Pressure and temperature transient analysis during hydraulic fracturing [electronic resource]

Recent developments in bottomhole data acquisition techniques, such as distributed temperature sensing systems (DTS), have brought attention to the potential increase of information that can be obtained from temperature data. Studies have shown the application of temperature surveys to estimate flowrate profiles, resolve the kind of damage around the well, and improve the robustness of the history matching, among others. Nonetheless, Temperature Transient Analysis (TTA) is not a mature technique and its capabilities have not been explored fully yet. In order to investigate the application temperature analysis to the hydraulic fracturing problem, in addition to pressure analysis, a numerical model was developed to calculate pressure and temperature responses. Regarding the fracture and reservoir fluid flow, a general approach can be adopted, where the formation permeability and fracture characteristics dictate how the fluids flow during and after fracture growth. We developed a comprehensive model, which accounts for the pressure effect on the temperature response, as well as a dynamic fracture that grows and eventually is allowed to close during falloff. In this work we analyzed the temperature and pressure responses during and immediately after hydraulic fracturing in order to improve our knowledge of this complicated physical problem. Based on this study, we can better understand not only the fracture properties, but also the reservoir itself. In addition, sensitivity analysis shows how reservoir permeability can impact final fracturing performance, as well as pressure and temperature responses. The developed model was also applied to simulate minifrac analysis, and a field example is presented that shows a good agreement with the simulated behavior during fracture closure. One of the main contributions of this research is related to the creation of multiple fractures along a horizontal well. This type of well and completion technique have become the key factors for success in development of unconventional resources. Both sequential and simultaneous fracture growth was studied. The presence of reservoir permeability heterogeneity was investigated and the capability of temperature data to identify the existence of such reservoir structure was explored. Capabilities and limitations of information carried by temperature data are presented through different geometry analyses. Also related to horizontal multifractured wells, a case was considered in which one of the fractures interconnects different zones vertically. This study is motivated by microseismic evidence of activity captured out of the target reservoir location. The temperature data analysis during the beginning of production life of the well was shown to be very effective to identify the existence of such interconnection. The difference in temperature due to geothermal gradient allows a very clear temperature signature, where the pressure analysis would not reveal the connection.

Keywords: Energy Resources Engineering.
Advisor: Horne Roland N. primary advisor. Thesis advisor
Tchelepi Hamdi advisor. Thesis advisor
Zoback Mark D. advisor. Thesis advisor