苏世龙, 贺振华, 刘玉莲, 张辉, 谷延斌, 郭伟. 城区勘探中激发药量对地震数据品质的影响及处理对策——以中国东部某油田CY城区为例[J]. 物探与化探, 2017,39(6): 1160-1166.
SU Shi-Long, HE Zheng-Hua, LIU Yu-Lian, ZHANG Hui, GU Yan-Bin, GUO Wei. The impact of explosive excitation weight on the quality of seismic data analysis in city exploration and countermeasures:A case study of CY City in an oilfield of eastern China[J]. Geophysical and Geochemical Exploration, 2017,39(6): 1160-1166.
The impact of explosive excitation weight on the quality of seismic data analysis in city exploration and countermeasures:A case study of CY City in an oilfield of eastern China
SU Shi-Long1,2, HE Zheng-Hua1, LIU Yu-Lian2, ZHANG Hui2, GU Yan-Bin2, GUO Wei2
1.State Key Laboratory of Oil & Gas Reservoirs Geology and Exploitation,Chengdu University of Technology,Chengdu 610059,China;
In order to solve the influence of different doses of explosive excitation on seismic data quality,the authors analyzed and tested the seismic data in indoor processing.Using such means as autocorrelation statistics,frequency statistics,and energy statistics of the seismic data,the authors found the correlation of explosive excitation weight and seismic wave characteristics and,by way of point-line-plane analysis,revealed the changes related to seismic data quality.On such a basis,the authors put forward the quantitative analysis and iterative processing technology in data processing and,by application of spherical divergence and absorption time and frequency domain compensation as well as the surface consistent amplitude and surface consistent deconvolution technique,the authors solved the problem of the influence of different doses of explosive excitation on the quality of seismic data with relatively satisfactory processing effect.The results provide reliable seismic data for the increasing production of the old oilfield in CY City
Keyword:
city exploration; explosive excitation weight; quantitative analysis; iterative processing; seismic data processing; seismic data
Zeng HL, KeransC. Amplitude verse frequency: applications to seismic stratigraphy and reservoir characterization, part I: model[C]//Expand ed Abstracts of 70th SEG Annual Internet Meeting, 2000: 721-724. [本文引用:1]
[7]
Zeng HL, KeransC, LuciaJ. Amplitude versus frequency-applications to seismic stratigraphy and reservoir characterization, part II: real 3-D data in Abo reservoir, Kingdom field[J]. West Texas: 725-728. [本文引用:1]
The complicated geologic conditions consistof two meaning:one is that surface seismic condilion is complicated;the other is severe varying geologic structure.The key of controlling field aequisilion quality of seismic exploration in complicated geologic condition is seizing of three factors;explosion of source,receiving of seismic wave and reasonable and scientific design of seismic setup.
It is very difficult to conduct seismic acquisition in Dulan,because it has a lot of salt ponds and salt lakes on the surface and extensive thick crystalline interbeds in the near-surface area. In this paper, the authors analyzed in detail the seismic response characteristics of the near-surface media in Dulan, with the emphasis placed on the characteristics of crystalline interbedded strata and beaded cavities by means of a model. Through the application of the actual seismic data, it is confirmed that the near-surface absorption decay law of the crystalline interbedded strata is correct. Moreover,the authors investigated the optimization techniques for the acquisition technology series by analyzing the stratification near the surface, and also optimized the depth design and the variable concept of the observation system. As a result, good results in the actual acquisition applications were acquired, and the problems concerning complex salt marsh area acquisition were successfully solved.
Loess plateau with very complex geological conditions is considered to be a world-class thorny problem.Liupanshan basin in southern Ningxia belongs to the typical loess tableland geomorphology and sedimentary basin,and its exploration is of low degree but has great potential.Geological conditions of the area is very complex with a great thickness of loess layer covering the surface,and deep conditions in different tectonic units are very different,so we must overcome the double impact of surface and underground in the seismic acquisition.In this paper,in combination with the data available and the application of new technologies and new methods,the authors analyzed the areas with different geological conditions and the difficulties in exploration and, on such a basis, summed up a series of seismic acquisition technologies with the purpose of guiding the exploration work in this area.
The special variations of near-surface litholo-gy in land seismic exploration lead to significant special changes in shooting energy and shooting wavelets,and then result in seismic reflection at-tributes of final imaged reservoirs.These changes are much more large than the changes in reservoir information caused by geology and oil/gas factors,leading to a difficulty for reservoir identification.Former compensation for spherical dispersion and absorption,surface-consistent amplitude compensa-tion and surface-consistent deconvolution can elim-inate certain near-surface influence in some degree,but are difficult to effectively eliminate near-sur-face influence in three domains:time,frequency and space.For that reason,on the basis of original method of compensation for spherical dispersion and attenuation by absorption in time-frequency domain,the paper presented the method of"Com-pensation for spherical dispersion and absorption in time-frequency-space domain".The method has been proved by processing,interpretation and pro-duction drilling of 3D development seismic data in real oil field that the compensation method can meet the processing demand for relative reservation of amplitude information of reservoir,while elimi-nating influence of near-surface on seismic at-tributes.Therefore,the method is effective method for compensation for near-surface and ground at-tenuation by absorption.
Generally, the layer medium are viscous.Due to absorption affect, seismic wave energy,especially high- frequency energy be absorbed and attenuated in downward propagation, reflection wave signal frequency bands be narrowed. For compensated those absorbed energy, the paper, adopt viscosity wave equation wave field continuation method, used to carry out energy compensation researching, and obtained better effect. At first, the paper from viscosity wave equation wave field continuation function theory, derived wave field continuation function stability condition;Secondly,author test the method availability;Finally, through forward simulation test, proved absorption and compensation method based on viscosity wave equation can carry on very well compensation of energy attenuation, improved processing effect.
The gas-bearing prediction was somewhat verified by frequency differences.The authors mainly probed into the reservoir prediction and hydrocarbon detection in Weixinan region,and described the application of the frequency domain information in detail.In addition,the purpose of reservoir prediction and hydrocarbon detection was fulfilled by summing up the frequency domain characteristics of the drilled water layer and oil layer,and the result has been confirmed in the actual production.
The surface velocity structure can be estimated by inverting the dispersion curve extracted from the dispersion image result of the Rayleigh-wave information in shot gathers of near-surface exploration.The dispersion image results from the difference of Rayleigh-wave data in different offset ranges,and will affect the extraction and inversion results of the dispersion curve.In this paper,the authors studied the dispersion imaging results in different collection arrangements and offsets by dispersion imaging resolution and continuity using box wave in LJ area of the Shengli oilfield,and found that the long collection arrangement can improve the dispersion imaging resolution effectively,and that the dispersion imaging result in near offset is better.The authors also tested and verified the effectiveness and applicability of the optimum offset formula proposed by Zhang in 2004,and the results show that it can be used as a standard of the optimum offset in near-surface Rayleigh-wave exploration.
In the oil field development stage,water or gas injection mining will change reservoir properties and the fluid inside the reservoir,which may provide a possiblity for time-lapse seismic monitoring.Mainly based on Gassmann equation,the authors discussed in detail the variation regularity of seismic velocity and density when the reservoir pore fluid is replaced,and established a seismic geological model for water saturation variation according to the forecast result.Through analyzing and optimizing the amplitude attributes extracted from the model,the sensitive time-lapse seismic attributes suitable for this area was finally found.The result provides a basis for predicting the distribution of remaining oil.
In the light of the processing requirements of the high-density wide-azimuth 3D3C seismic data and in consideration of the difference between the signal and the noise in such aspects as type,time,frequency,data field,processing step and surface area,the authors chose the means of multi-domain step-by-step de-noising.Under the prerequisite of not damaging the effective signal,the cross arranged cone wave filter was adopted first to remove surface wave and linear noise,then the low-frequency noise compilation was employed to remove residual surface wave and low-frequency noise,followed by frequency division de-noising for removing various kinds of random noise.At last,the refraction wave was removed.The monitoring display of single shot record and stacking profile has proved the effectiveness of this method and the improvement of the signal-to-noise ratio.
Seismic wavelet is changed in the wake of stratigraphic depth access.The improved S transform in combination with spectral modeling method can overcome time-varying seismic wavelet and avoid the complex window dimension problem.Spectral modeling in the time-frequency domain can well adapt itself to the assumption condition in that the seismic data are smooth and serve as steady signals.Spectral modeling is processed in time-frequency domain,which can overcome time-varying wavelet and improve seismic resolution.A comparison of the effects of the seismic data processing shows that the method can effectively broaden the frequency band and improve seismic resolution.
There are salt domes of great thickness deposited in Pre-Caspian basin.As the salt layer thickness varies dramatically,it is difficult to perform imagery for the sub-salt seismic data,and the structure features show distortions.The elimination of the salt velocity influence and the restoration of the real sub-salt structure form constitute the urgent problems in oil-gas exploration.Through the integrated study of processing and interpretation,the authors used the floating datum pre-stack time migration method to conduct imagery for high and steep structures based on pre-stack fidelity of the static correction and to make salt amplitude recovery.Finally,the pre-stack reverse-time depth migration method was used for the sub-salt structure accurate imaging and recovery.A technological series of integration of processing and interpretation for sub-salt structure was formed and applied in Pre-Caspian salt basin.
This authors describe a more efficient and adaptive high frequency noise suppression method in which a new adaptive threshold technique is combined with a continuous thresholding function to overcome the shortcoming that existing threshold de-noising technique by wavelet transform is not suitable for seismic data.The continuous hard thresholding function can combine both advantages of soft thresholding function and hard thresholding function,so it can enhance the fidelity of reconstructed signal and reduce the artificial noise.An adaptive threshold scheme is carried out by analyzing the statistical parameters of wavelet subband coefficients like standard deviation,arithmetic mean and geometrical mean in different subbands,which is based on the time-varying and spatial-varying energy distribution feature of nonstationary seismic signal.This threshold can adjust itself automatically with the variation of wavelet coefficient energy in different subbands to meet the requirement of high frequency seismic noise suppression.The actual seismic data processing result indicates that this method can not only raise the signal-to-noise ratio but also protect thoroughly the steep dip angle reflection event and enhance the fidelity of seismic signal after noise elimination.
