Development of an Optical based Single Well Seismic System (OSWS) for Improved Characterization and Monitoring of Fractures in UOG Systems

All subsurface energy production and storage applications require higher resolution large-volume true depth imaging and multi-mode sensing to be environmentally compliant, more sustainable, and economically efficient. This includes Unconventional Oil and Gas (UOG) production which today leaves 92-95% of the oil behind and Underground Gas Storage (UGS) with 20% of the current 15,000 wells at risk for leakage. It also includes injection and long-term storage of captured CO2 underground, with 14,000 wells estimated to be drilled in the next 28 years, to reduce the carbon in the atmosphere, and finally making high temperature Enhanced Geothermal (EGS) economically feasible. The Paulsson Single Well Seismic System (SWSS) will for the first time allow large volume high-resolution imaging around boreholes reaching 1,000 – 5,000 ft out from the survey wells depending on the depth of the wells, the geology, the formation velocities, and attenuation. The system will allow high-resolution imaging and multi-mode sensing of faults, fault zones and complex geology mapped from vertical and horizontal wells. The characterization of the geological architecture and reservoir components will be dramatically improved by recording 9C (3C x 3C) vector-seismic data from clamped high-frequency directional 3C seismic sources deployed in the same vertical or horizontal borehole that contains an array of high-fidelity optical seismic 3C vector sensors and optical pressure and temperature sensors. This will allow for effective development of and energy extraction from underground reservoirs by mapping in real-time the faults, induced fractures and fluid flows, both near and far from the deployment wells. The vector sources and sensors can be deployed in either the borehole used for injection or production or in nearby boreholes, providing for real-time monitoring of the production processes. A full production system will ultimately be developed, utilizing the real time data and Machine-Learning (ML), to optimize all the control parameters of the production processes to maximize the control of production and storage reservoirs, and resource recovery rates. Paulsson developed a high-frequency prototype borehole axial vibrator under the SBIR Phase-I project, which was extensively tested between 10-1,610Hz. In a small- scale field test this vibrator generated higher frequency and S/N ratio data than a 110 lbs. impulsive weight-drop source. Data were concurrently recorded using geophones and our Fiber Optic Seismic Vector Sensors (FOSVS). The detailed design of the borehole clamped axial seismic vibrator source was completed in Phase-II, with the objective of using our small-diameter drill pipe deployment system concurrently with our FOSVS, thereby providing an industry unique 9C single-well seismic capability. We will extend the current borehole 1C source to 3C, with clamped seismic sources built and deployed in Phase-IIB utilizing our existing proven field deployment system. The 3C source units will be tested in the laboratory and in the field with our 3C FOSVS receivers and our all optical pressure and temperature sensors. Accurate mapping and monitoring of the geology, fractures, faults, and fluid flow in the subsurface will support field development and storage operations, leading to dramatic improvements. This will be achieved using the 9C single-well seismic system which can map and monitor faults, fractures and production at a distance of 1-5,000 ft from UOG, UGS, CCS, conventional oil, and geothermal wells, thereby enabling smarter, more efficient, and safer operations.