Cementing Operations in Well Drilling Process

How many feet of casing will be full of the displacement fluid?

a) 3510
b) 2480
c) 80
d) 3412

Answer:

80 feet will be full of displacement fluid.

Cementing operations and the use of displacement fluids in well drilling processes are crucial to ensuring proper casing integrity and zonal isolation. In this scenario, a hole with a diameter of 8 1/2 inches is drilled 3,492 feet into the earth. Casing with an outside diameter of 5 3/4 inches is run to the bottom of the hole and cut even with the ground. A total of 135 barrels of cement slurry is pumped into the hole and up the annular space, while 89.39 barrels of fluid are pumped behind the cement slurry to displace the cement out of the casing.

After the pumping stops, there are 80 feet of cement slurry left in the casing, and the space between the casing and the drilled hole is completely filled with cement slurry. To determine how many feet of casing will be full of the displacement fluid, we need to calculate the length of the casing that is not filled with cement slurry. Since the cement slurry fills the entire space between the casing and the drilled hole, the length of the casing filled with the displacement fluid will be equal to the length of the casing minus the length of the cement slurry remaining in the casing.

Given that the casing extends to the bottom of the hole, the length of the casing will be equal to the depth of the hole, which is 3,492 feet. Subtracting the remaining 80 feet of cement slurry from the length of the casing, we find that 3,492 - 80 = 3,412 feet of casing will be full of the displacement fluid.