Effect of Well Diameter on Productivity of High Temperature Geothermal Wells

• Main Author: Kjartan Dór Kjartansson 1984-
• Other Authors: Háskóli Íslands
• Format: Thesis
• Language: English
• Published: 2011
• Subjects: Vélaverkfræði; Borholur; Hermilíkön; Iceland
• Online Access: http://hdl.handle.net/1946/9873

The purpose of this project is to create a method which can help designers choose a diameter when designing a well. This method can then show the effect of well diameter on the productivity of high temperature geothermal wells. There are generally two diameters used for wells in Iceland. It can be difficult to decide which diameter to use due to the unpredictability of the well characteristics. The basic idea of the method is to implement information from another well in production to create a simulation of the well to be drilled. The diameter can be changed in the simulation which then predicts which diameter is more productive. The numerical analysis calculation proved to perform very well but better void fraction correlation models for geothermal wells are needed so that the method can really work properly. The drawback of this method is that it does not take into account the changes of mass flow from the reservoir into the well when the diameter is changed, to be able to use this method a mass flow correction factor needs to be added to the method. Another fact is that to be able to show the effect of well diameter on the productivity of wells much more data is needed than the data from eight wells. It is also important that the data is accurate since little changes in measurements can alter the simulation results dramatically. Tilgangur þessa verkefnis er að skapa aðferð sem getur auðveldað ákvarðanatöku hönnuða að velja þvermál borhola. Þessi aðferð getur einnig sýnt áhrif þvermáls á afkastagetu háhitaborhola. Tvö þvermál eru algeng fyrir háhitaborholur á Íslandi svo valið stendur á milli þeirra tveggja. Það getur reynst erfitt að velja þvermál háhitaborhola því erfitt er að vita með vissu hvernig hegðun borholunnar mun verða. Grundvöllur aðferðarinnar er að nota upplýsingar frá annari borholu sem er í rekstri og byggja módel út frá henni. Það módel getur svo spáð fyrir um hvernig hegðun borholunnar verður og þannig sýnt hvort þvermálið er ákjósanlegra. Niðurstöður sýna að númeríska aðferðin notuð til ...