Well Yinggu 1 drilled on the tectonic belt of the Wumaying buried-hill in Huanghua Depression obtained non-H2S high-yield oil and gas flow from the Permian Lower Shihezi Formation sandstone. The oil and gas are derive...Well Yinggu 1 drilled on the tectonic belt of the Wumaying buried-hill in Huanghua Depression obtained non-H2S high-yield oil and gas flow from the Permian Lower Shihezi Formation sandstone. The oil and gas are derived from the Upper Paleozoic coal source rock, the petroleum reservoir is an inner buried-hill primary oil and gas accumulation, showing a good prospect of the Paleozoic inner buried-hill primary reservoir exploration. The formation and accumulation of the primary petroleum reservoir in the Wumaying inner buried-hill are discussed by studying the primary source conditions, the inner buried-hill reservoir-cap combinations and the hydrocarbon accumulation period. The primary petroleum reservoir has three preponderant characteristics of accumulation: secondary large-scale gas generation of coal source rock, multi reservoir-cap combinations and mainly late hydrocarbon charging, which formed the compound hydrocarbon accumulation of the above-source sandstone and under-source carbonate rock in the Paleozoic inner buried-hill. Along with the Mesozoic and Cenozoic tectonic activities, the formation of the primary reservoir in Wumaying inner buried-hill is characterized by "mixed oil and gas charge in local parts in early stage, adjustment accumulation due to structural high migration in middle stage, and large-scale natural gas charge and compound accumulation in late stage".展开更多
The distribution and genesis of secondary pores in Paleogene clastic reservoirs of Beidagang structural belt in the Huanghua depression have been systematically studied. We investigated sedimentary facies and carried ...The distribution and genesis of secondary pores in Paleogene clastic reservoirs of Beidagang structural belt in the Huanghua depression have been systematically studied. We investigated sedimentary facies and carried out a comprehensive analy-sis of the vast amount of data from casting thin sections, scanning electron microscope and physical data. Then we analyzed the pore types, pore evolution, distribution and genesis of secondary pores in our study area and discussed the factors controlling the distribution of secondary pores. The results show that pores in the study area are largely composed of intergranular dissolution pores and constituent dissolved pores. Three secondary pore zones were developed in the study area at depths of 2800~3400 m, 3600~4200 m and 4500~4800 m. Secondary pores have been formed mainly because carbonate cement, feldspar, clastic debris and other plastic substances were dissolved by organic acid, released during the evolution of organic matter and acid water formed by CO2. The development and distribution of secondary pores are vertically controlled by the maturity time of source rocks and hori-zontally by the distribution of acid water. As well, this distribution was affected by the sedimentary facies belt and the development of fault zones.展开更多
The gas field in the Bohai Bay Basin is a fractured metamorphic buried-hill reservoir with dual-media characteristics. The retrograde vaporization mechanism observed in this type of gas condensate reservoir differs si...The gas field in the Bohai Bay Basin is a fractured metamorphic buried-hill reservoir with dual-media characteristics. The retrograde vaporization mechanism observed in this type of gas condensate reservoir differs significantly from that observed in sand gas condensate reservoirs. However, studies on improving the recovery of fractured gas condensate reservoirs are limited;thus, the impact of retrograde vaporization on condensate within fractured metamorphic buried-hill reservoirs remains unclear. To address this gap, a series of gas injection experiments are conducted in pressure-volume-temperature(PVT) cells and long-cores to investigate the retrograde vaporization effect of condensate using different gas injection media in fractured gas condensate reservoirs. We analyze the variation in condensate volume, gas-to-oil ratio, and condensate recovery during gas injection and examine the influence of various gas injection media(CO_(2), N_(2), and dry gas) under different reservoir properties and varying gas injection times. The results demonstrate that the exchange of components between injected gas and condensate significantly influences condensate retrograde vaporization in the formation. Compared with dry gas injection and N_(2) injection,CO_(2) injection exhibits a superior retrograde vaporization effect. At a CO_(2) injection volume of 1 PV, the percentage shrinkage volume of condensate is 13.82%. Additionally, at the maximum retrograde condensation pressure, CO_(2) injection can increase the recovery of condensate by 22.4%. However, the condensate recovery is notably lower in fractured gas condensate reservoirs than in homogeneous reservoirs, owing to the creation of dominant gas channeling by fractures, which leads to decreased condensate recovery. Regarding gas injection timing, the effect of gas injection at reservoir pressure on improving condensate recovery is superior to that of gas injection at the maximum retrograde condensation pressure. This research provides valuable guidance for designing gas injection development plans and dynamic tracking adjustments for fractured gas condensate reservoirs.展开更多
基金Supported by the PetroChina Science and Technology Major Project(2018E-11-02)
文摘Well Yinggu 1 drilled on the tectonic belt of the Wumaying buried-hill in Huanghua Depression obtained non-H2S high-yield oil and gas flow from the Permian Lower Shihezi Formation sandstone. The oil and gas are derived from the Upper Paleozoic coal source rock, the petroleum reservoir is an inner buried-hill primary oil and gas accumulation, showing a good prospect of the Paleozoic inner buried-hill primary reservoir exploration. The formation and accumulation of the primary petroleum reservoir in the Wumaying inner buried-hill are discussed by studying the primary source conditions, the inner buried-hill reservoir-cap combinations and the hydrocarbon accumulation period. The primary petroleum reservoir has three preponderant characteristics of accumulation: secondary large-scale gas generation of coal source rock, multi reservoir-cap combinations and mainly late hydrocarbon charging, which formed the compound hydrocarbon accumulation of the above-source sandstone and under-source carbonate rock in the Paleozoic inner buried-hill. Along with the Mesozoic and Cenozoic tectonic activities, the formation of the primary reservoir in Wumaying inner buried-hill is characterized by "mixed oil and gas charge in local parts in early stage, adjustment accumulation due to structural high migration in middle stage, and large-scale natural gas charge and compound accumulation in late stage".
基金Financial support for this study by the National Basic Research Program of China (973) (No.2006CB 202300) is gratefully acknowledged
文摘The distribution and genesis of secondary pores in Paleogene clastic reservoirs of Beidagang structural belt in the Huanghua depression have been systematically studied. We investigated sedimentary facies and carried out a comprehensive analy-sis of the vast amount of data from casting thin sections, scanning electron microscope and physical data. Then we analyzed the pore types, pore evolution, distribution and genesis of secondary pores in our study area and discussed the factors controlling the distribution of secondary pores. The results show that pores in the study area are largely composed of intergranular dissolution pores and constituent dissolved pores. Three secondary pore zones were developed in the study area at depths of 2800~3400 m, 3600~4200 m and 4500~4800 m. Secondary pores have been formed mainly because carbonate cement, feldspar, clastic debris and other plastic substances were dissolved by organic acid, released during the evolution of organic matter and acid water formed by CO2. The development and distribution of secondary pores are vertically controlled by the maturity time of source rocks and hori-zontally by the distribution of acid water. As well, this distribution was affected by the sedimentary facies belt and the development of fault zones.
文摘The gas field in the Bohai Bay Basin is a fractured metamorphic buried-hill reservoir with dual-media characteristics. The retrograde vaporization mechanism observed in this type of gas condensate reservoir differs significantly from that observed in sand gas condensate reservoirs. However, studies on improving the recovery of fractured gas condensate reservoirs are limited;thus, the impact of retrograde vaporization on condensate within fractured metamorphic buried-hill reservoirs remains unclear. To address this gap, a series of gas injection experiments are conducted in pressure-volume-temperature(PVT) cells and long-cores to investigate the retrograde vaporization effect of condensate using different gas injection media in fractured gas condensate reservoirs. We analyze the variation in condensate volume, gas-to-oil ratio, and condensate recovery during gas injection and examine the influence of various gas injection media(CO_(2), N_(2), and dry gas) under different reservoir properties and varying gas injection times. The results demonstrate that the exchange of components between injected gas and condensate significantly influences condensate retrograde vaporization in the formation. Compared with dry gas injection and N_(2) injection,CO_(2) injection exhibits a superior retrograde vaporization effect. At a CO_(2) injection volume of 1 PV, the percentage shrinkage volume of condensate is 13.82%. Additionally, at the maximum retrograde condensation pressure, CO_(2) injection can increase the recovery of condensate by 22.4%. However, the condensate recovery is notably lower in fractured gas condensate reservoirs than in homogeneous reservoirs, owing to the creation of dominant gas channeling by fractures, which leads to decreased condensate recovery. Regarding gas injection timing, the effect of gas injection at reservoir pressure on improving condensate recovery is superior to that of gas injection at the maximum retrograde condensation pressure. This research provides valuable guidance for designing gas injection development plans and dynamic tracking adjustments for fractured gas condensate reservoirs.
