Inversion Scheme for Predicting Petrophysical Properties in the Blake Ridge Methane Hydrates Field from 3d Seismic Survey Data

Open Access
Author:
Braun, Keith Eric
Graduate Program:
Energy and Mineral Engineering
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
April 06, 2016
Committee Members:
  • Eugene C Morgan, Thesis Advisor
  • Shimin Liu, Thesis Advisor
  • Sridhar Anandakrishnan, Thesis Advisor
  • Luis F Ayala H, Thesis Advisor
Keywords:
  • hydrates
  • bayesian inversion
  • MCMC
  • petroleum
Abstract:
Accurately predicting petrophysical properties in a reservoir can be a very challenging process. Since most hydrocarbon reservoirs occur at extreme depths (> 5000 ft), very advanced tools must be used in order to estimate the values within the reservoir. These rock and fluid properties are predicted at one spot in the reservoir, however if there are multiple wells within the reservoir, then there can be multiple estimates, and an interpolation between those wells can be made, but the accuracy is likely to be compromised. Furthermore, since the downhole measurement of rock and fluid properties in a reservoir requires a large initial investment, it may be a total bust if the values collected prove the reservoir to be economically infeasible. This signifies the overwhelming importance of obtaining rock and fluid properties from the surface, to achieve the same results without such a large initial investment. This project applies an inversion scheme to a previously created model which predicts the absorption quality factor given the rock and fluid properties. Due to the inverse relationship between the absorption quality factor and the attenuation associated with seismic waves, the most important feature of the work is that it can predict these petrophysical properties from surface measurements of attenuation after a seismic survey is performed. This process may prove to be extremely beneficial to the oil and gas industry because it can determine rock and fluid properties by taking a seismic survey of the area instead of drilling a well and using expensive tools to predict these values. The proposed model is applied to a methane hydrate zone offshore the eastern coast of the United States in Blake Ridge.