A 15-in, hole is drilled to a depth of 4,000 The API water loss of the mud is 10 mL. Approximately 30% of the lithology is per- meable sandstone and the rest is impermeable shale. a. Construct a plot of estimated filtration loss in barrels vs. time in hours (0 to 24 hours) that would occur if the hole were drilled in- stantaneously. Assume porosity is 0.25. An- swer: 42.4 bbl after 24 hours. b. Compute the radius of the invaded zone for: Part a in inches after 24 hours. Answer: 9.62 in. c. Repeat Part a assuming a drilling rate of 200 ft/hr. Answer: 31.6 bbl after 24 hours. d. Do you feel the API water loss test is representative of conditions in the well during drilling operations? (Hint: Find an article on "dynamic filtration.")