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Hu Jun - One of the best experts on this subject based on the ideXlab platform.

  • Reservoir Characteristic and Controlling Factors on Physical Properties of Lower Jurassic Tight Sandstone in the Qiudong Sub-sag,Turpan-Harmi Basin
    Natural Gas Geoscience, 2013
    Co-Authors: Hu Jun
    Abstract:

    The Lower Jurassic of the Qiudong sub-sag in the Turpan Harmi basin is mainly a set of coal-bearing clastic rocks dominated by feldspathic lithic sandstones.The southern margin of the sub-sag is a braided river delta sand body,and the northern is a fan delta sand body.Both the delta plain and front sandstone have great thickness,good connectivity,and large composite area.They are mainly located in the Qiuling,Qiudong,Wenjisang,Kekeya and Shanle.Based on the analyses of conventional thin sections,casting thin sections,core physical properties,grain sizes and mercury injection data of the Lower Jurassic Reservoir,it is concluded that the Lower Jurassic rocks are relatively coarse,mainly belonging to medium-coarse sandstone or sandy conglomerate.The pore types are mainly intragranular dissolved pores,residual intergranular pores and micro-fractures.The pore combination is fracture-residual intergranular pore-intragranular dissolved pore.The content of montmorillonite(S%) is less than 25% and it is during the late diagenesis A1 Stage with strong compaction,strong particles plastic deformation,relative weak dissolution and weak cementation.The average porosity and permeability are 6.0% and 0.30×10-3μm2,respectively,and the maximum connectivity throat radius is less than 1.5μm,so the Reservoir was considered as a micro-throat tight Reservoir.The main controlling factors on the Reservoir development were sedimentary microfacies,diagenesis and tectonic process.The distribution of Reservoir sandstones was controlled by sedimentary microfacies.The compaction reduced pores and dissolution increased part of the pores.The micro-fractures resulting from the tectonic process improved Reservoir permeability.Areas east to the Dongshen 2 well-Ji 1 well were favorable distribution region for the J1s Reservoir in the southern margin of Qiudong Sag.Aktash,Kekeya and Zhao 4 well areas were more favorable area for J1b in the northern margin of Qiudong Sag.

Mercedes Pascual - One of the best experts on this subject based on the ideXlab platform.

  • networks of genetic similarity reveal non neutral processes shape strain structure in plasmodium falciparum
    Nature Communications, 2018
    Co-Authors: Qixin He, Shai Pilosof, Kathryn E Tiedje, Shazia Ruybalpesantez, Yael Artzyrandrup, Edward B Baskerville, Mercedes Pascual
    Abstract:

    Pathogens compete for hosts through patterns of cross-protection conferred by immune responses to antigens. In Plasmodium falciparum malaria, the var multigene family encoding for the major blood-stage antigen PfEMP1 has evolved enormous genetic diversity through ectopic recombination and mutation. With 50–60 var genes per genome, it is unclear whether immune selection can act as a dominant force in structuring var repertoires of local populations. The combinatorial complexity of the var system remains beyond the reach of existing strain theory and previous evidence for non-random structure cannot demonstrate immune selection without comparison with neutral models. We develop two neutral models that encompass malaria epidemiology but exclude competitive interactions between parasites. These models, combined with networks of genetic similarity, reveal non-neutral strain structure in both simulated systems and an extensively sampled population in Ghana. The unique population structure we identify underlies the large transmission Reservoir Characteristic of highly endemic regions in Africa.

R Thomas - One of the best experts on this subject based on the ideXlab platform.

  • unterhaching geothermal well doublet structural and hydrodynamic Reservoir Characteristic bavaria germany
    2007
    Co-Authors: Markus Wolfgramm, G Kittl, G Lenz, P Seibt, F Hoffmann, J Bartels, R Schulz, R Thomas
    Abstract:

    At Unterhaching, two wells – Gt Uha1a for production, Gt Uha2 for injection – were drilled and tested for the cogeneration of electricity and heat. Very high productivities of both could be determined. These good inflows are attributed to the influence of fault systems. In particular, the well Gt Uha2 was drilled through a fault with a vertical throw of 238 m. At the top of the aquifer, the temperature of the produced water was 123 °C (Gt Uha1a) or approx. 134 °C (Gt Uha 2). The high temperatures in the Gt Uha2 well are ascribed to waters circulating in a deepreaching fault system. Inflows within the Malm come exclusively from the Upper Malm (Malm Zeta).

Mamata Jenamani - One of the best experts on this subject based on the ideXlab platform.

  • Well tops guided prediction of Reservoir properties using modular neural network concept: A case study from western onshore, India
    Journal of Petroleum Science and Engineering, 2014
    Co-Authors: Soumi Chaki, Akhilesh K. Verma, Aurobinda Routray, William K. Mohanty, Mamata Jenamani
    Abstract:

    Abstract This paper proposes a complete framework consisting pre-processing, modeling, and post-processing stages to carry out well tops guided prediction of a Reservoir property (sand fraction) from three seismic attributes (seismic impedance, instantaneous amplitude, and instantaneous frequency) using the concept of modular artificial neural network (MANN). The dataset used in this study, comprising three seismic attributes and well log data from eight wells, is acquired from a western onshore hydrocarbon field of India. Firstly, the acquired dataset is integrated and normalized. Then, well log analysis and segmentation of the total depth range into three different units (zones) separated by well tops are carried out. Secondly, three different networks are trained corresponding to three different zones using combined dataset of seven wells and then trained networks are validated using the remaining test well. The target property of the test well is predicted using three different tuned networks corresponding to three zones; and then the estimated values obtained from three different networks are concatenated to represent the predicted log along the complete depth range of the testing well. The application of multiple simpler networks instead of a single one improves the prediction accuracy in terms of performance evaluators – correlation coefficient, root mean square error, absolute error mean and program execution time. Then, volumetric prediction of Reservoir properties is carried out using calibrated network parameters. This stage is followed by post-processing to improve visualization. Thus, a complete framework, which includes pre-processing, model building and validation, volumetric prediction, and post-processing, is designed for successful mapping between seismic attributes and a Reservoir Characteristic. The proposed framework outperformed a single artificial neural network in terms of reduced prediction error, program execution time and improved correlation coefficient as a result of application of the MANN concept.

Korovin, Mikhail Olegovich - One of the best experts on this subject based on the ideXlab platform.

  • Vertical permeability effect on terrigeneous oil field Reservoir adaptation
    'National Research Tomsk Polytechnic University', 2021
    Co-Authors: Коровин, Михаил Олегович, Korovin, Mikhail Olegovich
    Abstract:

    Актуальность исследования состоит в необходимости создания алгоритма расчёта проницаемости в трёхмерном пространстве по геолого-геофизическим данным. На данном этапе существует возможность учёта влияния анизотропии проницаемости в горизонтальной плоскости. Вертикальная проницаемость, как правило, задаётся соотношением проницаемости в горизонтальной плоскости и понижающим или повышающим коэффициентом. Фактически в таком случае не учитывается пространственное изменение вертикальной составляющей проницаемости по разрезу, что обусловлено незначительным количеством исследований вертикальной проницаемости и соответственно отсутствием уравнений для расчёта этого очень важного параметра. Это глобальная проблема недостатка исходной информации при исследованиях фактического кернового материала, который является основой для изучения анизотропных характеристик горных пород. Проницаемость, в свою очередь, является важнейшей характеристикой пласта и влияет на возможности добычи углеводородов из пластов коллекторов. В цели данной работы входило создание зависимости вертикальной проницаемости от пористости, распределение проницаемости в геологической и гидродинамической модели, проверка качества адаптации данных добычи и закачки. Объектом исследования является месторождение с терригенным типом коллектора. На данном месторождении уже были проведены расчёты анизотропии горизонтальной проницаемости, а в рамках данного исследования проведены расчёты вертикальной проницаемости и учтено её влияние на адаптацию месторождения. Особенностью данного месторождения является изменчивость направления улучшенных зон проницаемости, а также наличие лабораторных керновых исследований вертикальной проницаемости коллекторов. Такие исследования позволят определить вертикальную проницаемость горных пород и рассчитать распределение по вертикали разреза. Исследуемые пласты представлены верхнеюрскими отложениями с неоднородным распределением фильтрационных и ёмкостных свойств. Методы: построение зависимости вертикальной проницаемости от пористости по керновым исследованиям, внедрение в геологическую и гидродинамическую модели вертикальной составляющей проницаемости, расчёт адаптации фактических данных добычи после учёта вертикальной составляющей проницаемости. В результате исследования была уточнена петрофизическая модель исследуемого месторождения, что отразилось в более точном распределении петрофизических свойств в геологической модели. Таким образом, становится возможным учитывать реальные особенности геологического строения, так как в трёхмерном пространстве необходимо использовать все три компоненты вектора проницаемости. Одним из главных моментов является создание модели, максимально точно описывающей распределение свойств и отражающей реальные характеристики добычи. Только в этом случае можно проводить наиболее точный прогноз и планировать применение методов увеличения нефтеотдачи. Огромное количество накопленных данных позволяет создавать корреляции между различными петрофизическими параметрами. Необходимо дополнять и нарабатывать объём информации, который в ближайшем будущем может служить базой данных для месторождений аналогов, у которых отсутствуют данные для создания собственных подобных зависимостей.The relevance of the research lies in the need to create an algorithm for calculating permeability in three-dimensional space using geological and geophysical data. At this stage, the horizontal distribution of permeability should be taken into account. And the vertical permeability is usually set by the ratio of the permeability in the horizontal plane and the decreasing or increasing coefficient. In fact, in this case, the spatial change in the vertical component of the permeability along the section is not taken into account. This happens for two reasons: a small number of studies of vertical permeability and, accordingly, the absence of equations for calculating this very important parameter. This is a global problem of lack of initial information when examining actual core material. And the core material is the basis for studying the anisotropic Characteristics of rocks. Permeability, in its turn, is the most important Reservoir Characteristic and affects the ability to extract hydrocarbons from Reservoir strata. The aim of this work is to form a dependence of vertical permeability on porosity, the distribution of permeability in the geological and hydrodynamic model, check the quality of adaptation of production and injection data. The study object is a field with a terrigenous Reservoir type. In this field, calculations of the anisotropy of horizontal permeability have already been carried out, and within the framework of this study, calculations of the vertical permeability were carried out and its influence on the adaptation of the field was taken into account. A feature of this field is the variability of the direction of the improved permeability zones, as well as the presence of laboratory core studies of the vertical permeability of Reservoirs. Such studies will allow determining the vertical permeability of rocks and calculating the vertical distribution of the section. The studied formations are represented by Upper Jurassic deposits with a non-uniform distribution of filtration and Reservoir properties. Methods: plotting the dependence of vertical permeability on porosity based on core studies, introducing the vertical component of permeability into geological and hydrodynamic models, calculating the adaptation of actual production data after taking into account the vertical component of permeability. As a result of the study, the petrophysical model of the studied field was refined, it turned out to achieve a more accurate distribution of petrophysical properties in the geological model. Thus, it becomes possible to take into account the real features of the geological structure, hence all three components of the permeability vector are used. One of the main points is the creation of a model that describes the distribution of properties as accurately as possible and reflects the real Characteristics of production. Carrying out the most accurate forecast and planning the application of enhanced oil recovery methods. A huge amount of accumulated data makes it possible to create correlations between various petrophysical parameters. It is necessary to supplement and develop a database, which in the near future can serve as a storage for analogous fields that do not have the data to create their own similar dependencies