Nanotechnology to Boost Oil Recovery in Russia Up to 60-65 Percent

Russia ranks first globally in oil production, but an analysis of international data on Russian proven oil reserves shows that the industry has only 17 years’ worth of production left [2]. Note that Russian estimates of oil reserves are somewhat higher than international assessments

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Though Russian subsoil legislation requires the most complete exhaustion of oil deposits (i.e., the highest possible value of recovery factor), the “Energy Strategy of Russia until 2030” (ESR-2030) proposes the following recovery factor as an indicator of the strategic development of the oil industry: 2008 (actual) – 0.3; on the 1st stage (2013-2015) – 0.3-0.32; on the 2nd stage (2020-2022) – 0.32 -0.35; by 2030 – 0.35-0.37 [3].

These figures are low. The values of recovery achieved by Western countries, which are much higher, must be the benchmark for similar deposits in Russia [4].

In author’s opinion, the oil recovery factor should be a national priority for Russia; detailed studies of oil displacement, primarily at the nano-level, should be carried out to ensure high recovery factors [2, 5, 6]. The point is that oil displacement efficiency depends on structures at nano-levels: the surface has nanometric roughness, and are defined precisely by roughness. In other words, the challenges for controlling the deposit properties at the level of electrical interactions, wetting, and changes in the mineral structure (sizes 20-40 nm) are solved by applying the technologies of nano-events management (nanotechnologies).

Petroleum science, being an integral part of Earth Sciences, seeks to rationalize the development of hydrocarbon deposits aided by such disciplines as geology, mathematics, physics, chemistry, using a specific object of study – physical and chemical nano-events in geological bodies, formation fluids and industrial equipment, – which covers both nano-events and the way they are recorded in geologic-hydrodynamic and techno-economic calculations for development and operation of hydrocarbon deposits [2, 5, 6].

Nanotechnology operations for enhanced oil recovery (NTOEOR) include operations (methods, techniques) governed by nanoscale phenomena, or which employ nanoscale particles. The NTOEOR include, first of all, technologies based on application of thermo and physical fields, as well as biological substances. This group also includes technologies based on chemical and gaseous agents with nanoscale impact on the reservoir systems [2, 5, 6]. Some examples of modern NTOEOR include: [2, 6]

1. One problem in the oil and gas industry is retaining the reservoir features of the bottom zone after production operations (pump change, BHT, timed well-kills, etc.). Every such operation can reduce well productivity by 20-30 percent. Hydrophobic emulsion enriched with nano-particle stabilizers boosts the density by changing the percentage of heavier additives in the water phase in the range of 1,050-1,500 kg/cu.m and has high temporal stability (over 40 days), up to +80 С heat resistance, more than 50 hrs thermal stability, and a low pour point (below –8 С).

2. Leakage of cement sheaths leads to premature access of bottom water into the production, gas-water-oil crossflow, pollution of fresh water horizons, etc. Adding nano-dispersive modifiers to cement can enhance the strength of concrete and foam concrete 1.5-2 times. Advantages of nano-concrete conditioned on the specific structure formed by self-organization of cement stone at nanoscale levels. Proposed by the author combination of magnetic treatment for nano-concrete boosts quality of the material another 1.5-2 times.

3. Foam systems stabilized by nanoparticles have proven highly effective in reducing the water cut in oil and gas production wells. In the oil industry, this technology has been used in a number of Russian oil fields and has proved highly effective, achieving 15-20 percent reductions in water cuts and 1.5-1.7 times oil production growth, as well as providing 500-10,000 tons of extra crude per treated well. This technology (Fig. 1) was applied at the Urengoi gas field at 5 prematurely flooded wells for sand ingress prevention. The technological effect amounted to 16 million cubic meters per well.

4. Thermogenerator systems are used for the thermochemical treatment of the bottomhole formation zone. Exothermic reaction of metal particles and alkali or acids produces up to 4,000 kcal per kilo of metal. In order for such systems to get deep into oil reservoir, size of the metal particles must be less than 50 nm, which is achieved by their encapsulation.

5. Flooding is the most common domestic technology of oil displacement. Studies show that usage of special agents that sustain the permeability levels by preventing expansion (dispersion) of clay ensures retention or restoration of permeability after its fall [2, 6]. The conducted experimental field tests of this nanotechnology (NTOEOR) showed an increase in injection capacity rates by average 27 percent [6, 7] (Fig. 2). Experiments show that the use of clay stabilizers significantly (10-15 points) increases the rate of oil displacement, resulting in 0.08-0.10 better oil recovery [6, 8].

Field studies indicate that achieved recovery factor largely depends on the shale volume factor Кgl: in the same environment, increasing shale content from 2.5 percent to 5.5 percent leads to falling oil recovery factor (from 0.6 to 0.2) [6, 9 ] (Fig. 3). Shale content of 3-4 percent means oil recovery factor of 0.40-0.50. Hence, reducing the influence of clays on the permeability of the reservoir (due to NTOEOR) will increase oil recovery.

Thus, application of NTOEOR can reduce the effect water salinity has on the permeability factor. Application of NTOEOR for clay behavior control will boost oil recovery factor even for low-permeability reservoirs up to 0.40-0.45 – in the same scenario, usage of the flooding technologies will result recovery factor of only up to 0.25, regardless of costs invested [2, 6].

There is already a huge number of NTOEOR applications which guarantee recovery factor of over 0.4 at a production cost of $15 per barrel [2]. And since production costs make 25 percent of the price of Russian oil [10], the prices above $60 a barrel make 0.4 recovery factor profitable. Mass application of NTOEOR even more cost-effective and will provide the fastest and highest financial return compared to other investment areas, increasing both efficiency of the industry and the recovery factor. Therefore, mass application of already developed NTOEOR to improve production efficiency, as well as pilot testing of new NTOEOR [2, 5], must become the strategic goals of the oil industry.