How do you measure enhanced oil recovery efficiency?

1 Reservoir simulation

One of the main tools for estimating EOR efficiency is reservoir simulation, which is a numerical model that represents the physical and chemical processes that occur in the reservoir. Reservoir simulation can help you predict how different EOR methods, such as injecting gas, water, or chemicals, will affect the oil flow and recovery. However, reservoir simulation requires reliable data and parameters, such as reservoir properties, fluid properties, and injection rates, which may not be available or accurate. Moreover, reservoir simulation may not capture all the complexities and uncertainties of the real reservoir, such as heterogeneity, fractures, and scaling.

2 Production analysis

Another way to measure EOR efficiency is to analyze the production data, such as oil rate, cumulative oil, water cut, and gas-oil ratio, and compare them with the baseline or reference scenario. Production analysis can help you evaluate the incremental oil recovery and the economic viability of EOR methods. However, production analysis also has some limitations, such as the difficulty of isolating the effects of EOR from other factors, such as reservoir depletion, well interference, or operational changes. Moreover, production analysis may not reflect the long-term impact of EOR methods, such as the residual oil saturation or the sweep efficiency.

3 Tracer tests

A third method to measure EOR efficiency is to use tracer tests, which involve injecting a substance that can be detected and tracked in the reservoir. Tracer tests can help you measure the flow and transport properties of the reservoir, such as porosity, permeability, dispersion, and connectivity. Tracer tests can also help you quantify the effectiveness of EOR methods, such as the displacement efficiency, the contact area, and the breakthrough time. However, tracer tests also have some challenges, such as the selection of suitable tracers, the design of injection and sampling schemes, and the interpretation of tracer data.

4 Well testing

A fourth method to measure EOR efficiency is to use well testing, which involves applying a pressure or flow change at a well and observing the response at the same or other wells. Well testing can help you estimate the reservoir parameters, such as pressure, transmissibility, and skin factor, and how they change due to EOR methods. Well testing can also help you identify the flow regimes and boundaries of the reservoir, such as radial, linear, or spherical flow, and the presence of faults or fractures. However, well testing also has some limitations, such as the need for long and stable test periods, the interference of other wells or injection sources, and the complexity of analyzing non-linear or multiphase flow.

5 Field experiments

A fifth method to measure EOR efficiency is to conduct field experiments, which involve applying EOR methods to a small or pilot area of the reservoir and monitoring the results. Field experiments can help you test the feasibility and scalability of EOR methods, as well as their environmental and operational impacts. Field experiments can also help you calibrate and validate the reservoir simulation and other methods. However, field experiments also have some drawbacks, such as the high cost and risk, the difficulty of controlling and replicating the conditions, and the uncertainty of extrapolating the results to the whole reservoir.

6 Integrated approach

As you can see, each method of measuring EOR efficiency has its advantages and disadvantages, and none of them can provide a complete and accurate picture of EOR performance. Therefore, it is recommended to use an integrated approach that combines different methods and sources of information, such as reservoir simulation, production analysis, tracer tests, well testing, and field experiments. An integrated approach can help you reduce the uncertainties and errors, improve the confidence and reliability, and optimize the design and implementation of EOR methods.

7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?