Use of Partitioning Tracers to Estimate Oil Saturation Distribution in Heterogeneous Reservoirs

Abstract

Partitioning interwell tracer tests (PITTs) have been used to estimate remaining oil saturations during waterflooding. Compared to core tests, well logs and single well tracer tests, PITTs sample a much larger representative elemental volume (REV) and provide interwell estimates of remaining oil saturation. The test has historically been used to estimate residual oil saturation (Sorw) after waterflooding between injector-producer pairs when the oil is essentially immobile. During polymer flooding, especially with viscous oil, additional oil is displaced and traditional means of interpreting PITTs are not valid. In this paper we present the information gained from conducting a polymer PITT and the saturation estimated during the PITT. This paper presents mechanistic insights into tracer and polymer velocities during the PITT and hence allows for an estimate of remaining oil saturation left behind after polymer flooding and also presents a new log-normal fit which can be used to match multiple flow path responses as is seen in actual field tracer data and reduce the error in estimates of remaining oil saturation. The polymer PITT therefore allows characterization of polymer flood efficiency and is a useful tool in polymer flood evaluations in heterogeneous reservoirs.

Development of new oil/water partitioning tracers for the determination of residual oil saturation in the inter-well region of water-flooded reservoirs

“…Thus, the use of a new compound as partitioning tracer in the oilfield must be preceded by an evaluation of its capacity to resist the conditions encountered there. The potential benefits of using PITT as a characterization tool for efficient reservoir management are widely discussed in the literature Dean et al, 2016;Sanni et al, 2018; and such tests https://doi.org/10.1016/j.petrol.2019.106269 Received 6 September 2018; Received in revised form 14 June 2019; Accepted 12 July 2019 can be fundamental for the industry in the future. Increasing the number of compounds tested and thoroughly qualified for use as partitioning tracers in the oilfield will contribute to overcome one of the main current obstacles to the dissemination of this technology.…”

Solute Reactive Tracers for Hydrogeological Applications: A Short Review and Future Prospects

“…A large number of laboratory experiments and field-scale tests have been conducted to detect NAPL contaminations since the 1990s. The most commonly applied volume sensitive tracers are alcohols of varying chain length, such as 1-hexanol [57][58][59][60] [6,71] and fluorotelomer alcohols [72]. Additionally, sulfur hexafluoride (SF 6 ) [73][74][75][76][77] , perfluorocarbons [61,78], radon-222 [79][80][81], and fluorescent dyes (e.g., rhodamine WT, sulforhodamine B, and eosin) [82] have also been suggested for use as volume sensitive tracers.…”

Posterior Assessment of Parameters in a Time Domain Random Walk Model of Partitioning Tracer Tests in Two‐Phase Flow Scenarios

“…Tracers are typically employed in industrial (Dean et al., 2016; Huseby et al., 2015; Shen et al., 2017) and environmental (Solcova et al., 2022) settings to characterize attributes of subsurface systems (i.e., reservoirs/aquifer) such as, for example, permeability, porosity, or parameters driving geochemical interactions at a scale of interest. These are chemical compounds that can be added to the fluids residing in the porous formation.…”

“…Therefore, partitioning tracer tests are often performed for the estimation of the residual oil saturation and volume to support enhanced oil recovery operations, eventually through unconventional approaches to increase energy production. Studies related to this technique can be found at the laboratory and field scales (see, e.g., Annable et al., 1998; Dean et al., 2016; Dwarakanath et al., 1999; Huseby et al., 2015; Jin et al., 1995, 1997, Shen et al., 2017). Laboratory scale studies are particularly critical to increase our knowledge of the underlying mechanisms.…”