Why Laboratory Study?
Once an EOR method has been selected, it is important to evaluate the feasibility of the process for a given field and to optimize the solution at lab scale. Parameters such as temperature, salinity distribution, water quality, geological heterogeneities are key uncertainties that need to be carefully investigate from the beginning of any chemical EOR project in order to ensure the robustness of the chemical EOR process ultimately at pilot and full-field scales.
Our methodology consists in a step-by-step approach where, starting from thousands of possible
formulations, it progressively delivers the best solution in terms of chemical EOR process efficiency and robustness.
Step 1: Analysis of Reservoir Materials
The project generally starts with an extensive analysis of reservoir materials (fluids and rock). The results of these analyses, together with the reservoir data you provide us, are shared and discussed in order to define the most appropriate operating conditions for the reservoir. A thorough technico-economic analysis of the different possible water injection scenarios is also performed.
This task aims at:
- Selecting appropriate process (ASP, SP, …)
- Pre-selecting promising chemicals from our internal database
- Defining operating conditions and identify potential hurdles.
Thorough analysis of production brines
Hardness versus Salinity (note these are photo captions)
Step 2: Extensive Formulation Screening
In a second step, an extensive formulation screening is carried out, using the high- throughput tools developed by the EOR Alliance. Thousands of different formulations can be automatically tested to identify the best formulation, both in terms of efficiency (IFT, solubility, static adsorption) and in terms of robustness taking into account the main uncertainties (salinity distribution, facies heterogeneities, …).
Surfactant or alkaline surfactant formulations compatibility with several polymers is then evaluated using solubility measurements. A good solubility is essential to guarantee the final formulation injectivity. An in-house methodology can be used in order to assess the full formulation (ASP and/or SP) injectivity in representative cores. This allows discarding formulations with potential for plugging.
A formulation, giving ultra-low interfacial tension with reservoir crude oil, good solubility/injectivity and moderate adsorption is then designed using representative industrial surfactants (i.e. surfactants that can be provided at industrial scale).
Step 3: Coreflood Experiments at Reservoir Conditions
In a third step, the most promising formulation is evaluated using coreflood experiments at reservoir conditions. The pre-selected plugs are cleaned, fully characterized then saturated with fluids using advanced protocols in order to be representative of field conditions. Both oil recovery and chemicals dynamic adsorption are determined in order to give a first estimate of the economics of the process. Additional core flood experiments are performed to assess the sensitivity to main uncertain parameters and to lead to an optimal solution (high recovery, low adsorption).