DRILLING ENGINEERING

Question 2: (11 marks)

a. Based on the International Association of Drilling Contractor guideline, describe the 7-3-7 bit.

b. A 1.02 specific gravity brine mud will be used to drill 8 5/8 shaly sandstone hole section from 7,000 to 8,500 ft depth using 700 bbls mud with 50 psig overbalanced. If the formation pressure gradient from 7,000 7,800 ft depth is 0.47 psig/ft after which decreased to 0.45 psig/ft down to 8,500 ft depth, what the drillers need to do so that the drilling operation will be smoothly and safely running. Include related calculation in your answer.