Identification of Safe Injection Modes for Injection Wells

The target of the work was to determine the safe operating mode for the injection wells to prevent the propagation of hydraulic fractures beyond the target interval into a cup rock in environmentally sensitive offshore oilfield. The ranges of injection pressures and rates as well as monitoring techniques to ensure a cap rock integrity based on geomechanics was defined. The following steps have been taken to achieve the objectives: Our research has shown that previous injection modes have caused propagation of self-induced fractures. In addition, modeling such fractures in the novel planar 3D fracture simulator has excellent convergence with observations of DTS and SNL studies, and shows no fractures propagation beyond the interval of interest. The application of this approach makes it possible to assess the risks associated with top-seal integrity during water injection in the long terms. Use of the latest simulator based on the advanced planar 3D model to simulate the development of self- induced fractures coupled with DTS and SNL monitoring methods proves viability of top-seal integrity control. The study of fall-off tests at different stages of long-term injection allows to determine the current stress-strain state.