Modified Isochronal Testing in Patuha Geothermal Project Indonesia

Abstract

Modified Isochronal Testing (MIT) was employed in the two production wells 2-X and 4-X in Patuha-2 Geothermal Project, West Java, Indonesia, to test its applicability as an alternative option of determining the Bore Output Curve (BOC) or well deliverability of production wells. Test results were in good agreement with the flow parameters derived from standard Medium-Term Discharge (MTD) Test using Tracer Flow Test (TFT) measurements and orifice pressure drop measurements. Test duration is the key difference between Modified Isochronal Testing and Medium-Term Discharge Test. The MTD Test usually requires 30 days to complete while the MIT method can accomplish the same objective in 3 to 4 days allowing timely utilization of the well to produce revenue. The deliverability or Bore Output Curves of Patuha wells were obtained in about 4 days using MIT method, significantly reducing programmed test duration by about 85%. This would also translate to considerable cost savings to the project.