Drilling Success in Geothermal Fields Utilized by Major District Heating Services in Iceland Björn Már Sveinbjörnsson Prepared for Orkustofnun (National Energy Authority of Iceland, NEA) Í SOR-2018/043 ICELAND GEOSURVEY Reykjavík: Orkugardur, Grensásvegur 9, 108 Reykjavík, Iceland - Tel.: 528 1500 - Fax: 528 1699 Akureyri: Rangárvellir, P.O. Box 30, 602 Akureyri, Iceland - Tel.: 528 1500 - Fax: 528 1599 [email protected] - www.isor.is Report Project no.:15-0252 Drilling Success in Geothermal Fields Utilized by Major District Heating Services in Iceland Björn Már Sveinbjörnsson Prepared for Orkustofnun (National Energy Authority of Iceland, NEA) ÍSOR-2018/043 August 2018 Key page Report no. Date Distribution ÍSOR-2018/043 August 2018 Open Closed Report name / Main and subheadings Number of copies Drilling Success in Geothermal Fields Utilized by Major District 3 Heating Services in Iceland Number of pages 200 + Appendix Authors Project manager Björn Már Sveinbjörnsson Steinunn Hauksdóttir Classification of report Project no. 15-0252 Prepared for Orkustofnun (National Energy Authority of Iceland) Cooperators N/A Abstract The report describes success of 446 production wells drilled in the years 1928-2017 in 63 low- and medium enthalpy geothermal fields which are exploited by the 64 major district heating services in Iceland. The dataset on which the report is based has been collected from the National Well Registry of boreholes and available reports. To the extent verifiable data are available, the assembled dataset is presented in an Excel document accompanying the report on CD. About 93% of the drilled wells were productive, i.e. encountered feeders that could yield a flow from the well. Of the productive wells 164 are still in use, with an average production capacity of 31.7 l/s at 90.3°C. The main reasons for productive wells not in use are: a) drawdown of reservoir pressure, b) replaced by better wells or c) idle but could produce. About 49% of the main feeders are shallower than 500 m, 76% are shallower than 1,000 m and 95% are shallower than 1,600 m. About 88% of the 446 drilled production wells fulfilled the minimum criterion set for space heating of a discharge temperature of 60°C and 65% fulfilled the criterion of 80°C discharge temperature. The far largest low enthalpy geothermal field, Reykir in Mosfellsbær, has a present production capacity equivalent to 1.800 l/s of 85.4°C hot water or a thermal power potential of 367 MWth above 35°C. The largest well fields, Æsustaðir and Suður-Reykir, in the Reykir field have a thermal power potential above 35°C of 139.7 and 96.7 MWth respectively. The total thermal power potential of all the geothermal fields exploited by the 64 major district heating services is equivalent to 1,770 MWth above 35°C. Key words ISBN-number Low enthalpy geothermal fields, medium enthalpy geothermal fields, productivity of wells, drilling Project manager’s signature success, thermal power potential, Iceland Reviewed by BS, SThor, SvB Table of contents 1 Introduction ....................................................................................................................... 17 1.1 Potential for exploitation ............................................................................................ 18 1.1.1 Thermal power potential ................................................................................ 18 1.1.2 Geothermal utilization .................................................................................... 18 2 Definitions and Overview of the Dataset .................................................................... 19 2.1 Location of well ............................................................................................................ 20 2.2 Well status ..................................................................................................................... 20 2.3 Description of well ....................................................................................................... 21 2.4 Reservoir characteristics.............................................................................................. 21 2.5 Production characteristics ........................................................................................... 22 2.6 Thermal power potential of well field and geothermal field ................................. 22 3 Overview of the Major Geothermal District Heating Services in Iceland ............. 22 3.1 Largest operators of district heating services .......................................................... 22 3.2 Location of the major geothermal district heating services ................................... 23 4 Results of Drilling ............................................................................................................ 26 4.1 Seltjarnarnes .................................................................................................................. 26 4.1.1 Seltjarnarnes District Heating ........................................................................ 26 4.2 Reykjavík ....................................................................................................................... 28 4.2.1 Reykjavík District Heating (Veitur) ............................................................... 28 4.3 Mosfellsbær ................................................................................................................... 37 4.3.1 Mosfellsbær District Heating (Veitur) ........................................................... 37 The Suður-Reykir subfield ........................................................................................ 41 4.4 Kjósarhreppur ............................................................................................................... 50 4.4.1 Kjós District Heating (Kjósarveita) ................................................................ 50 4.4.2 Hvammsvík District Heating (Veitur) .......................................................... 51 4.5 Skorradalshreppur ....................................................................................................... 51 4.5.1 Skorradalur District Heating (Veitur) ........................................................... 51 4.6 Borgarbyggð ................................................................................................................. 52 4.6.1 Akranes/Borgarfjörður District Heating (Veitur) ........................................ 55 4.6.2 Húsafell District Heating ................................................................................ 58 4.6.3 Reykholt District Heating ............................................................................... 58 4.6.4 Kleppjárnsreykir District Heating ................................................................. 59 4.6.5 Brúarreykir District Heating ........................................................................... 60 4.6.6 Varmaland District Heating ........................................................................... 60 4.6.7 Stafholtstungur District Heating .................................................................... 61 4.6.8 Munaðarnes District Heating (Veitur) .......................................................... 61 4.6.9 Norðurárdalur District Heating (Veitur) ...................................................... 63 4.7 Helgafellssveit .............................................................................................................. 64 4.7.1 Stykkishólmur District Heating (Veitur) ...................................................... 64 - 5 - 4.8 Dalabyggð ..................................................................................................................... 67 4.8.1 Dalabyggð District Heating (RARIK) ............................................................ 67 4.9 Reykhólahreppur ......................................................................................................... 68 4.9.1 Reykhólar District Heating (OV) ................................................................... 68 4.9.2 Thorverk Seaweed Plant ................................................................................. 69 4.10 Ísafjarðarbær ............................................................................................................... 69 4.10.1 Suðureyri District Heating (OV) .................................................................. 69 4.11 Kaldrananeshreppur .................................................................................................. 70 4.11.1 Drangsnes District Heating .......................................................................... 70 4.12 Húnaþing Vestra ........................................................................................................ 71 4.12.1 Húnaþing Vestra District Heating ............................................................... 71 4.12.1 Hvammstangi/Laugarbakki District Heating ............................................ 73 4.13 Húnavatnshreppur .................................................................................................... 74 4.13.1 Blönduós District Heating (RARIK) ............................................................ 74 4.13.2 Skagaströnd District Heating (RARIK) ....................................................... 75 4.14 Skagafjörður ................................................................................................................ 75 4.14.1 Steinsstaðir District Heating (SKV) ............................................................