Gas deliverability and flow capacity of surveillance gas fields in Texas Railroad Commission, Disrict 8. [1981 to 2000 AD]

This report presents the findings of a pilot study that assessed the deliverability and flow capacity of 77 large (surveillance) gas fields in Texas Railroad Commission district 8. Gas production from the 77 surveillance gas fields was more than 80% of the gas well production and about 60% of the total gas production from district 8 during 1970-1980. Calculations of the flow capacity were made with a computer program that used the gas material balance equation with no water influx and the back-pressure equation. The flow capacity was calculated annually from 1981 to 2000. During this period, the number of surveillance fields decreased from 77 to 58 and the flow capacity decreased from 881,047 to 174,499 million standard cubic feet of gas (at 14.73 psia and 60/sup 0/F) per year. The calculated flow capacity for 1981 is only 3% more than the actual production during 1980. In 1981, 40 of the 77 surveillance fields deliver gas at maximum rate and by 1989 all of the surveillance fields are delivering gas at maximum rate. It can be concluded from this study that there will be little if any, reserve flow capacity from the 77 surveillance gas fields in district 8 aftermore » 1984. Future exploration must be very successful over the next 20 years to offset the declining deliverability and flow capacity of the surveillance fields.« less