Predicting Fracture Attributes in the Travis Peak Formation using
Quantitative Mechanical Modeling and Structural Diagenesis
Margaretha (Peggy) Rijken
The relationship between micro-fractures and macro-fractures has been established in previous studies. Likewise, subcritical fracture index has been shown to influence natural fracture pattern characteristics such as length, spacing and connectivity. However, the dependence of subcritical index on petrologic features is still largely unknown. In this study, suites of subcritical fracture growth experiments were performed on the Travis Peak Formation to investigate systematic variations in subcritical fracture index. Observations show that subcritical fracture index increases with decreasing grain size. Preliminary testing also suggests that subcritical index varies with carbonate cement. Additional tests were carried out in which artificial cement was added to samples. The added cement resulted in increased strength, but decreased subcritical index. We postulate that this kind of artificial cementing of the sample can be equated to secondary carbonate cementation. Using these techniques and understanding the depositional and diagenetic history of a reservoir provides for natural fracture pattern prediction without extensive sampling.