Friday Haggler
A reminder of last Friday’s Haggler
During the planning phase you have identified concerns over casing wear while drilling which may exceed the wear allowance allowed in the casing design at the KO depth (~4000ft). Due to supply chain and logistical issues it is not possible to change the casing design or install casing wear protectors on the drill pipe. However, there is flexibility in the trajectory design. Will either of the new trajectories (S-shape & J-Shape) reduce drilling side forces and help mitigate casing wear? If so, which is likely to produce the largest effect? No backreaming is planned.
The Answer
Short Answer: Both alternative trajectories reduce the casing wear risk. There is no difference between the S-shaped and J-shaped for the conditions described in the question.
Long Answer:
Both trajectories will reduce the side forces across the build section due to reduced DLS. While the S-shape will have higher P/U and lower S/O than the J-shape profile and would result in higher side forces while backreaming, rotating weight (drilling) is similar in both profiles. This results in similar side force of ~ 1.75klbs / jnt cross the build section. There is likely to be a benefit in the S-shaped profile in terms of casing wear due to the reduced well length (and therefore revolutions) required to drill to TD.
