Anisotropic Stress Profiling and Tectonic Strain Calibration in a Tight Basement Formation

Several wells in the Campamento 1 Field were drilled to target the deeper granitoid basement formations of the Neuquén basin. These wells were evaluated using anisotropic stress modeling to estimate the stress profile and identify suitable intervals to fracture. The effects of lateral tectonic strains are considered in the estimation of the horizontal stress profile, using a vertical borehole acoustic log for stiffness and compliance tensor characterization. The objective of this paper is to show the use of hydraulically induced fracture pressures to calibrate the magnitude of the horizontal stresses in a vertical well. The results show how fracture pressures can help in constraining the magnitude of the lateral tectonic strains. Examples of three wells in the Campamento 1 Field are shown where minifrac data were obtained. A non-constant, depth-dependent tectonic lateral strain model, calibrated with the minifrac data was applied in these wells. This calibration methodology is recommended in formations showing significant anisotropy, as elastic anisotropy in tight formation are important in wellbore completion.