Abstract

The Phillips Petroleum Company Austin #1 well (SEC 17 14S-36E) was completed in 1957 as the discovery well for the Austin upper Mississippian Field in Lea County, New Mexico. The well had a CAOF of 9.925 mmcfgpd plus 152 bcpd and no water from upper Mississippian (Chester) ooid grainstones. The Austin #1 has produced 4.149 bcf plus 58,684 be and no water.

Due to the exploratory nature of the well, a very complete logging suite was run which consists of: 1) 18’8” Lateral, 2) 10” Short Normal, 3) SP, 4) 32” Limestone Lateral, 5) Microlog, and 6) Gamma Ray-Neutron. This very complete 1957-era logging suite, plus the knowledge of the production history gives us an opportunity to compare different methods of “Old Log Analysis” and compare the log analysis to the production. In the petrophysical analysis, Rw (0.026 at Tf) was determined from the SP; true formation resistivity (Rt) was determined from the 18’8” lateral log. Porosity was determined from the 32” limestone lateral, the microlog, and the old neutron log. Calculated net pay and hydrocarbon pore-ft (HCPFT) thickness for the Austin #1 using Vcl < = 20%, Porosity > = 8% and Sw < = 30% are 27 ft and 2.4 ft, using neutron porosity. Net pay and hydrocarbon pore-ft are 36 ft and 4.3 ft, respectively, using microlog porosity. Net pay and hydrocarbon pore-ft are 27 ft and 2.1 ft, respectively, using 32” limestone lateral porosity. The different porosity logs did result in large variations in net pay and HCPT, however it is important to note that all calculated net pay and HCPFT values were enough so that the geologist or engineer would have made the correct decision to complete the well.