ650, XJ1000 and XJ1200 models. These rigs can be equipped with hydraulic walking bases for offset moves between wellheads on multi‑well pads.
| Model | Workover Depth (2-7/8″ DP, m) | Workover Depth (3½″ DP, m) | Nominal Hook Load (kN) | Max Static Load (kN) | Drawworks HP | Wireline Dia. (mm) | Traveling System | Mast Clearance (m) |
|---|---|---|---|---|---|---|---|---|
| XJ250 | 2,000 | — | 400 | 675 | 250 | φ22 | 3×4 | 21.0 |
| XJ350 | 3,200 | 2,500 | 600 | 900 | 350 | φ26 | 3×4 | 31.7 |
| XJ450 | 4,500 | 3,500 | 800 | 1,125 | 450 | φ26 | 4×5 | 34.0 |
| XJ550 | 5,800 | 4,500 | 1,000 | 1,350 | 550 | φ26 | 4×5 | 34.0 |
| XJ650 | 7,000 | 5,500 | 1,200 | 1,470 | 650 | φ29 | 4×5 | 35.0 |
| XJ1000 | 8,000 | 6,500 | 1,500 | 1,800 | 750 | φ29 | 5×6 | 38.0 |
| XJ1200 | 9,000 | 7,500 | 1,800 | 2,250 | 1,000 | φ32 | 5×6 | 39.3 |
XJ1000 Dual-Engine Workover Rig — Detailed Specifications
The XJ1000 is a large self‑propelled workover equipment with dual engines, primarily used for medium and deep well workover, oil testing, fishing, and pumping operations in offset and pad drilling campaigns.
| Parameter | Specification |
|---|---|
| Workover Depth (2-7/8" DP) | 8,000 m |
| Workover Depth (3½” DP) | 6,500 m |
| Workover Depth (4½" DP) | 5,000 m |
| Max Static Hook Load | 1,800 kN |
| Drawworks Horsepower | 750 hp |
| Traveling System | 5×6 |
| Wireline Diameter | φ29 mm |
| Mast Clearance Height | 38 m |
| Substructure Floor Height | 6 m |
| Carrier Drive Type | 14×8 |
| Power Configuration | Dual‑engine standard with paralleling gearbox |
XJ750 Dual-Engine Workover Rig — Mid-Range Offset Specifications
The XJ750 adopts double Caterpillar C15 engines with Allison transmissions. It is the best‑selling mobile drilling rig for both oil drilling and workover purposes, reaching 3,000m drilling depth and 8,000m workover depth with 1,700kN max hook load.
| Parameter | Specification |
|---|---|
| Drilling Depth (4½" DP) | 3,000 m |
| Workover Depth (2-7/8” DP) | 8,000 m |
| Workover Depth (3½" DP) | 6,500 m |
| Max Hook Load | 1,700 kN |
| Effective Lines | 10 |
| Wireline Diameter | φ29 mm |
| Traveling System | 6×5 |
| Mast Net Height | 38 m |
| Drawworks Rated Power | 373 kW (500 hp) × 2 |
| Engines | 2 × Caterpillar C15 ACERT AIII, 325 kW (440 hp) each |
| Transmissions | 2 × Allison M5610HR |
| Racking Board Height | 24 m |
| Racking Board Capacity | 3,000 m (4½” DP) |
| Max Wind Velocity | 30 m/s |
| Carrier Drive Type | 14×8 |
| Max Travel Speed | 45 km/h |
ZJ Series Land Drilling Rigs — Offset Drilling Configurations
The ZJ series includes AC‑VFD and AC‑SCR‑DC drive options with multi‑motor synchronous control — ideal for precise positioning in offset and cluster well drilling.
| Model | Drilling Depth (4½" DP, m) | Max Hook Load (kN) | Drawworks Power (kW/hp) | Motor Configuration | Drive Type |
|---|---|---|---|---|---|
| ZJ30/1700DB | 3,000 | 1,700 | 600 / 800 | Single or dual‑motor | AC‑VFD |
| ZJ40/2250DB | 4,000 | 2,250 | 800 / 1,100 | Single or dual‑motor | AC‑VFD |
| ZJ50/3150DB | 5,000 | 3,150 | 1,100 / 1,470 | Dual‑motor standard | AC‑VFD |
| ZJ70/4500DB | 7,000 | 4,500 | 1,470 / 2,000 | Dual or quad‑motor | AC‑VFD |
| ZJ90/6750DB | 9,000 | 6,750 | 2,200 / 3,000 | Quad‑motor | AC‑VFD |
ZJ series models use AC‑VFD electric drive with master‑slave motor control and regenerative braking capability.
ZJ70/4500DS Land Drilling Rig — Offset Specifications
The ZJ70/4500DS is a desert drilling rig with AC‑SCR‑DC drive system providing infinitely variable speed control for the drawworks, rotary table, and mud pumps. The dual‑motor drawworks configuration ensures balanced load sharing through master‑slave control architecture — critical for precision offset drilling.
| Parameter | Specification |
|---|---|
| Nominal Drilling Depth (114mm DP) | 7,000 m |
| Max Hook Load | 4,500 kN |
| Drawworks Rated Power | 1,470 kW (2,000 hp) |
| Drive System | AC‑SCR‑DC infinitely variable speed control |
| Drawworks Configuration | Dual‑motor with master‑slave control |
| Mast Type | Front-opening, single-pole, integral lift |
| Mast Height | 45 m |
| Effective Lines | 6×7 |
| Wireline Diameter | φ35 mm |
| Rotary Table Opening | 952 mm |
| Mud Pumps | 2 × FB-1300 (1,300 hp each) |
| Mud Pump Max Pressure | 35 MPa |
| Solid Control System | 4‑stage purification system |
| Mud Tank Capacity | 280 m³ |
| Generator Sets | 5 × 700 kW (total 3,500 kW) with wind and sand protection |
*Technical data source: SJ Petroleum Machinery ZJ70/4500DS desert drilling rig technical data.*
BigEasy Series — Trailer-Mounted Offset Rigs (BE770 and BE550)
The BigEasy series 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 using only six trailers — ideal for remote offset drilling campaigns.
| Parameter | BE550 (ZJ40D) | BE770 (ZJ50D) |
|---|---|---|
| Drilling Depth (4½" DP) | 4,000 m | 5,000 m |
| Max Hook Load | 2,450 kN / 550,000 lb | 3,430 kN / 770,000 lb |
| Drive System | AC‑VFD electric | AC‑VFD electric |
| Motor Configuration | AC synchronous (dual-motor capable) | AC synchronous (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 | 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 |
Technical data source: SJ and LOADMASTER BigEasy series joint development specification.
Offshore Workover Rigs — Fixed Platform Offset Specifications
SJ offers offshore workover rigs with maximum hook loads from 900kN to 3,150kN across six levels, suitable for different sea areas and platform requirements. Modular skid‑mounted structure using upper and lower bases, driven hydraulically for lateral and longitudinal movement, enabling efficient cluster well workover operations.
| Capacity Level | Max Hook Load (kN) | Power Configuration | Mobility |
|---|---|---|---|
| Level 1 | 900 | Diesel or AC‑VFD electric | Hydraulic walking base |
| Level 2 | 1,125 | Diesel or AC‑VFD electric | Hydraulic walking base |
| Level 3 | 1,350 | Diesel or AC‑VFD electric | Hydraulic walking base |
| Level 4 | 1,800 | Diesel or AC‑VFD electric | Hydraulic walking base |
| Level 5 | 2,250 | Diesel or AC‑VFD electric | Hydraulic walking base |
| Level 6 | 3,150 | Diesel or AC‑VFD electric | Hydraulic walking base |
Technical data source: Offshore workover rig specifications based on industry standards — whole rig skid-mounted structure using upper and lower bases, hydraulically driven for lateral and longitudinal movement.
Mast and Substructure — API 4F Compliance
All SJ masts comply with API Spec 4F and are available in multiple configurations:
| Mast Type | Cross‑Section | Application | Key Advantage |
|---|---|---|---|
| K-type (front‑open) | "П”‑shaped space truss | Land drilling and workover | Optimal driller visibility for offset operations |
| A‑type (A‑shaped) | Rectangular or triangular leg | Offshore platforms | "Full visibility” derrick — open front and back |
| Tower derrick | Four‑legged square | Heavy offshore, deep water | Excellent stability; high load capacity |
| Telescoping mast | Two‑section vertical | Mobile rigs, workover | Low transport height; fast setup |
API Certification Summary
| Specification | Scope | Relevance to Offset Rig |
|---|---|---|
| API Spec 4F | Drilling and well‑servicing structures | Ensures mast and substructure integrity for offset positioning |
| API Spec 7K | Drilling equipment (drawworks, rotary tables, pumps) | Guarantees reliable power transmission for offset moves |
| API Spec 8C | Hoisting equipment (traveling blocks, swivels, hooks) | Critical for safe pipe handling in close‑quarters drilling |
| API Spec 6A | Wellhead equipment | Required for pressure control at offset wellheads |
| API Spec 16C | Choke and kill manifolds | Essential for HPHT offset well control |
Product Types — SJ Offset Rig Configurations
| Type | Configuration | Drive Type | Depth Range | Primary Offset Application |
|---|---|---|---|---|
| Type 1 | XJ Series Dual-Engine Workover Rig | Diesel‑mechanical with paralleling gearbox | 2,000–9,000m workover | Pad workover; cluster well intervention |
| Type 2 | XJ Series Heavy-Duty Workover Rig (XJ750/XJ1000/XJ1200) | Dual-engine standard, paralleling gearbox | 8,000–9,000m workover; 3,000m drilling | Heavy offset workover; mobile drilling |
| Type 3 | ZJ Series AC‑VFD Synchronous Land Rig | AC‑VFD electric with master‑slave control | 3,000–9,000m drilling | Pad drilling; cluster well development |
| Type 4 | BigEasy Trailer-Mounted AC‑VFD Synchronous Rig | AC‑VFD electric, trailer-mounted, crane‑free | 4,000–5,000m drilling | Remote offset campaigns; crane‑free install |
| Type 5 | Offshore Workover Rig (hydraulic walking) | Diesel or AC‑VFD electric | 900–3,150kN capacity | Platform cluster wells; subsea intervention |
Type 1: XJ Series Dual-Engine Workover Rig — Pad Workover
Self-propelled, truck-mounted workover rigs with dual-engine paralleling capability and optional hydraulic walking base. Available from XJ450 (optional) through XJ1200 (standard). XJ1000 and XJ1200 models feature dual-engine as standard configuration for continuous operation.
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Best for: Pad workover operations requiring fast moves between wellheads
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Depth range: 2,000–9,000m workover depth
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Key advantage: Emergency power switching keeps rig running when one engine fails; hydraulic walking base moves between offset wellheads
Type 2: XJ Series Heavy-Duty Offset Workover Rig (XJ750/XJ1000/XJ1200)
Larger-capacity XJ models with dual-engine standard. XJ750 adopts double CAT C15 engines with Allison transmissions, reaching 8,000m workover depth and 3,000m drilling depth — providing drilling and workover capability in a single offset-capable package.
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Best for: Heavy offset workover, mobile drilling campaigns, deep well interventions
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Depth range: 8,000–9,000m workover; 3,000m drilling
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Key advantage: Dual-engine as standard configuration with maximum power availability for offset moves
Type 3: ZJ Series AC‑VFD Synchronous Land Rig — Pad Drilling
Full-scale land drilling rigs with AC‑VFD electric drive and master-slave motor control. Available from ZJ30 through ZJ90 with dual or quad-motor drawworks configurations. Features PLC-based control with VFD integration and regenerative braking.
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Best for: Precise pad drilling and cluster well development requiring millimeter-level positioning
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Depth range: 3,000–9,000m drilling depth
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Key advantage: Perfect load sharing eliminates mechanical "nodding” and "shaking”; smooth power for offset steering
Type 4: BigEasy Trailer-Mounted AC‑VFD Synchronous Rig — Remote Offset Campaigns
New conceptual AC VFD drilling rigs jointly developed by SJ and LOADMASTER. Features special module, trailer-mounted structure, and fast transportation without a crane. Entire rig installs using only six trailers — ideal for remote offset drilling campaigns in areas without heavy crane support.
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Best for: Remote desert offset operations, areas without heavy crane support
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Depth range: 4,000–5,000m drilling depth
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Key advantage: Fast mobilization with synchronous drive reliability and crane‑free setup
Type 5: Offshore Workover Rig — Platform Cluster Wells
Modular skid-mounted structure using upper and lower bases, driven hydraulically for lateral and longitudinal movement, specifically designed for efficient cluster well workover operations on fixed offshore platforms. Diesel or AC‑VFD electric drive adapts to different sea areas and platform requirements.
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Best for: Fixed platform offset drilling; cluster well development; subsea intervention
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Capacity range: 900–3,150kN max hook load (six capacity levels)
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Key advantage: Hydraulic walking base moves between offset wellheads on platform without repositioning rig
[Product images: SJ's modular skid-mounted workover rig on offshore platform — hydraulic walking system for cluster well offset operations]
Applications — Where SJ Offset Rig Specifications Matter Most
| Application | Why Offset Specifications Matter | Recommended Configuration |
|---|---|---|
| Multi-well pad drilling (land) | Wellheads spaced 5–10m apart — fast offset moves between slots minimize rig downtime | Type 3 (ZJ series) with hydraulic walking base |
| Cluster well development (land) | Dense well patterns require precise positioning to avoid collisions | Type 1 or Type 3 with master‑slave control |
| Platform-based cluster wells (offshore) | Fixed platform deck space constraints — hydraulic walking base moves between well slots | Type 5 (offshore workover rig) |
| Subsea well intervention | Jack-up rig with cantilever capability — offset positioning over subsea trees | Type 5 with offshore certification |
| Remote pad drilling (desert) | Long supply lines; frequent offset moves; no crane support | Type 4 (BigEasy trailer‑mounted) |
| Arctic pad drilling | Extreme cold (-45°C) — requires low‑temperature steel and hydraulic fluids | Type 1 or Type 3 with arctic package |
| Directional / horizontal drilling | Angular offset between motor highside and MWD highside requires precision control | Type 3 (AC‑VFD with master‑slave) |
| Workover on existing pads | Multiple existing wells — hydraulic walking base enables fast, accurate positioning | Type 1 (XJ series with walking base) |
Key references for offset operations:
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The angular offset (also referred to as the "rig floor offset”) between the motor highside (direction the motor will deviate the wellbore) and the MWD highside (tool measurement in relation to gravity or magnetic north) needs to be established so the driller steers the wellbore in the correct direction.
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Rotating pipe protectors may enable drilling at 2° lower flexible/ball joint mean angle, which doubles the rig offset range for rotating drill pipe.
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Self‑elevating drilling and workover rigs with fixed platform, self‑elevating platform, and semi‑submersible platform configurations are suitable for drilling operations of fixed platforms, self‑elevating platforms, and semi‑submersible platforms with different working water depths.
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Offsets are measured, in metres, positive from nominal to starboard and negative from nominal to port. Understanding offset measurement is critical for accurate well positioning in cluster development.
Why Choose SJ for Your Offset Rig Specifications?
1. Complete product line for all offset applications — SJ offers land workover rigs, land drilling rigs, trailer-mounted BigEasy rigs, and offshore workover rigs — all available with hydraulic walking bases and offset-specific engineering.
2. API-certified — every component meets global standards — All SJ rigs comply with API Spec Q1, 4F, 7K, 8C, 6A, and 16C. Manufacturing processes can be supervised by customers and inspected by any third‑party certification agency.
3. Field-proven in global offset operations — SJ's dual-engine workover rigs have been field-proven across China’s major oilfields and international markets. The XJ1000 and XJ1200 models are standard offerings with documented performance in pad workover and cluster well operations. Our offshore workover rigs are deployed across the South China Sea, Southeast Asia, and other major offshore regions.
4. Vertically integrated manufacturing — complete quality control — SJ designs, manufactures, and tests all components in-house across seven production lines and three assembly lines. Full vertical integration means you're not assembling components from multiple vendors and hoping they integrate.
5. 50,000 m² assembly yard with full FAT before shipment — Every SJ rig undergoes full factory acceptance testing at our 50,000 m² rig assembly yard with 24 rigging‑up positions, where 750‑ton load tests can be performed. Customer-witnessed testing is available.
6. Global after-sales support — SJ maintains regional support infrastructure across the Middle East and other key markets. 24/7 remote support desk and field service teams available for commissioning, operator training, preventive maintenance, and emergency service.
7. 70+ years of manufacturing heritage — From our founding in Lanzhou in 1941 to the present day, SJ has delivered more drilling and workover rigs to more oilfields than any other Chinese manufacturer. Our Technical Center employs 314 engineers and researchers across three research institutes.
8. Competitive pricing — the Chinese manufacturing advantage — SJ rigs are typically priced 30–50% below comparable Western brands for equivalent API-certified specifications, due to vertically integrated manufacturing and efficient production systems. Lower price does not mean lower quality — we build to Sinopec-grade standards and API certifications.
9. Modular design for fast offset moves — SJ rigs feature integrated modular design for rapid disassembly, transport, and reassembly — reducing rig‑up/down time for offset moves by up to 70% compared to conventional rigs. Our 9,000m ZJ90DB desert rig achieves two‑day rig‑up time, five days faster than comparable deep rigs.
Frequently Asked Questions (FAQ)
Q1: What is an offset rig in drilling applications?
In oil and gas drilling, an offset rig refers to a drilling or workover unit configured for operations in close proximity to existing wells — typically on multi-well pads, platform-based cluster wells, or subsea interventions requiring precise positioning over wellheads. Offset rig specifications include hydraulic walking systems, modular design for fast moves, and precise control systems for wellbore steering.
Q2: What are the key offset rig specifications engineers should evaluate?
The most critical offset rig specifications for pad drilling and cluster well operations are:
| Specification | Why Critical |
|---|---|
| Walking system type | Determines speed and accuracy between wellheads |
| Hook load capacity | Defines maximum depth and casing capability |
| Mast/derrick type | Affects driller visibility in congested pads |
| Power configuration | Redundancy ensures continuous offset operations |
| Control system precision | Enables millimeter-level positioning |
| API certification | Verifies compliance with international standards |
Q3: What is the difference between pad drilling and offset drilling?
Pad drilling refers to drilling multiple wells from a single prepared location (pad). Offset drilling refers to the specific act of positioning the rig over a wellhead that is laterally displaced from its previous position — often by small distances on a pad, or by larger offsets on a platform. SJ rigs with hydraulic walking bases are specifically designed for offset moves on multi-well pads.
Q4: What is the maximum offset distance for SJ rigs with hydraulic walking bases?
For land pad drilling, SJ's hydraulic walking systems are designed for offset moves up to 20–30 meters between wellheads on the same pad. For longer distances between pads, the rig is disassembled into modules and transported conventionally. For offshore platform operations, walking bases are designed to traverse the full length and width of the platform deck as required by the well layout.
Q5: What drilling depths can SJ offset rigs handle?
SJ offset-capable rigs cover the full depth range:
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Workover rigs (XJ series): 2,000–9,000m workover depth (depending on model)
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Land drilling rigs (ZJ series): 3,000–9,000m drilling depth (depending on model)
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Ultra-deep drilling (ZJ90DB): 9,000m (field-proven to 9,270m)
Q6: What is the typical offset move time on a multi-well pad?
For short offset moves (5–10 meters) between wellheads, SJ's hydraulic walking systems typically complete the move in 3–6 hours — including raising the rig, moving along rails, and lowering into position. This compares to 2–3 days of rig downtime for conventional rig-down/rig-up moves. Field data from China’s shale gas fields shows pad‑to‑pad transfers completed in under 4 hours with a crew of just 4 operators using integrated moving systems.
Q7: Do SJ offset rigs require disassembly for moves between pads?
For moves between wellheads on the same pad — no disassembly is required. The hydraulic walking system moves the fully assembled rig intact. For moves between different pads located several kilometers apart, SJ's modular design breaks the rig into road-transportable modules that reassemble in 2–4 days — not the 5–7 days required by conventional rigs.
Q8: What API certifications do SJ offset rigs hold?
All SJ rigs are API Q1, ISO 9001, and HSE management system certified, with API monograms for Spec 4F (drilling and workover structures), 7K (drilling and well‑servicing equipment), 8C (hoisting equipment), 6A (wellhead equipment), and 16C (choke and kill manifolds). Our facilities also follow SY/T 6680-2021 — China's petroleum industry standard for drilling rig and workover rig factory acceptance testing.
Q9: What is the operating temperature range for SJ offset rigs?
SJ offset rigs are available in multiple environmental ratings:
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Standard: -20°C to +50°C
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Desert package: +55°C continuous operation with enhanced cooling and sand protection
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Arctic package: -45°C with low‑temperature steel and hydraulic fluids
Q10: Can SJ provide training for offset rig operations?
Yes. SJ provides comprehensive training programs at our Jingzhou facility or on‑site at your location covering: hydraulic walking system operation and maintenance, precise wellhead positioning procedures, emergency protocols for offset operations, master‑slave control system programming (for AC‑VFD rigs), and preventive maintenance for offset-specific components.
