| Title | Tracer Test Using Naphthalene Disulfonates in Southern Negros Geothermal Production Field, Philippines |
|---|---|
| Authors | Orlando O. Maturgo, Dennis R. Sanchez and Godofredo B. Barroca |
| Year | 2010 |
| Conference | World Geothermal Congress |
| Keywords | tracer test, naphthalene disulfonates, reinjection, Southern Negros, Palinpinon, Philippines |
| Abstract | Tracer testing using naphthalene disulfonates (NDS) was conducted in the Palinpinon-II sector of Southern Negros Geothermal Production Field (SNGPF) with the following objectives: 1) to quantify the rate and extent of brine injection returns to the production wells, 2) to identify fluid flow paths/channels of the returning brine and 3) to predict possible cooling rates of production wells due to injection returns. Two types of NDS tracers (NDS-A and NDS-B) were pumped into two injection wells and monitored for recovery from 12 production wells. Three producing wells, namely NJ3D, NJ5D and OK5, showed tracer recovery 5-7 days after injection, with peak concentrations of 100-150 ppb between 15th and 36th day. The tracers were also recovered from 3 other wells with initial returns between 2 and 3 months. The tracer return curves were processed and interpreted using the one dimensional flow modeling utilizing the ICEBOX software package of the United Nations University, Iceland. The results were used to assess the reservoir response to increased mass extraction and injection rates from a planned additional 20 MWe modular power plant. Cooling predictions are consistent with observed historical cooling trends. The current injection load in two of the injection wells appears to be close to the optimum injection rates. Additional brine production during operation of additional 20 MWe power plant necessitates drilling of a new injection well farther away from the existing injection area. |