Inter-well moving device
Technical Specifications – Standard Device Models
The table below shows our standard inter-well moving devices. Custom capacities and stroke lengths available.
| Model | Type | Lift Capacity | Push/Pull Capacity | Stroke (Lift) | Stroke (Push) | Weight | Mounting |
|---|---|---|---|---|---|---|---|
| SJ-GJ-100 | Gripper jack (skid) | 100 tons | 50 tons | 6 in | 24 in | 800 lbs | Bolt-on |
| SJ-GJ-250 | Gripper jack (skid) | 250 tons | 125 tons | 8 in | 36 in | 1,800 lbs | Bolt-on |
| SJ-GJ-500 | Gripper jack (skid) | 500 tons | 250 tons | 10 in | 48 in | 3,200 lbs | Bolt-on |
| SJ-WU-100 | Walking unit | 100 tons | N/A (steps) | 8 in | 12 in (step) | 1,200 lbs | Bolt-on |
| SJ-WU-250 | Walking unit | 250 tons | N/A (steps) | 10 in | 18 in (step) | 2,500 lbs | Bolt-on |
| SJ-WU-500 | Walking unit | 500 tons | N/A (steps) | 12 in | 24 in (step) | 4,500 lbs | Bolt-on |
| SJ-RM-250 | Rotation module | 250 tons | 50,000 ft-lb torque | N/A | 360° rotation | 3,000 lbs | Bolts between substructure and skid base |
Applications – Where a Single Device Makes Sense
| Application | Device Recommended | Why |
|---|---|---|
| Adding skidding to an existing rig | 2–4 x SJ-GJ gripper jacks | Minimal substructure modification, no permanent pad rails |
| Workover rig that moves weekly | 4 x SJ-WU walking units | No beams needed – works on gravel pads |
| Offshore platform slot skidding | 2 x SJ-GJ (corrosion-protected) | Low profile fits under platform deck |
| Small rig (200 tons) cluster wells | 2–4 x SJ-GJ-100 | Lightweight, easy installation |
| Radial well pattern on platform | 1 x SJ-RM rotation module | Swing rig between slots without moving laterally |
Product Types – By Function
We offer three device families. Each can be purchased individually or as a set.
1. Gripper Jacks (Skidding Devices) – SJ-GJ Series
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Function: Push/pull the rig along steel rails or skid beams
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Best for: Rig owners with existing skid beams, or those willing to install simple steel rails
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Number needed: 2–4 units (one at each corner of the substructure)
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Control: Sequential – push with rear jacks, then retract front jacks, repeat
2. Walking Units – SJ-WU Series
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Function: Lift the rig, extend a foot, set down, retract – moving the rig step by step
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Best for: Pads without beams, soft ground, multi-directional movement
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Number needed: 4 units (one at each corner)
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Control: Simultaneous lift, then sequential walking steps
3. Rotation Modules – SJ-RM Series
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Function: Rotate the entire rig around a central pivot point
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Best for: Radial well patterns (offshore platform slots, circular pads)
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Number needed: 1 unit (installed under the center of the substructure)
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Control: Hydraulic rotary actuator with position feedback
Combo devices: For pads requiring both skidding and rotation, we offer a combined skid-rotate module.
Why Choose SJ Petro’s Inter-Well Moving Devices?
1. Retrofit-Friendly – You do not need to buy a new rig. Add our devices to your existing rig for a fraction of the cost (typically $50k–$200k per rig, depending on capacity and number of units).
2. Shipped as a Complete Kit – Each device comes with hoses, couplers, mounting bolts, and a detailed installation manual. No missing parts. Installation can be done by your local mechanics in 2–3 days.
3. Works with Your Existing Hydraulic System – Our devices are compatible with most rig hydraulic systems (2,500–3,500 psi). We provide adapters if your system uses different coupler types.
4. Interchangeable Across Rigs – If you have multiple rigs of similar size, you can move the devices from one rig to another. Quick-disconnect mounting and hoses make this practical.
5. Proven in the Field – Over 200 devices in operation globally. We have case studies of a workover contractor reducing move time from 2 days to 4 hours using SJ-GJ-250 gripper jacks.
6. 12-Month Warranty & 15-Year Spares – Full warranty on cylinders, valves, and hoses. We guarantee spares availability for 15 years – including seal kits, replacement cylinders, and control valves.
7. Free Installation Support – Our engineer is available by video call during your first installation. We also provide a step-by-step video guide.
Frequently Asked Questions (FAQ)
Q1: What is the difference between a gripper jack and a walking unit?
Gripper jacks require steel rails or beams – they push against the rail to move the rig. Walking units lift the rig, extend a foot, set down, and retract – no rails needed, but slower. Choose gripper jacks for linear moves on prepared pads; choose walking units for irregular pads or soft ground.
Q2: Can I install the device myself, or do you need to send a technician?
Most clients install the devices themselves using our manual and video guide. However, we can send a technician for the first installation (additional cost). Many clients have local welders/mechanics handle it.
Q3: How many devices do I need for my rig?
For skidding (linear moves): 2 devices (one at each side) for rigs up to 300 tons; 4 devices for heavier rigs (one at each corner). For walking (omni-directional): 4 devices minimum. For rotation: 1 device under the center.
Q4: What is the maximum rig weight your devices can handle?
Our largest gripper jack (SJ-GJ-500) handles 500 tons lift capacity. With 4 devices, total capacity = 2,000 tons. For heavier rigs, we can design custom devices – contact us.
Q5: Do the devices require permanent pad modifications?
Gripper jacks require steel rails or skid beams (bolted to concrete or embedded). Walking units require only level, compacted ground – no permanent modifications. Rotation modules require a circular steel track on the pad.
Q6: How fast can the rig move using these devices?
Gripper jacks: 60–100 ft per hour (depending on rig weight and hydraulic flow). Walking units: 30–60 ft per hour. Rotation modules: 15–30° per hour. Much faster than rig-down/move (2–5 days).
Q7: Can I use the devices on a workover rig that moves weekly?
Absolutely. Many workover contractors use our SJ-WU walking units for weekly moves. The devices stay bolted to the rig; just connect hoses and go.
Q8: What hydraulic power source do I need?
The devices need hydraulic pressure of 2,500–3,500 psi and flow of 10–30 GPM (depending on device size). Most rig hydraulic systems can provide this. If not, we can supply a standalone power pack (diesel or electric).
Q9: How do I control multiple devices simultaneously?
We provide a portable control console (wired or wireless) that synchronizes all devices. The console includes joysticks, pressure gauges, and emergency stop. Or you can use your rig’s existing hydraulic controls with our manifold kit.
Q10: What is the typical lead time for devices?
Standard devices (SJ-GJ-100, -250; SJ-WU-100, -250): 3–4 months. Larger devices (500-ton models, rotation modules): 5–6 months. Retrofit kits for specific rigs: 4–6 months (includes custom mounting plates).
Q11: Do you offer a trial or rental device?
Yes. We have a limited number of SJ-GJ-250 and SJ-WU-250 devices available for rent (3–6 months). Rental includes installation support. Contact us for current availability.
Q12: How do I get a quote for devices for my rig?
Provide: rig weight (tons), desired movement type (skid/walk/rotate), pad layout (well spacing, pattern), and photos of your current substructure. We will recommend device models, quantity, and provide a fixed price within 3 business days.
