Marine to borehole electromagnetic survey

An apparatus comprising:

• a marine electromagnetic source immersed in marine water above a seabed, wherein the marine electromagnetic source is configured to generate electromagnetic waves;
• one or more borehole receivers dispersed in one or more borehole locations to measure one or more borehole signal measurements, wherein the one or more borehole signal measurements comprise propagations of the electromagnetic waves received at respective borehole receivers;
• one or more marine receivers dispersed in one or more seabed locations to measure one or more seabed signal measurements, wherein the one or more seabed signal measurements comprise reflections of the electromagnetic waves from earth subsurface strata of the seabed received at respective marine receivers;
• and
• a processor configured to calculate a three-dimensional property distribution of a reservoir of interest by:
• using the one or more seabed signal measurements to determine electromagnetic parameters of the earth subsurface strata intervening between the seabed and the reservoir of interest via a first inversion operation;
• using the one or more borehole signal measurements and the electromagnetic parameters of the earth subsurface strata to generate inverted one or more borehole signal measurements via a second inversion operation;
• and
• determining the three-dimensional property distribution of the reservoir of interest based on the inverted one or more borehole signal measurements.

A method, comprising:

• providing, from one or more borehole receivers in one or more boreholes, one or more borehole signal measurements with corresponding depths, wherein the one or more borehole signal measurements comprise propagations of electromagnetic waves generated by an electromagnetic source and received at respective borehole receivers, and wherein the electromagnetic source is immersed in marine water above a seabed and configured to generate the electromagnetic waves;
• providing, from one or more marine receivers at the seabed, one or more seabed signal measurements with corresponding seabed coordinates, wherein the one or more seabed signal measurements comprise reflections of the electromagnetic waves from earth subsurface strata of the seabed received at respective marine receivers;
• using the one or more seabed signal measurements to determine electromagnetic parameters of the earth subsurface strata intervening between the seabed and a reservoir of interest via a first inversion operation;
• using the one or more borehole signal measurements and the electromagnetic parameters of the earth subsurface strata to generate inverted one or more borehole signal measurements via a second inversion operation;
• and
• determining, via a processor, a three-dimensional property distribution of the reservoir of interest from the inverted one or more borehole signal measurements.