The Lower Cambrian Longwangmiao Fm gas reservoir in the GaoshitieMoxi area,the Sichuan Basin,is a super giant monoblock marine carbonate gas reservoir with its single size being the largest in China.The key to the rea...The Lower Cambrian Longwangmiao Fm gas reservoir in the GaoshitieMoxi area,the Sichuan Basin,is a super giant monoblock marine carbonate gas reservoir with its single size being the largest in China.The key to the realization of high and stable production gas wells in this gas reservoir is to identify accurately high-permeability zones where there are dissolved pores or dissolved pores are superimposed with fractures.However,high quality dolomite reservoirs are characterized by large burial depth and strong heterogeneity,so reservoir prediction is of difficult.In this paper,related seismic researches were carried out and supporting technologies were developed as follows.First,a geologic model was built after an analysis of the existing data and forward modeling was carried out to establish a reservoir seismic response model.Second,by virtue of well-oriented amplitude processing technology,spherical diffusion compensation factor was obtained based on VSP well logging data and the true amplitude of seismic data was recovered.Third,the resolution of deep seismic data was improved by using the welloriented high-resolution frequency-expanding technology and prestack time migration data of high quality was acquired.And fourth,multiple shoal facies reservoirs were traced by using the global automatic seismic interpretation technology which is based on stratigraphic model,multiple reservoirs which are laterally continuous and vertically superimposed could be predicted,and the areal distribution of high quality reservoirs could be described accurately and efficiently.By virtue of the supporting technologies,drilling trajectory is positioned accurately,and the deployed development wells all have high yield.These technologies also promote the construction of a modern supergiant gas field of tens of billions of cubic meters.展开更多
In this paper, the 'spectral amplitude ratio method'(SAR) , 'energy method'(EN) and 'coda wave method'(CW) are used to calculate the Q value variations of gneiss in the preparing rupt...In this paper, the 'spectral amplitude ratio method'(SAR) , 'energy method'(EN) and 'coda wave method'(CW) are used to calculate the Q value variations of gneiss in the preparing rupture process. The obtained results show that the variation state of Q values by SAR features the shape of relative stability gradual increment to the maximum then decrement and final rupture.The variation state of Q values by EN is just contrary to that by SAR,i.e.with the shape of stability decrement increment and final rupture . The varation state of Q values by CW is similar to that by EN, its main frequency features the shape of relatively high value decrement to the minimum increment and final rupture.But to the high frequency (higher than the main frequency),the variation state of Q values features the shape of the stable value increment to the maximum decrement and final rupture.At the same time, the results by coda wave amplitude spectrum show that, when stress reaches 70% of rupture stress, the high frequency component of S wave rapidly reduces( Q c increasing); at the time of impending the main rupture, the main frequency component reduces with a large scale( Q c increasing again), this may be the reason which causes the different variation states of two coda Q values.The result of amplitude spectra of P, S(initial wave) waves also show that with the appearance of microcracks the frequency band of S wave turn to be narrow, the high frequency component is reduced quickly, i.e. the S wave spectra have different variation states with different frequeny components. That is why the Q s obtained by different methods have different variation characteristics.展开更多
文摘The Lower Cambrian Longwangmiao Fm gas reservoir in the GaoshitieMoxi area,the Sichuan Basin,is a super giant monoblock marine carbonate gas reservoir with its single size being the largest in China.The key to the realization of high and stable production gas wells in this gas reservoir is to identify accurately high-permeability zones where there are dissolved pores or dissolved pores are superimposed with fractures.However,high quality dolomite reservoirs are characterized by large burial depth and strong heterogeneity,so reservoir prediction is of difficult.In this paper,related seismic researches were carried out and supporting technologies were developed as follows.First,a geologic model was built after an analysis of the existing data and forward modeling was carried out to establish a reservoir seismic response model.Second,by virtue of well-oriented amplitude processing technology,spherical diffusion compensation factor was obtained based on VSP well logging data and the true amplitude of seismic data was recovered.Third,the resolution of deep seismic data was improved by using the welloriented high-resolution frequency-expanding technology and prestack time migration data of high quality was acquired.And fourth,multiple shoal facies reservoirs were traced by using the global automatic seismic interpretation technology which is based on stratigraphic model,multiple reservoirs which are laterally continuous and vertically superimposed could be predicted,and the areal distribution of high quality reservoirs could be described accurately and efficiently.By virtue of the supporting technologies,drilling trajectory is positioned accurately,and the deployed development wells all have high yield.These technologies also promote the construction of a modern supergiant gas field of tens of billions of cubic meters.
文摘In this paper, the 'spectral amplitude ratio method'(SAR) , 'energy method'(EN) and 'coda wave method'(CW) are used to calculate the Q value variations of gneiss in the preparing rupture process. The obtained results show that the variation state of Q values by SAR features the shape of relative stability gradual increment to the maximum then decrement and final rupture.The variation state of Q values by EN is just contrary to that by SAR,i.e.with the shape of stability decrement increment and final rupture . The varation state of Q values by CW is similar to that by EN, its main frequency features the shape of relatively high value decrement to the minimum increment and final rupture.But to the high frequency (higher than the main frequency),the variation state of Q values features the shape of the stable value increment to the maximum decrement and final rupture.At the same time, the results by coda wave amplitude spectrum show that, when stress reaches 70% of rupture stress, the high frequency component of S wave rapidly reduces( Q c increasing); at the time of impending the main rupture, the main frequency component reduces with a large scale( Q c increasing again), this may be the reason which causes the different variation states of two coda Q values.The result of amplitude spectra of P, S(initial wave) waves also show that with the appearance of microcracks the frequency band of S wave turn to be narrow, the high frequency component is reduced quickly, i.e. the S wave spectra have different variation states with different frequeny components. That is why the Q s obtained by different methods have different variation characteristics.
