Baghjan Oilfield : Snubbing Technology | UPSC
Over 5 months later, Assam’s Baghjan well blowout under control, fire doused: OIL
WHY IN NEWS:
The Baghjan well blowout led to the death of three people and displaced thousands.
SYLLABUS COVERED: GS 3: Energy : Oil and Natural Gas : Science and Technology
For PRELIMS snubbing technology is very important . Go through the procedure carefully.
For MAINS BP katakey committee recommendations should be revised today itself ! Let us dive in !
BAGHJAN WELL BLOWOUT UNDER CONTROL
- Five-and-a-half months after it erupted, Oil India Limited’s (OIL) Baghjan well in Assam’s Tinsukia district was brought under control on Sunday.
- The blowout was because of uncontrollable release of natural gas at well number 5 in the Baghjan oilfield.
- On June 9, the well erupted in flames, leading to possibly one of the longest and most challenging industrial disasters faced by the PSU.
- Also, it resulted in deaths of three employees — two fire-fighters in June and a 25-year-old electrical engineer.
- The incident led the state and Centre to order probes, and the National Green Tribunal (NGT) to constitute an expert panel in June.
- “Simultaneously, the well pressure came down to zero and we were able to successfully kill [or completely shut down] the well.”
HOW SNUBBING UNITS WORK
- There were several setbacks in control operations: on-site accident, delays caused by the annual floods, and a failed attempts.
- The company resorted to a technology called “snubbing” — brought in from Canada — to kill the well.
WHAT IS SNUBBING?
- It can be done in an existing well or in new well without the removal of the blowout preventer (Christmas tree) from the wellhead.
- Snubbing can only be carried out in a live well, i.e., when a well is not killed and is still under pressure.
COMPONENTS OF A SNUBBING UNIT
- One of the main components of a snubbing unit is the slip.
- Typically, a minimum of four slip bowls are used in snubbing operations.
- Two slip bowls are designated for “pipe light” operations.
- Pipe light is when the well bore forces are greater than the tubular weight in the well bore.
- The other two slip bowls are designated for “pipe heavy” operations.
- Pipe heavy occurs when either enough pipe has been snubbed into the well bore .
- In this process, the bottom hole assembly (BHA) on a drill string is run down into the wellbore with the help of a hydraulic workover rig, without removing the blowout preventer (BOP).
- Thereby exerts sufficient force on the drill string to overcome the wellbore pressure; thus the drill string can be pushed or snubbed back into the wellbore.
SOURCES : PETROPEDIA
- While snubbing into the hole, there is a transition point the tubular goes through from being pipe light, to pipe heavy.
- The balance point occurs when there is enough pipe weight in the wellbore to equal the snub forces generated against the pipe.
- In certain instances, thousands of feet of pipe can be moved with minimal effort since the pipe weight is at an equal state with the snub forces.
- If done correctly, the snubbing contractor can predict when this balance point will take place and can properly prepare for it.
MODERN SNUBBING TOOLS
- Modern snubbing units are powered by sophisticated hydraulic systems.
- These hydraulic units typically supply all power required by the components of a snubbing operation.
- Companies have been able to harness this hydraulic energy to develop precision controlled snubbing units.
- Pipe handling is performed by the snubbing units “gin pole” and “pipe winches“.
- The gin pole is typically telescoped out in excess of 40ft above the snubbing unit.
SOURCES : PETROPEDIA : Baghjan Oilfield : Snubbing Technology | UPSC
SNUBBING UNIT APPLICATIONS
- Today’s snubbing units can be employed to provide a wide range of services.
- A snubbing unit is a hydraulic rig that can do everything a rig can do, plus it can perform under pressure in an under balanced live well state.
- The industry has become more aware of damages caused by heavy kill weight fluids and mud.
- The operators often times do not wish to turn around and load the well with heavy fluids to complete the well dead.
- Another clear advantage to using a snubbing unit is its’ small footprint, which is critical on the tight locations in the unconventional shale’s.
HISTORY OF SNUBBING UNITS
- Snubbing units have evolved into one of the most capable and efficient well servicing tools in the oil & gas industry.
- In the 1920’s, the need for a rig to work with pressures at surface drove the invention of the snubbing unit.
- The first snubbing unit relied on the draw works of the companion rig to supply its’ power.
- A series of sheaves, cables and counter weights were rigged up so that as the rig’s traveling blocks hoisted up, the snubbing unit would snub in the hole.
- Conversely, when the traveling blocks on the rig were lowered, the snubbing unit would snub out of the hole.
- The NGT expert panel has fixed compensation of Rs 25 lakh to 173 families affected by the blowout and the fire and Rs 20 lakh to 439 families who were less affected.
- OIL, the company has released Rs 36.90 crore in compensation till date.
- OIL had to use the largest cargo transporter aircraft, AN 124 Russian, to fly in equipment weighing 60 tonnes from Canada
- When on June 9, the well caught fire, 57 homes were gutted and nearly 9,000 people displaced
SOURCES: THE IE | Baghjan Oilfield : Snubbing Technology | UPSC