延气2井区盒8段致密砂岩储层低产的微观孔喉原因  

Micro Pore Structure Reasons for Low Yield of Tight Sandstone Reservoir in He8 Formation,Yanqi 2 Area

作　　者：黄国丽[1] 张静[1] 薛辉 王卓[1] 张婷[1] 张乐乐[1] 

机构地区：[1]延安大学石油工程与环境工程学院,延安716000 [2]中国石油长庆油田勘探开发研究院,西安710065

出　　处：《科学技术与工程》2016年第14期146-151,共6页Science Technology and Engineering

基　　金：陕西省高水平大学建设专项资金项目(2013SXTS03);省级大学生创新创业训练项目(1262)资助

摘　　要：结合薄片鉴定、X衍射、压汞、气水两相相渗及核磁共振测试数据,研究认为延气2井区盒8段储层孔渗平均分别6.8%,0.81×10^(-3)μm^2,为典型致密砂岩气层;其发育溶蚀作用形成的孔隙,如岩屑溶孔、粒内溶孔,面孔率最大达3.5%;受溶蚀作用形成的溶孔与其他孔隙类型组合形成了复杂的孔隙空间,如晶间孔-粒间溶孔,面孔率达3.1%。压汞曲线分析表明,盒8段Ⅱ类储层最发育,局部出现裂缝,造成储层高渗、低饱特点。Ⅱ类储层孔喉虽多,但半径细小,绝大多数喉道无贡献,大于0.86μm喉道仅占21%,对渗透率贡献达78%;储层孔喉半径比484,孔喉结构差;加之高束缚水饱和度,强亲水,虽含气饱和度高于15%时,天然气就能流动,但可动流体饱和度普遍低于35%,造成盒8气层产能偏低,需采取措施改善增加连通性。According to the thin section authentication, X-ray diffraction, mercury injection, two phase relative permeability and nuclear magnetic resonance （ NMR） , it is concluded that：He 8 reservoir was a typical tight sand-stone gas-formation, with average porosity 8. 4%, permeability 0. 81 mD, dissolution pores with surface porosity 3. 5% developed most. The intragranular dissolved-intracrystalline pore was the main combination type. In terms of mercury injection parameters curve characteristics, the favorable reservoir is mainly the type II. Sometimes, be-cause of crack, reservoir with high permeability, low saturation characteristic in the study area. There are serious fine throats in type II reservoir, with no contribution most. Although the throat than 0. 86 μm account for only 21%, but contribution to permeability of 78%;the structure of pore-throat is bad with pore throat radius ratio 484. In additionally, He 8 reservoir, with strongly water wetting. As long as the gas saturation of reservoir is higher than 15%, the natural gas can flow under the appropriate pressure drop, the movable fluid saturation of the reservoir are generally less than 35%. Hence,improvement measures are essential to improve the yield of gas.

关 键 词：致密砂岩 孔隙结构 核磁共振 

分 类 号：TE112.23[石油与天然气工程—油气勘探]