In this study, we examined the rate at which oil and gas fields were discovered in the Frio strand plain exploration play, which is located in the central coastal plain of Texas, and estimated the size distribution of the oil and gas fields remaining to be discovered. The analysis of past rates of discovery in this play provides insight into the advanced stages of an exploration play in which many very small fields have been discovered. This observation was made during examination of changes in the distribution of field sizes as the play was driven toward total physical exhaustion by the increased petroleum demand due to the massive rise in oil and gas prices in the late 1970s and early 1980s. During this period, exploratory drilling was directed at a suite of prospects t at contained very small oil and gas fields (almost all having less than 1 million bbl of recoverable oil equivalent). Analysis of this data suggests that the size distribution of fields is log geometric in form. On the basis of data obtained through February 1982, when 5000 wildcat wells had been drilled in the play, we predicted that 1163.2 fields remained to be discovered. Each field was estimated to contain more than 95,000 bbl of recoverable oil. The total volume of oil equivalent remaining to be discovered was predicted to be 726.8 million bbl, 51.5% of which is in fields smaller than 1.52 million bbl in size.