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.
Determination of current reservoir gas saturations for the purposes of evaluation of the uniformity of reserve recovery across the reservoir body, and estimation of gas reserves remaining in the watered pay zone for a feasibility study on extraction thereof, constitutes one of the urgent tasks for gas fields, especially mature ones. This objective became particularly pressing due to introduction from January 1 2016 of a new Classification of reserves and Resources of Oil and Combustible Gases that mainly features an economic assessment of the development of hydrocarbon reserves, performed with varying degree of elaboration subject to the field exploration stage. The article describes the results of further development of the innovative technology of near-wellbore area logging at various depths with the use of SNGK and NNL logging methods under geological and technical conditions of mature gas wells.
The results of the analysis of the field of microseismic fracturing of a formation made for the gas field "Barnet" in the northeastern part of Texas are presented. The inversion of digital records of microseisms has been performed and data have been obtained not only about the coordinates of initiating micro-earthquakes, but also their focal mechanisms of cracks. These data were the basis for carrying out tectonophysical reconstruction of the stresses that existed in the depth of the massif at the time of Hydrofracturing. The results of stress reconstruction allowed obtaining data on the orientation of the axes of the principal stresses, the nature of thegeodynamic regime, and the relative level of the effective pressure of the massif in the fracturing region. On the basis of the stress field, areas of a sharp change in the types of geodynamic regimethat can respond to large deep discontinuous disturbances and areas of increased strength of the massif are identified.
Over several decades the meaning of fractured reservoirs in exploration geophysics is increasing steadily. Detection of fractured zones and estimation of its parameters became necessary stages of seismic interpretation. Essential difficulties during the determination of the model are associated with uncertainty of seismic interpretation and low resistance of estimated parameters. The approach, concerned with model selection and methodology of seismic interpretation, plays the key role, taking into account the facts, mentioned above. The main purpose of the article is to detect diagnostic features and physical proprieties of fractured reservoirs; it can help to construct effective model of reservoir and to avoid wrong alternative methods of seismic interpretation.
The article is concerned with the opportunity analysis of the remote retrospective monitoring of thermodynamic and fluidodynamic field as the management tool of process control system of the oilfield at the late stage of field research. As the data source, multi-year data of spacebased and observer thermal imaging system of far infrared band (7.5-14 micron) are used. Field patterns of heat radiation of Yelabuga oilfield (micro- and cross-section aspect to a depth of 5 km as on 1988, 1999, 2014) are compared in the article.
The well-known fact about Tatarstan is that reserves depletion from nonshale reservoir rocks on the territory of the most fields critically increases. New tasks are usually set before geologists for maintain production and keeping reserve base: searching for oil deposits and field work in unconventional reservoirs. Data interpretation of C/O logging of overlying section of the Domanic deposits is described in the article (fields of the Republic of Tatarstan are used as the example).
Observing the phenomena of paragenesis, subvertical, zonary annulars, geo-physical and geochemical areas provides possibility to explore the accommodation of oil-water suppression selvages of petroleum deposits, using onshore geochemical and geophysical methods and equipment-specific, new approach, concerning producing fields and peripheral areas. The article deals with identification of common factors of changes in geo-physical and geochemical fields above hydrocarbon reservoir and outside it.
Distributed acoustic sensing (DAS) has wide acceptance in well’s seismic prospecting since 2012. Practice work shows that these systems are effective. The records have positive quality and they allow you to simultaneously receive and record vibrations along the entire length of fiber-optic cable, which eliminates the need to navigate through the borehole of single or strings of geophones, minimize quantity of required affectings and them not sensitive to external electric and magnetic fields. These featuresof fiber-optic systems determine considerable prospects for their application.Application of fiber-optic systems are still experimental and methodological in nature and focused on the development and optimization of technologies of exploration and evaluation capabilities of new systems in the whole complex of borehole research.