SBIR-STTR Award

Large amounts of oil still remain to be extracted from mature oil fields within the continental United States and throughout the world. Much of this oil was bypassed during initial production and can still be extracted from existing wells. To exploit this oil it is necessary to locate it and to quantify relevant reservoir properties including porosity and oil saturation. Previous work has shown that it is possible to differentiate oil rich zones from those that are not by using acoustic logs recorded within existing cased wells. Phase I of this project will refine existing models and test those models quantitatively using previously acquired data. Computational tools will be developed that can be used by operators who have data from oilfield service companies. Phase II will comprise one or more staged field experiment(s) carried out in collaboration with the oilfield operators to apply these techniques to wells containing potentially exploitable bypassed oil.

Commercial Applications and Other Benefits as described by the awardee:
This project will provide computational tools to help oilfield operators maximize their production from existing wells, resulting in greater return on investment with relatively little additional cost. The techniques are applicable to most of the currently operating oilfields within the continental United States and to a significant number of fields worldwide. The techniques can be applied to crosshole or surface seismic data to map hydrocarbons away from existing wells. These same techniques can also be used in shallow geophysical investigations that utilize acoustic or seismic data to determine saturation and soil properties and the locations of fluid contaminants.

In the continental United States, almost 50% of the original oil in mature fields remains in the ground. In order to exploit this resource, it is necessary to detect and quantify the remaining reserves. This is best accomplished using seismic data acquired in existing cased holes. This project will develop computational tools (software) which utilize newly-developed relationships between compressional/shear wave velocities and properties of interest (namely, porosity, and hydrocarbon saturation). These new relationships have an advantage over existing relationships in which fluid saturation/velocities were used to predict the parameters of interest; these relationships did not work in complex lithologies. Phase I demonstrated that new rock physics models could improve the determination of porosity and fluid saturation and that the pressure dependence of rock properties is also important. The analysis highlighted the importance of obtaining accurate primary data from acoustic waveforms recorded in boreholes. Phase II will develop platform-independent, interactive software to apply these new models to field data. The software will allow the user to perform quality control of full waveform data, carry out velocity analyses, and interpret the resulting velocity logs to quantify fluid saturations and porosity. At the end of Phase II, a beta version of the software will be available for field use by interested partners.

Commercial Applications and Other Benefits as described by the awardee:
The availability of this software should lead to increased use of acoustic detection technologies, resulting in enhanced production in existing oil fields.