The pitting corrosion and crevice corrosion of oilfield production alloys (e.g., 13Cr/UNS S41000, 17-4PH/UNS S17400, 25Cr/UNS S32750, A286/UNS S66286, 718/UNS N07718) and proprietary austenitic stainless steels for directional drilling (PREN between ~20 to ~45) has been investigated. Specifically, series of electrochemical tests have been conducted to rank the alloys, establish simple correlations between electrochemical parameters, PRENmod, and 3-to-60-day immersion tests in 3.5% NaCl at ambient temperature. For all but one alloy, pitting was absent in stark contrast to crevices. Upon tracking populations and dimensional characteristics of crevices over time, trendlines comparing the susceptibility of the alloys towards crevice corrosion were established. Practical conclusions were reached, including the following: (1) 13Cr consistently developed crevices within days, (2) 17-4PH as well as all traditional directional drilling stainless steels developed crevices within one to five weeks, and, (3) neither 718, 25Cr, nor newer directional drilling alloys with both high nickel and high PRENmod showed any sign of crevices upon being tested up to 60 days. Through a variety of comparisons, this investigation also reveals useful technical directions for the development of new, economical, and fit-for-service Oil & Gas alloys for both production and drilling.