Horizontal wells combined with multi-stage fracturing technology have contributed to a significant increase in oil and gas production from reservoirs throughout the US. Results are often uneven across a field and between wells, however, due to limited control and characterization of created fractures. With increased application of fracturing in horizontal wells, it is critical to better characterize and monitor where the fractures go both to optimize production and at the same time to ensure fracture containment in the target interval to avoid inadvertent impact to potable water supplies or out of zone methane migration. There is limited understanding and few effective diagnostic tools available to characterize the actual fracture placed around the well, particularly in unconventional and naturally fractured formations GeoMechanics has analyzed well deformation and damage related to fractures which extend at oblique angles to the horizontal wellbore, noting from field observations and preliminary numerical modeling that deformation is highly dependent on fracture angle, opening displacement, and length. We propose to develop and investigate advanced techniques and tools to analyze dynamic static large strain deformation in casing during and after fracture operations, to characterize the orientation, width, and extent of created fractures. During Phase I we will summarize and document theoretical and analytical solutions describing strain imposed on well casing due to single and multiple hydraulic fractures of various size and orientation. We will also summarize and document the latest strain deformation monitoring techniques. We will develop sample integrated geomechanics and flow models for realistic field conditions involving single and multiple stage horizontal well fracturing, and apply the model to predict casing deformation due to a range of fracture geometry conditions. We will then develop and document inversion techniques to recover the fracture parameters from the casing strain observations, identifying and documenting typical required measurement accuracy, number of observations, and ideal locations. Finally, the techniques developed will be compared and the effectiveness demonstrated with actual field data. Successful development and demonstration of this new technique will provide industry with a more cost-effect and improved technique to characterize single and multiple fractures in a wide range of geologic conditions. This information can lead to more effective production and more reliable evaluation of environmental risks, including enhanced protection of potential underground sources of drinking water.
