Patented

 

Rig Assist #3 (Deep Throat)

 Piston Well Services introduced the world's first patented 8-foot stroke concentric snubbing unit.

The concentric snubbing unit in the extended position provides 16 feet (4.8m) lubricating space from bag to stripping rams and 22 feet (6.7m) bag to blind rams (shown below) and still has the ability to take a full 8-foot conventional stroke when the going gets really tough. This allows total flexibility while performing installations or removals of even the most complicated BHAs, all while being rigged up at the same height as would be to snub in slick tubing string. This configuration will rarely require spools or splitting the snubbing stack. The bottom-hole-assembly (BHA) is lowered into the stack, the concentric portion extended swallowing the BHA in its entirety, the stationary slips and annular (bag) are closed, the pressure equalized, the blind rams opened and the BHA is lowered into the well bore in one stroke. Conventional snubbing operations (snubbing tubing) then begin.

 

Features and Advantages of a Concentric Snubbing Unit

  1. Fast rig ups - no spools, extra BOPs or splitting snubbing stacks

  2. Lower working heights - safer more efficient operations, reduces derrick height restrictions

  3. Fast trip times through the elimination of staging.

  4. No staging - bottom hole assemblies enter the well fully equalized and fully guided

  5. No stripping though closed rams - bottom hole assembly is lowered into the well while being held in static position at the seal point

  6. Reduces expensive wireline lubricating operations of BHAs ( following the 6.7m rule)

  7. 4 full-opening slips with the ability to grip any size of pipe or tools from 2.375" - 7" (no changing dies)

  8. Allows more flexible BHA designs (the first 6.7m of BHA can be any configuration)

  9. Ideal for all Under Balanced Drilling (UBD) operations

  10. Reduced rental and expendable charges

  11. Ideal for all fishing operations (Example: a 5m perforating gun c/w overshot and jars can be retrieved in one stroke with no spools and no wireline lubricating).

  12.  

Applications

All Workovers, Completions, Under-Balanced-Drilling (UBD) and Fishing operations to 3000 P.S.I.

Specifications:

Truck: 2000 Kenworth T800 tridem drive axle c/w Caterpillar C12 (425 hp) engine c/w positive emergency air shut down

Hydraulic System: 3000# working pressure, 300 gpm c/w 30 gallon accumulator system

Cylinders: 7" x 4" x 96"

Conventional Snub Stroke: 2.4m (8 feet)

Concentric Snub Stroke: 2.4m (8 feet)

Concentric Snub Capacity: 235K

Conventional Pull Capacity: 235K

Conventional Snub Capacity: 155K

Height: 4.1m (rotating flange to top slip)

Well Control Equipment:

1 - 7 1/16" 3000# Shaffer Annular BOP

1 - 7 1/16" 3000# Shaffer single gate BOP c/w stripping rams

2 - MEI 5000# 1" plug valves c/w Dan Foss hydraulic actuators for equalize / bleed-off functions

Power Tongs: 4 1/2" Farr c/w hydraulic backup

Pipe Handling: 2 3/8 " - 5 1/2 "

Rotary: Passive

 

Here is a cycling animation of RA#3 going through the motions of:

1.) Swallowing a BHA

2.) Lowering it into the well bore

3.) Conventional snubbing (3 strokes)

This is why we call it the "Mother of All" Snubbing Units

Shown is 8' concentric stroke with a full 8' conventional stroke overhead

 

  

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