The Yuanba （元坝） area is considered another potential large-scale reef-bank gas field following the Puguang （普光） field. However, there are lots of difficulties on the spatial and temporal distribution of reef-b...The Yuanba （元坝） area is considered another potential large-scale reef-bank gas field following the Puguang （普光） field. However, there are lots of difficulties on the spatial and temporal distribution of reef-beach and the detailed prediction of the effective reservoir in the sequence stratigraphic framework. In this paper, based on the seismic data, well, log and core, we conduct a high-resolution sequence division and build an isochronal sequence stratigraphic framework for the Changxing （长兴） Formation by the methods of wavelet transformation, FMI, etc.. Then, the corresponding relationship among the lithologic facies, logging facies, seismic facies, seismic attribute facies and reservoir of Changxing Formation were established through well-seismic calibration and geological-geophysical modeling. Furthermore, detailed study on the spatial and temporal distribution of microfacies of the reef-beach was carried out by means of seismic attribute extraction. Meanwhile,combined with impedance inversion, the spatial distribution of porosity of reef-beach reservoir was predicted. The results show that the revolution of the reef-beach system contains three stages which are initial bioclastic bank establishment stage, reef development stage and exposure stage. Also, porosity inversion shows that the region with high value of porosity is located in the reef cap, fore reef and back reef.Seismic Sedimentology Study in the High-Resolution Sequence Framework展开更多
The large reef complexes of the Upper Permian Changxing Formation, with a significant breakthrough for petroleum exploration, are an important target for petroleum exploration in the Yuanba area of the Sichuan Basin i...The large reef complexes of the Upper Permian Changxing Formation, with a significant breakthrough for petroleum exploration, are an important target for petroleum exploration in the Yuanba area of the Sichuan Basin in SW China. The storage space types of reef complexes are dominated by the dissolved pore-fracture（DPF）. However, using only single geophysical methods, it is difficult to predict effective distribution of DPF. Based on a combination of geological models and geophysics technology, this study proposes two new geophysical methods, including anisotropy coherence technique（ACT） and fracture intensity inversion（FII）, to research the characteristics of DPF by faciescontrolling in Changxing Formation in Yuanba area. Two major findings are presented as follows：（1） the characteristics of DPF varying with facies are the result of different diagenetic and petrophysical property. The intensity of DPF decreases from reef and bioclastic bank to interbank sea and slope;（2） ACT can qualitatively identify the distribution of DPF with no-directional and dispersed distribution, while FII can quantitatively characterize the intensity of DPF development within various sedimentary facies. When integrated into the geological study, ACT and FII can provide an effective way to predict the distribution of DPF in similar geological settings and the predicted DPF have been supported by the historical well data.展开更多
In recent years,drilling data from wells Pengshen 10,Heshen 9,Tongshen 17 and Zhengyang 1 in the Sichuan Basin have confirmed the presence of a set of porous reef-beach limestone reservoirs in the Upper Permian Changx...In recent years,drilling data from wells Pengshen 10,Heshen 9,Tongshen 17 and Zhengyang 1 in the Sichuan Basin have confirmed the presence of a set of porous reef-beach limestone reservoirs in the Upper Permian Changxing Formation,which breaks the traditional view that deep carbonate oil and gas are only distributed in porous dolomite reservoirs and karst fracture-cavity limestone reservoirs.Through core and thin section observations,geochemical analysis,and well-seismic based reservoir identification and tracking,the study on formation mechanism of pores in deep reef-beach limestone reservoirs is carried out,this study provides insights in four aspects.(1)Porous reef-beach limestone reservoirs are developed in the Changxing Formation in deep-buried layers.The reservoir space is composed of intergranular pores,framework pores,intra-fossil pores,moldic pores and dissolution pores,which are formed in depositional and epigenetic environments.(2)The intermittently distributed porous reef-beach complexes are surrounded by relatively dense micrite limestone,which leads to the formation of local abnormal high-pressure inside the reef-beach complexes with the temperature increased.(3)The floor of the Changxing Formation reservoir is composed with interbedded tight mudstone and limestone of the Upper Permian Wujiaping Formation,and the roof is the tight micrite limestone interbedded with mudstone of the first member of Lower Triassic Feixianguan Formation.Under the clamping of dense roof and floor,the abnormal high-pressure in the Changxing Formation is formed.Abnormal high-pressure(overpressured compartment)is the key to maintain the pores formed in the depositional and epigenetic environments in deep-buried layers.(4)Based on the identification of roof,floor and reef-beach complexes,the favorable reef-beach limestone reservoir distribution area of 10.3×10^(4) km^(2) is predicted by well-seismic integration.These insights lay the theoretical foundation for the development of deep porous limestone reservoirs,expand the new field of exploration of deep-buried limestone reservoirs in the Sichuan Basin.展开更多
基金supported by the SINOPEC Group Project (No. 2009026324)
文摘The Yuanba （元坝） area is considered another potential large-scale reef-bank gas field following the Puguang （普光） field. However, there are lots of difficulties on the spatial and temporal distribution of reef-beach and the detailed prediction of the effective reservoir in the sequence stratigraphic framework. In this paper, based on the seismic data, well, log and core, we conduct a high-resolution sequence division and build an isochronal sequence stratigraphic framework for the Changxing （长兴） Formation by the methods of wavelet transformation, FMI, etc.. Then, the corresponding relationship among the lithologic facies, logging facies, seismic facies, seismic attribute facies and reservoir of Changxing Formation were established through well-seismic calibration and geological-geophysical modeling. Furthermore, detailed study on the spatial and temporal distribution of microfacies of the reef-beach was carried out by means of seismic attribute extraction. Meanwhile,combined with impedance inversion, the spatial distribution of porosity of reef-beach reservoir was predicted. The results show that the revolution of the reef-beach system contains three stages which are initial bioclastic bank establishment stage, reef development stage and exposure stage. Also, porosity inversion shows that the region with high value of porosity is located in the reef cap, fore reef and back reef.Seismic Sedimentology Study in the High-Resolution Sequence Framework
基金supported by the National Science and Technology Major Project of China (Nos. 2011ZX05025-002-02-05)the National Natural Science Foundation of China (Nos. 41202086, 41202087, 41102068)
文摘The large reef complexes of the Upper Permian Changxing Formation, with a significant breakthrough for petroleum exploration, are an important target for petroleum exploration in the Yuanba area of the Sichuan Basin in SW China. The storage space types of reef complexes are dominated by the dissolved pore-fracture（DPF）. However, using only single geophysical methods, it is difficult to predict effective distribution of DPF. Based on a combination of geological models and geophysics technology, this study proposes two new geophysical methods, including anisotropy coherence technique（ACT） and fracture intensity inversion（FII）, to research the characteristics of DPF by faciescontrolling in Changxing Formation in Yuanba area. Two major findings are presented as follows：（1） the characteristics of DPF varying with facies are the result of different diagenetic and petrophysical property. The intensity of DPF decreases from reef and bioclastic bank to interbank sea and slope;（2） ACT can qualitatively identify the distribution of DPF with no-directional and dispersed distribution, while FII can quantitatively characterize the intensity of DPF development within various sedimentary facies. When integrated into the geological study, ACT and FII can provide an effective way to predict the distribution of DPF in similar geological settings and the predicted DPF have been supported by the historical well data.
基金Supported by the National Natural Science Foundation of China(U23B20154)General Program of the National Natural Science Foundation of China(42372169)。
文摘In recent years,drilling data from wells Pengshen 10,Heshen 9,Tongshen 17 and Zhengyang 1 in the Sichuan Basin have confirmed the presence of a set of porous reef-beach limestone reservoirs in the Upper Permian Changxing Formation,which breaks the traditional view that deep carbonate oil and gas are only distributed in porous dolomite reservoirs and karst fracture-cavity limestone reservoirs.Through core and thin section observations,geochemical analysis,and well-seismic based reservoir identification and tracking,the study on formation mechanism of pores in deep reef-beach limestone reservoirs is carried out,this study provides insights in four aspects.(1)Porous reef-beach limestone reservoirs are developed in the Changxing Formation in deep-buried layers.The reservoir space is composed of intergranular pores,framework pores,intra-fossil pores,moldic pores and dissolution pores,which are formed in depositional and epigenetic environments.(2)The intermittently distributed porous reef-beach complexes are surrounded by relatively dense micrite limestone,which leads to the formation of local abnormal high-pressure inside the reef-beach complexes with the temperature increased.(3)The floor of the Changxing Formation reservoir is composed with interbedded tight mudstone and limestone of the Upper Permian Wujiaping Formation,and the roof is the tight micrite limestone interbedded with mudstone of the first member of Lower Triassic Feixianguan Formation.Under the clamping of dense roof and floor,the abnormal high-pressure in the Changxing Formation is formed.Abnormal high-pressure(overpressured compartment)is the key to maintain the pores formed in the depositional and epigenetic environments in deep-buried layers.(4)Based on the identification of roof,floor and reef-beach complexes,the favorable reef-beach limestone reservoir distribution area of 10.3×10^(4) km^(2) is predicted by well-seismic integration.These insights lay the theoretical foundation for the development of deep porous limestone reservoirs,expand the new field of exploration of deep-buried limestone reservoirs in the Sichuan Basin.
