Foreland basins on the western edge of Ordos are characterized by typical loess geomorphologic features. Its surface is severely cut, and its underground geological structures are complicated.Making use of the advanta...Foreland basins on the western edge of Ordos are characterized by typical loess geomorphologic features. Its surface is severely cut, and its underground geological structures are complicated.Making use of the advantage of CEMP in exploration in frontland as well as successful multi-year exploration experiences in West China, we first employed the CEMP method to conduct exploration on the western edge of the Ordos basin and its surrounding areas. The practices proved that rich and reliable geological results have been achieved with the CEMP method in complicated areas covered with loess. This can provide important evidence for researching the contact relationship among basins and mountains, structural feature of target layers and predict favourable areas.展开更多
The Carboniferous and Pre-Carboniferous formations in Ludong, Zhungar basin, contain favorable oil/gas reservoirs. The Carboniferous formations, however, are complex in structure and exhibit lateral variations in lith...The Carboniferous and Pre-Carboniferous formations in Ludong, Zhungar basin, contain favorable oil/gas reservoirs. The Carboniferous formations, however, are complex in structure and exhibit lateral variations in lithology. Seismic reflections from Pre-Triassic formations are poor and the volcanic reservoirs are very difficult to identify. The analysis of physical properties concluded that the major targets in this region, i.e., the top of the Jurassic and Carboniferous formations, provide distinct density interfaces. The basic, intermediate and acid volcanic rocks were also different in density,resulting in distinguishable gravity anomalies. The differences in magnetism in this region existed not only between the volcanic rocks and clastic sedimentary rocks but also among volcanic rocks with different compositions. All formations and volcanic rocks of different lithologies presented high and low resistance interbeds, which are characterized by regional trends.The modeling study demonstrated that non-seismic integrated geophysical techniques should be feasible in this region, especiaUy the high-precision gravity/magnetic methods combined with long offset transient electromagnetic sounding.展开更多
Discussed in this paper was the pre-processing procedure for gravity data, including topographical correction,intermediary layer correction etc. The necessity to utilize aerial photogram to do topographical correction...Discussed in this paper was the pre-processing procedure for gravity data, including topographical correction,intermediary layer correction etc. The necessity to utilize aerial photogram to do topographical correction in middle area was discussed, and a real examples given showing the effect. We discussed the problems caused by the maximum radius for conventional correction, the necessity of extending the radius for topographical correction, the corresponding method for calculation of topographical correction, and the standard of optimally selecting the radium for topographical correction.This method could raise the data accuracy of gravity survey in the complex mountainous areas by several millil-gals-several tens milli-gals reaching the exploration effect as well as in plain area almost.展开更多
The two-component multi-parameter time-frequency electromagnetic method, used for the development of oilfields,makes use of both the traditional individual conductivity parameters of oil-producing layers and the dispe...The two-component multi-parameter time-frequency electromagnetic method, used for the development of oilfields,makes use of both the traditional individual conductivity parameters of oil-producing layers and the dispersion information of the conductivity, i.e., the induced polarization parameter. The frequency-domain dispersion data is used to delineate the contacts between oil and water and the time domain dBz/dt component is used to estimate the depths to the un-known reservoirs so as to offer significant data in many aspects for oil exploration and detection.展开更多
The gap between China''s integrated geophysical technology and the world''s advanced technologies has been significantly narrowed as the result of developments in the last decade.The new technology has...The gap between China''s integrated geophysical technology and the world''s advanced technologies has been significantly narrowed as the result of developments in the last decade.The new technology has played a very important role in oil and gas exploration in China, especially for the purposes of targeting seismically opaque zones, decreasing exploration risk, and improving exploration efficiency in the western territories and complex areas in China. The current status and future development of non-seismic integrated geophysical teams in China is discussed.展开更多
The Yanqi basin is small and located at the northeastern corner of the Tarim basin. Before April 1993, the Yanqi basin was only surveyed with surface geology and seldom known among the explorers. After that, the gravi...The Yanqi basin is small and located at the northeastern corner of the Tarim basin. Before April 1993, the Yanqi basin was only surveyed with surface geology and seldom known among the explorers. After that, the gravitational, magnetic and MT prospecting were carried out and found some interesting local structures, which might be oil-and-gas-bearing. A few seismic lines were utilized to confirm them. An exploratory well was drilled in the summer of 1994 and discovered oil flow with industrial value in Oct., the same year. The petroleum exploration obtained breakthrough in the Yanqi basin in only 18 months.展开更多
The Qinshui basin, with good petroleum geological conditions, possessed two sets of Carboniferous-Permian and Ordovician carbonate source rocks. The Carboniferous-Permian formations were the stable regional low-resist...The Qinshui basin, with good petroleum geological conditions, possessed two sets of Carboniferous-Permian and Ordovician carbonate source rocks. The Carboniferous-Permian formations were the stable regional low-resistance marker. The underlying Ordovician formations constructed the high-resistance basement in shallow depth. These electric characteristics were very beneficial to the CSAMT method,which could replace the seismic method to find the potential zones and speed up the exploration processes.展开更多
Experience gained in many years proved that oil explorations were very difficult to complete with seismic methods only in seismic-unfeasible areas. The expected results in these places could only be obtained with the ...Experience gained in many years proved that oil explorations were very difficult to complete with seismic methods only in seismic-unfeasible areas. The expected results in these places could only be obtained with the integrated geophysical surveys, the combination of gravity, electric, magnetic,geochemistry and seismic methods. The high-precision gravity,magnetic and electric techniques used in seismic-unfeasible areas in Qaidam Basin had achieved many astonishing results,which demonstrated a feasible way for oil exploration in Qaidam Basin and offered a basis for data interpretation in complex areas where seismic data was not able to acquire.展开更多
Based on the geology of the Kuche area, the authors designed model for CEMP for the overthrust belt and made the calculation of 2D forward and inverse modeling.Through the processing and interpretation of the data acq...Based on the geology of the Kuche area, the authors designed model for CEMP for the overthrust belt and made the calculation of 2D forward and inverse modeling.Through the processing and interpretation of the data acquired in the Kuche sag, it is revealed that the contacting relationship between the mountain range and the basin is that in the eastern part it is mainly overthrusts, and in the western part reverse faults. The moving distance for the nappes is generally over 20 km. It is predicted that there is a row of buried structural zone with a trend of nearly E - W, under the Tianshan nappe. The main feature of the structural zone is uplifting gradually to the west, and the buried depth is increasing toward the north.展开更多
Geochemistry has been utilized in the petroleum exploration for tens of years. The hydrocarbon halo in the near surface above the oil and gas pool has three kinds of state, i.e., free gaseous HC, absorbed HC and disso...Geochemistry has been utilized in the petroleum exploration for tens of years. The hydrocarbon halo in the near surface above the oil and gas pool has three kinds of state, i.e., free gaseous HC, absorbed HC and dissolved HC.The optimum choice in the geochemical prospecting is directly testing the free HC. The gas chromatography for free HC was imported and improved in the Division in the early 1990s, realizing the acquiring, analyzing, processing and interpreting free HC samples in the field and in real time. Marked geological result and economical effect were achieved during the many years'' practices.展开更多
The deep information of the Turfan sag was extracted and analyzed through the re-processing of the magneto-gravitational data of the Turfan sag in the Turfan-Hami basin. It is considered that the basement faults have ...The deep information of the Turfan sag was extracted and analyzed through the re-processing of the magneto-gravitational data of the Turfan sag in the Turfan-Hami basin. It is considered that the basement faults have played an important role in the controlling of the framework, lithology and the distribution of volcanic rocks in the basement of the Turfan sag. The deep crystalline basement and the upper Hercynian folded basement were studied part by part in the sag through the combined data of aeromagnetic and electric methods. It is revealed that the Huoyanshan fault is steep in the upper and lower parts but gentle in the middle, displaying a “S” type texture, and discovered that there are at least a row of local structures in the down-thrown block of the Huoyanshan fault, through the CEMP prospecting in Huoyanshan. The result is very important for the studying of the Turfan sag as a whole.展开更多
The Qiangtang basin is one of the large-scale basins in China, which is located in the high-altitude and cold area. In 1994 the preliminary gravity, magnetic and electric prospecting work was undertaken in this area. ...The Qiangtang basin is one of the large-scale basins in China, which is located in the high-altitude and cold area. In 1994 the preliminary gravity, magnetic and electric prospecting work was undertaken in this area. Over three years the gravity, magnetic and electric reconnaissance work had been completed. The integrated interpretation of complex gravity, magnetic and electric data had identified the boundary of the basin. The relationship between the basin and mountains is a south-north ramp structure. The basin structure consisted of one uplift and two sags, five depressions and two arches. The complex evaluation showed that the regions of Baitanhu and Youyiquan in the Qiangtang basin were considered to be the most perspective ones in sense of oil-gas bearing.展开更多
This paper introduces two types of rapid inversion imaging techniques for long offset transient electromagnetic sounding: namely S-inversing algorithm based on the conductive sheet model and quasi-wave equation based ...This paper introduces two types of rapid inversion imaging techniques for long offset transient electromagnetic sounding: namely S-inversing algorithm based on the conductive sheet model and quasi-wave equation based on wavefield transform. The corresponding software was developed with VC++. Application of the algorithms to the processing of the real Lotem data from the western part of China proved that two the algorithms and the developed software package are effective, fast and stable.展开更多
Vibratory excitation generates not only reflections and refractions of wave fields on the subsurface interfaces but also electromagnetic waves with different frequencies. In this paper we address the vibration-induced...Vibratory excitation generates not only reflections and refractions of wave fields on the subsurface interfaces but also electromagnetic waves with different frequencies. In this paper we address the vibration-induced effects on the spontaneous potential field. The effects of controllable vibration on the spontaneous potential field were studied under real field geologic conditions. Experimental data confirmed that the vibration-induced effects on the spontaneous potential field do exist under field conditions. Monitoring records over a long time interval showed that there existed three information zones in the vibration-induced effects on spontaneous potential field:These are the signal-variant zone, the extreme-stable zone and the relaxation-recovery zone. Combined with different well-site data, it was concluded that the time-variant features of the anomalies in the information zones was closely related to the properties of the subsurface liquid (oil and water).展开更多
Addressed in this paper was the comprehensive interpretation of all kinds of data and its applications in oil/gas exploration. Real examples were used to illustrate the importance of the comprehensive interpretation o...Addressed in this paper was the comprehensive interpretation of all kinds of data and its applications in oil/gas exploration. Real examples were used to illustrate the importance of the comprehensive interpretation of gravity/magnetic/electric/seismic data as well as the results.展开更多
Addressed in this article is a new approach to investigating the near-surface structures through the use of the electromagnetic sounding. The advantages of the electro-magnetic sounding method and the problems of the ...Addressed in this article is a new approach to investigating the near-surface structures through the use of the electromagnetic sounding. The advantages of the electro-magnetic sounding method and the problems of the nearssurface investigation and their solutions are described. Actual examples from the southwestern Takelamagan, western Qaidam and northern Xinjiang are taken to demonstrate the results and the capability of this approach in solving the nearsurface problems. It is also pointed out that the new approach could become both the basis for designing seismic acquisition parameters and determining the seismic shot locations,as well as supplying near-surface velocity models for seismic data processing so as to improve the quality of seismic sections.展开更多
The utilization of MT and CEMP methods has been extended from plains to mountainous areas. The rugged topography not only brings about difficulties in field electro-magnetic measurements but also affects data processi...The utilization of MT and CEMP methods has been extended from plains to mountainous areas. The rugged topography not only brings about difficulties in field electro-magnetic measurements but also affects data processing, interpretation and results. Analyzed in this paper were the 2D and 3D forward modeling of the fluctuated topography and the real examples to discuss the topographic effects on electric data and the practical methods to avoid these effects.展开更多
In 1997, the TZ- 162 well in Tazhong area of the Tarim basin hit the lower Paleozoic dolomite reservoir at a depth of 5,900 m. The distribution of the dolomite reservoir, however,was very difficult to delineate due to...In 1997, the TZ- 162 well in Tazhong area of the Tarim basin hit the lower Paleozoic dolomite reservoir at a depth of 5,900 m. The distribution of the dolomite reservoir, however,was very difficult to delineate due to the complex surface conditions and poor seismic properties. High-precision transient electromagnetic sounding (TEM) was conducted and good results obtained in this area. This paper discussed the principle,data processing and interpretation of this method. The resultsof studying the dolomite reservoirs demonstrated the effectiveness of the method in studying the low-resistance dolomite reservoirs in the high-resistance carbonates. This method should be an effective one to study reservoirs in areas with similar physical properties as well.展开更多
文摘Foreland basins on the western edge of Ordos are characterized by typical loess geomorphologic features. Its surface is severely cut, and its underground geological structures are complicated.Making use of the advantage of CEMP in exploration in frontland as well as successful multi-year exploration experiences in West China, we first employed the CEMP method to conduct exploration on the western edge of the Ordos basin and its surrounding areas. The practices proved that rich and reliable geological results have been achieved with the CEMP method in complicated areas covered with loess. This can provide important evidence for researching the contact relationship among basins and mountains, structural feature of target layers and predict favourable areas.
文摘The Carboniferous and Pre-Carboniferous formations in Ludong, Zhungar basin, contain favorable oil/gas reservoirs. The Carboniferous formations, however, are complex in structure and exhibit lateral variations in lithology. Seismic reflections from Pre-Triassic formations are poor and the volcanic reservoirs are very difficult to identify. The analysis of physical properties concluded that the major targets in this region, i.e., the top of the Jurassic and Carboniferous formations, provide distinct density interfaces. The basic, intermediate and acid volcanic rocks were also different in density,resulting in distinguishable gravity anomalies. The differences in magnetism in this region existed not only between the volcanic rocks and clastic sedimentary rocks but also among volcanic rocks with different compositions. All formations and volcanic rocks of different lithologies presented high and low resistance interbeds, which are characterized by regional trends.The modeling study demonstrated that non-seismic integrated geophysical techniques should be feasible in this region, especiaUy the high-precision gravity/magnetic methods combined with long offset transient electromagnetic sounding.
文摘Discussed in this paper was the pre-processing procedure for gravity data, including topographical correction,intermediary layer correction etc. The necessity to utilize aerial photogram to do topographical correction in middle area was discussed, and a real examples given showing the effect. We discussed the problems caused by the maximum radius for conventional correction, the necessity of extending the radius for topographical correction, the corresponding method for calculation of topographical correction, and the standard of optimally selecting the radium for topographical correction.This method could raise the data accuracy of gravity survey in the complex mountainous areas by several millil-gals-several tens milli-gals reaching the exploration effect as well as in plain area almost.
文摘The two-component multi-parameter time-frequency electromagnetic method, used for the development of oilfields,makes use of both the traditional individual conductivity parameters of oil-producing layers and the dispersion information of the conductivity, i.e., the induced polarization parameter. The frequency-domain dispersion data is used to delineate the contacts between oil and water and the time domain dBz/dt component is used to estimate the depths to the un-known reservoirs so as to offer significant data in many aspects for oil exploration and detection.
文摘The gap between China''s integrated geophysical technology and the world''s advanced technologies has been significantly narrowed as the result of developments in the last decade.The new technology has played a very important role in oil and gas exploration in China, especially for the purposes of targeting seismically opaque zones, decreasing exploration risk, and improving exploration efficiency in the western territories and complex areas in China. The current status and future development of non-seismic integrated geophysical teams in China is discussed.
文摘The Yanqi basin is small and located at the northeastern corner of the Tarim basin. Before April 1993, the Yanqi basin was only surveyed with surface geology and seldom known among the explorers. After that, the gravitational, magnetic and MT prospecting were carried out and found some interesting local structures, which might be oil-and-gas-bearing. A few seismic lines were utilized to confirm them. An exploratory well was drilled in the summer of 1994 and discovered oil flow with industrial value in Oct., the same year. The petroleum exploration obtained breakthrough in the Yanqi basin in only 18 months.
文摘The Qinshui basin, with good petroleum geological conditions, possessed two sets of Carboniferous-Permian and Ordovician carbonate source rocks. The Carboniferous-Permian formations were the stable regional low-resistance marker. The underlying Ordovician formations constructed the high-resistance basement in shallow depth. These electric characteristics were very beneficial to the CSAMT method,which could replace the seismic method to find the potential zones and speed up the exploration processes.
文摘Experience gained in many years proved that oil explorations were very difficult to complete with seismic methods only in seismic-unfeasible areas. The expected results in these places could only be obtained with the integrated geophysical surveys, the combination of gravity, electric, magnetic,geochemistry and seismic methods. The high-precision gravity,magnetic and electric techniques used in seismic-unfeasible areas in Qaidam Basin had achieved many astonishing results,which demonstrated a feasible way for oil exploration in Qaidam Basin and offered a basis for data interpretation in complex areas where seismic data was not able to acquire.
文摘Based on the geology of the Kuche area, the authors designed model for CEMP for the overthrust belt and made the calculation of 2D forward and inverse modeling.Through the processing and interpretation of the data acquired in the Kuche sag, it is revealed that the contacting relationship between the mountain range and the basin is that in the eastern part it is mainly overthrusts, and in the western part reverse faults. The moving distance for the nappes is generally over 20 km. It is predicted that there is a row of buried structural zone with a trend of nearly E - W, under the Tianshan nappe. The main feature of the structural zone is uplifting gradually to the west, and the buried depth is increasing toward the north.
文摘Geochemistry has been utilized in the petroleum exploration for tens of years. The hydrocarbon halo in the near surface above the oil and gas pool has three kinds of state, i.e., free gaseous HC, absorbed HC and dissolved HC.The optimum choice in the geochemical prospecting is directly testing the free HC. The gas chromatography for free HC was imported and improved in the Division in the early 1990s, realizing the acquiring, analyzing, processing and interpreting free HC samples in the field and in real time. Marked geological result and economical effect were achieved during the many years'' practices.
文摘The deep information of the Turfan sag was extracted and analyzed through the re-processing of the magneto-gravitational data of the Turfan sag in the Turfan-Hami basin. It is considered that the basement faults have played an important role in the controlling of the framework, lithology and the distribution of volcanic rocks in the basement of the Turfan sag. The deep crystalline basement and the upper Hercynian folded basement were studied part by part in the sag through the combined data of aeromagnetic and electric methods. It is revealed that the Huoyanshan fault is steep in the upper and lower parts but gentle in the middle, displaying a “S” type texture, and discovered that there are at least a row of local structures in the down-thrown block of the Huoyanshan fault, through the CEMP prospecting in Huoyanshan. The result is very important for the studying of the Turfan sag as a whole.
文摘The Qiangtang basin is one of the large-scale basins in China, which is located in the high-altitude and cold area. In 1994 the preliminary gravity, magnetic and electric prospecting work was undertaken in this area. Over three years the gravity, magnetic and electric reconnaissance work had been completed. The integrated interpretation of complex gravity, magnetic and electric data had identified the boundary of the basin. The relationship between the basin and mountains is a south-north ramp structure. The basin structure consisted of one uplift and two sags, five depressions and two arches. The complex evaluation showed that the regions of Baitanhu and Youyiquan in the Qiangtang basin were considered to be the most perspective ones in sense of oil-gas bearing.
文摘This paper introduces two types of rapid inversion imaging techniques for long offset transient electromagnetic sounding: namely S-inversing algorithm based on the conductive sheet model and quasi-wave equation based on wavefield transform. The corresponding software was developed with VC++. Application of the algorithms to the processing of the real Lotem data from the western part of China proved that two the algorithms and the developed software package are effective, fast and stable.
文摘Vibratory excitation generates not only reflections and refractions of wave fields on the subsurface interfaces but also electromagnetic waves with different frequencies. In this paper we address the vibration-induced effects on the spontaneous potential field. The effects of controllable vibration on the spontaneous potential field were studied under real field geologic conditions. Experimental data confirmed that the vibration-induced effects on the spontaneous potential field do exist under field conditions. Monitoring records over a long time interval showed that there existed three information zones in the vibration-induced effects on spontaneous potential field:These are the signal-variant zone, the extreme-stable zone and the relaxation-recovery zone. Combined with different well-site data, it was concluded that the time-variant features of the anomalies in the information zones was closely related to the properties of the subsurface liquid (oil and water).
文摘Addressed in this paper was the comprehensive interpretation of all kinds of data and its applications in oil/gas exploration. Real examples were used to illustrate the importance of the comprehensive interpretation of gravity/magnetic/electric/seismic data as well as the results.
文摘Addressed in this article is a new approach to investigating the near-surface structures through the use of the electromagnetic sounding. The advantages of the electro-magnetic sounding method and the problems of the nearssurface investigation and their solutions are described. Actual examples from the southwestern Takelamagan, western Qaidam and northern Xinjiang are taken to demonstrate the results and the capability of this approach in solving the nearsurface problems. It is also pointed out that the new approach could become both the basis for designing seismic acquisition parameters and determining the seismic shot locations,as well as supplying near-surface velocity models for seismic data processing so as to improve the quality of seismic sections.
文摘The utilization of MT and CEMP methods has been extended from plains to mountainous areas. The rugged topography not only brings about difficulties in field electro-magnetic measurements but also affects data processing, interpretation and results. Analyzed in this paper were the 2D and 3D forward modeling of the fluctuated topography and the real examples to discuss the topographic effects on electric data and the practical methods to avoid these effects.
文摘In 1997, the TZ- 162 well in Tazhong area of the Tarim basin hit the lower Paleozoic dolomite reservoir at a depth of 5,900 m. The distribution of the dolomite reservoir, however,was very difficult to delineate due to the complex surface conditions and poor seismic properties. High-precision transient electromagnetic sounding (TEM) was conducted and good results obtained in this area. This paper discussed the principle,data processing and interpretation of this method. The resultsof studying the dolomite reservoirs demonstrated the effectiveness of the method in studying the low-resistance dolomite reservoirs in the high-resistance carbonates. This method should be an effective one to study reservoirs in areas with similar physical properties as well.
