| Title | Correlation and Modeling of Reservoir Pressure Changes in the Tiwi Geothermal Field, Republic of the Philippines |
|---|---|
| Authors | Anthony J Menzies, Carla K.D. Co and Oluwole Sotunde |
| Year | 2014 |
| Conference | Indonesian Geothermal Association Conference |
| Keywords | Tiwi, Matalibong, Production, Injection, Interference, Reservoir Pressures, Capillary Tubing, Modeling |
| Abstract | Deep liquid reservoir pressure changes in the Matalibong sector of the Tiwi Geothermal Field have been monitored on a continuous basis since November 2005 by using capillary tubing systems installed in Mat-25, Mat-29 (March 2007 to April 2008) and Mat-30 (since July 2008). Monitoring of the Mat-25 and Mat-30 wellhead pressures provides similar information on the overlying steam reservoir. With the precision provided by continuous pressure monitoring, the reservoir pressure trends in the deep liquid and shallow steam reservoir zones have been well defined. Analysis of the deep liquid response has indicated strong interaction between the production area and injection wells located approximately 2km to the north. This was not expected, considering the distances involved and the locations of the observation wells within the production area. However, the noted interaction is consistent with other evidence, such as changes in discharge characteristics, results from tracer tests and changes in micro-gravity, collected during the same time period. Understanding the noted pressure responses is important to resource management in the Matalibong area as a rising liquid-steam interface has negatively affected the productivity of steam wells. This is expected to continue unless changes are made and knowing that injection is a factor in this process makes it possible to design a reservoir management strategy to mitigate this. To help with the development of this strategy, the deep reservoir, including both the production and injection areas, has been modeled using “Saphir©” well test software. After successfully matching the measured pressure responses, the resulting model is being used to provide forecasts of how the deep pressure trend will change in response to various production/injection scenarios. |