Biochemical engineering is a new technology that is being introduced and applied in many different disciplines. Across an array of industries these biochemically engineered products offer superior and unique performance at less cost and are environmentally preferred. Akin to the conversion of the vacuum tube to the silicon chip, the new generation of engineered biofluids (EBF) is superior to the first generation of biopolymers because they provide biochemically engineered solutions on the molecular level. These EBFs use selectively grown polymers combined with precise molecular substitution to fit the specific use. This new capability provides many industries, including the petroleum business, a new class of superior, low-cost solutions for the first time.
Biotechnology in the oil field
Biopolymer technology is not new to the petroleum business. For example, two popular products, guar and xanthan gum, are biopolymers. What is unique with this new EBF technology is that it is possible to design a product on a molecular level that is more chemically specific for the desired task.
Biopolymers are grown to provide different shapes and molecular exchange characteristics to optimize base-level features for a wide range of industries. To give some perspective on EBF polymer types for the petroleum industry, their features can vary for friction reduction, coating of target surfaces such as clays, surfactant usage and particle size, hydrogen sulfide sequestration, dust control, cement workability, etc. The same polymer type can be developed to have different molecular interaction characteristics, providing significant versatility on the molecular substituent level. In the biochemical engineering design phase, molecular customization provides the ability to fine-tune the design via specific molecular substitution to fit each approach.
A good example of this complete process is HPPE LLC’s CS3315 clay control and fines stabilization product. The base polymer’s molecular interaction design is optimized to be attracted to clays and then enhance the clay coating and fines stabilization process with its long-chain polymer structure. With molecular-level substitution reactions, select molecules are attached to the base biopolymer to provide advanced performance. The final product is the first to aggressively address both clay swelling and migration in one chemical. Because it is an EBF, it is superior in design, sustainable, environmentally compliant and less expensive.
These functionalized biopolymers are designed with several advantages. They are built with robust functionality in the molecular structure, providing for enhancement, evolution and simplification. They are stable within a range of typical pH, salinity and trace metal scenarios, and they have robust electron exchange characteristics.
Biopolymers for clay stabilization, fines control
Clay control and shale stabilization are important aspects in the optimization of petroleum reservoirs in the hydraulic fracturing process as well as any operation that subjects the formation to extraneous fluids. HPPE has released a biopolymer-based clay stabilizer product line to the hydraulic fracturing industry: ClayStabilizer (CS) CM3300, CM3315 and CM3330. These products are engineered biopolymers, more particularly high molecular-weight functionalized polysaccharide-based molecules that have been shown to be extremely effective at controlling clay swelling/stabilization and fines migration.
In all third-party independent clay control analysis laboratory testing on unconventional reservoir rocks, the CS series controls clay swelling and migration better than the commercially available clay control products. Consistently, it is superior in capillary suction test, roller oven and clay pack flow tests.
One item that is not typically documented is the nature of the filtrate effluent from a packed column flow test. This visual observation is a good way to determine a chemical’s fines migration tendencies. Figure 1 is an image of the effluent following a typical clay pack flow test. The image shows significant amounts of migrated fines with a leading clay control product. With the HPPE CS series, the effluent is clear. It shows that the engineered biofluid is a tangibly superior fines migration control fluid. This is because it is specifically designed to achieve this task with its long-chained polymer and electron exchange attraction optimization. Considering the cloudiness of the other sample and small size of the clay pack flow test apparatus, a practical observation is that significant fines migration would be expected with the typical industry clay swelling control product. This is a typical observation with many applications in formations that contain both swelling and migrating clays when only the swelling mechanism is addressed.
Typical oilfield applications must pump two separate chemicals to aggressively address each problem, clay swelling and migration. This functionalized biopolymer is specifically designed to accomplish both tasks with one chemical. Additionally, because it is a liquid, it is dispersed throughout the reservoir and fracture system, providing the best approach to address migrating as well as swelling clays. For cost and logistical reasons it is common for operators to take approaches to arrest the clay swelling piece but not the migration component, which as observed can be significant. With HPPE’s biochemically engineered clay control biopolymers, the need to pump two separate chemicals and the associated cost problem is eliminated.
Biosurfactants for the oil field
Surfactant use in the oil field is wellestablished for application in stimulation, completion and drilling fluids. A primary use is to reduce interaction issues associated with the fracturing and formation fluids in the reservoir and fracture system, thereby reducing formation damage and optimizing the hydrocarbon production. The HPPE surfactants consist of nanometer-sized surfactant droplets. This droplet size is a valuable new feature and yields a stable, small internal phase that lowers surface tension of liquid-liquid and liquid-mineral contact surfaces while permitting its access to the lowest permeability zones in unconventional reservoirs. Additionally, some testing indicates that the HPPE EBF surfactants reduce absorption depletion, which is a typical problem in reservoir completion applications.
Interfacial tension is the work required to increase the size of the interface between two adjacent immiscible phases. Lowering the interfacial tension with a surfactant increases the mobilization of oil from the formation to increase the total recovery of oil. HPPE biosurfactant interfacial tension is very competitive with common industry surfactants, while the breakthrough times and oil volumes recoveries are superior. These properties combined with of one of the smallest nano-emulsions in the market maximize reservoir contact and optimize the effectiveness of the application (Figure 2). These features produce a stable solution of nano-scale droplets capable of reducing contact angles at liquid interfaces and providing film-forming geometries in the reservoir (Figure 3). These biosurfactants deliver superior properties to the industry at typical concentrations of 0.5 to 2.0 gallons per thousand (gpt, for treatment rates of gallons of product per thousand gallons of makeup water).
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