Department of Petroleum Engineering
Indian School of Mines, Dhanbad – 826004
Factors Influencing Well Completion Design
Completion is the lowest cost completion that needs or nearly made the demand played upon a form the most of his life. To intelligently design will completion, a reasonable estimate of producing characteristics during the life overwhelm must be made. Both reservoir and mechanical considerations must be evaluated.
Reservoir under consideration was the location of various fluids in the formation of penetrated by wellbore , the flow of these fluids to the reservoir rock, and characteristic of rock itself. Producing rate to provide maximum economic recovery is often the starting point for the completion design. Among other factors producing rate should determine the size of the producing conduit. Multiple reservoirs penetrated by a well pose the problem of multiple completion in one drilled hole. Possibilities include multiple completion inside casing separated by packer, are several strings of smaller casing cemented in one bore hole to provide effect separate wells. Other possibilities include the commingling of hydrocarbons from separate reservoir downhole, or drilling several borehole from one surface location.
Mechanical considerations or "well hook up" is often the key to being able to deplete the reservoir effectively, monitor down performance, and modify the well situation when necessary. The mechanical consideration of well is the key to being able to do what ought to be done in the well promised a standpoint of controlling the offer reservoir of fluids, oil, gas and water.
Formation damages related to the well hookup, both minimising damage initially and relieving the effects of the damage. Mechanically will commission design is a complex engineering problem.
Basic philosophy is to design as they signal complete condition well condition and area conditions.
1. Maximise profit
2. Keep the installation simple
3. Overall reliability
4. Anticipate all operating conditions
Basic decisions to be reached in designing the well completion are ::-
1. The methods of completion
2. The number of completions within the well go
3. The casing tubing configuration
4. The diameter of the production conduit
5. The completion interval
Methods of completion::-
Basically there are two methods of completing a well,
• Open Hole: - Where casing is set on the top of the producing toward.
• Perforated Casing Completion:- Where casing is cemented through the producing interval and communication is established by perforating.
Each method has a day of predominant use depending on formation characteristics. Generally open hole has greater application Cabinet Jones. But each has inherent advantages and limitations.
Open hole completion
1. Adaptable to special drilling techniques to minimise formation damage, or to prevent loss circulation into the producing zone. 2. With gravel back, provides excellent stand control method where productivity is important. 3. No perforating expense.
4. Log interpretation is not critical since entire interval is open. 5. For the diameter opposite pay.
6. Easily converted to linear or perforated completion.
1. Excessive gas or water production difficult to control.
2. Selective fracing or digitising more difficult.
3. Requires more rig time on completion.
4. Chasing set" in the dark"before the pay is drilled or logged. 5. May require frequent clean out.
1. Excessive gas or water production can be controlled more easyly. 2. Can be selectively stimulated.
3. Logs and formation samples available to assist in the decision to set casing or abandon. 4. Full diameter opposite...