Connection Selection for Tie Back Production Casing in Geothermal Wells According to Finite Element Analysis and Physical Thermal Well Testing Protocol

Abstract

Determining the proper connection for tie back production casing in geothermal wells is crucial. This casing and its connection experience various loads not only while drilling but also in the production phase. In order to assess the suitable connections, various loads to the casings and connection during drilling and production are simulated. Three types of connections are compared i.e standard API buttress connection (BTC), semi premium connection and manufacturer premium connection. We evaluate the premium connection design (thread and seal), with L-80 grade material that generally uses by a geothermal operator, using finite element analysis (FEA) and physical testing following international standard qualification protocols based on guidelines of ISO/PAS 12835:2013 Thermal Well Casing Connection Evaluation Protocol to simulate load in geothermal well. After two evaluation method, the proper connection for tie back production casing is determined.