西峰油田DZ—ZY地区长8储集层长石溶蚀特征及溶蚀强度计算

发布时间：2018-03-25 17:31

本文选题：鄂尔多斯盆地　切入点：上三叠统　出处：《新疆石油地质》2017年01期

【摘要】：长石溶蚀作用是鄂尔多斯盆地西峰油田DZ—ZY地区长8储集层次生孔隙发育的主控因素。为了分析研究区长8储集层长石溶蚀特征,综合利用铸体薄片、扫描电镜、电子探针等分析技术,同时基于长石非全等溶解的性质,通过对各长石溶蚀理论次生孔隙度和溶解率的计算,准确划分长石溶蚀强度:弱溶蚀(溶解率小于25%)、中溶蚀(溶解率25%~50%)、强溶蚀(溶解率50%~75%)和极强溶蚀(溶解率大于75%)。研究表明:长石溶蚀现象在研究区普遍存在,长石溶孔对储集空间贡献率高达60%.但不同长石类型溶蚀程度存在明显差异,其中,钾长石溶蚀程度高于斜长石,且钾长石溶孔比例最大。研究区长石溶蚀强度以中溶蚀(约占40%)和强溶蚀(约占36%)为主;钾长石溶蚀贡献率随溶解率的增加而增加,斜长石则相反,即钾长石溶孔率将会直接影响长石溶蚀强度,而斜长石溶孔对孔隙度的贡献较小,尤其是在溶蚀强度较高的情况下。
[Abstract]:Feldspar dissolution is the main controlling factor for the development of porosity at Chang 8 reservoir level in DZ-ZY area of Xifeng Oilfield, Ordos Basin. In order to analyze and study the characteristics of feldspar dissolution in Chang 8 reservoir, the casting thin section and scanning electron microscope (SEM) are used comprehensively to study the characteristics of feldspar dissolution. Based on the properties of feldspar incomplete dissolution, the secondary porosity and dissolution rate of feldspar dissolution theory are calculated by using electron probe and other analytical techniques. Accurate division of feldspar dissolution intensity: weak dissolution (dissolution rate less than 25%), medium dissolution (dissolution rate less than 25%), strong dissolution (dissolution rate 50%) and extremely strong dissolution (dissolution rate greater than 75%). The results show that feldspar dissolution is widespread in the study area. The contribution rate of feldspar solution pore to reservoir space is as high as 60%, but the dissolution degree of different feldspar types is obviously different, and the dissolution degree of potassium feldspar is higher than that of plagioclase. The dissolution strength of feldspar is mainly medium dissolution (about 40 percent) and strong dissolution (about 36 percent), while the contribution rate of potassium feldspar solution increases with the increase of dissolution rate, whereas plagioclase is opposite. That is, the dissolution porosity of potassium feldspar will directly affect the dissolution strength of feldspar, but the contribution of plagioclase dissolution pore to porosity is small, especially in the case of high dissolution strength.
【作者单位】：西安石油大学地球科学与工程学院;中国石油长庆油田分公司勘探开发研究院;中国石油大学地球科学学院;
【基金】：国家油气重大专项(2011ZX05044) 国家自然科学基金(41102083)
【分类号】：P618.13

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