ENHANCED OIL RECOVERY
ONE SPOT PILOT
Quick Answers. Entire test sequence is typically completed within about a month.
Established Technology. One-Spot pilots have successfully evaluated: ASP, Surfactant-Polymer, Lignin-Surfactant-Polymer, Alkaline-Polymer, Miscible Hydrocarbon and Carbon Dioxide.
Cost Effective Solution. Existing well and field facilities can be used. One-Spot project costs are generally a small fraction of conventional pilot study costs.
OPERATIONAL STEPS
| 1. |
Measure initial Sor by injecting and producing water plus ester-alcohol tracers through test zone. |
| 2. |
Inject a small EOR process flood into the same zone of known Sor. This flood is scaled to a pore volume (PV) representing a 20-foot radius from the well. |
| 3. |
Inject a small volume of water to move oil/EOR beyond a 20' radius. |
| 4. |
Determine Sor change by conducting a second tracer test. The SWCT test is non-destructive and can be repeated over and over without effecting Sor. |
| 5. |
Compare Sor results before and after EOR process. The Sor change reflects the effectiveness of the EOR process. |
| 6. |
Produce back and monitor the EOR process chemicals. In cases where chemical flooding is tested, the consumption of the surfactants, alkaline agents and polymer is a critical concern for scale up. By back producing the small chemical flood and measuring the remaining chemicals during production we can make a direct assessment of adsorption and competing reaction effects. This step requires an additional one to two weeks of work but is well worth the effort. In AP and ASP flooding, it is critical to know that the oil recovery chemicals remain active and are recoverable on the scale of the One-Spot-Pilot. If the alkaline is spent during the One-Spot-Pilot, for example, more pre-flush is needed to displace the hardness ions. |
MORE INFORMATION
Technical Bulletin » Download PDF
Brochure » Download PDF
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What we learn from a One-Spot-Pilot
The One-Spot-Pilot has become the most popular approach to field implementation of an EOR flood. The One-Spot-Pilot gives the operator direct insights into the following essential issues:
- Is there enough residual oil available to make the flood economical? The initial SWCT test is a direct, in situ measurement of the target oil saturation.
- How does the EOR chemical blend behave in the field? CTI personnel prepare the EOR chemical blend, in the case of chemical flooding, in the field using the same water that will used for the larger scale flood and portable oil field tanks and mixers. If the chemicals are difficult to handle in the field, hard to mix, or easily compromised by field temperature effects, this is learned in the field on a scale of several hundred barrels. CTI field personnel carry out a high degree of quality control chemical analysis to make sure the chemical flood meets laboratory-established specifications.
- How hard is it to inject the flood agents? CTI personnel prepare and inject the chemical or miscible flood agents and learn first hand if there are any injection problems associated with the flood.
- Does the EOR agent mobilize residual oil in the reservoir? The second SWCT test is a direct in situ measurement of exactly how much residual oil is mobilized. If no oil is mobilized, the first and second SWCT test will give identical Sor answers. Hopefully, this is not the case but it is pointed out here to verify that the SWCT test is an unbiased measurement of Sor both before and after the flood.
- In the case of ASP or AP flooding, was the pre-flush adequate? For these cases, a 0.2 PV or 0.3 PV or 0.4 PV etc, is injected before the ASP chemicals to try and displace the hardness ions in the formation water or on the reservoir rock surface. By producing back the small flood bank after the second SWCT test and measuring how much of the alkaline, for example, is recovered, we can make a direct determination of how extensive competing reactions are and answer this question.
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Measure Base Sor Using SWCT
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Inject Small EOR Flood Followed
by Water to Mobilize Oil
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