The fundamental geophysical method of searching for oil deposits on the territory of the Volga-Urals region is seismic exploration; however, one should not underestimate the reliability of simple geophysical methods, such as gravel and
magnetic exploration, when predicting oil and gas deposits in the studied area. In the present work, the analysis revealed certain spatial relationships of geophysical parameters with the presence of hydrocarbon deposits in the lower floors (upper devon, lower carboniferous) of the sedimentary cover of the Volga-Ural oil and gas-bearing province: most of the traps are located in the zones of positive values of the anomalous magnetic field and in the zones of negative values of the local magnetic field.
Materials and methods
Complex interpretation of data obtained by methods: magnetic exploration (field ΔТа), engraving (field Δg) together with seismic exploration data.
geophysical search methods, oil deposit, magnetic exploration, engraving, seismic exploration
The paper presents results of research, the purpose of which is to obtain additional information on the tectonic structure of the pre-Jurassic complex at an oil deposit in Western Siberia, obtained from seismic data in the field of diffracted waves. A complex geological structure and a large number of tectonic dislocaitions characterize the Pre-Jurassic complex within the field. Diffraction imaging is the method of detecting diffractors of wavefield that represent fracture zones, faults and other objects . The main idea of the method is to use diffraction as additional information, which in the method of reflected waves is a noise. The method was used at this oilfield for the first time. As a result of the studies, polygons of the distribution of zones of fracture and tectonic dislocations were obtained.
Materials and methods
Seismic data were obtained from the study area, which is located in the northern part of the Frolovskoye megavasin of Western Siberia. The diffraction imaging method was used.
diffraction visualization, pre-Jurassic complex, tectonic dislocations
New seismic onshore acquisition is led in regions with low signal/obstacle ratio. In this conditions it is necessary to use complex field 3D systems and conduct special experiments to receive good field materials. Some of this
questions are discussed in the article with showing the results of experiments.
Materials and methods
Description of methodical and results of application two 3D onshore high density acquisitions technology and special experiments to optimization onshore seismic technology.
onshore shooting, acquisition, productivity, vibrator, distortion, bin, experiment, digital system
The results obtained by methods of electrical exploration and GPR in the area of hazardous engineering and permafrost processes in the territory of oil and gas facilities located in the cryolithozone are presented. On the geoelectric and GPR sections, the presence of ground ice lenses was determined from the contrast difference of electrical resistivity and amplitudes of electromagnetic waves, respectively. In the immediate vicinity of engineering structures, a significant decrease in electrical resistance is observed, presumably associated with the degradation of permafrost soils as a result of the technogenic impact of engineering structures on changes in snow accumulation and changes in surface and groundwater runoff. The high efficiency of geophysical methods in solving engineering and geocryological problems at the stages of design, construction and operation of engineering structures is shown.
In article are described some examples of high effectiveness of modern land acquisition, of new field technique and constructing and testing of new marine vibrator.
The results of applying new methodological approach to the integrated study of lithologic and petrophysical properties and the saturation nature of Cenonian reservoir formations by using the multi-method multiple sonde gamma-ray logging (MGRL) are presented.
MGRL capabilities are demonstrated during the study of poorly studied lower Bereyozovsk opokamorphic low-permeable reservoir beds with raw hydrocarbons that are hard to recover (RHR).
The possibilities of detailed lithological formation typing are confirmed, which significantly increases the reliability of processing and interpretation of GIS results using MGRL. The advantages of the technology for forecasting and additional exploration of raw hydrocarbon reserves are presented.
Onshore seismic technology is a complex of methods that ensure seismic prospecting in different geological conditions with receiving good materials with good accuracy, wide wave frequency and high productivity.
The article reports an overview of effective media methods in the context of computation elastic properties of rocks (Rock Physics) with constraints of applicability. For comparison purposes, several methods were applied to estimate effective elastic properties of modeled space consisting of the calcite matrix and the pore space divided according to double porosity model. For the three types of carbonate rocks parameter-oriented elastic models on the core scale were constructed based on generalized singular approximation method, using data of rocks microstructure analysis at various scales, as well as measurements of the elastic waves velocities on the standard samples. The parameters of petroelastic models were obtained during solving the inverse problem.
The current level of seismic exploration and the expectations of geophysical customers require an increase in the seismic resolution. This is necessary to obtain More detailed depth images of a fragment of the earth's crust are to be obtained, as well as the accuracy of inversion and migration transformations is to be improved. For this purpose, the frequency range of the signal should be extended, and the complications of the seismic wavelet shape should be corrected by means of inverse filtering. The paper describes the signature deconvolution optimization method. The inverse filtering operator is calculated from a known signal, and then adaptive filtering of the input data is performed. The algorithm is robust in the sense that it does not lead to an increase of the random and the regular noise. Adaptation is applied in a sliding rectangular window.
The possibility of prediction of the geologic section below the TD distinguishes the method of vertical seismic profiled (VSP) from all other methods of geophysical researches of wells. In the VSP method the incident waves and waves rifled from the seismic boundaries, located under the well bottom, are recorded simultaneously. Thus, in contrast to surface seismic exploration, a more correct solution of the inverse kinematic and dynamic problems, aimed for the study of the section below the well bottom, is provided. Several versions of the VSP method are currently used, each of which has a number of advantages and disadvantages. The combination of different versions allows one to study the elastic properties of the subsurface and the section under the bottom of the well by using of kinematic and dynamic parameters of waves of different types and classes.
The article shows a method for the continuous determination of the elasticstrength properties of rocks by the method of controlled scratching. The created installation allows obtaining information about the resistance to displacement of the indenter, scratching on cylindrical samples of synthetic and natural materials (cores). The developed technique allows to recalculate the values of force obtained by setting the strength of the tensile strength with unlimited uniaxial compression.
The article describes the importance of improving existing and developing new technologies for joint interpretation of geophysical methods aimed at prospecting and exploration of hydrocarbon fields. The potential of seismic prospecting and electromagnetic exploration by transient electromagnetic method in the near field zone (TEM) in solving oil and gas exploration problems in Western Siberia are considered. Regarding to seismic prospecting, the possibility of analyzing scattered waves for the prediction of fracture and cavernousness zones is considered in detail. Conducting TEM survey makes it possible to clarify the contours of hydrocarbon fields identified by seismic prospecting. Based on drilling data, petrophysical studies and reservoir capacitance characteristics (by seismic survey), it is possible to proceed to the saturation type prediction - to determine the water saturation value. It is shown that the results obtained by integrating seismic and electromagnetic surveys make it possible to significantly increase the detail and reliability of the survey area geological model at all stages of geological exploration: from prospecting to the development and exploitation stage of hydrocarbon fields.
The paper presents a technique for constructing a parametric petroelastic model of oolitic limestone on the core scale using the approaches of the Effective Medium Theory (Rock Physics), data on the microstructure of the rock, and the velocities of elastic waves in the rock. Parameters of the petroelastic model characterize the structure of the void space of the rock and include the shape of intergranular and oolitic pores, as well as the degree of connectivity of pores in the matrix and oolites. The results of petroelastic modeling justify the importance of taking into account the specific microstructure parameters of each particular rock for which this simulation is carried out.
High requirements to the quality and productivity of marine seismic exploration determine the modern technology of field observations.The acquaintance of Russian survey geophysicists with the materials of the international geophysical conference is of some interest, since The reports reflect the development trends in marine seismictechnology, which illustrate the efficiency and good prospects for the future and can be useful to domestic marine seismic surveys.
The study discusses the experience of Gazprom Neft Shelf LLC in implementing stationary tracing monitoring technology for horizontal wells in the Prirazlomnoye oilfield. The paper explores the technology of inflow profiling based on the data from intelligent inflow tracers installed in completion strings of production wells in the Prirazlomnoye oilfield.
The statistic shows that in the north of West Siberia basin about 60% of all prospects turned out to be water-bearing. Most of them are structural prospects, that were not confirmed by more recent seismic data. To avoid mistakes in the future, and to increase the exploration drilling success rate, one needs to establish the reasons for these failures. For this purpose, the so called “dry hole analysis” or post well analysis was carried out for all dry wells, drilled in the region in 1970-90s. During the analysis the values of seismic depth prediction errors in comparison with the estimated structural uncertainty were determined. Based on collected data, typical morphological features and seismic amplitude characteristics of water-bearing, false anticlines were revealed.
Possibilities of the vertical electric sounding - one of mobile geophysical methods for quantitative determination of the salinity of the subsurface water of the main aquifers, situated on the territory of oil fields of the south-east of the Republic of Tatarstan - are analyzed in the article. The proposed methodology allows to construct detailed maps of the salinity of aquifers of the areas and to determine the protection rate of the groundwater from pollution.
The questions, concerning with the development of hard-to-recover reserves assume prominence under the conditions of volume growth of hydrocarbon production, taking into account the reserves depletion of middle and low-density and viscosity of the oil of shallow horizons. The article is devoted to the description of geological conditions of occurrence (deep depth, the complex structure of deposits, etc.) and the characteristics of oils with abnormal physical-chemical properties, especially characteristics of sulfur oils. Sulfur oils are considered to be hard to-recover oils as they are characterized with the properties, that make the development difficult.