How do you choose the right oil recovery method for your reservoir?

1 Primary recovery

Primary recovery is the first stage of oil production, where the natural pressure of the reservoir drives the oil to the surface through wells. This is the easiest and cheapest method, but it usually recovers only a small fraction of the original oil in place (OOIP), typically 5% to 15%. The main factors that affect primary recovery are the reservoir pressure, the permeability of the rock, the viscosity of the oil, and the well spacing and location. To optimize primary recovery, you need to monitor and maintain the reservoir pressure, drill more wells or use horizontal wells, and reduce the oil viscosity by heating or diluting it.

2 Secondary recovery

Secondary recovery is the second stage of oil production, where external fluids are injected into the reservoir to maintain or increase the pressure and displace the oil towards the wells. The most common fluids used are water and gas, either natural or injected. Secondary recovery can improve the recovery factor (RF) by 5% to 25%, depending on the reservoir and fluid properties. The main factors that affect secondary recovery are the injectivity and productivity of the wells, the compatibility and mobility of the fluids, and the sweep efficiency of the reservoir. To optimize secondary recovery, you need to design and operate an effective injection and production system, balance the fluid rates and pressures, and avoid fingering, channeling, or breakthrough of the fluids.

3 Enhanced oil recovery

Enhanced oil recovery (EOR) is the third stage of oil production, where advanced techniques are applied to alter the physical or chemical properties of the oil and the reservoir to increase the recovery. There are three main types of EOR: thermal, chemical, and miscible. Thermal EOR uses heat to reduce the oil viscosity and increase its mobility. Chemical EOR uses substances such as polymers, surfactants, or alkaline to improve the water-oil ratio and reduce the interfacial tension. Miscible EOR uses gases such as CO2, N2, or hydrocarbons to dissolve in the oil and make it more fluid. EOR can boost the RF by 5% to 20%, but it is also the most complex and costly method. The main factors that affect EOR are the reservoir temperature, pressure, and heterogeneity, the oil composition and saturation, and the availability and cost of the EOR agents. To optimize EOR, you need to conduct a thorough reservoir characterization, select the most suitable EOR technique, and evaluate its technical and economic feasibility.

Choosing the right oil recovery method for your reservoir is a challenging but rewarding task. It requires a comprehensive understanding of the reservoir and the oil behavior, as well as a careful analysis of the potential benefits and drawbacks of each method. By applying the best practices and the latest technologies, you can maximize the oil recovery and the value of your reservoir.

4 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?