PEGN 361:
Completion Engineering
Section A
Maurice Polycarp
MPOLYCAR
Project 2
Pages:
Date: 4/20/2016
Minimum Casing Requirement (Onshore)
There are a few types of casings which are commonly installed. Therefore, it is imperative to understand the design criteria for these casings in order to prevent any well problems.
1) Conductor Casing
Conductor casing is the first pipe installed in the wellbore. It is shallow and serves to prevent the hole from washing out under the rig. It also supports the weight of other casing strings. Besides, it returns drilling fluids to elevated pits while drilling the next section of the well.
For the burst design of conductor casing, the internal pressure should be the lower value of either the
2) Surface Casing
Surface casing serves to protect freshwater aquifer and also protects the borehole from potentially poor shallow formations. It is also the initial anchor for the blowout prevention equipment (BOPE). It also helps suspend the weight of the remaining casing strings. …show more content…
On the other hand, the external pressure should be assumed to be 0 kPa at the surface and to have a 10 kPa/m fluid gradient. There are three available design factors while considering burst design. First, a design factor of 1.1 should be used for sweet or sour wells with pp H2S less than 0.3 kPa. Next, 1.2 is utilized if pp H2S ranges from 0.3 kPa to 10 kPa and pp CO2 is less than 2000 kPa. Lastly, if pp H2S is larger than 10 kPa, a design factor of 1.25 is employed for burst