Definition WO- where? WO- How? WO – procedure WO Rigs Summery

Work over is any operation performed on a well to restore or increase its production or Injection which requires Rig .

W O Operation is one of well service operation such as well testing, well completions, well stimulations, etc.

Remedy to well problems Well abandonment also comes under work

over operations

WO is to improve production from a non- flowing well

Non-flowing well means sick wells with reservoir related problems and wells which can't produce due to mechanical or physical problem in well equipments

Flow assurance in well is the main objective of WO Operations. So WO is referred as well Doctor.

Water Shut-Off Gas Shut-Off Gravel Packing Installation / Servicing Artificial Lift System Fishing Testing & Transfer to Other Objects Fishing, Milling & Stuck-up Removal &

Recompletion Detection & Repair of Casing Damage Detection & Repair of Channeling Behind

Casing

Identification of problem Design a plan that will correctly for

solving the well problem Formulate a step-by-step field plan to

implement the design Design the repair procedure logically Optimize the work over time and money Plan to avoid further work over rig

deployment Work over plan is to be designed to

meet the need of the problem

Load capacity P/O tubing or not Weight of tubing ppf Size of tubing Pump capacity Rotary requirements Depth of well Depth of water (For Offshore)

Precaution to be taken care against Kick

Truck Mounted Rigs Modular Rigs Jack Up Rigs Floaters Rigs

Anchor Moored Rigs Dynamic positioning Vessels Semi submersibles Rigs

Modular Rigs are basically a platform mounted work over rigs with light weight components

Platforms have to be checked for their structural as well as space adequacy for installation of such rigs on top of platform.

The modular rig is equipped with hydraulic skidding system that allows it to reach all the wells on the platform, as and when required.

Limited crew members are allowed

The slot-type jack-up rig has 03 individual legs which can be independently raised/lowered to make the rig structure level and stable at any location.

The drilling mast can be shifted from one slot to another without moving the rig

Water depths not more than 90 m.

Also, such rigs cannot be deployed at locations with varying / soft soil conditions which can lead to sudden unsafe tilting of the rig.

Anchor Moored Rigs - placement of 6 to 8 anchors on the sea bed.

The anchors are kept under tension to hold the vessel on place.

Water depths up to 1000 m. In DP (Dynamic Positioning) vessels ,

the station keeping is achieved through propellers and water depths up to 3000 m. However, since the propellers have to be in operation continuously, the operating cost of such vessels is very high.

Semi submersibles