Knowledge of reservoir porosity, permeability, and capillary pressure is essential to exploration and production of hydrocarbons. Although porosity can be interpreted fairly accurately from well logs, permeability and capillary pressure must be measured from core. Estimating permeability and capillary pressure from well logs would be valuable where cores are unavailable. This study is to correlate permeability with porosity to predict permeability and capillary pressures. Relationships between permeability to porosity can be complicated by diagenetic processes like compaction, cementation, dissolution, and occurrence of clay minerals. These diagenetic alterations can reduce total porosity, and more importantly, reduce effective porosity available for fluid flow. To better predict permeability, effective porosity needs to be estimated. A general equation is proposed to estimate effective porosity. Permeability is predicted from effective porosity by empirical and theoretical equations. A new capillary pressure model is proposed. It is based on previous study, and largely empirical. It is tested with over 200 samples covering a wide range of lithology (clean sandstone, shaly sandstone, and carbonates dominated by intergranular pores). Parameters in this model include: interfacial tension, contact angle, shape factor, porosity, permeability, irreducible water saturation, and displacement pressure. These parameters can be measured from routine core analysis, estimated from well log, and assumed. An empirical equation is proposed to calculate displacement pressure from porosity and permeability. The new capillary-pressure model is applied to evaluate sealing capacity of seals, calculate transition zone thickness and saturation above free water level in reservoirs. Good results are achieved through integration of well log data, production data, core, and geological concepts.

Masters of Science / The Bredasdorp basin is situated off the south coast of the Republic of South Africa, southeast of Cape Town and west-south-west of Port Elizabeth. It covers approximately 18,000 sq. km beneath the Indian Ocean along the southern coast of South Africa, which is in the southwest of Mosselbay. Bredasdorp basin contains South Africa’s only oil and gas production facilities and has been the main focus for oil and gas exploration in South Africa. It is one of the largest hydrocarbon producing block in South Africa, rich in gas and oil prone marine source rocks of kimmeridgian to berriasian age. The wells of interest for this study are located within block 9 which is made up of 13 wells but for this study the focus is only on 3 wells, which are well F-01,F-02 and F-03. The goal of this study is to predict as accurately as possible the areas within and around the sandstone reservoir intervals of these wells with abnormal pressure, using well logs and production test data. Abnormal pore pressure which is a major problem for drillers in the oil industry can cause serious drilling incidents and increase greatly drilling non-production time if the abnormal pressures are not predicted accurately before and while drilling. Petrophysics log analysis was done to evaluate the reservoirs. The intervals of the reservoir are the area of interest.Pore pressure gradient, fracture gradient, pore pressure and fracture pressure model were run. Pressures of about 6078.8psi were predicted around the zone of interest in well F-01, 7861 psi for well F-02 and 8330psi for well F-03. Well F-03 was the most pressured of the three wells. Abnormal pressures were identified mostly at zones above and below the area of interest and predicted pressure values were compared to actual pressure values to check for accuracy.

Arenitos do Cretáceo Superior da Bacia de Santos correspondem aos principais reservatórios clásticos de hidrocarbonetos da bacia, localizada na margem leste brasileira. Alguns desses arenitos exibem porosidades anormalmente altas, considerando suas atuais profundidades maiores que 4000 m. A preservação da porosidade nesses arenitos, assim como em diversos outros reservatórios clásticos profundos vem sendo atribuída à inibição da cimentação por crescimentos de quartzo e da dissolução por pressão exercida por franjas e cutículas de clorita autigênica. Por esse motivo, o estudo da distribuição espacial e temporal das cloritas, assim como de seus hábitos, relações paragenéticas e condições genéticas, é de grande importância. Os arenitos cretácicos de Santos são arcósios e arcósios líticos, ricos em fragmentos de rochas vulcânicas (FRV). Clorita é o constituinte diagenético mais abundante, ocorrendo principalmente como franjas e cutículas cobrindo os grãos (pore-lining), rosetas preenchendo parcialmente os poros e agregados microcristalinos substituindo grãos. A precipitação de clorita foi favorecida pela presença de cutículas eogenéticas de argila esmectítica, que foram parcialmente preservadas ao longo de contatos intergranulares apertados. Além disso, a composição primária dos arenitos exerceu um controle fundamental na autigênese das cloritas. O enriquecimento de clorita nos arenitos arcósios líticos, ricos em FRV, sugere que esses grãos são uma significativa fonte de íons de Fe e Mg para a precipitação de clorita nesses arenitos. Além dos FRV, minerais pesados instáveis, biotita e intraclastos lamosos atuaram como fonte e/ou substrato para a autigênese da clorita. Adicionalmente à composição primária, a história térmica e de soterramento, assim como o padrão de fluxo de fluidos, certamente tiveram um papel importante na distribuição da diagênese da clorita e na evolução da qualidade dos reservatórios. Prováveis fontes externas de íons devem ter envolvido as reações de transformações de argilominerais esmectíticos em lutitos associados, e a espessa seção de evaporitos Aptianos. Os diferentes hábitos das cloritas exerceram impacto distinto na qualidade dos reservatórios. Cloritas pore-lining inibiram a cimentação por quartzo, isolando as superfícies dos grãos de quartzo e reduzindo a nucleação de crescimentos secundários, contribuindo assim para a preservação da porosidade. No entanto, franjas e cutículas finas e descontínuas não foram capazes de inibir efetivamente a cimentação por quartzo, enquanto que as muito espessas reduziram severamente a permeabilidade dos reservatórios. Rosetas de clorita, por sua vez, não inibiram a cimentação de quartzo e ainda reduziram a porosidade intergranular. Estudos específicos são necessários para um melhor entendimento dos diferentes processos diagenéticos nos arenitos da Bacia de Santos, assim como de sua distribuição temporal, estratigráfica e espacial, de modo a basear o desenvolvimento de modelos que possam efetivamente contribuir para a redução dos riscos durante a exploração por esses reservatórios. / Upper Cretaceous sandstones from the Santos Basin, eastern Brazilian Margin, correspond to the main clastic hydrocarbon reservoirs of the basin. Some of these sandstones show abnormally high porosities, considering their present depths larger than 4000 m. The preservation of porosity in these sandstones, as in other deep clastic reservoirs, has been ascribed to the inhibition of quartz overgrowth cementation and pressure dissolution by rims and coatings of authigenic chlorite. Therefore, the study of the space and time distribution of the chlorites, as well as of their habits, paragenetic relations and genetic conditions, is of great importance. Santos cretaceous sandstones are arkoses and lithic arkoses, rich in volcanic rock fragments (VRF). Chlorite is the most abundant diagenetic constituent, occurring mostly as rims and coatings covering the grains (pore-lining), as rosettes partially filling the pores, and as grain-replacive microcrystalline aggregates. Chlorite precipitation was favored by the presence of eogenetic coatings of smectitic clays, which were partially preserved along tight intergranular contacts. Besides these, the primary composition of the sandstones exerted a key control in chlorite authigenesis. Chlorite enrichment in the lithic arkoses, rich in VRF, suggests that these grains are significant source of Fe and Mg ions for chlorite precipitation in these sandstones. Besides VRF, unstable heavy minerals, biotite and mud intraclasts acted as source or substrate for chlorite authigenesis. In addition to the primary composition, thermal and burial histories, as also the fluid flow patterns, certainly played an important role in chlorite diagenesis and in the evolution of reservoir quality. Probable external ionic sources must have involved the transformation of smectitic clays in associated mudrocks, and the thick section of Aptian evaporites. The diverse chlorite habits exerted distinct impact on the quality of the reservoirs. Pore-lining chlorites inhibited quartz cementation isolating quartz grains surfaces, reducing the nucleation of overgrowths, thus contributing to porosity preservation. However, thin and discontinuous rims and coatings were not able to effectively inhibit quartz cementation, while those very thick severely decreased the permeability of the reservoirs. In turn, chlorite rosettes have not inhibited quartz cementation, but have reduced intergranular porosity nonetheless. Specific studies are required for a better understanding of the diverse diagenetic processes wthin Santos Basin sandstones, as also of their time, stratigraphic and space distribution, in order to support the development of models that may effectively contribute to the reduction of risks during the exploration for these reservoirs.

Arenitos do Cretáceo Superior da Bacia de Santos correspondem aos principais reservatórios clásticos de hidrocarbonetos da bacia, localizada na margem leste brasileira. Alguns desses arenitos exibem porosidades anormalmente altas, considerando suas atuais profundidades maiores que 4000 m. A preservação da porosidade nesses arenitos, assim como em diversos outros reservatórios clásticos profundos vem sendo atribuída à inibição da cimentação por crescimentos de quartzo e da dissolução por pressão exercida por franjas e cutículas de clorita autigênica. Por esse motivo, o estudo da distribuição espacial e temporal das cloritas, assim como de seus hábitos, relações paragenéticas e condições genéticas, é de grande importância. Os arenitos cretácicos de Santos são arcósios e arcósios líticos, ricos em fragmentos de rochas vulcânicas (FRV). Clorita é o constituinte diagenético mais abundante, ocorrendo principalmente como franjas e cutículas cobrindo os grãos (pore-lining), rosetas preenchendo parcialmente os poros e agregados microcristalinos substituindo grãos. A precipitação de clorita foi favorecida pela presença de cutículas eogenéticas de argila esmectítica, que foram parcialmente preservadas ao longo de contatos intergranulares apertados. Além disso, a composição primária dos arenitos exerceu um controle fundamental na autigênese das cloritas. O enriquecimento de clorita nos arenitos arcósios líticos, ricos em FRV, sugere que esses grãos são uma significativa fonte de íons de Fe e Mg para a precipitação de clorita nesses arenitos. Além dos FRV, minerais pesados instáveis, biotita e intraclastos lamosos atuaram como fonte e/ou substrato para a autigênese da clorita. Adicionalmente à composição primária, a história térmica e de soterramento, assim como o padrão de fluxo de fluidos, certamente tiveram um papel importante na distribuição da diagênese da clorita e na evolução da qualidade dos reservatórios. Prováveis fontes externas de íons devem ter envolvido as reações de transformações de argilominerais esmectíticos em lutitos associados, e a espessa seção de evaporitos Aptianos. Os diferentes hábitos das cloritas exerceram impacto distinto na qualidade dos reservatórios. Cloritas pore-lining inibiram a cimentação por quartzo, isolando as superfícies dos grãos de quartzo e reduzindo a nucleação de crescimentos secundários, contribuindo assim para a preservação da porosidade. No entanto, franjas e cutículas finas e descontínuas não foram capazes de inibir efetivamente a cimentação por quartzo, enquanto que as muito espessas reduziram severamente a permeabilidade dos reservatórios. Rosetas de clorita, por sua vez, não inibiram a cimentação de quartzo e ainda reduziram a porosidade intergranular. Estudos específicos são necessários para um melhor entendimento dos diferentes processos diagenéticos nos arenitos da Bacia de Santos, assim como de sua distribuição temporal, estratigráfica e espacial, de modo a basear o desenvolvimento de modelos que possam efetivamente contribuir para a redução dos riscos durante a exploração por esses reservatórios. / Upper Cretaceous sandstones from the Santos Basin, eastern Brazilian Margin, correspond to the main clastic hydrocarbon reservoirs of the basin. Some of these sandstones show abnormally high porosities, considering their present depths larger than 4000 m. The preservation of porosity in these sandstones, as in other deep clastic reservoirs, has been ascribed to the inhibition of quartz overgrowth cementation and pressure dissolution by rims and coatings of authigenic chlorite. Therefore, the study of the space and time distribution of the chlorites, as well as of their habits, paragenetic relations and genetic conditions, is of great importance. Santos cretaceous sandstones are arkoses and lithic arkoses, rich in volcanic rock fragments (VRF). Chlorite is the most abundant diagenetic constituent, occurring mostly as rims and coatings covering the grains (pore-lining), as rosettes partially filling the pores, and as grain-replacive microcrystalline aggregates. Chlorite precipitation was favored by the presence of eogenetic coatings of smectitic clays, which were partially preserved along tight intergranular contacts. Besides these, the primary composition of the sandstones exerted a key control in chlorite authigenesis. Chlorite enrichment in the lithic arkoses, rich in VRF, suggests that these grains are significant source of Fe and Mg ions for chlorite precipitation in these sandstones. Besides VRF, unstable heavy minerals, biotite and mud intraclasts acted as source or substrate for chlorite authigenesis. In addition to the primary composition, thermal and burial histories, as also the fluid flow patterns, certainly played an important role in chlorite diagenesis and in the evolution of reservoir quality. Probable external ionic sources must have involved the transformation of smectitic clays in associated mudrocks, and the thick section of Aptian evaporites. The diverse chlorite habits exerted distinct impact on the quality of the reservoirs. Pore-lining chlorites inhibited quartz cementation isolating quartz grains surfaces, reducing the nucleation of overgrowths, thus contributing to porosity preservation. However, thin and discontinuous rims and coatings were not able to effectively inhibit quartz cementation, while those very thick severely decreased the permeability of the reservoirs. In turn, chlorite rosettes have not inhibited quartz cementation, but have reduced intergranular porosity nonetheless. Specific studies are required for a better understanding of the diverse diagenetic processes wthin Santos Basin sandstones, as also of their time, stratigraphic and space distribution, in order to support the development of models that may effectively contribute to the reduction of risks during the exploration for these reservoirs.

Arenitos do Cretáceo Superior da Bacia de Santos correspondem aos principais reservatórios clásticos de hidrocarbonetos da bacia, localizada na margem leste brasileira. Alguns desses arenitos exibem porosidades anormalmente altas, considerando suas atuais profundidades maiores que 4000 m. A preservação da porosidade nesses arenitos, assim como em diversos outros reservatórios clásticos profundos vem sendo atribuída à inibição da cimentação por crescimentos de quartzo e da dissolução por pressão exercida por franjas e cutículas de clorita autigênica. Por esse motivo, o estudo da distribuição espacial e temporal das cloritas, assim como de seus hábitos, relações paragenéticas e condições genéticas, é de grande importância. Os arenitos cretácicos de Santos são arcósios e arcósios líticos, ricos em fragmentos de rochas vulcânicas (FRV). Clorita é o constituinte diagenético mais abundante, ocorrendo principalmente como franjas e cutículas cobrindo os grãos (pore-lining), rosetas preenchendo parcialmente os poros e agregados microcristalinos substituindo grãos. A precipitação de clorita foi favorecida pela presença de cutículas eogenéticas de argila esmectítica, que foram parcialmente preservadas ao longo de contatos intergranulares apertados. Além disso, a composição primária dos arenitos exerceu um controle fundamental na autigênese das cloritas. O enriquecimento de clorita nos arenitos arcósios líticos, ricos em FRV, sugere que esses grãos são uma significativa fonte de íons de Fe e Mg para a precipitação de clorita nesses arenitos. Além dos FRV, minerais pesados instáveis, biotita e intraclastos lamosos atuaram como fonte e/ou substrato para a autigênese da clorita. Adicionalmente à composição primária, a história térmica e de soterramento, assim como o padrão de fluxo de fluidos, certamente tiveram um papel importante na distribuição da diagênese da clorita e na evolução da qualidade dos reservatórios. Prováveis fontes externas de íons devem ter envolvido as reações de transformações de argilominerais esmectíticos em lutitos associados, e a espessa seção de evaporitos Aptianos. Os diferentes hábitos das cloritas exerceram impacto distinto na qualidade dos reservatórios. Cloritas pore-lining inibiram a cimentação por quartzo, isolando as superfícies dos grãos de quartzo e reduzindo a nucleação de crescimentos secundários, contribuindo assim para a preservação da porosidade. No entanto, franjas e cutículas finas e descontínuas não foram capazes de inibir efetivamente a cimentação por quartzo, enquanto que as muito espessas reduziram severamente a permeabilidade dos reservatórios. Rosetas de clorita, por sua vez, não inibiram a cimentação de quartzo e ainda reduziram a porosidade intergranular. Estudos específicos são necessários para um melhor entendimento dos diferentes processos diagenéticos nos arenitos da Bacia de Santos, assim como de sua distribuição temporal, estratigráfica e espacial, de modo a basear o desenvolvimento de modelos que possam efetivamente contribuir para a redução dos riscos durante a exploração por esses reservatórios. / Upper Cretaceous sandstones from the Santos Basin, eastern Brazilian Margin, correspond to the main clastic hydrocarbon reservoirs of the basin. Some of these sandstones show abnormally high porosities, considering their present depths larger than 4000 m. The preservation of porosity in these sandstones, as in other deep clastic reservoirs, has been ascribed to the inhibition of quartz overgrowth cementation and pressure dissolution by rims and coatings of authigenic chlorite. Therefore, the study of the space and time distribution of the chlorites, as well as of their habits, paragenetic relations and genetic conditions, is of great importance. Santos cretaceous sandstones are arkoses and lithic arkoses, rich in volcanic rock fragments (VRF). Chlorite is the most abundant diagenetic constituent, occurring mostly as rims and coatings covering the grains (pore-lining), as rosettes partially filling the pores, and as grain-replacive microcrystalline aggregates. Chlorite precipitation was favored by the presence of eogenetic coatings of smectitic clays, which were partially preserved along tight intergranular contacts. Besides these, the primary composition of the sandstones exerted a key control in chlorite authigenesis. Chlorite enrichment in the lithic arkoses, rich in VRF, suggests that these grains are significant source of Fe and Mg ions for chlorite precipitation in these sandstones. Besides VRF, unstable heavy minerals, biotite and mud intraclasts acted as source or substrate for chlorite authigenesis. In addition to the primary composition, thermal and burial histories, as also the fluid flow patterns, certainly played an important role in chlorite diagenesis and in the evolution of reservoir quality. Probable external ionic sources must have involved the transformation of smectitic clays in associated mudrocks, and the thick section of Aptian evaporites. The diverse chlorite habits exerted distinct impact on the quality of the reservoirs. Pore-lining chlorites inhibited quartz cementation isolating quartz grains surfaces, reducing the nucleation of overgrowths, thus contributing to porosity preservation. However, thin and discontinuous rims and coatings were not able to effectively inhibit quartz cementation, while those very thick severely decreased the permeability of the reservoirs. In turn, chlorite rosettes have not inhibited quartz cementation, but have reduced intergranular porosity nonetheless. Specific studies are required for a better understanding of the diverse diagenetic processes wthin Santos Basin sandstones, as also of their time, stratigraphic and space distribution, in order to support the development of models that may effectively contribute to the reduction of risks during the exploration for these reservoirs.

Geologic sequestration has been suggested as a viable method for greenhouse gas emission reduction. Regional studies of CO₂ storage capacity are used to estimate available storage, yet little work has been done to tie site specific results to regional estimates. In this study, a 9,258,880 acre (37469.4 km²) area of the coastal and offshore Texas Miocene interval is evaluated for CO₂ storage capacity using a static volumetric approach, which is essentially a discounted pore volume calculation. Capacity is calculated for the Miocene interval above overpressure depth and below depths where CO₂ is not supercritical. The goal of this study is to determine the effectiveness of such a regional capacity assessment, by performing refinement techniques that include simple analytical and complex reservoir injection simulations. Initial refinement of regional estimates is performed through net sand picking which is used instead of the gross thickness assumed in the standard regional calculation. The efficiency factor is recalculated to exclude net-to-gross considerations, and a net storage capacity estimate is calculated. Initial reservoir-scale refinement is performed by simulating injection into a seismically mapped saline reservoir, near San Luis Pass. The refinement uses a simplified analytical solution that solves for pressure and fluid front evolution through time (Jain and Bryant, 2011). Porosity, permeability, and irreducible water saturation are varied to generate model runs for 6,206 samples populated using data from the Atlas of Northern Gulf of Mexico Gas and Oil Reservoirs (Seni, 2006). As a final refinement step, a 3D dynamic model mesh is generated. Nine model cases are generated for homogeneous, statistically heterogeneous, and seismic-based heterogeneous meshes to observe the effect of various geologic parameters on injection capacity. We observe downward revisions (decreases) in total capacity estimation with increasingly refined geologic data and scale. Results show that estimates of storage capacity can decrease significantly (by as much as 88%) for the single geologic setting investigated. Though this decrease depends on the criteria used for capacity comparison and varies within a given region, it serves to illustrate the potential overestimation of regional capacity assessments compared to estimates that include additional geologic complexity at the reservoir scale. / text

L’analyse stratigraphique et tectono-sédimentaire des séries sédimentaires du Paléozoïque qui remplissent le bassin de Ghadamès et son extension au nord, le bassin de Jefarah en Libye et en Tunisie, ont été étudiées. Ces formations appartiennent au cycle de Gondwana et sont, généralement, interprétées comme étant déposées dans un bassin cratonique tronqué par la discordance hercynienne. Cette étude est basée sur l’analyse des électrofaciès et des électroséquences dans plus de 130 puits. Les corrélations stratigraphiques entre puits sont basées sur la définition des cycles de 1er et de 2ème ordre. Cela a permis de comprendre l’évolution des environnements sédimentaires dans les deux bassins, de reconstituer des cartes isopaques de répartition des faciès et de reconstruire la paléogéographie des différentes unités stratigraphiques. Ces données permettent d'aborder la nature de la déformation et clarifient également le comportement des zones actives régionales élevées durant le Paléozoïque. La succession paléozoïque dans les bassins de Ghadamès et de Jefarah peut être divisée en cinq séquences de 1er ordre, délimitées par des discontinuités tectoniques majeurs avec une durée de séquence de 40 à 70 Ma. Dans ces cinq séquences, dix-huit séquences de 2ème ordre (10 à 40 Ma) ont été différenciées, décrivant les limites de séquence (SB), les surfaces d'inondation maximales (MFS) et les caractéristiques sédimentologiques. Vingt-huit puits ont été analysés afin d’identifier et d’évaluer les systèmes réservoirs paléozoïques dans les bassins Ghadamès et de Jefarah illustrant comment les propriétés réservoirs changent latéralement et verticalement dans le temps en fonction des environnements de dépôt. Deux logiciels ont été utilisés, le logiciel pétrophysique JLog pour l'analyse des propriétés réservoirs et PETREL pour la construction de modèles de corrélation stratigraphique. Les réservoirs dans la zone d'étude sont répartis sur une large gamme de réservoirs silicoclastiques s'étendant du Cambrien au Permien. Les hydrocarbures dans les bassins de Ghadamès et de Jefarah proviennent de deux roches mères principales, à savoir la Formation de Tanezuft du Silurien inférieure et la Formation d'Awaynat Wanin du Dévonien moyen-supérieur. Les neuf principaux réservoirs paléozoïques sont respectivement les formations de Hasawnah, de Hawaz et de Mamouniyat (Paléozoïque inférieure), d’Akakus, de Tadrart, d’Ouan Kaza et de Tahara (Paléozoïque moyen) et les Formations de M'rar et d’Asadjefar (Paléozoïque supérieur). Six sections transversales stratigraphiques dans la région ont été reconstruites pour illustrer les extensions verticales et latérales des réservoirs. L'ensemble de données acquises démontre que les propriétés réservoirs des séries paléozoïques sont influencées par les deux, les faciès et les environnements de dépôts. / The sedimentology and tectonics and their relationship of the Paleozoic series that fill the Ghadames basin and its northern extension consisting of the Jefarah basin in Libya and Tunisia was studied. These formations belong to the Gondwana cycle and are typically interpreted as being deposited in a cratonic basin truncated by the Hercynian unconformity. This study is based on wells. The stratigraphic correlation between the wells is based on the definition of second order cycles. This allowed to produce isopach maps of facies distributions and to reconstruct the paleogeography of the different stratigraphic units. These data allow to address the nature of the deformation and also clarifies the behavior of active high regional areas during the Palaeozoic. The Paleozoic succession in the Ghadames and Jefarah basins can be divided in to five first order sequences, bounded by major tectonic unconformities with sequence duration of 40 - 70 Ma. Within these five sequences eighteen second order sequences (10 - 40 Ma) were differentiated, describing Sequence Boundaries (SB), Maximum Flooding Surfaces (MFS) and sedimentological characteristics. Twenty six wells with its geological well reports and well logs have been used in the study area, i.e. the Ghadames and Jefarah basins (Libya) illustrate how reservoir properties changes laterally and vertically through time (from a proximal to a distal sitting). Two softwares were used, JLog (version 4) petrophysical software for reservoir property analysis and PETREL (Schlumberger software 2014 version) for constructing stratigraphic correlation models. The Paleozoic reservoirs in the study area are spread over a large range of siliciclastic reservoirs with the prospective section extending from Cambrian to Permian. Hydrocarbons within the Ghadames and Jefarah basins originated from two major source rocks: i.e. the Lower Silurian Tanezoft Formation and Middle-Upper Devonian Aouinat Ounine Formation. The nine main Paleozoic reservoirs are respectively the Hassaouna, Haouaz and Memouniat Formations (Lower Paleozoic), Acacus, Tadrart, Ouan Kaza and Tahara Formations (Middle Paleozoic) and M’rar and Asadjefar Formations (Upper Paleozoic). Six stratigraphic cross sections through the area have been reconstructed to illustrate the vertical and lateral reservoir extensions. The dataset demonstrates that the Paleozoic reservoir properties are influenced by both, depositional facies and position within the paleogeographical setting (from proximal to distal part).