WELLBORE MODELLING OF A MULTI-LATERAL WELL FROM STEAM DOMINATED GEOTHERMAL FIELD

• Main Author: XAVERIUS GUWOWIJOYO - NIM : 22615306 , FRANSISCUS
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/27394
• Institution: Institut Teknologi Bandung

<p align="justify">Production well drilling is one of the major investment capital required for geothermal energy production and well drilling costs have a major impact on the economic feasibility of the project. Therefore, optimizing the design of geothermal wells to exploit the geothermal reservoir by minimizing the cost of drilling, is the main focus of this study. Possible solutions are the multi-lateral well drilling that has been commonly used in the oil and gas industry. The multi-lateral well has two or more holes in a wellhead where the production capacity can be predicted by well modelling. <br /> <br /> <br /> This study examines multi-lateral wells that produce dry vapor at the wellhead. Dry steam acts as a single-phase fluid in a homogeneous state, and the calculation of pressure drop can be done by simple equations. Junction between the initial and branching holes is a prime location in the wellbore as this is the point where the vapor from the original hole and the forked hole are mixed and flowing into the wellhead. Modeling is aided by software and validated using actual data of a multilateral well based on published papers. Model using Macro Excel yields output curve and updated mass flow rate equation for multi-lateral well. The result conclude that the best model was using GeoFlow software with model validation for the deliverability curve yields a total PI value of 7.31 kg / s.bar. <br /> <br /> <br /> Basic economic studies are conducted to see the general picture and comparison between multi-lateral and multi-lateral wells. The drilling strategy simulates four conditions: single standard holes, multi-lateral standard holes, single big holes and multi-lateral big holes. Multi-lateral wells are more economically advantageous if the mixing holes have the same capacity or more than the initial hole. The cost for multi-lateral big hole wells is USD 227k per kg/s compared to standard single hole well at a cost of USD 543k million per kg/s. When examined from the decision tree analysis, the cost of drilling a well without multi-lateral is more effective than the multi-lateral with EV value of USD (+) 66.7 M compared to EV USD (+) 63.5 M. <p align="justify"> <br />