A rapid injection flowback test (RIFT) to estimate in-situ stress and pore pressure

Abstract

Extended leak-off test (XLOT) and pump-in and flow-back test (PIFB) are commonly used during drilling operations to estimate minimum stress. These estimates are adversely affected by hoop stress and drilling mud. Diagnostic Fracture Injection Tests (DFIT) can estimate both in-situ stress and pore pressure, but it takes days or weeks to conduct the test in low permeability formations. In this study, we present a novel rapid injection flow-back test (RIFT) to estimate in-situ stress and pore pressure. Our new approach not only provides an unambiguous way to estimate in-situ stress (even in naturally fractured formations where DFIT fails to do so), but also allows us to estimate pore pressure with data from a test that lasts only a few hours, in addition, the effective fracture volume can also be estimated. Both simulations and field cases are presented to demonstrate the advantages of RIFT, along with a discussion of cautions and the potential pitfalls when designing and executing RIFT.