莺歌海盆地海口A区储层特征与天然气低丰度影响因素  

Reservoir characteristics and causes of low-abundance natural gas of the Haikou A block,Yinggehai basin

作　　者：张新顺[1] 黄志龙[2] 朱建成 吴红烛 

机构地区：[1]中国石油勘探开发研究院,北京100083 [2]中国石油大学(北京)地球科学学院,北京102249 [3]中海石油(中国)有限公司湛江分公司,广东湛江524057 [4]浙江省地球物理地球化学勘查院,浙江杭州310005

出　　处：《东北石油大学学报》2015年第1期1-8,125,共8页Journal of Northeast Petroleum University

基　　金：国家科技重大专项(2011ZX05023-004-008)

摘　　要：针对莺歌海盆地海口A区虽然具有较为良好的油气成藏条件,但预探结果显示为低丰度气藏的问题,采用储层孔渗实验、扫描电镜镜下观察、黏土矿物质量分数测定和储层孔隙度恢复等方法,分析海口A区储层特征,结合埋藏史分析成岩演化特征,根据天然气成藏条件分析天然气低丰度影响因素.结果表明:海口A区三亚组储层主要为分选差、磨圆差的粉砂岩,具有中低孔、低渗特点,现今处于中成岩B期,孔隙以粒间溶蚀孔、铸模孔和粒内溶蚀孔为主;储层在黄流组沉积末期已致密,后因酸性水进入,孔隙度增加;储层天然气主要来源于三亚组,充注期为2Ma左右,成藏期储层致密是导致该区天然气低丰度的主要原因.该结论为在莺歌海盆地寻找优质储层、改善开发效果提供参考.Haikou A block of Yinggehai basin have oil and gas accumulating conditions,however,preliminary prospecting only finds low-abundance gas reservoir.Based on the former exploration of Haikou A block in Yinggehai basin,through reservoir porosity and permeability experiments,scanning electron microscope,measurement of clay mineral content,reservoir porosity recovery and some other means and methods,we described the reservoir characteristics and its evolution characteristics of Haikou A block with the buried history.In combination with some other gas accumulation conditions of this block,such as origin of the natural gas and formation time of the trap,the primary reason of low-abundance natural gas has been further analyzed.The results show that:reservoir rock of Sanya formation at Haikou A block has moderate porosity and low permeability siltstone with poor sorted and poor rounded.Now it has already been in B stage of middle diagenetic phase,and intergranular dissolved pore,moldic pore,intragranular dissolved pore are the main type of pore.Silklike illite and albite microcrystal block the throat and result in low permeability of the reservoir,while the dissolution of feldspar and carbonate keep the porosity from decreasing.The reservoir rock of Sanya formation had already become tight at the end of Huangliu formation depositing,and then the porosity increased because of acid ground water accessing.Combined with analysis of the geochemical data,the natural gas of Sanya formation in Haikou A block mainly originated from the source rock in Sanya formation rather than the Yacheng formation deeply buried.From the hydrocarbon inclusion experiment,the main charging time is 2 Ma to present,which is also match with the maturity of source rock in Sanya formation.The tightness of reservoir hindered the natural gas charging and results in the low-abundance natural gas formation.Therefore,the further natural gas exploration should be focused on the qualified reservoir to reduce the risks.The results will provide information for fu

关 键 词：储层特征 天然气 低丰度 成岩作用 孔隙度演化 海口A区 莺歌海盆地 

分 类 号：TE122.2[石油与天然气工程—油气勘探] P618.13[天文地球—矿床学]