Involvement of Brine in Oil Recovery Processes
Oilfield brine is both a by-product during oil extraction and can also be used as the ‘leaching carrier’ for mature (tertiary) oil fields. In general, new wells initially produce only oil/gas (hopefully long term) but as the oil reservoir becomes depleted, water from nearby brine aquifers tends to encroach into the reservoir and oil bearing strata.
Managing and minimizing this water production is one of the most important parts of the field of petroleum engineering.
There are a variety of geological and geophysical factors behind the rate of water production, but in simple terms almost all oil wells eventually start producing brine. And eventually that brine can be repumped back down the well after its oil content has been salvaged. This can be a continuous process.
Generally speaking, the older the well, the more brine and less oil it produces. When the cost to treat the oil bearing brine is more than the value of the oil produced, the well is abandoned and should be capped. The executives of FORTecx have considerable experience in operating tertiary wells in east Texas, using beam pumps (aka nodding donkeys) and venturi processes, so as to process brine containing as little as 1% of oil. However, as the % oil recovery drops, the costs per barrel escalate, so such tertiary wells are very susceptible to the varying ambient values of oil. They can become uncompetitive ‘overnight’.
Oil Recovery from Brine
The traditional method is by simply letting gravity do the work. Because oil is less dense than water, it will float to the top if left to settle long enough. This can be done in open ponds or specially designed ‘Gun Barrel Separators’.
However, this is a very slow process, sometimes taking weeks or months and with open ponds, they are subject to rain fall and many other contaminant elements, both organic and inorganic.
In addition, simple gravity separation (phase separation) does not precipitate any permanent or semi-permanent oil/water emulsions that have formed. A more effective process for separating oil from brine is by the use of demulsifiers, which break down any emulsions formed between the oil and water phases.
Demulsifiers are chemicals specifically designed to destabilize and separate emulsions by reducing the interfacial tension between oil and water droplets, thus reversing coalescence and facilitating phase separation.
A general process for separating oil from brine using demulsifiers is as follows:
- Selection of Demulsifier: Choose an appropriate demulsifier based on factors such as the composition of the emulsion, temperature, salinity, and other conditions specific to the application. Different types of demulsifiers may be required for different types of emulsions.
- Dilution: Dilute the emulsion by adding water or adjusting the brine concentration if necessary. This step can help reduce the viscosity of the emulsion and improve the effectiveness of the demulsifier.
- Demulsifier Addition: Add the demulsifier to the emulsion at the recommended dosage. The demulsifier can be added directly to the emulsion or mixed with a carrier solvent for better dispersion.
- Mixing: Agitate or mix the emulsion thoroughly to ensure proper dispersion of the demulsifier throughout the mixture. Mixing helps promote contact between the demulsifier molecules and the oil-water interface, facilitating the destabilization of the emulsion.
- Coalescence: Allow sufficient time for coalescence to be broken down. Demulsifiers work by reducing the interfacial tension between oil and water droplets, allowing then small, separated droplets to coalesce, forming larger droplets that are easier to separate.
- Phase Separation: After the demulsifier has been given adequate time to work, allow the mixture to settle to allow for phase separation. Gravity separation can be enhanced by using centrifuges, or other separation equipment as needed.
- Separation and Recovery: Once phase separation has occurred, separate the oil phase from the brine phase using appropriate separation equipment. The recovered oil can be further processed or treated as necessary, while the treated brine can be disposed of or reused as appropriate.
- Monitoring and Optimization: Monitor the separation process and adjust the demulsifier dosage or other parameters as needed to optimize separation efficiency and quality of the recovered oil and brine, at the least cost.
Disposal of Brine
Brine is usually disposed of by reinjecting it into the ground, on the edges of the same oil field , as a way of flushing more oil out of the wells, or in dedicated disposal wells. Such brine can be very toxic because the subterranean environment is loaded with dissolved metals and can have naturally occurring radioactivity. It’s certainly possible to extract and recover many types of metal from brine eg. it’s an existing method of uranium mining in many parts of the world.
Also great care must be taken when reinjecting brine if it passes through freshwater tables etc. It can severely affect drinking water and result in significant penalties and costs.
FORTecx R&D
FORTecx IP is split into 2 overarching disciplines:
* leading edge demulsifiers and emulsifiers, that are not only highly effective but due to their potency, provide for very low dosing ratios, which determines their most economic value to FORTecx clients.
* advanced wastewater treatment formulas and processes – SEE: “Residual Water Treatments” section.
As with all FORTecx chemical formulas, all its elements and ingredients are ‘green’, sourced from sustainable processes and eco safe.
IP& Patents
As required by its clients (on a virtual bespoke basis), FORTecx continues to improve the strength, effectiveness, versatility and costing, of both its demulsifiers and its wastewater formulas and processes.
As significant milestones are achieved, updated patents will be filed.