Environmental Impact of Bitumen Extraction with Thermal Recovery

Abstract

The continuous and growing demand for energy and carbon based products requires the extraction of massive bitumen resources. Due to extremely high viscosities of bitumen, the most effective bitumen extraction methods are thermal enhanced oil recovery (EOR) methods such as In-situ Combustion (ISC), Steam Assisted Gravity Drainage (SAGD), Steam Flooding (SF), and Hot Water Injection (HWI) which are known as environmentally unfriendly bitumen extraction methods. In this study, we investigated the environmental impact of in-situ bitumen extraction by ISC, SAGD, SF, and HWI, experimentally. The original oil, water, and rock, produced oil and water, and spent rock samples originated from each recovery method were analyzed through Fourier Transform Infra-Red (FTIR) spectroscopy, Inductive Coupled Plasma – Mass Spectroscopy (ICP-MS), pH, viscosity, and API gravity measurements. The environmental impact was investigated according to the amount and content of produced water and gas samples and the quality of oil to reduce the impact during bitumen refining. The experimental results showed that while with ISC, the least amount of water is produced; the produced water requires more severe treatment due to its high metal and sulfur contents, and low pH level. On the other hand, since the amount of the produced water for SAGD, SF, and HWI is higher, the produced water management poses handling problems. The oil production from ISC results in the greatest recovery with upgraded oil which will reduce the environmental impact for oil processing when compare to SAGD, HWI, and SF. While all processes produced more or less the same amount of gases, SAGD and SF have additional gas production due to steam generation. As conventional resources decline, it is essential to address environmental challenges to produce from these massive oil sand resources. In this study, the environmental impacts of bitumen extraction with thermal EOR were examined extensively.

Laboratory screening tests on the effect of initial oil saturation for the dynamic control of in-situ combustion

“…Therefore, the experimental sets presented in this study should be repeated with varying initial oil and water saturation cases in which the total liquid saturation will be equal to 100%. However, in our previous studies, which are conducted on the same bitumen sample, we investigated the impact of water and 100% initial liquid saturation cases on ISC performance [17,28]. These findings can help us to estimate the ISC performance for the field-scale scenario in which both water and oil will vary.…”

“…Therefore, the oil in the oil bank has different qualities than the initially in-placed oil [15,16]. The heteroatoms (elements other than carbon and hydrogen) in crude oil deposited on the rock surface in the form of ash or produced in water or gas also contributes to the upgrading of crude oil [17,18].…”

“…Apart from the in-situ oil upgrading, which will reduce the cost and environmental impact of transportation and refinery of the produced oil, another advantage of ISC is the high oil recovery factor [1,17,19]. During combustion, the crude oil is swept completely from the reservoir by the combustion front, thus, the oil displacement efficiency of the combustion process is very high.…”

Design of flow control devices in steam-assisted gravity drainage (SAGD) completion

“…As mobilization of bitumen is dependent on delivering thermal energy via steam, it is unsurprising that the economics of SAGD are controlled by the costs of generating steam and waste water treatment/recycling of the produced condensate (Yang et al 2009;Morrow et al 2014;). Additionally, SAGD is often criticized for its environmental footprint; in spite of its viability as a bitumen extraction technique, SAGD generates considerable greenhouse gas (GHG) emissions in the process of generating the quantities of steam necessary for the process (AlMurayri et al 2011;Brandt 2012;Kovscek 2012Welch 2011.…”

Flow Control Devices in SAGD Completion Design: Enhanced Heavy Oil/Bitumen Recovery Through Improved Thermal Efficiencies

“…Additionally, the SAGD method is often criticized for its environmental footprint; in spite of its viability as a bitumen extraction technique, SAGD generates considerable greenhouse gas (GHG) emissions in the process of generating the quantities of steam necessary for the process (Al-Murayri et al 2011;Brandt 2012;Kovscek 2012;Morrow et al 2014;Welch 2011). Based on field data, between 2 and 5 tons of steam are injected into the reservoir to produce each ton of bitumen (Gates and Leskiw 2010).…”