EXPLOITING HIGH-RATE INJECTION AND FRACTURING TO IMPROVE AREAL THERMAL CONFORMANCE IN CYCLIC STEAM STIMULATION

Achieving good areal thermal conformance is a key component in develop ing an effective steam-based recovery process. This paper describes a test where high-rate pulsed injection (HRPI) of steam has been used to improve areal thermal conformance as part of an operation that uses c yclic steam stimulation. In this process, steam was repeatedly injecte d at high rates [almost-equal-to 2000 m3/d, cold water equivalent volu me (CWEV)] for relatively short periods (hours), rather than constantl y injecting at lower rates (200 to 300 m3/d) for several weeks or mont hs. The objective of the high-rate injection was to create extensive h orizontal fractures at a well. Then, the heat transport capability of steam flow in the fractures was exploited to improve areal thermal con formance. The well at which this test was conducted is surrounded by s ix observation wells. In the previous 5 years of cyclic steam stimulat ion at the injector, little temperature change had occurred in these w ells. Within hours of starting HRPI, significant heat was seen at thre e of the surrounding observation wells. After several pulses, a fourth observation well showed significant temperature increases. This paper documents the procedures used in the test and data collected during t he test.