Distributed seismic sensing for in-well monitoring

A seismic sensing system, comprising:

• an outer cable mechanically coupled to a formation, wherein the outer cable experiences one or more seismic waves propagating through the formation;
• an outer fiber component embedded in an exterior of the outer cable, wherein the outer fiber component is coupled to a distributed acoustic sensing system, and wherein a centralizing component is disposed exterior to the outer cable;
• a solid between the seismic sensing system and the formation, wherein the solid provides mechanical coupling between the seismic sensing system and the formation, and wherein the solid comprises fillers to optimize acoustic impedance;
• an inner cable disposed within the outer cable;
• an inner fiber component proximate to the inner cable, wherein the inner fiber component is coupled to the distributed acoustic sensing system, and wherein the inner fiber component is more sensitive to strain and displacement measurements than the outer fiber component;
• an innerduct between the outer cable and the inner cable, wherein the innerduct comprises one of a liquid or a gas that minimizes transference of one or more seismic S-waves of the one or more seismic waves from the outer cable to the inner cable while allowing transference of one or more seismic P-waves of the one or more seismic waves;
• a plurality of centralizers disposed in the innerduct between the outer cable and the inner cable, wherein the plurality of centralizers allow propagation of the one or more seismic P-waves to the inner cable while minimizing propagation of the one or more seismic S-waves to the inner cable, wherein the inner fiber measures the one or more seismic P-waves;
• and
• wherein the inner fiber component measures the one or more seismic P-waves when the one or more seismic P-waves experienced by the inner cable cause strain and displacement on the inner fiber component;
• and
• wherein the outer fiber component measures a combined effect of the one or more seismic P-waves and the one or more seismic S-waves, when the one or more seismic P-waves and the one or more seismic S-waves experienced by the outer cable cause strain and displacement on the outer fiber component.