准噶尔盆地储层中的锰元素及其原油运移示踪作用

Manganese in reservoir calcite cement and its implication for tracing oil migration in Junggar Basin

储层(弱)碱性矿物在酸性原油流体运移过程中易遭受溶蚀,从而可能记录有原油运移信息,这给寻找原油运移示踪新指标提供了可能。以准噶尔盆地玛湖—盆1井西复合含油气系统为例,应用该思路进行了研究,结果发现,在储层油气流体成岩环境的方解石胶结物中,锰元素的含量与含油气丰度呈正相关关系,这种正相关性取决于本区二叠系油源流体中初始富集锰元素,进而在运移过程中通过流体—岩石相互作用将锰元素转移到方解石中。基于锰元素的地球化学行为,可能是示踪原油运移的新指标参数。应用该指标进一步研究了典型地区的原油来源与运移方向、通道,取得良好效果,展示了这一研究新思路与新参数的有效性与良好应用前景。

The acidic petroleum fluid can dissolve the alkaline（including weak alkaline） minerals during oil migration process.Consequently,the minerals may record the geological information of oil migration and provide the good conditions for investigating tracers of oil migration.The case study on the hybrid petroleum system of Mahu-Pengyijingxi in Junggar Basin shows that manganese content of calcite cement in reservoir has good correlation with hydrocarbon-bearing abundance,which may record the information of oil migration. The manganese content was accumulated primarily in the Permian oil source, then it was transferred to reservoir calcite cement in oil migration under the interaction of fluid and rock. The geochemistry characteristic of manganese element can provide the fundamentals for tracing oil migration. Manganese element of calcite cement was effectively used to study the source, direction and pathway of oil migration in some special areas, and good results have been achieved, thus the new method and tracers showed prom ising prospects.