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Abstract Current technologies for in-situ heavy oil recovery involve either heating the reservoirs to liquefy the hydrocarbons or attacking the deposits with solvents. This is usually accomplished by providing a source of external energy such as using natural gas to heat the oil or subjecting it to mechanical stimulation. However, a challenging case is in ultra-shallow reservoirs where the recovery is limited only to matrix oil drainage by gravity. In these cases, many heavy oil reservoirs are too thin to use thermal processes for enhanced heavy oil recovery due to the heat losses to overburden and underburden. In this paper, a study to develop a new technology to increase heavy oil recovery using alkali, surfactant and polymer is presented. It has been found that novel surfactants can create a stable emulsion for heavy oil and formation brine, by which viscosity of heavy oil can be reduced significantly. At 25 °C, the viscosity of heavy oil is 15,785 cP. But when the heavy oil and synthetic brine are emulsified with some new surfactants, the viscosity reduces about 2.88 to 3.46 cP. Therefore, the mobility of heavy oil is improved significantly. In order to analyze the contribution of the various components to viscosity, a heavy oil sample was separated with a silica gel column. It was found that asphaltenes and resins, the two heaviest and most polar components in the heavy oil, exert the largest influence on the viscosity of heavy oils. Viscosity decreases as temperature increases, which is leveraged by thermal technology for heavy oil recovery. The decrease in viscosity is most pronounced, however, at temperatures below 60 °C. The high viscosity of heavy oil can be dramatically reduced further by emulsification with proper surfactants and alkali, which is the principle behind non-thermal technology for heavy oil recovery. In this research, emulsions created by the surfactants B and E are stable at 25 °C, and their performance in non-thermal heavy oil recovery was evaluated using sand pack flooding test. 23% of heavy oil recovery was achieved by injection of surfactant B and polymer Superfloc A-110 HMW. It has also been found that injection of 1.0 PV of surfactant solution followed by injection of 1.0 PV of polymer solution to be the optimum methods for both surfactants B and E. In most cases, Superfloc A-110 HMW polymer seems to be slightly better than Superfloc A-120 V for enhanced heavy oil recovery.
- Energy > Oil & Gas > Upstream (1.00)
- Materials > Chemicals > Commodity Chemicals > Petrochemicals (0.36)
Abstract High molecular weight polyacrylamides are key components in oil recovery, particularly in the stimulation, production, and enhanced oil recovery of oil and gas wells. These polymers can be divided into three broad classes based on their physical state: dry polyacrylamides (DPAMs), emulsion polyacrylamides (EPAMs) and solution polyacrylamides (SPAMs). While the molecular weights of these polymers can range from 1 million to more than 30 million Daltons, molecular weight is limited by physical state. In general, EPAMs can reach higher molecular weights and consequently exhibit better performance than DPAMs and SPAMs. However, standard EPAMs exhibit poor freeze tolerance and irreversible inversions, while DPAMs suffer from extremely slow dissolution rates and require additional capital expenses such as makedown and storage equipment. Next-generation winterized EPAMs have been developed that are capable of withstanding temperatures down to −35 °C without freezing. These polymers invert rapidly, reaching complete dissolution within 60 seconds in fresh water, hard water, and other concentrated brines, allowing for higher throughput and overall energy savings. The new EPAMs were compared to commercially available EPAMs used in friction reduction and EOR applications. The emulsion stability was assessed by freeze-thaw and rheological measurements, while stimulation and EOR performance were characterized using a friction loop and core flooding apparatuses. These next-gen EPAMs demonstrate values for viscosities, shear resistance, inversion times, freeze tolerance, and filterability that make them superior to commercially available dry and emulsion polyacrylamides. Furthermore, these polymers are formulated to be environmentally friendly and readily biodegradable. A family of emulsion polymers has been developed that exhibits low-temperature tolerance, increased dissolution rates and biodegradability without sacrificing EOR and stimulation performance in various brines. The modular nature of these products has led to the creation of a flexible polymer platform that allows for customizing products for specific application needs.
- North America > Canada (0.47)
- North America > United States (0.47)