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2nd EAGE St Petersburg International Conference and Exhibition on Geosciences
- Conference date: 16 Oct 2006 - 19 Oct 2006
- Location: Saint Petersburg, Russia
- ISBN: 978-90-73781-64-1
- Published: 16 October 2006
201 - 209 of 209 results
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The Processing of Seismic Data with Help of Building Special Discrete Wavelets
Authors O.M. Sagaidachnya and K.A. DunaevaThe opportunities of applying mathematical apparatus of wavelet transform for processing and compression of seismic and vibroseis data with use of specially designed classes of wavelets, which were (wavelets) built on the basis of seismic impulses, were explored. The practical meaning of using special wavelets, built on wave impulses of Berlage, Klauder, and Puzyrev, is presented with help of mathematical models and survey materials. Application of wavelets, built on the basis of seismic impulses, and opportunity of applying a priory information about input data (frequency range of a signal constituent, frequency of discretization, the speed of frequency change of sweep-signal) let improve the quality of processing of wave field in a target area by suppression of regular and random noise. The program apparatus of discrete wavelet transform and multi-resolution analysis, which is based on this discrete wavelet transform, provide an opportunity for effective compression (up to 10 times depending on signal/noise rate) of seismic information with preservation of characteristics of dynamic waves especially for the first-arrival wave.
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Multiscale Modification of Shepard’s Method for Geophysical Gridding
Authors V.V. Masjukov and A.V. MasjukovRecently developed multiscale modification of Shepard’s method is discussed. Advantages of our method for geophysical gridding are shown, especially in the case of wide and irregular well spacing.
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Efficiency of Microseismic Infrasonic Prediction of Oil-and-Gas
Authors A. Suntsov, S.L. Aroutunov, S.M. Karnaukhov, M.S. Kunaev and V.V. DvornikovMicroseismic and infrasonic technology of oil and gas prospecting ANCHAR had been devised in Russia and patented in 1992, then in 1998. First industrial application of the technology start in 1994 in Russia, then was kept on in Russia and took place in Kazahstan, and beyond the bounds of FSU in Morocco and Bulgaria (ADD-HR).
Basically, the technology of stimulation of a geologic area by seismic source in use, rarely – its ‘light’ modification. In the use of microseismic prospecting methods like ‘passive’ ANCHAR, its imitation HyMAS, and etc. which don’t apply any artificial seismic sources a number of principle problems has been found by the authors of the technology. On basis of the discovered quality of Microseismic Background Noise Order in the areas of HC beds a new Entropy Criterion of HC identification has been formulated that solved a part of the problems in using of ‘passive’ ANCHAR and its analogues.
For the period of more than 10 years of using the technology there were tested 75 exploring and prospecting wells. Success factor was more than 80%.
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Microseismic Background Study for Gas Field Exploration
Authors S.B. Turuntaev, V.N. Burchik and D.S. TuruntaevOne of the novel and promising methods of hydrocarbon field exploration includes recording of microseismic background before and after a vibrator work. Comparison of spectrums of microseismic background recorded at different sites showed, that in case of records made over several gas fields a low frequency peak appeared in the spectrum ratios. At the same time, processing of some of the data showed low reliability of that conclusion for some of gas fields. In presented paper we consider application of non-linear dynamics method (method of Grassberger & Procaccia) for the microseismic data processing, which looks to be more adequate for such type of data. It was found, that in studied cases vibration action within gas field contour leads to change of microseismic background characteristics. Out of gas reservoir contour any changes of microseismic background were not detected.
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Laboratory Study of Microseismicity Caused by Pore Pressure Increase
Authors S.B. Turuntaev, E.V. Zenchenko and A.M. DmitrievResults of laboratory study of microseismicity relation with pore pressure increase are considered. Spatial-temporal correlation between microseismic emission and pore pressure change was studied under different stress states: stiff-confined loading and “soft”-confined loading. It was found, that in case of water injection a front of AE propagation corresponds to propagation of pore pressure change. In experiments with “soft”-confined loading propagation of AE corresponds to pore pressure increase up to values approximately equal to uniaxial unconfined compression strength (which depends on porosity of the sample). In experiments with “soft”-confined loading the value of pressure for AE starting is smaller and approximately equal to 0.2 – 0.4 of compression strength. The velocity of AE front propagation depends approximately linear on the sample permeability.
The results can be used for estimation of a reservoir average strength and permeability and for correct interpretation of passive seismic monitoring data during hydro fracturing
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Velocity Properties Analysis of Stratigraphic Sequences of Surgutsky and Tobolsky Hydrocarbon-Bearing Regions
Authors V.Z. Koksharov, N.A. Volkova and A.N. PervukhinVSP and acoustic logging data as well as velocities at the core samples derived from wells located in Surgutsky, Tobolsky and Nizhnevartovsky hydrocarbon-bearing regions are analyzed. Reference beds, more precisely layer differences, are detected after division of well sections into suites and subsuites and definition of interval lithology based on a well log complex. Layer velocities of compressional and shear waves as well as ? coefficient are obtained. Velocity properties analysis has revealed that it is possible to detect beds with relatively stable acoustic properties.
In general, all wells are marked with appropriate increase of velocity and decrease of gamma coefficient with depth. The exception is an interval of the Bazhenovsky suite. From the depth of ~ 1500 m velocities significantly vary from one well to another. It is explained by increase of fracturing with depth and peculiarities of rock transformation at the stage of earlier catagenesis.
The intervals of the Lulinvorsky and Berezovsky suites are distinguished by their specific peculiarities of change in velocity of compressional and shear waves, and, first of all, of coefficient ?. Such changes are due to presence of opoks in the mineralogical content (opal (SiO2) of cristobalite- thrimidite type). Decrease of ? value for the Berezovsky suite intervals, is obviously associated with presence of gas.
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Automatic Well-Log Correlation - Expectations and Real Opportunities
Authors E.V. Kovalevskiy, G.N. Gogonenkov and M.V. PerepechkinThe problem considered is a detailed well correlation by log data, related to oilfields with a developed borehole grid. A special software is designed, with automatic correlation procedure for log intervals of 50-100 m wide as a main part of it. In the result of the procedure each well gets a mark, alignment on which provides the maximal correlation of given log intervals in a horizontal direction. Well marks are used to compute correlation surface, while the latter is found to be very close to stratigraphical surface on the appropriate depth. A number of correlation surfaces, obtained by this way through vertical intervals in 25-50 m define a directing skeleton for log data interpolation in 3D space. Research of interpolated data by tools of 3D visualization allows to a geologist to reveal all essential features of the ancient sedimentation environment. In the process correlation surfaces are used to present interpolated data in a paleoreconstructed view. After the research manual well correlation turns to a simple fixing of notion obtained. It is also shown, that model sceleton boundaries, when based on automatic correlation, give much better result in lithological bodies interpolation. The last conclusion is supported by indicator variogram view.
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Thermometry of Well in the Conditions of Multiphase Flow and Unsteady Pressure Distribution
Authors R.A. Valiullin, A.A. Sadretdinov and R.F. SharafutdinovAt present time technique of research and interpretation of data of thermometry research is based especially on the basis of data research, for one-phase flow of oil, water and gas. But in the real-life environment multiphase flows in the formation and well are observed. Start and stop processes of the well, swabbing and compressor oil well completion are characterized by unsteady pressure distribution. Pressure in the well can increase above the reservoir pressure and then decrease below reservoir pressure and pressure of oil saturation by gas.
Thus regimes of multiphase flows dependent on change from water pumping from the wellbore to the oil-saturated reservoir to fluid production from reservoir with oil degassing are realized. Reservoir temperature distribution in that case is caused by Joule-Thomson effect, adiabatic affect and heat of degassing of fluid. Oil and water throttling leads to temperature increasing and oil degassing leads to temperature decreasing.
Informativity of the thermometry technique of well and formation research is based on the regularities of changes of temperature anomalies.
Principal regularities of temperature distribution formation during arbitrary bottom-hole pressure changes in the conditions of multi-phase flow taking into consideration thermo-dynamical effects and oil degassing are numerically researched in this work. The possibility of solving of the filed problems according to data of thermo-hydro-dynamical well researches is shown.
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Compound-Structured Oil Deposits Modelling and Hydrocarbons Reserves Estimation by Attribute Analysis Results – Drilling Control Results
Authors O.A. Smirnov, V.V. Kolesov and G.A. ZakharovaIntegrated geophysical and seismic prospecting data interpretation based on attribute analysis has been conducted and is shown as example at one of the Western Siberian oil field. Measured parameters validation and hydrocarbons reserves estimation discovered via wildcat drilling in the Jurassic deposits were the main objectives. Oil field modelling was conducted by forecasting SP relative amplitude parameter. Predicted sections were used for calculation of the following maps: a) areal distribution maps of oil deposits' effective thicknesses, b) substantiation maps of oil reservoirs' substitution boundaries. Technology of complex interpretation developed in PANGEA Inc. efficiently allowed accomplishing deposits geometrization task under conditions of compound sandstone allocation, their inner nonuniform structure typical for alluvial formations, hosting Tyumen suite pay reservoirs. The conclusion is grounded at results of prognosis matching made by one well and data from 7 well drilled later. Refined deposits models made essential changes in reserves estimation and allowed allocating new structural features of the pay section part, thus giving grounds for high prospects of oil reserves and production growing at the deposit studied.
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