1.24 The following bit records were obtained on a well drilled in Maverick County, Texas. Depth Out (ft) Bit Size Bit Time No. (hours) (in.) 500 2.0 17.5 2 1,925 2,526 2,895 3,177 3,452 3,937 4,286 4,621 4,973 5,171 5,298 5,424 5,549 5,625 5,743 5,863 6,006 6,158 6,340 6,602 6,783 6,978 7,165 7,292 7,386 15.0 17.5 3 14.9 20.2 26.3 23.2 17.5 4 17.5 5 17.5 17.5 7 29.7 17.5 8 27.3 17.5 28.2 17.5 10 31.3 19.4 17.5 11 17.5 12 13 14 15 16 15.9 15.9 15.7 13.8 17.5 17.5 17.5 17.5 17.5 17.5 17.5 17.5 15.8 17 18.9 18 19 16.2 18.4 27.3 20 17.5 21 29.8 23.9 17.5 22 17.5 23 26.4 17.5 24 27.3 21.5 20.5 26.5 17.5 17.5 25 26 17.5 27 28 29 7,528 7,637 7,741 7,795 7,855 7,917 7,988 17.5 22.8 23.8 17.5 17.5 30 17.2 12.0 31 26.4 12.0 32 33 26.9 12.0 12.0 26.8 39 34 35 36 37 8,060 8,494 8,614 8,669 8,737 8,742 8,778 9,661 9,874 9,973 10,016 10,219 10,408 10,575 10,661 25.8 12.0 12.0 12.0 270.0 35.1 19.0 12.0 38 29.7 8.5 39 3.4 8.5 8.5 8.5 40 8.5 179.3 65.0 30.0 I1.8 64.7 57.2 61.2 41 42 8.5 8.5 43 44 8.5 45 46 47 8.5 8.5 8.5 48 36.1 8.5 a. Plot a depth vs. rotating time curve for this well. b. Evaluate the use of Eq. 1.19 in this area. c. Assuming that the rig can pull thribbles at an average time per stand of 4 minutes, plot the trip time per trip vs. depth. Answer: t,=0.00148 D. d. Using the bit records, make a plot of total trip time vs, depth. e. Compare the performance of Bits 34 and 35. Assume a daily operating cost of $24,000/D, a bit cost of $3,000 for Bit 34, and a bit cost of $12,000 for Bit 35. Answer: $565/1l and $679/ft.