Real Time Fracture Placement and Completion Design Using an Azimuthal LWD Sonic and Spectral Gamma Ray Analysis for an Anisotropic Unconventional Reservoir Evaluation

Abstract

The geological complexities of shale formations dominated by lamination deposition mechanisms make formation evaluation a challenge for hydraulic fracture operations. Logging While Drilling technologies have evolved to provide valuable information for a reliable approach in anisotropic shales. One of the most frequent considerations is well productivity and how the new technologies and evaluation methods can help to mitigate the uncertainty of the completion and improve fracturing performance. The incorporation of the TIV anisotropy evaluation from LWD azimuthal acoustic measurements can help characterize the impact of the laminations stage by stage or even a more detailed cluster by cluster analysis. Information from the LWD azimuthal sonic tool can help provide a better understanding in regards to the rock mechanical behavior in horizontal shale wells, as well as the brittleness interpretation providing a more realistic approach to the lamination structure of the shale deposition. Quantifying TIV anisotropy is a very important key evaluation factor to optimize the completion program likewise the well productivity. In conjunction with the LWD azimuthal sonic information, the LWD spectral gamma ray measures isotope concentrations (such as Uranium, Potassium, and Thorium) can be confidently integrated into the unconventional petrophysical interpretation calculations of Total Organic Content. This analysis is incorporated with the geomechanical and anisotropy evaluation to select the best fracture placement and design in an unconventional environment. The anisotropic brittleness analysis identifies the zones where the best fracture propagation will be achieved while the petrophysical analysis indicates how productive these fractures should be. Through the geometric fracture simulation the best set of recommendations for the fracturing operation are developed to predict the conductivity area which contributes to the well productivity. This paper will show the impact of the TIV anisotropy into the geomechanical evaluation, beginning with the unique real-time fracture placement methodology leading to an optimization of the anisotropy analysis to generate the best frac design to avoid expensive completion programs and reduce uncertainty on fracture placement evaluation.