川东南旺隆及周边地区T_1j^(2-1)-T_1j^1储层地球物理响应特征分析

Research on geophysical responses for Jialingjiang Formation in Wanglong and surrounding areas,Southeast Sichuan,China

川东南地区嘉陵江组T1j2-1-T1j1碳酸盐岩储层具有低孔隙度、低渗透率、单层厚度薄、非均质性强的特征,勘探难度较大。综合考虑T1j2-2,T1j2-1和T1j1地层的地质特征,通过地质、测井进行合成记录层位标定,建立正演模型,探讨了旺隆及周边地区储层的测井响应特征和地震响应特征,提取了地震属性对储层进行横向预测研究。结果显示,中-强振幅、同相轴下拉、同相轴分叉、频率降低现象代表储层发育。地震属性分析结果表明太和、旺隆地区储层较发育,这与钻井显示较吻合,说明该方法可以较好地预测出该套储层的分布范围,为进一步勘探提供了依据。

This paper analyzes the exploration prospect of Sinian in the centre of Sichuan Basin from hydrocarbon accumulation history.The apatite fission track analysis and Easy Ro（vitrinite reflectance） chemical kinetic model are carried out to compute the thermal history of the Cambrian source rocks and Sinian reservoirs.The hydrocarbon generation history of the Cambrian source rocks indicates that secondary generating hydrocarbon has ever happened obviously.These events lead to multiple phase hydrocarbon fluid charge in the Sinian reservoirs.With the change of temperature and pressure of formation,the phase of hydrocarbon fluid in the Sinian reservoirs has produced a series of changes as follows： oil → condensate oil and wet gas → natural gas due to oil cracking to gas → liquid methane（water soluble gas）→gaseous methane.With regard to the hydrocarbon accumulation,the most important processes are the formation of water-soluble gas resulting from generating abnormal overpressure in the process of oil cracking to gas,and the exsolution of the water soluble gas with the change of temperature due to the structural uplift.In this area,the Cambrian source rocks have a strong hydrocarbon-generating capacity,and the formation and development of the Sinian palaeo-structure match well with the hydrocarbon-generating history.All these evidences indicate that there is a great exploration prospect in Sinian of Central Sichuan Basin.