Hydraulic Workover
THE HYDRAULIC WORKOVER (SNUBBING) UNIT
The Hydraulic Work over Unit (HWU) is a diesel powered and hydraulic operated unit used in generating push, pull and torsion forces on the work-string and completion tubing for achieving specific tasks and objectives.
Well configuration and objective determines the rig up mode. Units are designed to be rigged up quickly and can be mounted on a Christmas tree using a sub structure through which the forces/load transmitted is shared or distributed (so the tree sub structure is not overloaded, as an added safety measure).
It can also be rigged up directly on the wellhead, but it must be capable of supporting the weight of the unit and the force generated during the pull and push effect.
The units are designed to handle pipe without the use of a conventional workover rig. All components are compact and utilized for minimized rig up time. They operate in any terrain including land, swamp, shallow and deep offshore.
The HWU has 3 Modes of Operation
1. SNUBBING MODE
Applicable when the well is ‘live’ and the unit is rigged up on Christmas tree. Used mostly for thru-tubing intervention.
2. WORKOVER MODE
Applicable when the well is ‘killed’ (or dead). Christmas tree is removed and BOP’s/HWU unit is rigged up on the wellhead or on a substructure.
3. DRILLING MODE
When is mounted on a substructure and easy racking system used, rotary torque capacity increased. Fluid circulation, segregation and conditioning unit configured for drilling purposes
TARGET DRILLING HWU APPLICATIONS
• Running and pulling of production strings.
• Fishing of parted tubing or lost wire-line tools.
• Squeeze cementing or setting of cement plugs.
• Gravel packing/ESS installation.
• Well abandonment
• Milling/retrieval of permanent packers, cement retainers etc.
• Cement drill out operation.
• Completion or re-completion with packers, safety valves and gas-lift valve, ESP’s and flow controls
• Well control services.
• Sand washing/well clean out services.
• Ability to Rig Up Coiled tubing, Slick and Electrical wir-line for logging, setting of permanent parkers, plugs, slick-line operation, etc.
• Acid washing and acid stimulation.
• Unloading with Nitrogen or foam.
• Drill Stem Test (DST).
• TCP perforating.
HYDRAULIC POWER PACK
The Hydraulic power pack’s supplies hydraulic power to the unit. The unit is equipped with two power packs one on standby while the other active. The power packs has a one piece skid frame, which encloses a Detroit Diesel, 8V series 60, engine and or VOLVO TAO1242VE code II 383KW engine and a complete hydraulic system.
OUR WORKOVER UNITS
TARGET DRILLING currently own 3 x 340,000 lbs. RDE hydraulic snubbing/workover units, all actively in operation in Nigeria, one of which is truck mounted which also has the capability to work both on land and swamp locations.
They include
340K RDE HWU – GRACE 101
340K RDE HWU – DIVINE 102 (TRUCK MOUNTED)
340K RDE HWU
The choice of unit for a particular job is determined by its suitability, capabilities, client’s preference and availability from their busy well work programs with various operating companies.
MAJOR COMPONENTS OF A HYDRAULIC WORKOVER UNIT
A typical Hydraulic workover unit (HWO) can contain the following groups and components:
1. A Blowout preventer stack (BOP) comprises of Ram type, annular bop and mud cross.
2. The pipe handling equipment consists of Hydraulic Jack assembly with traveling slips, stationary slips, work window, Rotating head.
3. Counterbalance winch, this allows the operator to handle two joints of tubing at once. While a joint is being pulled or run into the well bore another joint can be laid down or picked up.
4. A power pack system consisting of a diesel Engine, Hydraulic fluid pumps and air compressor and tanks to power all the components of the unit.
5. Workbasket, set on top of Hydraulic Jack this provides a work platform for the control of the process.
6. Remote control console to operate the Bop’s.
Miscellaneous equipment including, storage tanks, pumping equipment ladders guy wire assembly tubbing lay down unit.
