articles

 

It was established experimentally that the effect of a coherent low-frequency seismic signal arises spontaneously in the body of an oil and gas deposit. By the example of this effect, we discuss at a conceptual level some methodological approaches for study of geophysical fields and processes. These processes are based on representations of nonlinear geophysics, thermodynamics of irreversible processes and processes of self-organization of difficult nonlinear systems.

The earlier proposed model of ensemble of emitting coherent active sources (area) into HC deposit had been developed in the paper. In the model the initial radiating active centers are fluid phase which has changed its volume due to first-order phase transition.

The earlier proposed model of ensemble of emitting coherent active sources (area) into HC deposit had been developed in the paper. The expressions for the second order cross correlator spectrum of the microseismic noise field emitted by HC was derived. It was obtained for broad class of source types.

This article considers the possible features of microseism spectra caused by fluctuations of a liquid phase in a matrix of a rock which is affected by a transmitted wave. The possible manifestations in connection with low-frequency seismic are discussed.

It is presented physical mechanism for explanation of lowfrequency microseismic emission above oil and gas deposits by the elastic modules difference between oil and water saturated part of stratum.

We are considering the technique of the low–frequency seismic sounding based on the ANCHAR effect. We provide some phenomenological discussion of the effect, formulate its theoretical description, and then show some results of numerical simulation and comparison with real data. We describe the basic technological aspects of the method and the brief geological results.

We made the assessment of an energy part of microseismic noise connected with possible resonant effects observed above an oilfield in this article. We shown that hypothesis of frequency resonance above a deposit simultaneous for all observation stations is not reliably confirmed in the context of the offered model.

We consider possibilities of nonlinear dynamics approaches application for an analysis of microseismic background within the ANCHAR technology. We use Grassberger - Prokachchia's technique of attractors reconstruction for an assessment of existence a regular component in a microseismic noise. We make the assessment of the technique sensitivity to existence of a harmonic signal with constant or decaying amplitude in random series. Also, this article contains some examples of nonlinear dynamics techniques application for processing of data received on reservoirs.

This article considers a statistical analysis of using the ANCHAR technology while solving problems of oil and gas prospecting. Comparison of the results obtained with the ANCHAR technology forecast with the results of drilling in 30 oil and gas provinces is reported. The relations between characteristics of microseismic, geological features and reservoir properties are established on the base of the observations near wells.

The experience of applying microseismic infrasonic exploration method ANCHAR to the time lapse monitoring the outlines of pay zones of oil and gas reservoirs under production accounts for more than 15 years. The prospecting, exploration and monitoring of oil and gas targets with the technology are demonstrated. The high efficiency of the applying technology is showed.

We describe the results of traditional seismic exploration methods and their integration with the ANCHAR technology while solving a problem of forecasting the oil-and-gas content of Bokhan area (the south of Angara-Lenskaya step). The location of the groups of the microseismic wavefield anomalous points is determined with the ANCHAR technology. The relation between these anomalies and geology of the region of interest is shown up. Few single zones of hydrocarbons accumulation are mapped. These zones are still to be researched in a detailed way using reflection seismic and the ANCHAR technology.

Presently the microseismic survey is widely applied in commercial seismic projects for oil and gas survey on land and off shore. Of much interest is application of low frequency microseismic survey in the areas characterized by complicated geological conditions and salt tectonics where the results of classical CDP seismic are ambiguous. Presented are examples and results illustrating application of the low frequency microseismic survey ANCHAR under complicated geological conditions on land and off shore of West Kazakhstan.

We present the detailed mathematical description of primary mechanical coefficient of transformation for a fluid microseismometer. Material is meant for using in case of engineering calculations.

Practice of field exploration works for oil and gas with the ANCHAR technology demands usage of seismometers which have high sensitivity in an infrasound frequency range. However, traditional mechanical sensors do not have a sufficient sensitivity to record infrasound microseismic noise with sufficient accuracy. We focus attention on the structure and the principle of functioning of an electrochemical sensor. Also, this article contains information about the frequency features of electrochemical and mechanical transformation coefficients. These coefficients determine the amplitude-frequency characteristic of the described electrochemical sensor. The results descried in this article were patented.
 

In the paper the method of the estimate technology of the seismology measure device spectral power of the intrinsic noise on earth surface conditions is proposed. The efficiency of the one has been showed with comparing results of the method applying to the different situations: in earth surface and adit conditions.

The most microseismic technologies of HC exploration, in particularly, passive ones use low frequency band which are overlapping by frequency band of mancaused noise. So the problem of elimination of noise in microseismic exploration is more important then in ordinary seismic exploration. In the work the modification and applying of the Noise Compensation Method are demonstrated with the field data. It was showed that the method can be effective even with 0,1 signal/noise ratio.