Earth Resources Laboratory :: Describing Fractured Reservoirs

Broken Rocks Flow Hydrocarbons:

Describing Fractured Reservoirs

A large percentage of the world’s oil and natural gas is contained in rocks where it is difficult to extract fluids unless the rocks are broken up by natural or human-made fractures. Historically, it was difficult to produce oil and gas from these fractured reservoirs because it was not possible to predict the location, orientation, and permeability of the fractures in the rocks. We have developed new methods to find subsurface fractures from the scattered seismic energy that is ignored by conventional methods. This scattered energy behaves differently depending on the direction of the illuminating surface seismic energy.

We examine this variation in the scattered energy and can detect areas with high fracturing and as well as the trend and spacing of the fracture systems. These factors are critical for deciding where to drill the next well. Our methods were calibrated with numerical model data, applied to field data and validated by actual well measurements.

This image shows a scattered wavefield analysis of 3-D seismic data volume in a fractured carbonate reservoir under the Adriatic Sea. The left panel shows the seismic faults and well locations—this is the structural information from standard 3-D seismic interpretation. The right panel shows the spatial distribution of fracture density and orientation (the direction of each line segment gives the orientation estimate). The center panel shows the estimated spacing of fracture corridors, with the spacing values given by the color bar on the far right.

Contacts:

Dr. Mark Willis (mewillis@mit.edu)
Dr. Dan Burns (burns@mit.edu)
Yang Zhang (yzhang@mit.edu)
Prof. Nafi Toksoz (toksoz@mit.edu)