Abstracts Category : Other

Sequence stratigraphic analysis & anisotropic elastic moduli determination of the Vaca Muerta Formation, Neuquen Basin, Argentina.

by Murillo Paula Barbosa

The Vaca Muerta Formation (VM) is considered the fourth largest shale oil play in the world with an estimated 27 billion barrels of recoverable oil. The VM, as other unconventional reservoirs, contains layers with substantial velocity anisotropy. Former studies performed an isotropic characterization of the VM. Fernandez-Concheso M. (2015) worked on post and pre-stack seismic inversions to supply a tool to characterize the VM. Bishop (2015) developed a mechanical stratigraphy for the VM to evaluate its influence in the success of stimulation jobs. This study involves sequence stratigraphic analysis as a basis for estimating anisotropic elastic moduli, which can help improve geomechanical models to be built for the VM. Basin floor and slope environments were identified for the VM with unique characteristics. Rock-physics modeling is used to explain the log response of the VM in terms of rock properties. Anisotropy analysis is utilized to describe the VM as a VTI (transverse isotropic with a vertical symmetry axis) model. Parasequences were implemented to group and interpolate well log and core data. Linear relationships were observed between the stiffness coefficients measured on cores. Parameters of those relations (per parasequence) were used to compute stiffness coefficients where not enough data were available. The VTI model was fully described and anisotropic Youngs modulus and Poissons ratio were estimated. I found that acoustic impedance may be used to predict the Total organic content (TOC). TOC influences the hydrocarbon pore volume. A methodology is proposed to calculate the anisotropic elastic moduli. The spatial variations of anisotropic elastic moduli impacts the response of the VM under hydraulic fracturing which should be considered in the design of well-related operations. In summary, this research provides tools for locating sweet spots and optimization of well drilling and stimulations operations, which should help unlock this huge resource.Advisors/Committee Members: Davis, Thomas L. (Thomas Leonard), 1947- (advisor), Vorobiev, Sergey (committee member), TSvankin, I. D. (committee member), Prasad, Manika (committee member).