The Daqing exploration area in the northern Songliao Basin has great potential for unconventional oil and gas resources,among which the total resources of tight oil alone exceed 109 t and is regarded as an important r...The Daqing exploration area in the northern Songliao Basin has great potential for unconventional oil and gas resources,among which the total resources of tight oil alone exceed 109 t and is regarded as an important resource base of Daqing oilfield.After years of exploration in the Qijia area,Songliao Basin,NE China,tight oil has been found in the Upper Cretaceous Qingshankou Formation.To work out tight oil’s geological characteristics,taking tight oil in Gaotaizi oil layers of the Upper Cretaceous Qingshankou Formation in northern Songliao Basin as an example,this paper systematically analyzed the geological characteristics of unconventional tight oil in Gao3 and Gao4 layers of the Qijia area,based on the data of the geological survey,well drilling journey,well logging,and test.It is that three sets of hydrocarbon source rocks(K2qn1,K2qn2+3,and K2n1)develop in the examined area,and exhibit excellent type I and II kerogens,high organic matter abundance,and moderate maturity.The reservoir is generally composed of thin-bedded mudstone,siltstone,and sandstone,and presents poor porosity(average 8.5 vol.%)and air permeability(average 4 mD).The main reservoir space primarily includes intergranular pores,secondary soluble pores,and intergranular soluble pores.Three types of orifice throats were identified,namely fine throat,extra-fine throat,and micro-fine throat.The siltstone is generally oil-bearing,the reservoirs with slime and calcium become worse oil-bearing,and the mudstone has no obvious oil-bearing characteristics.The brittleness indices of the sandstone in the tight oil reservoir range from 40%to 60%,and those of the mudstone range from 40%to 45%,indicating a better brittleness of the tight oil reservoir.Based on the study of typical core hole data,this paper gives a comprehensive evaluation of the properties of the tight oil and establishes a tight oil single well composite bar chart as well as the initial evaluation system with the core of properties in the tight oil reservoir.This study has theoretical gui展开更多
砂岩油气储层在地震剖面上一般表现为“亮点”,但钻探发现四川盆地中江气田的一些砂岩储层在地震剖面上表现为“暗点”,不易识别。这里依据钻测井资料,采用地震正演模拟方法分析了这些储层地震响应表现为“暗点”的机制,认为是Ⅱb类AVO(...砂岩油气储层在地震剖面上一般表现为“亮点”,但钻探发现四川盆地中江气田的一些砂岩储层在地震剖面上表现为“暗点”,不易识别。这里依据钻测井资料,采用地震正演模拟方法分析了这些储层地震响应表现为“暗点”的机制,认为是Ⅱb类AVO(Amplitude variation with offset)响应砂岩在特定厚度的薄层调谐作用下,在叠前道集中发生了极性反转,从而使得原本在叠后剖面上应为较“亮点”的反射变成了“暗点”。针对这种储层隐蔽机制,采用高分辨处理与AVO分析相结合的方法,成功识别出了消隐的河道砂储层,为“暗点”型薄砂岩储层的识别提供了可参考的成功范例。展开更多
基金funded by the shale oil and gas geological survey project in Quemoco sag,Qiangtang Basin of China Geological Survey(DD20221855,DD20230315).
文摘The Daqing exploration area in the northern Songliao Basin has great potential for unconventional oil and gas resources,among which the total resources of tight oil alone exceed 109 t and is regarded as an important resource base of Daqing oilfield.After years of exploration in the Qijia area,Songliao Basin,NE China,tight oil has been found in the Upper Cretaceous Qingshankou Formation.To work out tight oil’s geological characteristics,taking tight oil in Gaotaizi oil layers of the Upper Cretaceous Qingshankou Formation in northern Songliao Basin as an example,this paper systematically analyzed the geological characteristics of unconventional tight oil in Gao3 and Gao4 layers of the Qijia area,based on the data of the geological survey,well drilling journey,well logging,and test.It is that three sets of hydrocarbon source rocks(K2qn1,K2qn2+3,and K2n1)develop in the examined area,and exhibit excellent type I and II kerogens,high organic matter abundance,and moderate maturity.The reservoir is generally composed of thin-bedded mudstone,siltstone,and sandstone,and presents poor porosity(average 8.5 vol.%)and air permeability(average 4 mD).The main reservoir space primarily includes intergranular pores,secondary soluble pores,and intergranular soluble pores.Three types of orifice throats were identified,namely fine throat,extra-fine throat,and micro-fine throat.The siltstone is generally oil-bearing,the reservoirs with slime and calcium become worse oil-bearing,and the mudstone has no obvious oil-bearing characteristics.The brittleness indices of the sandstone in the tight oil reservoir range from 40%to 60%,and those of the mudstone range from 40%to 45%,indicating a better brittleness of the tight oil reservoir.Based on the study of typical core hole data,this paper gives a comprehensive evaluation of the properties of the tight oil and establishes a tight oil single well composite bar chart as well as the initial evaluation system with the core of properties in the tight oil reservoir.This study has theoretical gui
文摘砂岩油气储层在地震剖面上一般表现为“亮点”,但钻探发现四川盆地中江气田的一些砂岩储层在地震剖面上表现为“暗点”,不易识别。这里依据钻测井资料,采用地震正演模拟方法分析了这些储层地震响应表现为“暗点”的机制,认为是Ⅱb类AVO(Amplitude variation with offset)响应砂岩在特定厚度的薄层调谐作用下,在叠前道集中发生了极性反转,从而使得原本在叠后剖面上应为较“亮点”的反射变成了“暗点”。针对这种储层隐蔽机制,采用高分辨处理与AVO分析相结合的方法,成功识别出了消隐的河道砂储层,为“暗点”型薄砂岩储层的识别提供了可参考的成功范例。
