The flow of homogeneous fluids through porous media: analogies with other physical problems

Coalbed methane: A review

Asphaltene adsorption at solid surfaces is a ubiquitous phenomenon that begins within the production well and continues through the entire production chain. It is generally an undesirable phenomenon that causes damage within reservoirs, fouling of pipelines and transportation equipment, and fouling of refining and upgrading equipment. However, by virtue of this phenomenon, problematic asphaltenes may also be selectively removed from petroleum streams to produce partially upgraded petroleum, which has significantly improved handling, processing, and upgrading qualities. This review covers many basic aspects regarding the chemical and physical nature of asphaltenes and sorbents related to asphaltene adsorption.

Asphaltene Adsorption, a Literature Review

The Upper Triassic Yanchang Formation in the Ordos Basin, central China, is a typical sandstone reservoir with an ultra-low permeability. High-angle tectonic fractures and diagenetic fractures, such as near-horizontal bedding fractures, intragranular fractures, and grain-boundary fractures, are abundant. Fractures are major pathways and enhance fluid flow in sandstone reservoirs with ultra-low permeability. Because of their weak lateral continuity and their small apertures under lithostatic pressure, bedding fractures make a relatively small contribution to the overall permeability of reservoirs. As they are both of small size and low permeability, intragranular fractures and grain-boundary fractures mainly improve the connectivity of reservoirs by connecting the matrix pores. High-angle tectonic fractures control the fluid movement in the ultra-low-permeability reservoirs. Under the effect of different successive tectonic stress fields, four assemblages of high-angle tectonic fractures developed in the sandstone reservoirs. Under the present-day stress, differently oriented fractures have different connectivities, apertures, and permeabilities. The northeast–southwest fractures parallel to the maximum principal stress have a good connectivity, large apertures, and a high permeability, forming the dominant flow paths. Knowledge of these paths can be used for optimizing well placement. Because of their sensitivity to pressure, fractures in different directions will show varying apertures as the formation pressure decreases. Therefore, the permeability of the fractures of different orientations and its impact on reservoirs vary at different developmental stages.

Fractures in sandstone reservoirs with ultra-low permeability: A case study of the Upper Triassic Yanchang Formation in the Ordos Basin, China

Ultrasonic-microwave assisted synthesis of stable reduced graphene oxide modified melamine foam with superhydrophobicity and high oil adsorption capacities

Influences of fracture orientation on oil recovery by water and polymer flooding processes: An experimental approach

An ultrasonic irradiation technique for treatment of asphaltene deposition

Factors affecting contact-angle measurement of reservoir rocks

Formation Damage Caused by Simultaneous Sulfur and Asphaltene Deposition

Reservoir heterogeneity represents one of the most dominant factors affecting the performance of CO 2 miscible flooding and its expected oil recovery. The main goal of this study is to investigate the influence of different modes of reservoir heterogeneity on oil recovery by supercritical CO 2 miscible flooding. The investigated heterogeneity modes include: 1) different single fractured reservoirs of different inclination angles, 2) different permeability configurations of layered reservoirs, and 3) the sequence of permeability distributions in composite reservoirs. Complete reservoir rock and oil compositional analyses were performed. The minimum miscibility pressure (MMP) of oil-CO 2 was mathematically calculated using several empirical correlations and determined experimentally using slim tube tests. The core flood tests were achieved using actual fluids injected through 12 actual reservoir rock samples. Of these, four samples were of different fracturing angles as single fractured reservoirs, four samples were of different permeability configurations as layered rocks and four samples represented composite reservoirs. The slug size of supercritical CO 2 was optimized to be 0.15 PV, injected and chased by actual reservoir brine through these different simulated modes of reservoir heterogeneity. The results indicated that all different modes of reservoir rock heterogeneity have a crucial influence on oil recovery by CO 2 miscible flooding in carbonate oil reservoirs. Of note, unfractured reservoirs produced higher oil recovery by CO 2 miscible flooding than single fractured ones. An oil reservoir with a 30 degree inclination angle of single fracture produced the highest oil recovery, whereas, fractured rocks with a 45 degree fracture produced the minimum oil recovery in this category. The rock permeability sequences of medium-low-high (MLH) mode for composite reservoirs and medium-high-low (MHL) distribution mode for layered reservoirs are highly recommended for CO 2 miscible flooding. The results have proven the suitability of the CO 2 application for layered and composite heterogeneous carbonate reservoirs, however, it does not recommend this EOR process for single fractured reservoirs. The results have also shown a real impact on oil recovery of the reservoir heterogeneity mode prevailing in the reservoir under development by this EOR process.

Shedid A. Shedid

Papers

Influences of fracture orientation on oil recovery by water and polymer flooding processes: An experimental approach

An ultrasonic irradiation technique for treatment of asphaltene deposition

Factors affecting contact-angle measurement of reservoir rocks

Formation Damage Caused by Simultaneous Sulfur and Asphaltene Deposition

Influences of Different Modes of Reservoir Heterogeneity on Performance and Oil Recovery of Carbon Dioxide Miscible Flooding