Well Completion.ppt

WELL COMPLETION

There are four basic types of well completion:

1. Conventional Single zone Completion

2. Conventional Multiple zone Completion

3. Tubingless Completion

4. Horizontal and Multilateral Completions

Conventional Single Zone Completion

Open Hole Completion

This is the simplest of all completion types, where casing is run and cemented just above the producing zone.

The pay section is drilled with a non-damaging fluid.

WELL COMPLETIONOpen Hole Barefoot

WELL COMPLETION

Conventional Single Zone Completion

Open Hole Completion

Open hole completions can be barefoot, where tubing is run and a packer is set in the casing above the open hole the well put on production.

Another option is to run a gravel pack liner or screen and gravel pack the open interval.

This is known as an Open Hole Gravel Pack completion.

The open hole can also be widened using an under-reamer and then gravel packed.

Open hole gravel packWELL COMPLETION

WELL COMPLETION

Conventional Single Zone Completion

Productivity of open hole gravel packs is higher than the cased hole gravel packs because the hydrocarbon flows into a larger tube.

Some features of open hole completions:

1. It is run in unconsolidated sandstone or carbonate reservoirs2. Perforating expense is eliminated

3. It provides good sand control

4. The entire pay section is produced

5. It can easily be converted to cased hole completion

WELL COMPLETION

Conventional Single Zone Completion

6. It is difficult to selectively stimulate using acid or fracturing

7. The casing is set in the dark before the pay section is drilled

8. It is difficult to eliminate water or gas production

Single Zone Cased Hole Completion

Casing is run and cemented to the bottom of the pay zone.

Single zone cased hole completions may be with gravel packed screens or liners for sand control.

WELL COMPLETIONSingle zone cased hole

WELL COMPLETION

Single Zone Cased Hole Completion

Some features of cased hole completions:

- It is easier to selectively stimulate using acid or fracturing

- Water or gas production can be eliminated- Multiple completion is possible

- The well can be easily deepened

- Perforating cost can be high

- Various sand control techniques can be utilized

WELL COMPLETION

WELL COMPLETION

Conventional Multiple Completion

Utilized when there are two zones in a well that contain significantly different reservoir pressures.

If both are produced together and allowed to mix, some production from the higher pressure zone will preferably flow into the lower pressure zone, especially when the well is shut in.

Thus it is necessary to isolate production from both zones.

This is achieved by placing a dual packer between both zones and allowing flow up two different tubing strings

WELL COMPLETIONDual completion

WELL COMPLETION

Conventional Multiple Completion

Tubingless Completion

Casing is small and no inner tubing is run in the hole.

Tubingless completions can be single zone or multiple zone.

The zones are perforated using orienting guns which utilize magnetism to orient the guns away from the other casing strings in the hole, while perforating the selected zone.

Tubing

Tubing is set inside the casing to transmit fluids from downhole to surface, with minimal pressure drop.

HORIZONTAL WELL COMPLETIONS

WELL COMPLETIONOpen hole horizontal

WELL COMPLETION

WELL COMPLETIONSlotted liner in Open hole with external casing packers

WELL COMPLETION

Tubing

Another factor is gas expansion in the tubing, which assists in the lifting of the liquids to the surface.

To achieve this, tubing is usually small in diameter e.g 2 3/8, 2 7/8, 3 .

In choosing the optimum size of tubing the following is considered:

1. The desired flow rate

2. Gas and liquid ratio for liquid loading in the tubing

3. Possible artificial lift method to be employed.4. Special requirements for completion e.g. sand control

WELL COMPLETION

Packers

Set in the wellbore to provide a seal between the tubing and casing.

They also serve an anchors/hangers for the production tubing.

A packer may be classified by the way it is set: hydraulic or mechanical set, by the way it is run: wireline or tubing, or by whether permanent or temporary.

Packers are run for:

- Casing protection from pressure or fluid in the tubing

- Separation of zones

- Subsurface pressure and fluid control for safety

- Artificial lift support equipment

WELL

COMPLETION

Packers

WELL COMPLETION

Packers

Wellheads

Wellheads are the connection points for the tubing and the surface flow lines as well as being the surface control point in all wells.

The selection of the wellhead is based on the pressure, temperature and corrosivity of the produced fluids.

Both the casing and tubing strings are landed in the wellhead.

The casing also acts as a conduit allowing for all types of workover operations.

Wellheads plays a major role in preventing oncontrolled flow from downhole, through its configuration of valves.

Functions of a wellhead:

Provide a means of casing suspension.

Provides a means of tubing suspension.

Provides a means of pressure sealing and isolation between casing at surface when many casing strings are used.

Provides access to annuli between the different casing/tubing strings.

Provides a means of attaching a blowout preventer during drilling.

Provides a means of attaching a christmas tree for well control during production, injection, or other operations.

Provides a reliable means of well access.

Provides a means of attaching a well pump.

Wellhead for a flowing well

Wellhead for a pumping well