| Title | A Well by Well Method for Estimating Surface Heat Flow For Regional Geothermal Resource Assessment |
|---|---|
| Authors | George STUTZ, Mitchell WILLIAMS, Zachory FRONE, Tim REBER, David BLACKWELL, Teresa JORDAN, Jefferson TESTER |
| Year | 2012 |
| Conference | Stanford Geothermal Workshop |
| Keywords | heat flow calculation, bottom hole temperature, EGS mapping, data incorporation and analysis |
| Abstract | The economic success of any potential low grade Enhanced Geothermal System (EGS) in the United States will depend on locating geothermal anomalies with sufficient spatial granularity. In the Eastern United States particularly, due to the relative low grade of potential geothermal energy resources, maps of localized heat flow variations are of greater importance than in conventional, hydrothermal dominated areas where gradients are generally much higher. To locate these small variations, resource assessments have relied largely on bottom hole temperature (BHT) measurements, primarily from oil and gas wells. As the volume of BHT data grows year after year due to increased drilling activity, the ability to quickly analyze and incorporate additional data is critical. Currently, in the Appalachian basin of West Virginia and Pennsylvania, more than 1,000 wells are being drilled every year. Incorporating this number of BHT points using current techniques may take weeks to months. This paper presents an approach to quickly and easily incorporate newly acquired well data into existing maps within hours or days after receiving the BHT points. The process utilizes the techniques of mapping potential geothermal resources by the Southern Methodist University (SMU) Geothermal Laboratory and new functional routines to quickly and efficiently calculate the estimated surface heat flow, temperature at depth, and various other properties from large quantities of well data. In addition, this technique permits incorporation of a more accurate estimate of sediment thickness at each well location and can utilize these estimates of thickness in subsequent calculations, greatly increasing their accuracy. The combination of improved accuracy and speed in incorporating additional data will enable more flexibility in analyzing potential EGS resources. The resulting maps will aid in locating the type of small temperature variations required for any proposed EGS system. |