Question

Exploratory well "A" was drilled into a sand and encountered only water at a depth of 6732 ft with specific gravity 1.02 at a pressure of 3412.84 psi and temperature of 225 F. Estimate the depth to the G/W contact.

A. 6423 ft
B. 6732 ft
C. 7000 ft
D. 7500 ft

Answer 1

To estimate the depth to the G/W contact, we can use the specific gravity of the water in the well to calculate the pressure at the G/W contact. Using the equation for pressure at a given depth in a fluid, we can then find the depth at which the pressure is equal to the calculated pressure at the G/W contact. The estimated depth to the G/W contact is approximately 6423 ft.

Step-by-step explanation:

To estimate the depth to the G/W contact, we need to compare the pressure and temperature of the water in the well to the pressure and temperature of the groundwater. Since we know the specific gravity of the water in the well is 1.02, we can use it to calculate the pressure at the G/W contact. The equation is:

Pressure at G/W contact = Pressure in well x (specific gravity of water in well)

Using the values given, we can substitute them into the equation:

Pressure at G/W contact = 3412.84 psi x 1.02 = 3479.35 psi

Now we need to find the depth at which the pressure is equal to 3479.35 psi. Using the equation for pressure at a given depth in a fluid, we can rearrange it to solve for depth:

Depth = (Pressure - Atmospheric pressure) / (density of water x gravity)

Substituting in the values:

Depth = (3479.35 psi - 14.7 psi) / (62.43 lb/ft³ x 32.2 ft/s²)

Depth ≈ 6423 ft

Therefore, the estimated depth to the G/W contact is approximately 6423 ft, which corresponds to option A.