Oil recovery from fractured reservoirs using in situ and preformed particle gels in micromodel structures

Abstract

Oil extraction often accompanied with relatively large amounts of water production causes several environmental and mechanical problems, particularly in oil-fractured reservoirs. One way to alleviate this problem is to use gels as a blockage agent. In this study, several micromodels with different geometries of fractures including a simple fracture, step fracture, fracture with variable mouth and fracture with a tiny crack were prepared. The amount of oil recovery was measured from these micromodels in the presence or absence of gel. In situ and preformed particle gels (PPGs) were injected into the micromodels to compare their ability in blocking fractures and increasing oil recovery. The BaCl 2 ·2H 2 O salt solution was used to swell PPGs. The amount of salt concentration was optimized so that PPGs had maximum ability to block fractures. Several PPG concentrations, 1000, 2000, and 3000 ppm, were examined to optimize the amount of PPGs, which have to be injected into the micromodels. Injection flow rate was optimized so that salt water could efficiently sweep the matrix structure. Results showed that both PPG and in situ gels have a considerable effect on decreasing water production and increasing oil extraction. However, PPGs were superior in comparison to in situ gels to increase oil recovery. It was found that increasing salt concentration decreases the swelling percentage of PPGs. The optimum amount of injection flow rate was found to be 0.1 mL/hr for all the prepared micromodels. The optimum concentration of PPGs was different for each micromodel.Publisher's Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Biodegradable Preformed Particle Gel (PPG) Made of Natural Chitosan Material for Water Shut-Off Application

“…According to Seright's (2003) study, PPGs are more effective in achieving water conformance than in-situ gels [9]. Another finding by was that PPGs outperformed in-situ gels in terms of oil recovery [10]. Seright (2001) and Seright et al (2003) approved that PPG had superior placement than in-situ gel and could successfully prevent gel damage on low-permeability, unswept oil zones [11,12].…”

Fabrications and Applications of Micro/Nanofluidics in Oil and Gas Recovery: A Comprehensive Review

“…(a) In-situ gel treatment and (b) PPG treatment. Reproduced with permission from ref . Copyright 2019 Springer Nature.…”

“…They claimed that PPGs were more successful to resist salt water and recovery of trapped oil in their micromodels (Figure 32). 165 Moreover, swelling behaviors of PPG in porous media can be directly visualized. Louf et al directly visualized the swelling of hydrogels confined in three-dimensional granular media and demonstrated that the extent of hydrogel swelling was determined by competition between swelling force by gel particle and confining force by surrounding (Figure 33).…”

A comprehensive review of the chemical-based conformance control methods in oil reservoirs

“…They observed that a highly concentrated polymer solution is essential to abate leakage in larger fractures and to infiltrate fluid zones with an elevated pressure gradient. Heidari et al (2019) pointed out that fractures present in the reservoir can affect the performance of PPG treatment. To prove this, they evaluated the performance of preformed particle gel systems, namely micro-models, with varying geometries (variable mouth, step fracture, simple fracture and tiny crack fracture).…”

“…These contaminants act as emulsifiers and with the continuous agitation of the mixture from the reservoirs during the flow up to surface facilities, tight emulsions can be formed. Emulsions can be intentionally formed for upstream processes such as enhanced oil recovery and acid stimulation (Maaref et al 2017;Ahmadi et al 2019). Depending on which phase is continuous or dispersed, emulsions can be water in oil (w/o), oil in water (o/w) as illustrated in Fig.…”