Spontaneous Potential In The Ordos Basin And Petroleum Geology Significance

The validation of oil exploration using spontaneous potential(SP) methods in the Ordos Basin is studied in this paper. Mechanism of survey and research progress at home and abroad for exploring oil and gas reservoirs using spontaneous potential (SP) are reviewed. For a long time, different causes of forming SP, large disturbances and measurement accuracy issues, have affected the natural potential in oil and gas exploration. Measurement accuracy is mainly decided by the stability, anti-interference ability of instruments and equipment and measurement method. So, Choosing the right methods and improving the stability and anti-jamming capability is the key to the natural potential measurement method.Inadaptability of traditional SP measurement and processing in oil and gas exploration is analyzed in the paper. A multi-channel superposition measurement mode of SP method is proposed and the instrument (GDZD-16) is developed based on the new observation method. The multi-channel continuous observation in one time and timing curve observations of low-frequency range are performed, and the cycle basis points observation method compatible with the traditional SP measurement method are implemented. The actual observation results show that this Instrument is superior to conventional instruments in aspect of the interference device, data acquisition precision. Time-varying electric field studies in Ordos Basin indicate that a large area, long natural gas exploration using SP method need diurnal correction and quarter correction. According to the measured data and theoretical analysis, composition of natural electric field in the Ordos Basin is proposed, and that Mountain filtering natural electric field is the mainly interference in oil and gas exploration in the Ordos Basin is pointed.In the data processing: potential relative to oil and gas reservoirs is extracted in the potential timing curve using a variety of statistical methods, which better suppressed the interference of time-varying electric field and improved the accuracy of observation; Mountain filter the electric field In Ning and Heshui County, Jiyuan - Ma Huang area is corrected with correlation analysis method, and the results show that preferable solving the problem of Mountain filtering electric field in the Ordos Basin; the regional natural electric field was eliminated using window filtering technique using different scales and total trend analysis method, and the SP of local oil and gas is highlighted; topographic correction is performed based on the theory of virtual current source with boundary integral method to the natural electric field(commonly known as ' reduction of curved surface into a horizontal plane'); method of interpretation for oil and gas exploration using the current flow direction and determination of the boundaries of SP anomalies making using of coefficient of variation is proposed; pattern recognition technology oil and gas SP is presented and the SP processes of oil and gas exploration in the Ordos Basin is established.Through SP processing and analysis of observational data for stack of nearly 2,000 square kilometers of natural potential in In Ning and Heshui County, Jiyuan - Ma Huang area in the Ordos Basin, it shows that exploration of oil and gas reservoirs using SP method is feasible. The statistics and analysis of superposition of the known oil and gas reservoirs SP anomaly showed that the total effective rate was 60% -70%, the success rate of oil well was about 20%, proportion of dry wells was reduced 20%..