The Role of Boron Cycling and Superheat Monitoring for Field Production and Injection Strategies at the Darajat Geothermal Field, Garut, Indonesia

Abstract

Boron is a conservative element that prefers to exist as a dissolved species in the liquid. One of the benefits of this particular chemical characteristic is that the migration of the liquid condensate injectate can be tracked through time.
The increasing trend of boron concentration in produced steam and injectate at Darajat is hypothesized to be a result of efficient containment and re-injection of plant condensate back into the reservoir. From a geothermal reservoir perspective, the increasing trend of boron in steam represents a more active boiling of the condensate injected in the reservoir, and it has increased the amount of condensate injection-derived steam. This steam contains increasing amount of boron as the re-injected condensed steam and accompanying boron are re-cycled.
This study describes boron cycling at the Darajat Reservoir, and correlation of bottom-hole superheat and produced non-condensable gas trends of some older wells at Darajat. It is suggested that condensate migrates away from injectors as liquid and partially boils concentrating the boron. Through time steam boiled from the more concentrated liquid injectate boils and increases the boron and decreases the non-condensable gas of the Darajat Reservoir. Another effect of the migration of partially boiled liquid injectate is that expected superheat increases are muted and delayed. This study will be used to help develop a 3D-conceptual reservoir model, to aid in the development of production and injection strategies for management of the Darajat Resource.