SBIR-STTR Award

Our aim is to increase low oil level recoveries from tight shale formations by designing formation-specific water chemistries that simultaneously minimize oil reservoir adhesion and frac water usage- Tight shale formations in North America contain billions of barrels of oil, however, the industry average recovery is typically well below 10%, especially compared to an average of 30% for conventional reservoirs- Battle Born Algorithms will develop an algorithm that predicts salinity-driven imbibition in tight formations so that fracking fluids can be precisely tailored to produce more oil through a combination of osmotic countercurrent imbibition and wettability alteration- The work will be done in conjunction with researchers from Sandia National Laboratories who have worked out frac water chemistry controls over wettability alteration in tight formations- Tight formations imbibe frac water through capillary and osmotic effects where it displaces oil into fractures and interbeds with large pores and low capillary pressure- The extent of imbibition, and the amount of oil recovered, depends on the osmotic pull of water into the system and wettability alteration-the degree to which the frac water decreases oil-reservoir adhesion and draws water into pores and pushed oil out- For example, dilutefracfluidswillbemorestronglyimbibedintohypersalinereservoirsbecauseofthegreater osmotic pressure difference thus producing more oil- However, lower salinities might result in greater oil adhesion, reducing oil mobility and recovery- Conversely, use of more concentrated fluids will reduce counterflow but enhance oil mobility by decreasing adhesion-The idea is that both osmotic and adhesion forces must be known to design a frac fluid that maximizes oil recovery- A major benefit of an optimized water composition would be reduction of fracking demands for freshwater-

The current recovery from Unconventional Oil and Gas (UOG) reservoirs is a small fraction of the Original-Oil-In-Place (OOIP). Recovery rates as low as 6-8% are referenced in the literature. To improve the recovery rates much better real-time reservoir characterization methods must be developed and deployed. Borehole seismic acquisition techniques are the most effective and highest resolution techniques to investigate complex UOG reservoirs. The characterization of the stratigraphic and structural architecture and the geological components making up these reservoirs will be dramatically improved by recording vector seismic data from clamped high frequency directional seismic sources deployed in the same vertical, deviated or horizontal borehole as an array of high-fidelity optical seismic vector sensors. This will allow for the safe and the effective development of UOG resources by mapping in real time natural and induced fractures and flows both near and far from the deployment wells. The vector sources and sensors can be deployed in either the borehole used for fracturing, providing for the highest resolution, or in a nearby borehole, providing for real time monitoring of the fracturing process. Paulsson developed an effective and high-frequency prototype borehole axial, or vertical, vibrator under the SBIR Phase I project. The vertical vibrator was tested between 10-1,600 Hz and extensively tested between 10-210 Hz and 10-410 Hz. In a small-scale field test the vertical vibrator proved to generate higher frequency data than an impulsive source deployed at the same location. Data were concurrently recorded using both standard geophones and Paulsson Fiber Optic Seismic Vector Sensors (FOSVS). The borehole 3C clamped seismic sources will be designed, built and deployed in Phase II. We plan to build a field system consisting of borehole axial, torsional and radial vibrators. The units will be tested in the laboratory, in a local field test and in a deep borehole provided by an oil company. The new clamped seismic sources will be designed to be deployed using our small diameter drillpipe deployment system concurrently with our existing optical clamped 3C receivers providing for an industry unique 9C single- well seismic capability. Commercial Applications and Other

Benefits:
Accurate mapping and monitoring of the geology and the fractures in UOG systems will significantly increase recovery of the vast resources present in these reservoirs. Paulsson will achieve this with the proposed 9C single-well seismic system. A single-well seismic system can map and monitor faults, natural and induced fractures and salt-domes at a large distance from the wells in UOG, conventional oil reservoirs, geothermal reservoirs and CO2 storage reservoirs.