Petrophysics and software development, and 3D analytical modeling of stimulated reservoir volume for tight and shale reservoirs
Creators: name: Yu, Guang
Publisher: name: Graduate Studies
Year: 2012
Subjects: subject: Engineering--Petroleum
subject: petrophysics
subject: Software Development
subject: Stimulated Reservoir Volume
subject: Shale
subject: tight reservoirs

description: Shale and tight formations have long been a challenge for petrophysical interpretation due to their complexity. Equally complex is the estimation of the Stimulated Reservoir Volume (SRV) in vertical and horizontal wells that have been hydraulically fractured. The methodologies available to address these problems require complete data sets, including advance well logs, that most of the time are not available particularly in the case of horizontal wells. In order to facilitate these evaluations when the available data are scarce, the research presented in this thesis concentrates on developing: 1) A new method for evaluation of shale reservoirs, which is extendable to the case of tight formations. 2) A new 3D analytical model for calculating the SRV. 3) A new software system that integrates the petrophysical methods developed in this thesis as well as previous methods developed by members of the GFREE Research Team at the University of Calgary. Item 1 includes the development of a quick yet accurate method for petrophysical interpretation of shale reservoirs with commonly available well logs. The method extends Pickett plots from the estimation on only water saturation to the inclusion of Total Organic Carbon (TOC) and Level of Organic Metamorphism (LOM), and to the identification of dominant flow types concentrating particularly on distinguishing between viscous (continuous) vs. diffusion-like flow at any pressure of interest. Two examples are presented to illustrate the method application in different shale reservoirs. The same approach is used for tight gas formations without the inclusion of TOC and LOM. Item 2 includes the development of a new 3D analytical model capable of simulating stimulated reservoir volume (SRV) in an anisotropic reservoir based on information from microseismic data. The model is extended next to the case where detailed information is not available. Porosity and permeability from petrophysical models discussed in this thesis can be used as input data for the 3D analytical model. The application of this model for both horizontal and vertical wells is demonstrated with the use of two case studies, one from the Barnett shale and one from the Marcellus shale in the United States. Item 3 incorporates the petrophysical evaluation methods into a software system. Practical workflows for performing the calculations are organized and integrated. System development life cycle (SDLC) and object-oriented programming techniques are utilized for the development of this software. Two case studies using data from both tight and shale reservoirs are presented to illustrate the software development and the application of the software. In addition to the TOC, LOM and dominant flow regimes (continuous vs. diffusion-like) mentioned above, the software also incorporates other critical petrophysical parameters such as matrix, fracture, non-connected and effective porosities, water saturation, Young’s modulus, Poisson’s ratio, and minimum principal horizontal stress.