压力对页岩原位加热产出油气特征的影响——以鄂尔多斯盆地三叠系延长组7段3亚段页岩为例  

Pressure effect on the characteristics of oil and gas produced by in-situ heating of shale:a case study of the third submember of Member 7 of Yanchang Formation in Ordos Basin

作　　者：侯连华[1] 米敬奎[1] 罗霞[1] 于志超[1] 林森虎[1] 廖凤荣 庞正炼[1] 赵忠英[1] Hou Lianhua;Mi Jingkui;Luo Xia;Yu Zhichao;Lin Senhu;Liao Fengrong;Pang Zhenglian;Zhao Zhongying(PetroChina Research Institute of Petroleum Exploration and Development,Beijing 100083,China)

机构地区：[1]中国石油勘探开发研究院,北京100083

出　　处：《石油学报》2024年第4期629-641,共13页Acta Petrolei Sinica

基　　金：国家自然科学基金项目(No.42172170)资助。

摘　　要：鄂尔多斯盆地三叠系延长组7段(长7段)页岩成熟度低、有机碳含量高、有机质类型较好,原位加热开发页岩油气的潜力巨大。为了探讨原位加热过程中压力对页岩产出油气特征的影响,为原位加热开发长7段页岩油气方案提供可靠依据,以长7段3亚段页岩为研究对象,对其典型样品以20℃/d的升温速率进行了4组不同压力(0 MPa、2 MPa、4 MPa、8 MPa)的原位加热模拟实验。实验结果表明:在相同加热条件下,压力变化对长7段页岩的最大产油量和产出油性质均有影响,对产出气体组成的影响更大。在4组不同压力下,长7段页岩原位加热的最大产油量为36.97~41.47 kg/t,产油量随压力增加有一定减少。随着压力增加,产出油中轻质组分增加,油品变好,其原因在于高压下有机质生成的重质油的裂解程度相对较高;当加热到450℃时,总产气量为14.28~21.05 m^(3)/t,总产气量随压力增加而增加。4组实验序列产出页岩油气的气油比(289.70~427.04 m^(3)/m^(3))随着压力增加而增大;不同气体组分随着压力增加产量变化差异较大,其中,烃类气体与CO_(2)的总产气量随压力增加而增大,H_(2)产量随压力增加而明显减少,H_(2)S产量随压力增加变化较小。不同气体组分的产量随压力增加呈现出不同的变化规律,这与加热温压范围内不同气体的形成机理、页岩对不同气体组分吸附能力的差异和一些次级反应等因素有关。根据不同压力下页岩原位加热的产油量、油品、不同气体组分的产率,结合考虑油气价格与油气处理成本,提出在实施原位加热开发长7段页岩油气时应尽量保持低的生产井井底流压的建议,这一认识对长7段原位加热页岩油气开发方案的确定具有重要的参考意义。The shale in Member 7 of Triassic Yanchang Formation(Chang-7)in Ordos Basin has a giant potential to produce oil and gas by in-situ heating,which is attributed to its low maturity,high organic carbon content and good type of organic matter.To explore the impact of pressure during in-situ heating on the characteristics of oil and gas from shale reservoirs and provide a reliable basis for the development of Chang-7 shale oil and gas by in-situ heating,a study was performed on the third submember of Member 7 of Yanchang Formation,and in-situ heating simulation experiments were conducted on typical samples at the heating rate of 20 ℃/d and different pressures of 0 MPa,2 MPa,4 MPa and 8 MPa,respectively.The experimental results show that under the same heating conditions,pressure changes have an effect on the maximum oil production from Chang-7 shale and also the oil characteristics,and a greater effect on the composition of the gas produced.Under four different pressures,the maximum production of Chang-7 shale by in-situ heating is 36.97-41.47 kg/t,and the oil production decreases with the increasing of pressure.As pressure increases,the light components of the produced oil increase,and the oil quality becomes better,which is attributed to a high-degree cracking of heavy oil generated by organic matters under high pressure.When heated up to 450 ℃,the total gas production is 14.28-21.05 m^(3)/t,and increases with pressure.Moreover,the gas-oil ratios of shale oil and gas generated in four experimental sequences ranges from 289.70 m^(3)/m^(3) to 427.04 m^(3)/m^(3),and increase with pressure.However,there is a great difference in the production of various gas components that increase with pressure,i.e.,the total production of hydrocarbon gases and CO_(2) increases with pressure,while H_(2) production obviously declines and H_(2S) production changes little with pressure.The production of different gas components presents different changing laws with the increasing pressure,which has relation with many factors,such as

关 键 词：鄂尔多斯盆地 延长组 页岩 原位加热 压力 页岩油气产率 

分 类 号：TE122.1[石油与天然气工程—油气勘探]