The Thermal 15 Relief Well and Production Performance of the Thermal Shallow Reservoir

Abstract

Thermal 15 was drilled in November, 1983, to a TD of 700 feet. A steam entry encountered at 490 feet was found to communicate with the highpermeability upflow zone of the Thermal Shallow Reservoir. A low-flowrate, higher-pressure steam entry at 600 feet was not detected while drilling but was indicated during a subsequent spinner survey. The pressure, flowrate, and enthalpy of the five wells completed in the upflow zone, including the Thermal 4 blowout, were monitored and recorded over a four month period before, during and after Thermal 15 was drilled. It was found that the Thermal 4 blowout communicat'es with the upf low zone of the Thermal Shallow Reservoir, the Thermal 4 flowrate is controlled by the shallow reservoir pressure, and the high permeability of the upflow zone allows such strong interference effects that three of the four commercial production wells will maximize production from this reservoir. A simple model was developed which describes the pressure-production characteristics of the reservoir over the normal range of operating conditions.