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Workover Safety

David Calvert, True Oil Enterprises Inc

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December 4 -5, 2012

SAFETY..Safe operating practices and procedures are vitalin the drilling business because the work is hazardous,

involving massive machinery, heavy tools and great physical

strength.

Yesterday Today

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December 4 -5, 2012

Squeezing Cement

Acidizing

Wireline

Casing Running or Pulling

Snubbing Operations

Workover Operations Safety

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Squeezing Cement

A remedial cementing operation

designed to force cement into leak pathsin wellbore tubular. The required

squeeze pressure is achieved by

carefully controlling pump pressure.

Squeezing is performed to:

1. repair poor primary cement jobs

2. isolate perforations

3. repair damaged casing or liner

Formation

Casing

Mud Slurry

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Pressure is the main concern. Squeezing cement can require

pressures that may supersede equipment used from the well

service company.

Care needs to be given to ensure all connections and equipment

ratings are known and tested.

Cement dust from the mixing process is an irritant. Proper PPE

should be considered.

Wet cement should be washed off of oneself ASAP.

Wet cement in the eyes will cause serious if not permanent

damage.

Squeezing Cement Safety Concerns

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Acidizing

The pumping of acid into the wellbore to remove near-well formationdamage and other damaging substances.

This procedure commonly enhances production by increasing theeffective well radius.

When performed at pressures above the pressure required tofracture the formation, the procedure is often referred to as acidfracturing.

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Same as Cementing J ob.

Can be spotted in the well bore with no additional pressure required.

Squeezing acids adds a whole new level of danger due to the risk fromfailure of equipment due to increased pressure.

Also types of acid used can be very corrosive to the human body ifcontacted.

Great degree of attention needs to be used in PPE selection

Acidizing Safety Concerns

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Wireline

Wireline - a cable conveyancetechnology where a current issent to downhole tools in oilwell exploration andcompletions.

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Many incidents were related to dropped tool strings resulting from pullingthe tool string into the top sheave or stuffing box causing the wire to part

and while laying tools down.

When the dropped tool string is contained within the well bore/lubricator,there is little risk to personnel.

However, when it is dropped prior to being inserted into the lubricator orwell bore, there is the potential for serious or fatal injury to personnel.

Significant underlying causes of the incidents were failures orinadequacies in:

Risk Assessment Training and Competence Supervision Communication

Wireline

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Perforating is the most dangerous wireline operation because of

the use of explosives.

Guns have gone off prematurely killing workers.

High risk tool entrapment causing wireline parting.

Well blow out after perforating due to inadequate/improper testing

of or not using a lubricator

Wireline operator dropping tool strings on floor when laying

down or picking up

Wireline Safety Concerns

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Steel pipe cemented in place during

the construction process to stabilizethe wellbore to:

prevent the formation wall fromcaving into the wellbore

isolate the different formations toprevent the flow or cross flow offormation fluid

provide a means of maintainingcontrol of formation fluids and pressureas the well is drilled.

Casing Running or Pulling

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Odd pipe sizes make it an unusual operation on a workover rig.

Cutting and pulling casing can subject the rig structure to high hookloads.

Special care needs to taken to ensure weight indicators are properlycalibrated

Workers should not be on the floor during excessive pulling operations.

Casing Running or Pulling Safety Concerns

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The act ofpushing drill pipe into the wellbore when theblowout preventers (BOPs) are closed and pressure iscontained in the well.

In ordinary operations, the pipe falls into the wellboreunder its own weight, and no additional downward force

or pushing is required.

In snubbing operations, the pressure in the wellboreacting on the cross-sectional area of the tubular canexert sufficient force to overcome the weight of the drill

string, so the string must be pushed (or "snubbed") backinto the wellbore.

Snubbing

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Snubbing Unit can be tall so

the potential for falling parts orworkers are possible issues.

Operations are done with thewell under pressure.

Always need good supervision.

Snubbing Safety Concerns

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We have come a long way from Yesterday

Torpedoes of dynamite used to extinguish a well

http://www.sjvgeology.org/history/lakeview/torpedos_tn.jpghttp://www.sjvgeology.org/history/lakeview/torpedos_tn.jpghttp://www.sjvgeology.org/history/lakeview/torpedos_tn.jpg

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REMEMBER..

No job is so important

No service is so urgent

that we cannot take time to perform our work safely.

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Im ready to worksafe.

Hello..Is anyone there?

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Questions?