Diagnosis of Production Performance After Multistage Fracture Stimulation in Horizontal Wells by Downhole Temperature Measurements Academic Article uri icon

abstract

  • Summary Downhole temperature data that are measured by production logging tools (PLTs) or fiber-optic distributed-temperature sensors are used frequently today to diagnose multistage fracture treatments in horizontal or highly deviated wells. These temperature data, measured at the wellbore during fracturing and post-fracture, provide important transient-flow information that helps engineers understand the process of fracturing and the performance of fractured wells, to optimize fracture design. The interpretation models developed to translate temperature data to flow conditions can be fully numerical simulations or analytical/semianalytical approaches. With reasonable assumptions, analytical/semianalytical models are more suitable for real-time field applications. This paper presents the application of a coupled semianalytical fracture model and a wellbore model to predict temperature and pressure behavior in multiple-fracture horizontal wells during production. The thermal model calculated the heat transfer in the fracture/reservoir/wellbore system, considering subtle temperature changes caused by the Joule-Thomson cooling effects. The results showed that transient temperature behavior is sensitive enough to estimate the fracture-initiation points, the number of created fractures, and the flow profile along the wellbore. We discuss the characteristics of transient temperature behaviors and flow-rate distribution along a fractured horizontal wellbore. The temperature decreases when the gas entering the wellbore is strong at the toe and weak toward the heel and when the fractures are more evenly created along the wellbore because of the fluid mixture inside the wellbore. Two field cases are presented to illustrate the application of the temperature model to understand the fracture/flow distribution. The estimation of flow-rate distribution from the temperature model is compared with the interpretation of flow by PLTs. Although this is a single-phase gas model, we can identify the water sump at certain locations by identifying fast temperature recovery to geothermal value. Flow distribution from the temperature model presents a consistent trend with PLT measurement. It is more sensitive to the fluid entries (fracture locations) and less sensitive to the influence of the flow pattern inside the wellbore when compared with PLTs. This work shows that temperature data can identify fracture locations (fluid-entry points) and estimate flow-rate distribution. Because of the complexity of flow in a multistage, fractured horizontal well, any measurement alone would not be able to provide clear description of the created fracture system. A combination of temperature data with other diagnostic methods will provide a better description of the production performance of such a well.

published proceedings

  • SPE PRODUCTION & OPERATIONS

author list (cited authors)

  • Cui, J., Zhu, D., & Jin, M.

citation count

  • 35

complete list of authors

  • Cui, Jingyuan||Zhu, D||Jin, Minquan

publication date

  • November 2016