Introduction to
Hydraulic Workover Solutions
History of Hydraulic Workover
Hydraulic Workover “HWO” is a well
workover performed using a hydraulic
workover (snubbing) unit to run and/or pull
tubulars – with or without surface pressure
present on the wellhead.
Hydraulic Workover Techniques in use since
1920’s
First Hydraulic Units developed in 1959
Definition of Snubbing
Snubbing is the process of running and pulling tubing, drillpipe, or casing with
surface pressure present on the wellhead.
Snubbing also describes a force-balance condition (or the “pipe-light” condition)
where an external force is required to prevent the workstring from being force out
of the hole.
In some situations, Hydraulic Workover (HWO) may also be used to trip tubulars into
and out of wells with no existing or anticipated surface pressure.
Reasons for Utilizing HWO
When CT or Wireline is incapable of performing the task
When reservoir damage is anticipated
When platform infrastructure is inadequate
Cost considerations
HPHT/Critical Deviation - Emergency Work
Benefits of HWO Services
Operations are completed while under pressure, well does not need to be
killed.
Reduces Costs by eliminating need for kill fluids
Eliminates risk of damaging producing formation with kill fluids
Compact size, mobile, fast rig up/rig down
Reduces overall costs
Well remains in production
Versatile - Rotational ability allows drilling/milling
Misconceptions for Using HWO Services
Ø For “Last Ditch” effort on problem/critical wells in emergency
situations.
Can be used for all applications - routine or critical.
Ø For only “live” well remedial services.
Can be used on “live” or “dead” wells.
Ø For only high pressure applications.
Can be used on low pressure applications as well.
Ø Very expensive.
Can be a very cost effective tool.
Safety Considerations For HWO
Thorough Pre-Job Planning
Required Employee Training & PPE
Perform Preventive Maintenance Service to Equipment
Location Safety Meetings Conducted
Location Standards Adhered To
Engineering Calculations Considered
Location Layout of Equipment
Hydraulic Workover Unit
Conventional Stand Alone Hydraulic Workover
units are self contained operating systems
consisting of modular equipment groups that
are easily transported and rigged up.
Components of HWO Unit
Work Basket and control panel
Hydraulic Jack assembly
Traveling Slips
Rotary Table
Guide Tubes
Stationary Slips
Hydraulic power pack, accessories, and
hydraulic hoses
Circulating swivel, kelly hose, and pumps
BOP Stack
Workbasket
The workbasket, located on top of
the jack, is used as a work
platform. Controls for the jack,
traveling and stationary slips,
BOPs, and counterbalance are
located in the work basket.
Control Panel
Typically there are two control panels,
one for the jack operator and one for
the helper. The operator controls the
vertical movement of the jack and the
operation of the slips. The helper
operates a counterbalance that lifts
and lowers joints of pipe to and from the
basket.
Traveling and Stationary slips
Traveling Slips – located on the
traveling assembly, which moves
vertically up and down as the
cylinder rods are extended and
retracted
Stationary Slips – attached to the
base of the jack and are used to
hold the pipe while the traveling
slips are not engaged
Hydraulic Jack Assembly
Hydraulic jack – one or more hydraulic
cylinders configured to move the pipe
into and out of the hole
Guide Tube – placed in the bore of the
jack to provide the lateral support
necessary to prevent buckling of the
workstring
Rotary Table
Hydraulically driven
and used for milling
and fishing operations
Power Tongs
Power tongs – rigged up
in the basket to make up
pipe connections
