Unique, Dual-Injection Cementing Process Contains Gas-Breakthrough Zone in a Geothermal Well: Case History

Abstract

Cementing in severe lost-circulation zones can pose significant challenges in geothermal well construction. These challenges can be aggravated by the presence of gas breakthrough in lost-circulation zones. Traditional methods consist of setting lost-circulation plugs in an attempt to stop the gas and cure the losses. These methods might not always prove successful. To overcome these challenges in a geothermal well in California, a unique cementing method was used. This paper presents the unique pumping method used to combat both the losses and gas breakthrough that consisted of pumping cement simultaneously down the annular space and the casing of the wellbore. The dual-injection process, cement-slurry design, and operational considerations are discussed in detail.