Exploiting High-Rate Injection and Fracturing To Improve Areal Thermal Conformance in Cyclic Steam Stimulation

Abstract

Summary Achieving good areal thermal conformance is a key component in developing 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 cyclic steam stimulation. In this process, steam was repeatedly injected at high rates [≈ 2000 m3/d, cold water equivalent volume (CWEV)] for relatively short periods (hours), rather than constantly injecting at lower rates (200 to 300 m3/d) for several weeks or months. The objective of the high-rate injection was to create extensive horizontal fractures at a well. Then, the heat transport capability of steam flow in the fractures was exploited to improve areal thermal conformance. The well at which this test was conducted is surrounded by six observation wells. In the previous 5 years of cyclic steam stimulation at the injector, little temperature change had occurred in these wells. Within hours of starting HRPI, significant heat was seen at three 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 the test.