Abstract: A method of determination of fluid pressures in a subsurface region of the earth uses seismic velocities and calibrations relating the seismic velocities to the effective stress on the subsurface sediments. The seismic velocities may be keyed to defined seismic horizons and may be obtained from many methods, including velocity spectra, post-stack inversion, pre-stack inversion, VSP or tomography. Overburden stresses may be obtained from density logs, relations between density and velocity, or from inversion of potential fields data. The seismic data may be P-P, P-S, or S-S data. The calibrations may be predetermined or may be derived from well information including well logs and well pressure measurements. The calibrations may also include the effect of unloading. The determined pressures may be used in the analysis of fluid flow in reservoirs, basin and prospect modeling and in fault integrity analysis.

Abstract: A method of determination of fluid pressures in a subsurface region of the earth uses seismic velocities and calibrations relating the seismic velocities to the effective stress on the subsurface sediments. The seismic velocities may be keyed to defined seismic horizons and may be obtained from many methods, including velocity spectra, post-stack inversion, pre-stack inversion, VSP or tomography. Overburden stresses may be obtained from density logs, relations between density and velocity, or from inversion of potential fields data. The seismic data may be P-P, P-S, or S-S data. The calibrations may be predetermined or may be derived from well information including well logs and well pressure measurements. The calibrations may also include the effect of unloading. The determined pressures may be used in the analysis of fluid flow in reservoirs, basin and prospect modeling and in fault integrity analysis.

Abstract: The problem of detecting sedimentary formations having an abnormally high fluid pressure that are underneath a relatively impermeable formation having normal fluid pressures is addressed. At shallow depths, a formation with abnormally high fluid pressure has a shear velocity that is close to zero, and is thus significantly different from the shear velocity of overlying sediments. The high shear wave velocity contrast is detected by measuring a change in the amplitude of seismic waves reflected from the top of the abnormally pressured formation. This may be done by an amplitude versus offset (AVO) analysis of the reflected amplitudes of compressional or shear reflections. Measurements of the amplitude of reflected shear waves from a formation at some depth below the anomalous zone are may also be used to detect the presence of abnormally pressured intervals with low shear velocity and high shear wave attenuation.

Abstract: A method for modeling geological structures includes obtaining seismic data and using these data to derive an initial density model. Potential fields data is used to update the initial geophysical model by an inversion process using vector or tensor components of gravity and/or magnetic data. In regions having an anomalous density zone, the initial model includes a topographic or bathymetric surface and a 2D or 3D density model including the top of any zones of anomalous density. Potential fields data is then used to derive the lower boundary of the anomalous density zones by using an inversion process. The final density model from the inversion may be further refined using the seismic data in conjunction with the model obtained by inversion of the potential fields data. The model data are integrated two or three dimensions to determine an overburden stress for the subsurface that includes a proper treatment of the anomalous density zone.

Abstract: A method of determination of fluid pressures in a subsurface region of the earth uses seismic velocities and calibrations relating the seismic velocities to the effective stress on the subsurface sediments. The seismic velocities may be keyed to defined seismic horizons and may be obtained from many methods, including velocity spectra, post-stack inversion, pre-stack inversion, VSP or tomography. Overburden stresses may be obtained from density logs, relations between density and velocity, or from inversion of potential fields data. The seismic data may be P-P, P-S, or S-S data. The calibrations may be predetermined or may be derived from well information including well logs and well pressure measurements. The calibrations may also include the effect of unloading. The determined pressures may be used in the analysis of fluid flow in reservoirs, basin and prospect modeling and in fault integrity analysis.

Abstract: A method of determination of fluid pressures in a subsurface region of the earth uses seismic velocities and calibrations relating the seismic velocities to the effective stress on the subsurface sediments. The seismic velocities may be keyed to defined seismic horizons and may be obtained from many methods, including velocity spectra, post-stack inversion, pre-stack inversion, VSP or tomography. Overburden stresses may be obtained from density logs, relations between density and velocity, or front inversion of potential fields data. The seismic data may be P-P, P-S, or S-S data. The calibrations may be predetermined or may be derived from well information including well logs and well pressure measurements. The calibrations may also include the effect of unloading. The determined pressures may be used in the analysis of fluid flow in reservoirs, basin and prospect modeling and in fault integrity analysis.

Abstract: Pulsed power sources are installed in one or more wells in the reservoir interval. The pulse sources include (1) an electrohydraulic generator that produces an intense and short lived electromagnetic pulse that travels at the speed of light through the reservoir, and an acoustic pulse from the plasma vaporization of water placed around the source that propagates through the reservoir at the speed of sound in the reservoir and (2) an electromagnetic generator that produces only an intense and short lived electromagnetic pulse that travels at the speed of light through the reservoir. The combination of electrohydraulic and electromagnetic generators in the reservoir causes both the acoustic vibration and electromagnetically-induced high-frequency vibrations occur over an area of the reservoir where stimulation is desired.

Abstract: A method for determining formation pore pressure uses seismic data to derive an initial density model. Potential fields data are then used to derive the lower boundary of anomalous density zones (e.g., salt, shale diapirs, igneous or magmatic formations) by an inversion process. The model data are integrated vertically in two or three dimensions to determine an overburden stress for the subsurface that includes a proper treatment of the anomalous density zone. The velocity measurements determined from the seismic data are used to determine the effective stress based on appropriate relationships between effective stress and velocity. The fluid pressure is then obtained as the difference between the overburden stress and the effective stress.

Abstract: A method for modeling geological structures beneath anomalous density zones includes receiving seismic data and using this data to derive the top of a geologic model. Non-seismic data, such as gravity or magnetic data are used to derive the lower boundary of the geologic model in an inversion process. In one embodiment, the predicted parameters are combined with seismic data to obtain a depth image and to derive a velocity model in delineating formations of interest. In another embodiment, the processed seismic data is used to further constrain the inversion of the non-seismic data. Another novel aspect of the invention is the filtering of the non-seismic data during the inversion process in a manner that is consistent with Laplace's equation.

Abstract: Pulsed power sources are installed in one or more wells in the reservoir interval. The pulse sources include (1) an electrohydraulic generator that produces an intense and short lived electromagnetic pulse that travels at the speed of light through the reservoir, and an acoustic pulse from the plasma vaporization of water placed around the source that propagates through the reservoir at the speed of sound in the reservoir and (2) an electromagnetic generator that produces only an intense and short lived electromagnetic pulse that travels at the speed of light through the reservoir. The combination of electrohydraulic and electromagnetic generators in the reservoir causes both the acoustic vibration and electromagnetically-induced high-frequency vibrations occur over an area of the reservoir where stimulation is desired.

Abstract: Pulsed power sources are installed in one or more wells in the reservoir interval. The pulse sources include (1) an electrohydraulic generator that produces an intense and short lived electromagnetic pulse that travels at the speed of light through the reservoir, and an acoustic pulse from the plasma vaporization of water placed around the source that propagates through the reservoir at the speed of sound in the reservoir and (2) an electromagnetic generator that produces only an intense and short lived electromagnetic pulse that travels at the speed of light through the reservoir. The electromagnetic pulse produces a high frequency vibration of the reservoir that is active at the scale of the pores in the rock that acts to decrease the effective viscosity of the oil and lower the resistance of the crude oil to flow, and the acoustic pulse from the plasma effect enhances the mobility of the crude further.