Coiled tubing simulator

Coiled tubing is a continuous steel pipe spooled on a reel; the injector head pushes it into a live well through the stripper and BOP without killing the well. It is used for sand cleanouts, scale removal, nitrogen kick-offs, stimulation and tool runs.

In this simulator you are the operator in the control cab: you review the well data, build the BHA, rig up and test the stack on the tree, then drive the injector, pump, nitrogen and choke while you read the weight indicator, pressures and alarms. The physics is simplified but consistent: buoyancy and friction in the deviated section, hydrostatic and friction pressures, sand transport and settling, gas expansion and cumulative pipe fatigue.

How to use the simulator

• Job: Pick sand cleanout (300 ft of fill over the perforations) or N2 lift (kick off a dead well under a brine column).
• Mode: At the start, choose guided or free mode. Guided mode highlights the next tool or control, explains why each BHA piece goes where it does and blocks the wrong order, then gives short coach tips in the cab based on what is really happening in the well; free mode starts with the stack rigged up and tested.
• Setup: Confirm the well data, build the BHA in the right order, rig the stack bottom to top, function-test every ram, run the low then high pressure test, and equalize before you open the swab.
• Injector: The slider sets chain speed (POOH left, RIH right), with ±1, ±10 and STOP. Watch the weight: it drops when you set down on sand and rises when you pull.
• Pump / N2: Start the pump, set the rate and choke; on the N2 lift job set the nitrogen rate and watch BHP fall until the well starts to flow.
• Fault: Add a fault: stuck under a sand bridge, stripper leak, losses to the formation or a failed check valve, then apply the right response.
• Info: Tap any component or gauge to read its function, typical problems and what to check. Every BHA tool has an (i) button that opens a card with a cut-away drawing, its function, why it sits there and which jobs need it.

Safety note: coiled tubing works on a live, pressured well. Never open the swab before a passed pressure test and equalization, never exceed the approved pull limit of the pipe, and never close blind rams on CT. Stop at once on any stripper leak or pressure reversal. Always follow the approved job program, your company procedures and the supervisor.

What each part does

• Injector headTwo chains of gripper blocks clamp the CT and push or pull it; traction pressure sets the grip, and maximum pull is limited by the injector and the pipe yield.
• Gooseneck / reelThe gooseneck guides the pipe from the reel into the injector. Every trip over the gooseneck and reel is a plastic bend that uses up fatigue life.
• Stripper (side-door)Elastomer element that seals around the moving CT and holds well pressure; its pressure follows WHP, and the element is changed when it leaks.
• Quad BOPTop to bottom: blind rams (seal with no pipe), shear rams (cut the CT), slip rams (hold it), pipe rams (seal around it).
• Weight indicatorReads the load on the injector: hanging weight minus buoyancy, friction and WHP force on the pipe area. PU and SO at the same depth are the baseline for spotting overpull and stuck pipe.
• Dual flapper check valve (DFCV)Two flappers that stop well fluids flowing back up the CT; if they fail, the CT becomes an open path to surface.
• Hydraulic disconnectReleased by dropping a ball: separates the CT from stuck tools and leaves a fishing neck.
• Circulating sub (burst disc)A disc that ruptures at a set pressure to open a side circulation path if the nozzle plugs.
• Jet / rotating nozzleTurns the pressure drop into jets that break up the fill ahead of the BHA; annular velocity then lifts it to surface.

Simplified teaching model: the well, the pipe (1.75 in × 0.134 in) and every number are illustrative, and time is compressed. Not a job-design tool and no substitute for validated tubing-forces and hydraulics software or certified training.

Sources

1. NOV CTES: Coiled Tubing Manual (tubing forces, fatigue, hydraulics)
2. ICoTA – Intervention & Coiled Tubing Association: An Introduction to Coiled Tubing https://www.icota.com/
3. IWCF Well Intervention Pressure Control (coiled tubing module) https://www.iwcf.org/
4. API RP 16ST: Coiled Tubing Well Control Equipment Systems https://www.api.org/products-and-services/standards
5. API RP 5C7: Coiled Tubing Operations in Oil and Gas Well Services https://www.api.org/products-and-services/standards
6. SLB Energy Glossary: “coiled tubing”, “injector head”, “stripper”, “BOP”, “nitrogen lift” https://glossary.slb.com/
7. Dawson, R. & Paslay, P. R. (1984). Drillpipe buckling in inclined holes. JPT, SPE-11167
8. Johancsik, C. A., Friesen, D. B. & Dawson, R. (1984). Torque and drag in directional wells. JPT, SPE-11380
9. Zuber, N. & Findlay, J. A. (1965). Average volumetric concentration in two-phase flow systems. J. Heat Transfer
10. Richardson, J. F. & Zaki, W. N. (1954). Sedimentation and fluidisation. Trans. IChemE