| Title | A Case Study of Radial Jetting Technology for Enhancing Geothermal Energy Systems at Klaipeda Geothermal Demonstration Plant |
|---|---|
| Authors | Rohith NAIR, Lies E.PETERS, Saulius SLIAUPA, Robertas VALICKAS, Sigitas PETRAUSKAS |
| Year | 2017 |
| Conference | Stanford Geothermal Workshop |
| Keywords | Radial Jetting, Stimulation, Low Enthalpy Geothermal |
| Abstract | In 1996 a geothermal energy project was initiated at Klaipeda, Lithuania, to demonstrate the feasibility of using low enthalpy geothermal water as a renewable energy resource in district heating systems. The Klaipeda geothermal plant is situated within the West Lithuanian geothermal anomaly with a relatively high heat flow density of 70-90 mW/m2 and contains two geothermal injectors and producers. The reservoir is composed of the fine-grained friable sandstone. The injectivity of the wells has been deteriorating ever since plant start-up due to chemical precipitation, fines mobilisation and scaling. In November 2014, radial jetting technology was identified as a possible solution for enhancing injectivity of the wells. With radial jet drilling, several open hole laterals of 100 m maximum length and with a diameter of 1 to 2 inch are jetted from the main well bore in order to enhance the connectivity of the well to the rock and thereby the well productivity or injectivity. In one of the injection wells at Klaipeda, 12 horizontal laterals of around 40 m in length were jetted in a number of highly permeable layers present in the aquifer. Production data post drilling of the laterals suggest an improvement in injectivity of approximately 10%. This paper presents simulation results analyzing the improvement in the injectivity as a result of jetting of radials at Klaipeda. A sensitivity analysis was carried out to investigate the impact of uncertainties in radial length, positioning, diameter, inclination, and pre-existing near wellbore damage on the injectivity increase. Additionally, the upper limit in injectivity increase resulting from the radial jetting stimulation done at Klaipeda was estimated. The results show a large impact of the highly heterogeneous permeability on the performance of the laterals when taking into account the uncertainty. |