Application of Nanofluids to Control Formation Damage and Improved Oil Recovery Process

Faculty Development Competitive Research Grants 2020-2022

Project Background:
Satisfying the increasing demand for oil is critical. As most of the producing oil fields are already matured, the importance of improving oil production efficiency by controlling formation damage in wells, wells production enhancement, and EOR techniques is highly understood. As such, oil and gas industry needs technological innovations to improve damage remediation and EOR methods to meet the energy challenges. Breakthroughs in nanotechnology have the potential to move the industry beyond the current alternatives for producing more oil from the existing wells and oil reservoirs by introducing efficient technologies. In this proposal, our target is to apply this new technology to control fines migration as a main source of formation damage and also to improve the oil recovery from reservoirs.
Fines are loose unconsolidated particles (smaller than 37 μm) that move with fluid flow inside oil reservoirs and cause blocking because of the filtering action of the porous media. Also, clays, especially in sandstone formations, start to swell by alteration in salinity and pH in the porous media due to different operations. These two mechanisms, fines migration and clay swelling, are sources of formation damage in oil reservoirs. At the near wellbore area, these mechanisms can impair the permeability of the formation due to pore plugging and blockage. These mechanisms reduce the productivity of wells. Figure 1 schematically shows that how migration of fines, and swelling and release of clays can block pores and limit the area for the fluid flow.
Figure 1- Schematic of pores blockage due to formation damage
Various surface forces have been found to be responsible for fines detachment and release from the pore surfaces. When the total interaction energy between fines and pore surface becomes positive, the repulsive forces become bigger than attractive forces, and fines detachment occurs. This may happen due to invasion of incompatible fluids and solids into the porous media during drilling, completion, or waterflooding, which affects the force equilibrium between fines and rock surfaces and initiates damage.
Different stabilizers are used to control damage and prevent pore blocking by fines and released clays. A new approach is to apply nanotechnology to stabilize fines and clay particles in formation. Nanoparticles (NP) size ranges from 1 to 100 nm, and NPs have high specific surface area and unique properties, such as
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very high adsorption potential. Studies have been done to use NPs to control formation damage control, enhance oil recovery, and alter wettability. NPs can easily pass through pores due to their nano size and attached to the surfaces. Due to their high specific surface area, they can affect the forces between fines and rock surfaces and make it attractive to keep fines at their places.
Project Objectives:
Hence, as the purpose of this work, our plan is to continue different experimental/modeling studies to improve the performance of special nanomaterials to reduce formation damages such as fines migration in sandstone reservoirs. Also our studies will lead to design and application of nanoparticles to change the rock surface properties and increase the oil recovery.
Application of nanotechnology in the field of damage control is novel which can be proved by publications in this area which are mostly from our team after 2013. Also only one industrial product is available which is used for a different application in fracturing (Confine Agent, Baker Hughes Company). As an outcome of this work, nanoparticles in the form of particles or dispersed fluids as a commercial product will be produced to be offered to oil companies worldwide for injection to the near wellbore area for formation damage control and to the reservoir as an enhanced oil recovery agent.
Previous Research:
Past studies in this field can be divided in two main categories:
1) Application of nanomaterials to fix fines and reduce clay swelling: Different stabilizers are used to control damage and prevent pore blocking by fines and released clays. Salts of aluminum and zirconium and cationic organic polymers are examples of these stabilizers. There are not effective in many cases due to their inability to migrate through throats, difficulty in handling and disposal, environmental effects, and cost. Various types of nanoparticles at different operational conditions were tested and studied to select the most efficient particle to control fines migration and formation damage. Different tests have been completed to study different practical parameters such as salinity, pH, fluid flow type, and flow rate. Also the interaction between nanoparticles and surfaces was modeled to study the process better. References 1-12 show some of papers published by our team in this field. Based on our tests, dispersed nanoparticles as nanofluids are appropriate for the injection to oil fields. This product can be used as a strong stabilizer to control damage in the near wellbore area in especially in sandstone formations. This technology is critical for oil industry as it can prevent permeability reduction and increase the oil production. Completion of this proposal as a continue to our previous studies will enhance our knowledge in the field and extend the application of this method to more complicated and realistic two phase fluid flow conditions in oil formations.
2) Application of nanoparticles to improve oil recovery: As the production rate of existing fields starts to decline, increasing the recovery factor is of great importance. Increasing the recovery factor by a few per cent may provide billions of dollars in additional profit. Enhanced oil recovery (EOR) techniques are designed to increase the oil recovery and are considered as a hot topic in petroleum engineering. In EOR processes, interactions of rock/oil/brine are changed to detach oil droplets from rock surface to be produced. For example, by appropriate chemicals such as surfactants, wettability of rock are changed to more water wet to recover more oil.
Nanofluids as stable dispersions can be used to enhance the recovery of hydrocarbon from oil reservoirs. The nanoparticles in the nanoparticle dispersions form a self-assembled wedge-shaped
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film on the contact with a discontinuous phase. This wedge film separates formation fluids from rock surfaces, thereby recovers more fluids. Our team consists of experts in the field of EOR. We did several experimental/modeling studies to investigate different applications of chemicals and nanotechnology to improve oil recovery (References 13-33). Appropriate nanoparticles were selected and optimized to change the oil/water/rock interaction parameters such as wettability in carbonate formations to increase the oil recovery. By this proposal, we want to extend the work and try to apply EOR by nanoparticles to oil fields in Kazakhstan and introduce this method to oil companies in the country. Hence, our plan is to design and select appropriate nanoparticles to affect crude oil/brine/rock (CBR) interactions in selected field(s) in Kazakhstan to produce more oil.
Social and Economical Impact:
In the field scale this amount of incremental oil recovery means a noticeable benefit from an oil well. For example consider a well which produces 100 barrel per day. This is not a high productivity and a reason may be the possible damage in the near wellbore area. So if we can increase the production of the well for 10%, it means about 300,000 $ more income in a year. Therefore, this can be very attractive for an oil company operating and developing a field with tens of wells.
Scientific Novelty:
In this proposal our plan is to work on mentioned directions to control the formation damage and also change the surface properties in an oil reservoir. This will increase the oil production which is the main goal of oil industries and can solve their problems in decline due to damage and high residual oil in porous media which has a noticeable effect on economics of oil industry in the country.