High-Temperature Wells with Lost-Circulation Demands and Reverse Circulation Placement Technique Using Foamed Cement Systems: Two Case Histories

摘要

Drilling activities in diverse areas can pose significantchallenges for conventional cement systems and circulationmethods. To overcome these challenges, a unique cementingsystem and circulation method has been tested in the field withgreat success. This paper details how these technologies andtechniques were successfully used in the cementation processof one casing string in a relatively shallow geothermal well incentral California and a relatively deep string incentral Wyoming.Globally, a great many wells experience lost-circulationproblems that require the reduction of circulation pressures toallow proper placement of cement to provide annularcoverage. To help minimize these circulation pressures,cement was pumped into the annulus directly, significantlyreducing placement pressures and allowing placement of thecement with no apparent losses—a process referred to as thereverse circulation placement technique (RCPT). In each ofthe deep and shallow applications discussed, the placementtechnique and the individual slurry designs addresstemperature issues.