Captains Meeting 2009Introduction to Well Testing- Expro

Edwin Schoorl

Introduction to Well Testing - Expro

Agenda

• Oil and Gas presence• Well construction• Well testing• Welltest System• Welltest Equipment• Welltest Video• Questions

Introduction to Well Testing - Expro

• Oil and gas is formed through millions of years of heat and pressure applied to the remains of microscopic plant and animal life..

• This mass is buried with the accumulating sediment and reach an adequate temperature, something above 50 to 70 °C t hey start to cook.

• This transformation, changes them into the liquid hydrocarbons that move and migrate, and will become our oil and gas reservoir.

• The gas and oil is present in porous rock or sandstone.

Introduction to Well Testing - Expro

• Finally the gas and oil must be stopped from migrating to surface, and get trapped.

Introduction to Well Testing - Expro

Once seismic has determined that there is a potential for hydrocarbon presence at a certain depth, an exploration well is required.

A Drilling rig is than mobilized to carry out that operation.

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Introduction to Well Testing - Expro

• Drilling starts with a large (up to 36”) drill bit

• To prevent collapsing of the hole, at regular intervals casing is set.

• The drilling is than continued with a slightly smaller bit, etc until they reach target.

• Hence the telescopic well design

Introduction to Well Testing - Expro

Once the drilling operation is completed, the well requires a “production tubing” or “production string”.

This is used to safely produce the hydrocarbons to surface

During well testing operations this can be : � Permanent Completion

� Temporary Completion (DST)

Finally the well is equipped with a range of valves to safely connect the well to the testing facilities and allow maintenance to be done to the well itself:

� The X-Mass Tree

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Introduction to Well Testing - Expro

Well design

Introduction to Well Testing - Expro

Completion design

Introduction to Well Testing - Expro

Wellhead design design

Introduction to Well Testing - Expro

Perforating

Once the well is completed with the production tubing and x mass tree, the well is still isolated from the reservoir

To allow production from the reservoir, the casing wall needs to be perforated with “guns”to allow influx of the hydrocarbons

These perforating holes are exactly opposite the reservoir

Now the well is ready for testing.

Introduction to Well Testing - Expro

What is Welltesting

Exploration wells

� Physical producing of the reservoir, flowing the oil and gas to the rig burner booms, or production facilities.

� Record well behaviour and production rates, over time.

� Collect representative fluid samples.

Production wells

� Well / Reservoir Clean up after drilling or workover operation and CONFIRM expectations

� Well Clean up after well maintenance

� Reservoir stimulation

� Coiled tubing clean outs

Introduction to Well Testing - Expro

Why Welltesting

Provide data for reservoir analysis and prediction

:

� Size of reservoir, i.e. gas or oil in place.� Evaluation if it a commercial find.

� Design field development plans

• How many wells

• Type and size of platform and pipeline• Production forecast

• Field life.

• Expected sustainable production rates

• Etc

Introduction to Well Testing - Expro

Introduction to Well Testing - Expro

Logistics process

Decision to test (exploration well) is often taken based on final logs after the drilling is completed.That’s only days before actual test equipment is required onboard

This put a lot of strain on logistics process .

A typical exploration test requires about 14 truckloads of test equipment.

In a short time frame that immense equipment package is

� Handled on Expro yard� Handled on Quay side

� Handled on Board, and spotted on deck

� Rigged up and pressure tested

� Carry out the test operation

� And reverse the logistics process

Introduction to Well Testing - Expro

Process flow diagram

Introduction to Well Testing - Expro

Flowhead or test tree

Function

• provide means of isolation of the well to the welltest facilities

• Allow a pump inlet to the wellbore (kill side)

• Allow production via the production out let

• Allow slickline operations to be carried out

• Means to pick up and rotate the test string

Introduction to Well Testing - Expro

Sand Filter

FunctionRemove any solids from the well stream and protect equipment against erosion.

Solids such as

• Reservoir Sand

• Perforating debris

• Proppant

Introduction to Well Testing - Expro

Choke Manifold

FunctionTo control the well production rate during the test

With Adjustable chokes (throttling) or fixed size chokes

Introduction to Well Testing - Expro

Heater

FunctionTo Heat expanded gas before separation

During the production of a well, the gas pressure is reduced.

This causes the volume to increase and results in a lower temperature.

Introduction to Well Testing - Expro

Separator

Function

Separate and measure all phases produced

• Water

• Oil / Condensate

• Gas

Introduction to Well Testing - Expro

Surge tank

Function

• Pressurised 15 m3 tank to degas the liquid produced from the separator

• Measure and temporarily store the liquid produced

• Safely route all associated residue gas to safe are.

Introduction to Well Testing - Expro

Gauge Tank

Function• Atmospheric enclosed 30 M3

storage/ gauge tank.

• Liquids are either burnt (oil) or transferred to transport tanks (IMO tanks)

Introduction to Well Testing - Expro

Flare Booms

FunctionTo provide safe distance to the rig structure for allowing gas / condensate or oil to be burnt.

The booms provide

• Large bore Gas lines

• Atomising heads for liquid burning

• Ignition system

• Vent lines

• Water screens

Introduction to Well Testing - Expro

Temporary Piping

• Faster temporary hook up of equipment

• Flexible in size and pressure rating • Easy connections

Introduction to Well Testing - Expro

Welltest Video

Introduction to Well Testing - Expro

Any Questions

Introduction to Well Testing - Expro

Thank you for your attention