Air and Gas Drilling Manual: Applications for Oil and Gas Recovery Wells and Geothermal Fluids Recovery Wells, Third Edition

This appendix presents the detailed MathCad solutions for the illustrative examples in Chapter 11.
| Illustrative Example No. 11.1: DTH MathCad Solution (USCS) | F-2 |
| Illustrative Example No. 11.2: PDM MathCad Solution (USCS) | F-10 |
| Illustrative Example No. 11.1: DTH MathCad Solution (SI) | F-37 |
| Illustrative Example No. 11.2: PDM MathCad Solution (SI) | F-45 |
Basic input data
| 1 s := 7.1 | length of piston chamber (in) |
| e s := 0.8 | stroke approximate ratio of length |
| | convert chamber length to ft |
| L s = 0.592 | (ft) |
| d p := 5.9 | diameter of piston (in) |
| d b := 7.875 | diameter of drill bit (in) |
| | cross-sectional area of piston (ft 2) |
| A p = 0.19 | (ft 2) |
| | cross-sectional area of drill bit (ft 2) |
| A b = 0.338 | (ft 2) |
| W p := 97.0 | weight of piston (lb) |
| | acceleration of gravity (ft/sec 2) |
| ? st := 0.0763 | specific weight of standard air (lb/ft 3) |
| ? at := 0.0679 | specific weight of 4000 ft atmos air (lb/ft 3) |
| q cat := 2400 | compressor 4000 ft atmos air (acfm) |
| | equivalent standard air (scfm) |
| q cst = 2.136 10 3 | (scfm) |
| | convert to ft 3/sec |
| Q cst = 35.596 | (ft 3/sec) |
| | depth of drilling (ft) |
| p at := 12.685 | atmos pressure at 4000 ft (psia) |
| P at := p |