Snubsmart System

The base Snubsmart system detects the position of the snubbing unit pipe rams then signals the beacons that are mounted on top of the snubbing unit dog house. They will flash red if closed or not fully open and green if open. There are also red and green LED’s, by the driller that indicate ram position - one set of LED readouts for each set of rams. We are set up to monitor 3 sets of rams independently but we have the ability to monitor up to 8 sets of rams. Ram position is constantly logged, time stamped then saved within the system.

Another part of the base system is the pre-job calculations. The snubbing unit operator enters pipe OD, weight, and grade, the number of jack legs on the snubbing unit, the rod and cylinder sizes of the jack legs, well depth, and well pressure. The system then calculates:

Snub force required in lbs and daN,
Snub area (cylinder area minus rod area) in square inches and square centimeters,
System hydraulic pressure required (to equal the snub force required ) in PSI and KPA,
Maximum safe unsupported pipe length in inches and centimeters,
Maximum pull the pipe can handle in PSI and KPA,
Lift area of the jack (cylinder area) in square inches and square centimeters,
Minimum and maximum tong torque in foot pounds,
Tubing displacement – barrels per foot and meter, cubes per foot and meter, and total tubing displacement (based on well depth) in barrels and cubes,
Neutral depth of pipe (i.e., between pipe light and heavy) in meters or feet,
Theoretical string weight at any depth (default is well depth but the operator can modify this value without affecting any of the other calculations) in lbs and daN,
Theoretical tubing hanger lift (default values are well depth and well pressure at surface but the operator can easily manipulate these entries without affecting any of the other calculations) in lbs and daN,
BHA max unsupported pipe length (if, for instance, the string is 2 3/8 but you need to take a long stroke to snub in a packer and can only close the BOPs on a 3 1/16 blast joint, this dramatically changes the amount of lift force on the string held by the traveling slips – BHA max unsupported pipe length calculation looks at lift area on the 3 1/16 blast joint and the strength of the 2 3/8 pipe held in the traveling slips then re calculates the max unsupported pipe length) in inches and centimeters. Snub force required and System hydraulic pressure required to snub the BHA into the hole is also recalculated.

Calculations are based on new pipe with a 30% safety margin.

Snubsmart has added an additional key component to the safety benefits of the Snubsmart system. An adjustable throttle control has been added which ties into the throttle of the service rig. This allows for pre job calculations to be performed and the throttle to be set to work within safe working perimeters of the tubing string. Throttle control also senses BOP ram position, if a set of rams is closed, the throttle on the service rig is ramped down to a pre set position leaving the clutch engaged protecting the tubing string and BOP’s from damage. There is an over ride built into the throttle control to allow staging operations to proceed safely within the perimeters of the tubing string.