Q3) You are in charge of drilling operations in a sedimentary basin. The figure bellow gives the setting. Prior to drilling you have performed a numerical analysis. The table below states the necessary information at the bottom of the shale layer and at the top of the sandstone layer. Assume hydrostatic pore pressure throughout the reservoir. Stress results from your numerical models at 2250m: Rock layer Sv [MPa] S [MPa] S [MPa] [deg] S [MPa] T. [MPa] Shale 55.2 20 0.25 Sandstone 55.2 30 25 65 40 30 30 10 5 10 0.25 Shake this - 235 planned with Sandstone thiness - 250 A. Your drilling crew on the rig wants to drill with a setting P=Po through the shale. Will you approve this and give permission? Prove your decision by calculating the necessary stresses and show a Mohr Circle construction so that the driller can understand your reason. If unsafe, which borehole failure mechanism do we expect? (10 Marks) B. Should they increase, decrease P, or stay with P=Po? Why? (10 Marks) C. Determine the save mud weight window to drill through the Sandstone formation. (10 marks)