The document discusses the casing design process for oil and gas wells. It notes that the design engineer must consider casing as part of the overall drilling system. The casing design process involves: 1) collecting data on anticipated loads and well conditions over the life of the well to ensure mechanical integrity; 2) designing casing strings to minimize total well costs; and 3) providing clear documentation of the design basis for operational personnel. The detailed design phase includes selecting pipe weights and grades for each casing string based on design loads and safety standards.

1. To arrive at the optimal
solution, the design engineer
must consider casing as a part
of a whole drilling system. A
brief description of the
elements involved in the
design process is presented
next.
Ensure the well’s
mechanical integrity by
providing a design basis
that accounts for all the
anticipated loads that
can be encountered
during the life of the
well.
Design strings
to minimize
well costs
over the life
of the well.
Provide clear
documentation of
the design basis
to operational
personnel at the
well site.
Detailed Design
Casing Design
The engineer
responsible for
developing the well plan
and casing design is
faced with a number of
tasks that can be briefly
characterized.
Hawler Petroleum Institute
Casing Design
Department of Drilling , Erbil – Iraq , 2nd Stage , 2016-2017
Prepared by : Shevan A.Sabir
Casing Design Process
Data
Collection
Casing Seat
Selection
Design Calculation –
Preliminary &
Detailed ( including
Triaxial checks)
Documentation
Of Design
Process
The detailed design phase includes selection
of pipe weights and grades for each casing
string. The selection process consists of
comparing pipe ratings with design loads and
applying minimum acceptable safety
standards (i.e., design factors). A cost-effective
design meets all the design criteria with the
least expensive available pipe
The most important mud program parameter
used in casing design is the “mud weight.” The
complete mud program is determined from:
Pore pressure.
Formation strength (fracture and borehole
stability).
Lithology.
Hole cleaning and cuttings transport
capability.
Potential formation damage, stability
problems, and drilling rate.
Formation evaluation requirement.
Environmental and regulatory requirements.
Typically the largest opportunities for saving money
are present while performing this task. This design
phase includes:
Data gathering and interpretation.
Determination of casing shoe depths and number
of strings.
Selection of hole and casing sizes.
Mud-weight design.
Directional design.
Mud ProgramDesign Objective
Preliminary Design