| Title | Example Case of Geothermal Well Control Event |
|---|---|
| Authors | Tommy SOUVANIR, Redha Bhawika PUTRA, Doddy DARMAWAN |
| Year | 2020 |
| Conference | World Geothermal Congress |
| Keywords | geothermal well, well control, geothermal drilling |
| Abstract | Geothermal well control is an example of well control event in subnormal and under balance condition where formation pressure is lower than hydrostatic column in the wellbore. Well control event may occur in shallow section above the reservoir or in the reservoir. Those well control events have different cause mechanism. The shallow well control caused by abnormal high formation temperature that exceeds saturation temperature, while high temperature may occur due to natural heat flow path to surface through fracture or fault. For well control event in the reservoir section correlates with severe losses where hydrostatic column head in the annulus is lower than steam entry zone that allows steam flow to surface. To prevent those well controls, the prediction of pressure and temperature are crucial information in well planning phase and needs to correlate with losses prediction. The estimation of continuous required water supply during losses condition is essential, as well as in worst well control event. The water supply must be tested to prevent the shortage. In execution stage, monitoring wellbore pressure and temperature closely is critical and in losses condition, back side pumping is required to prevent steam flow to surface. This paper will describe one case of geothermal well control event. In order to explain the sequence of well control event (from the normal condition to steam flow occurred), in that certain well the sensors must have been installed. Understanding the mechanism of well control event will provide safe practice in geothermal well. By preventing well control event, it will increase the efficiency of drilling process, as well as deliver environmental friendly operation. |