It is estimated that about 7,000 billion barrels of oil will remain in reservoirs after production by conventional methods. This value is the target for Enhanced Oil Recovery (EOR) techniques. The purpose of the water-soluble polymers in EOR application is to enhance the rheological properties of the displacing fluids. These polymers have been successfully implemented in China’s oilfields. Given the harsh conditions present in most oil reservoirs, new problems and challenges arise with the use of such polymers. Currently partially hydrolyzed polyacrylamides (HP AMs) are the major class of polymers used for chemical EOR application. However, due to the high flexibility of HP AM chain in aqueous solutions, particularly at high temperature (HT) and at high salinity (HS), the molecular chains begin to fold irreversibly resulting in a significant loss in viscosity. In this paper, we are reporting a bench-scale development of new PAM-based polymers with improved performance in HSHT conditions. The new polymers were evaluated conditions for their viscosity performance at various temperatures and salinities. The polymers were dissolved at different concentrations in brines with TDS (Total Dissolved Solids) of 34,655 ppm and 180,000 ppm. Viscosity measured at room temperature is in the range of 30 to 120 cP at the shear rate of 6 RPM. After aging at 90 °C and 120 °C for six months under ultralow oxygen level (< 5 ppb), viscosity remains relatively stable for some polymers while show a decline for others. Compared with the conventional HPAM polymers, these new polymers have much better stability at HTHS conditions.

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.

It is estimated that the Athabasca Oil Sands in Alberta, Canada, contain 1.7 trillion barrels of oil, but producing one barrel of oil from surface-mined oil sands also produces 1.8 metric tons of solid tailings suspended in 2 m 3 of water. Traditionally, tailings slurries were discharged into settling ponds, where solids slowly settled over periods of decades or longer. Since Canadian ERCB Directive 74 went into effect on 1 July 2010, however, regulatory pressure to quickly and efficiently separate tailings from the water has mounted. Directive 74 mandates that by 1 July 2012, 50% of tailings solids must be removed from waste streams. Furthermore, the captured solids should be trafficable after five years, defined as possessing a shear strength of at least 10 kPa. The flocculation performance of chemical additives ranging from inorganic salts to high molecular weight organic polymers has been previously assessed, but a procedure for meeting Directive 74 is still uncertain because any proposed solution must deal with a wide range of water quality conditions, mineralogical substrates, and particle sizes.Bench-scale evaluations of novel polymeric additives on Athabasca oil sands were performed in both 1-L graduated cylinders and a thickener. The compactness of captured solids was measured by density and solids content, dewatering was assessed by capillary suction times, and the shear strength of flocculated particles was determined rheologically. The additives were observed to greatly improve flocculation, dewatering, and growth of shear strength relative to conventional polymer treatments.

Current water management strategies require recycling and reuse of oil sand process affected water (OSPW) to as much as 80%. Continuous recycling and reuse of OSPW degrades water quality as the concentrations of total dissolved solids (TDS) and dissolved organic materials (DOM) accumulate. This results in a net increase in operating and maintenance costs and an impact on the extraction process and bitumen recovery. Remaining water containing fines and suspended clays adds to the mature fine tailings and associated problems for tailings pond treatment and management. Presence of residual bitumen and other organics is known to create difficulties in common practices for flocculation and dewatering of tailings. With the problems stated above, one may consider a pre-treatment approach rather than the common post-treatment remedies. The ore grade profoundly affects the efficiency of bitumen recovery in the hot water extraction of bitumen, the principal step in the bitumen extraction process. Sodium hydroxide is commonly added to the conditioning step to improve bitumen recovery. As the sodium ions build in concentration, they disperse clays in the ore and create tailings that resist dewatering. This is especially true for low-grade and oxidized ores, which present the greatest challenges in bitumen recovery and produce the major portion of tailings due to high fines content. With current trends for increasing production from mining operations to almost double by 2020, industry has to adopt new technologies to manage tradeoffs between water and energy. We present a new approach toward total water management by introducing environmentally friendly process aids that can improve bitumen recovery from low-grade oil sands ores. Lab-scale experimental data from a Denver flotation cell and hydrotransport loop were analyzed to evaluate the efficiency on the processability of high and low grade oil sands, water chemistry and tailings management. The results demonstrate that using new process aids during the conditioning stage improves bitumen recovery from low-grade oil sands and can accelerate tailings settling. This pretreatment approach can be incorporated into current oil sands mining processing facilities and delivers environmental and economical benefits. A critical evaluation for use of new process aids versus sodium hydroxide is given in detail.

Current water management strategies require recycling and reuse of oil sand process water (OSPW) as much as 80%. Continuous recycling and reuse of OSPW results in a degradation of the quality of water namely increases of total dissolved solids (TDS) and dissolved organic materials (DOM). This results in a net increase in operating and maintenance costs and an impact on extraction process and bitumen recovery. Remaining water containing fines and suspended clays adds to the mature fine tailings and associated problems for tailing ponds treatment and management. Presence of residual bitumen and other organics is known to create difficulties in common practices for flocculation and dewatering of tailings. With problems stated above, one may consider a pre-treatment approach in place of the common post-treatment remedies.The ore grade profoundly affects the efficiency of bitumen recovery in the hot water extraction of bitumen which is a principal step in the current commercial technology for bitumen extraction in mining operations. Sodium hydroxide is often added to the conditioning step of the process and is needed to obtain higher bitumen recovery from most oil sand feeds. Use of NaOH, however, results in accumulation of sodium ions in recycled water, causing higher clay dispersion and producing tailings with poor geotechnical properties that turn into mature fine tailings. This is especially true for low grade and oxidized ores, which present the greatest challenges in bitumen recovery and produce the major portion of tailings. With current trends for increasing production from mining operations to almost double by 2020, industry has to adopt new technologies to manage tradeoffs between water and energy.We present a new approach toward total water management by introducing novel process aids for sodium-free processing of various oil sands ores. Lab experimental data were analyzed to evaluate the efficiency on the processability of low grade oil sands, water chemistry and tailing management. Our results demonstrate that the use of new process aids during the conditioning process leads to an improvement in bitumen recovery from low grade oil sands and can accelerate tailings settling resulting in better water management. The process aids were also used in combination of polymer flocculants to treat process tailings, resulting in better tailings dewatering and consolidation. This approach offers a potential chemical solution for total water management that can be incorporated into current ore processing facilities and delivers some operational and economic benefits.