Direct Reservoir Imaging
The seismic methods being used today for imaging reservoirs rely on the propagation of seismic waves through earth and mapping the reflected signals from the interfaces of the subsurface rocks. The current science of seismic imaging is based on the assumption that the earth behaves as an elastically linear medium. This assumption over-simplifies the behavior of the fluid-saturated reservoir rock and avoids the complexity of dealing with the dynamic physical properties of the oil and gas fluids stored in the porous reservoir rocks. What is needed is the development of a new methodology that will provide a new seismic approach that will allow us to map the reservoir porosity profile, permeable flow units, location and orientation of fractures, and the distribution of different viscosity pore fluids.
Criteria for the future technology should be such that it has to directly indicate the subsurface accumulations of the hydrocarbons. This new technology needs to be sophisticated enough to satisfy the requirements of the large companies with budgets of tens of billions of dollars for mapping the interwell geologic profile of the reservoir rocks and their flow characteristics (including porosity, permeability, pockets of oil left behind) to achieve more efficient secondary and tertiary recovery, and at the same time be simple enough that it can be effectively used by a small-size independent explorationist, whose budget may be limited to finding small pockets of oil reserves in his or her local area of operation. Ideally, it is not going to be capital-intensive and the current hardware/software can be used, so that the rewards will be directly related to the exploration efforts of the oil companies.
Using current extraction capabilities, hydrocarbon reserves can be economically produced if a seismic imaging technology is introduced to provide unique and unambiguous results for identifying and locating the hydrocarbons in the reservoirs. The introduction of a new technology, which can make direct measurements of the reservoir pore fluids and the relevant reservoir characteristics, will open a new world of possibilities for oil and gas exploration and production.
For oil and gas, Nonlinear Seismic Imaging is considered a breakthrough technology that will solve many of the complex challenges we will face in the next few decades as the easy oil has been extracted. Using Nonlinear Seismic Imaging, we do not lose anything that the existing imaging provides. Nonlinear Seismic is additional information which gives us a better understanding of the reservoir rocks and their pore fluids that are of the primary interest in exploration for oil and gas.
The topic covers this technology for direct reservoir imaging, which is based upon mapping the changes in the reflection and propagation characteristics of the seismic waves according to the physical properties of the reservoir fluids and the pore space. The work so far has resulted in a portfolio of U.S. Patents that describe new seismic imaging methods to directly map the porosity, permeability, fractures, and reservoir fluids. The most recent invention is Direct Reservoir Signature using the Drag Wave™.
AAPG Search and Discovery Article #90205 © AAPG Geoscience Technology Workshop, Permian and Midland Basin New Technologies, September 4-5, 2014, Houston, Texas