Page 19 - Offshore Well Construction

CHAPTER 15
Completion Equipment
Petroleum Extension-The University of Texas at Austin

INTRODUCTION
Completion design is the process of converting a drilled wellbore into a safe and efficient production or injection system.

Prior to starting any design the following information is required:
• Reservoir parameters
• Porosity, permeability, homogeneity, thickness, angle, water/gas/oil pressure profiles
• Rock characteristics
• Rock strength, formation damage potential
• Production constraints
• Fluids handling, injection pressures
• Fluid characteristics
• Density, composition, gas-oil ratio, toxicity, pour point, scaling tendency, wax, asphaltene, CO ,
2
contaminants
• Well appraisal data
• Rates, pressure, temperatures, samples
• Facilities information
• Control line pump pressures, flow-line sizes, sampling/testing/monitoring, safety constraints
• Drilling data
• Well profile, casing program (and constraints), safety valve depth constraints
• Field economics
• Time frame and importance of fluids, life of field, trade off between capital expense and operating expense,
tax implications
Some of the above information might not be readily available or can be reached by discussion with other members of
the project team. If a specific tubing size is required to meet a flow rate, then it needs to fit inside the production casing,
so discussion is needed with the drilling engineer.

The information is used to determine what type of completion is run, the tubing size, material specification, and the
additional completion equipment used.
Tubing design (similar to casing design) is undertaken. The design needs to accommodate collapse, burst, and tensile
load cases for the complete life of the well.

Generally speaking, the simpler the completion the greater its reliability.

COMPLETION TYPES/CLASSIFICATION
There are a number of ways of classifying completions. However, the main types are as shown below.
Interface between wellbore and reservoir – Open hole
– Cased and uncemented
– Cased and cemented
Production method – Flow naturally
– Require artificial lift
Stage of completion – Initial
– Recompletion
– Workover

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