Modeling Discharge Requirements for Deep Geothermal Wells at the Cerro Prieto Geothermal Field, Mexico

Abstract

During the Mid-19801s, Comisibn Federal De Electricidad (CFE) Drilled a Number of Deep Wells (M-200 Series) at the Cerro Prieto Geothermalfild, Baja Calijomia, Maico to Investigate the Continuation of the G E O T H D Reservoir to the East of the Cerro Prieto-I1 and I L L Production Areas. the Wells Encountered Permeability at Depths Ranging from 2,800 to 4,400 M but Due to the Reservoir Depth and the Rehtively Cold Temperatures Encountered in the Upper 1,000 to 2,000 M (< 5OoC), It Was Not Possible to Initiate Discharge in All of the Wells.

The Wells at Cerro Prieto Are Generally Discharged by Injecting Compressed Air Below the Water Level Using 2-3/8-inch Tubing Installed with Either a Crane or Workover Rig. the Impact of Heat Loss on the Stimulation Process is Believed to Be Signijkant and Was Investigated Using Both a Numerical Model of the Reservoir/wellbore System and Steady-State Wellbore Modeling. the Resultsfrom the Study Show That $flow Rates of at Least 300 Liters/minute Can Be Sustained, the Well Can Probably Be Succes&lly Stimulated; This is Consistent with the Succes&l Stimulations of Wells M-202 and M-203. If the Flow Rate is Closer to 60 Liters/minute, the Heat Loss is Signijkant and It is Unlikely That the Well Can Be Successfklly Discharged. These Results Are Consistent with the Unsuccessfkl Discharge Attempts in Wells M-201 and M-205.