Heavy Oil Recovery by Alkaline-Cosolvent-Polymer Flood: A Multiscale Research Using Micromodels and Computed Tomography Imaging

Abstract

Summary For reservoirs containing oil with a high total acid number, the alkali-cosolvent-polymer (ACP) flood can promote the formation of microemulsion rather than viscous macroemulsion and achieve good mobility control. The enhanced oil recovery (EOR) performance of ACP flood has been studied at core and reservoir scale in detail; however, the effect of ACP flood on residual oil still lacks enough research. In this paper, a micromodel with a single channel is used to clarify the dynamic effects of alkali-cosolvent (AC) and ACP solutions on the residual oil after waterflood. Based on this, medical computed tomography (Medical-CT) scan and microcomputed tomography (Micro-CT) scan are used in combination to visualize microscale flow and reveal the mechanisms of residual oil reduction during ACP flood. The heterogeneous core plugs containing two layers of different permeabilities are used for coreflood experiments to clarify the EOR performance of ACP flood in heterogeneous reservoirs. The oil saturation is monitored by Medical-CT. Then, two core samples are drilled in each core plug that is used in the coreflood experiment. The decrease of residual oil saturation caused by ACP flood is further quantified by Micro-CT imaging. Results show that ACP flood is 14.5% oil recovery higher than AC flood (68.9%) in relative high permeability layers (HPLs) and 17.9% higher than AC flood (26.3%) in relative low permeability layers (LPLs). Compared with AC flood, ACP flood shows a more uniform displacement front, which implies that the injected polymer effectively weakened the viscosity fingering. This is similar to the experimental results demonstrated visually in the micromodel experiments. ACP solution first generates an oil bank by the mobility ratio improvement to mobilize residual oil and then dissolve and emulsify residual oil under ultralow interfacial tension (IFT) conditions. Moreover, a method that can calculate the ratio of oil/water distribution in each pore is developed to establish the relationship between the residual oil saturation of each pore and its pore size, and concluded that they follow the power-law correlation.

Acidificação de matriz em reservatórios de petróleo utilizando ácidos orgânicos: uma revisão

“…A acidificação de matriz é uma técnica de estimulação empregada em carbonatos que tem por objetivo remover o dano e aumentar o fluxo de óleo e gás em regiões próximas aos poços (KREBS et al, 2015;KARIMI et al, 2018;SU et al, 2022), injetando ácidos a uma pressão abaixo da pressão de fraturamento de formação das rochas, promovendo sua dissolução (KHALIL et al, 2021;FURUI et al, 2022), criando canais de alta permeabilidade, chamados wormholes FOGLER, 1999;RODRIGUES et al, 2021;WANG et al, 2023).…”

“…Para que os mecanismos de formação de dano e as heterogeneidades não interfiram na produção do poço, técnicas de estimulação são empregadas para aumentar sua produtividade ou injetividade; dentre elas, estão o fraturamento hidráulico, a acidificação de matriz e o fraturamento ácido. A acidificação de matriz tem como objetivo remover o dano e aumentar o fluxo de óleo e gás em regiões próximas aos poços (ZHOU et al, 2020;SU et al, 2022), aumentando a produtividade em reservatórios de hidrocarbonetos (JAFARPOUR et al, 2019). A técnica consiste em injetar ácidos fortes (HCl, por exemplo) ou fracos (a serem citados os ácidos acético e fórmico) a uma pressão abaixo da pressão de fraturamento de formação das rochas, Contribuciones a Las Ciencias Sociales, São José dos Pinhais, v.17, n.3, p. 01-24, 2024 promovendo sua dissolução (KHALIL et al, 2021;FURUI et al, 2022), removendo o dano proveniente de atividades operacionais e criando canais de alta permeabilidade, chamados wormholes (RODRIGUES et al, 2021;WANG et al, 2023), que conduzem os hidrocarbonetos do reservatório até o poço (JAFARPOUR et al, 2021).…”

Microfluidic devices, materials, and recent progress for petroleum applications: A review

“…Glass beads devices have been proven to be a useful tool for the quantitative investigation of sub-resolution liquid/liquid displacement. [63] They have been reported in various applications, including EOR [30,32,62,[64][65][66] and the study of formation damage during low salinity waterflooding. [33] The fabrication stages of this type of device include (1) rock extraction, (2) conditioning of minerals, and (3) assembly, which is achieved by sequentially injecting suspensions of grains with different mineralogy.…”

Preparation and Performance Study of Microemulsion Acid for Comprehensive Plugging Removal in Carbonate Reservoir

“…Inorganic sediments are mainly due to the corrosion of pipelines and equipment, forming iron scales such as iron hydroxide and ferrous hydroxide precipitation. In addition, when the injected water is incompatible with the formation water, inorganic scales will be produced [ 31 ].…”