Influence of fluid-mechanical coupling in gas generation in undersaturated petroleum reservoirs

Among the several mechanisms of producing an oil reservoir, the gas expansion mechanism is an important primary recovery process. During the depletion of the reservoir, the pore pressure may reach values below the bubble pressure of the oil, allowing the gas release. From the geomechanical point of view, the change in pore volume, due to production, changes the dynamics of gas generation, since it is dependent upon the change in pore pressure. Studies considering the fluid-mechanical coupling show the relationship between variations of fluid pressure and porous structure of the reservoir. This work aims to study the influence of the fluid-mechanical partial coupling (one and two-way) in the process of gas release during recovery of hydrocarbon. It was used the partial coupling methodology developed by ATHENA/GTEP – PUC-Rio. The model called “A” has only one producing well, while the model called “B” has four injection wells, besides the producer. Initially, the oil present in the reservoir is in undersaturated condition. In model “A” was observed that the pressure drop of fluid is more accentuated, until it reaches the bubble pressure, when considering the two-way coupling. Consequently, the gas release initiation occurs earlier than one-way coupling scheme. After starting gas generation, the rates of pressure change in both partial coupling scenarios tend to equalize. In terms of compaction and subsidence, it was observed most significant displacements values in two-way coupling, highlighting the rigorous consideration of the geomechanical effects in the applied methodology. In model “B”, it was observed that the consideration of the two-way coupling resulted in a recovery scenario without generation of gas, unlike the results shown by the one-way coupling in which gas was generated during 40% of total simulation time. In geomechanical terms it was observed, as presented previously, that the values of vertical displacement were greater in the two-way coupling. The methodology used in this paper proved to be capable of simulating coupled process in a blackoil reservoir, as could be observed by the results. Furthermore, the use of one-way partial coupling scheme, which is widely used in the oil industry, showed results quite different in terms of gas liberation, when are compared with the two-way partial coupling scheme, which was developed in a more rigorous way

Influence of fluid-mechanical coupling in gas generation in undersaturated petroleum reservoirs

Among the several mechanisms of producing an oil reservoir, the gas expansion mechanism is an important primary recovery process. During the depletion of the reservoir, the pore pressure may reach values below the bubble pressure of the oil, allowing the gas release. From the geomechanical point of view, the change in pore volume, due to production, changes the dynamics of gas generation, since it is dependent upon the change in pore pressure. Studies considering the fluid-mechanical coupling show the relationship between variations of fluid pressure and porous structure of the reservoir. This work aims to study the influence of the fluid-mechanical partial coupling (one and two-way) in the process of gas release during recovery of hydrocarbon. It was used the partial coupling methodology developed by ATHENA/GTEP – PUC-Rio. The model called “A” has only one producing well, while the model called “B” has four injection wells, besides the producer. Initially, the oil present in the reservoir is in undersaturated condition. In model “A” was observed that the pressure drop of fluid is more accentuated, until it reaches the bubble pressure, when considering the two-way coupling. Consequently, the gas release initiation occurs earlier than one-way coupling scheme. After starting gas generation, the rates of pressure change in both partial coupling scenarios tend to equalize. In terms of compaction and subsidence, it was observed most significant displacements values in two-way coupling, highlighting the rigorous consideration of the geomechanical effects in the applied methodology. In model “B”, it was observed that the consideration of the two-way coupling resulted in a recovery scenario without generation of gas, unlike the results shown by the one-way coupling in which gas was generated during 40% of total simulation time. In geomechanical terms it was observed, as presented previously, that the values of vertical displacement were greater in the two-way coupling. The methodology used in this paper proved to be capable of simulating coupled process in a blackoil reservoir, as could be observed by the results. Furthermore, the use of one-way partial coupling scheme, which is widely used in the oil industry, showed results quite different in terms of gas liberation, when are compared with the two-way partial coupling scheme, which was developed in a more rigorous way

NEOTROPICAL ALIEN MAMMALS: a data set of occurrence and abundance of alien mammals in the Neotropics

Biological invasion is one of the main threats to native biodiversity. For a species to become invasive, it must be voluntarily or involuntarily introduced by humans into a nonnative habitat. Mammals were among first taxa to be introduced worldwide for game, meat, and labor, yet the number of species introduced in the Neotropics remains unknown. In this data set, we make available occurrence and abundance data on mammal species that (1) transposed a geographical barrier and (2) were voluntarily or involuntarily introduced by humans into the Neotropics. Our data set is composed of 73,738 historical and current georeferenced records on alien mammal species of which around 96% correspond to occurrence data on 77 species belonging to eight orders and 26 families. Data cover 26 continental countries in the Neotropics, ranging from Mexico and its frontier regions (southern Florida and coastal-central Florida in the southeast United States) to Argentina, Paraguay, Chile, and Uruguay, and the 13 countries of Caribbean islands. Our data set also includes neotropical species (e.g., Callithrix sp., Myocastor coypus, Nasua nasua) considered alien in particular areas of Neotropics. The most numerous species in terms of records are from Bos sp. (n = 37,782), Sus scrofa (n = 6,730), and Canis familiaris (n = 10,084); 17 species were represented by only one record (e.g., Syncerus caffer, Cervus timorensis, Cervus unicolor, Canis latrans). Primates have the highest number of species in the data set (n = 20 species), partly because of uncertainties regarding taxonomic identification of the genera Callithrix, which includes the species Callithrix aurita, Callithrix flaviceps, Callithrix geoffroyi, Callithrix jacchus, Callithrix kuhlii, Callithrix penicillata, and their hybrids. This unique data set will be a valuable source of information on invasion risk assessments, biodiversity redistribution and conservation-related research. There are no copyright restrictions. Please cite this data paper when using the data in publications. We also request that researchers and teachers inform us on how they are using the data