鄂尔多斯盆地姬塬油田长6储层成岩作用特征及孔隙度演化研究

Research on the characteristic of diagenesis and porosity evolution of Chang 6 Reservoir in Jiyuan Oilfield,Ordos Basin

利用粒度、物性、铸体薄片、扫描电镜、X射线衍射等实验资料,开展姬塬油田长6储层物性致密成因机理研究。通过成岩作用研究,分析了储层成岩作用的特征,建立了孔隙度演化的数学模型。孔隙度演化计算结果表明,研究区未固结砂岩孔隙度为37.42%,压实过程的孔隙度损失22.13%,早期胶结-交代过程中孔隙度损失3.97%,中晚期胶结-交代过程中孔隙度损失6.76%,溶蚀作用产生的孔隙度为5.56%,计算孔隙度为10.12%。通过对比姬塬油田、华庆油田、安塞油田长6储层孔隙度演化的路径表明,应用孔隙度演化模拟方法寻找相对"甜点"砂体能获取可靠的科学数据。

The mechanism of pore evolution to the physical property of chang 6 Formation in the Jiyuan Oil field were studied by grading analysis, physical property, casting lamella, scanning electron microscope （SEM） and X-ray diffraction. According to the effect of diagenesis to the reservoir property, by studying the diagenesis of reservoir, its characteristics and evolution degree were analyzed, and the mathematical model of the porosity evolution built. The calculating results of the porosity evolution show that, the porosity of uncon- solidated sands was 37.42% ; the porosity loss-rate during the compaction was 22. 13% ; the porosity loss-rate during the early cementation-metasomatism was 3.97%, and was 6. 76% during the mid and late cementation- metasomatism. The dissolution of the reservoir sandstone improved the porosity by about 5.56%, The porosity from calculation was 10. 12%. By contrasting porosity evolution way in Chang 6 Reservoir in Jiyuan Oilfield, Huaqing Oilfield and Ansai Oilfield showed that reliable science data were available from the process of lookingfor ＂sweet point＂ sand bodies by applying the pore evolution simulation method.