Low Alkali Surfactant
Polymer Flood (LASP)
The LASP process applies the same principals as ASP
but use lower concentrations of the alkali. In general,
the LASP process is suitable for formations that have
high divalent cation connate water to minimize the scale
formation. The LASP process applies the same principles
as ASP, but uses lower concentrations of alkali.
In the LASP process, the alkali concentration
is reduced to 0.1% - 0.8%, compared to the 0.6 - 1.5%
generally used for ASP. A very low concentration of
the surfactant is used with the alkali to achieve ultra
low interfacial tension between the residual oil and
the injection fluid. Polymer is generally used to increase
the viscosity of the injection fluid, to minimize channeling,
and provide mobility control.
Advantages:
- Combines the advantages of ASP and SP
- Use 0.1 - 0.6% alkali
- Reduces surfactant adsorption
- Reduces polymer degradation
- Reduce the maintenance cost
- Reduce the scale formation
- Reduces the total cost of the treatment
The approximate savings of the LASP system is shown
below using 0.1% ORS HF surfactant, 1.0% NaOH in the
ASP and 0.1% ORS HF surfactant, 0.2% NaOH in LASP system.
| |
ASP |
LASP |
| Alkali Surfactant, $/bbl* |
$0.63 |
$0.39 |
| Additional Cost Due to Alkali |
$$$ |
$ |
| Equipment Corrosion |
$$$ |
$ |
| Scale Formation |
$$$ |
$ |
* Based on 1/1/04 prices for NaOH and ORS HF.
The interfacial tension of the LASP at various concentrations
of the NaOH is shown below:
Oil Chem Technologies's ORS, ORS-HF and Super Surfactant
series surfactants can be optimized and used in the
LASP system.
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