(90a) Using Temperature Measurements from Production Logging/Downhole Sensors to Diagnose Multistage Fractured Well Flow Profile

The temperature log as a part of a production logging package has been used in the industry for many years. Recent developments in downhole fiber optic sensing technology introduced a more continuous measurement of temperature both temporally and spatially for flow diagnosis. One of the powerful applications of temperature measurements is to diagnose multistage fracture treatments. Because the fiber optic temperature measurements can be available during fracturing, during shut-in, and during production, the integrated interpretation provides information of fracture/flow distribution. This information helps to understand what happened during the fracture treatment stages, to identify problems in treatment design and execution, and to improve the efficiency of multistage fracture stimulation.

The key component of fracturing diagnosis by temperature measurements is the interpretation models. In this paper, we will introduce the models developed for the purpose of fracture diagnosis. The mathematical models are built on mass, momentum and energy balances of each component (reservoir, fracture, well completion and wellbore) in the system, and the components are linked through the boundary conditions. All models can be solved numerically, but for computational efficiency, analytical/semi-analytical solutions are preferred when available. To correctly simulate heat transfer during fracture propagation, a fracture geometry model with appropriate leakoff description is integrated in the model buildup. For flow problem in a fractured well, analytical model, streamline approach and reservoir simulation can all be the solution methods. The paper compares the advantages of each approach.

Field cases from the Eagle Ford, the Marcellus, and the Vaca Muerta shale formations will be presented in the paper to illustrate how the models can be used to generate the fracture/flow distribution. The results show that temperature measurement is a comprehensive tool for fracture diagnosis.