阳江凹陷深层低渗储层成岩作用及对储层影响  

Diagenesis of Deep Low-permeability Reservoirs in Yangjiang Depression and Its Impact on Reservoirs

作　　者：闫洁 YAN Jie(SINOPEC Shanghai Offshore Oil&Gas Company,Shanghai 200120,China)

机构地区：[1]中国石油化工股份有限公司上海海洋油气分公司,上海200120

出　　处：《海洋石油》2024年第3期44-50,70,共8页Offshore Oil

摘　　要：珠江口盆地阳江凹陷深层油气资源巨大,但目前储集层深层成岩作用研究相对薄弱。该文基于岩心资料,对研究区恩平组深层低渗砂岩储层的成岩作用及其对储层物性的影响进行了综合分析。研究结果表明:阳江古近系恩平组储层成分成熟度较高,储集空间以溶蚀孔隙为主,占比超过50%,储层总体为低孔低渗的孔隙型储层。恩平组整体处于中成岩阶段(IIA-IIB),其成岩序列为:早成岩A期(IA)—机械压实/绿泥石包壳→早成岩B期(IB)—机械压实/凝灰质蚀变/长石溶蚀→中成岩A期(IIA)—机械压实/方解石胶结/长石溶蚀/岩屑溶蚀/高岭石胶结→中成岩B期(IIB)—化学压实/白云石胶结/孔隙绿泥石/石英加大。恩平组深层低渗储集层储集空间受成岩作用影响明显,其中压实作用显著地改变了恩平组储集层的孔隙度,减孔量为11.8%~26.3%(平均19.5%);胶结作用减孔量2.3%~30.1%(平均12.3%);溶蚀作用增孔量1.3%~24.8%(平均9.4%)。综合分析油气充注和储层孔隙演化匹配关系可知,该区深层储层属于“先致密后成藏”。The oil and gas resources in the deep of Yangjiang Depression of Pearl River Mouth Basin are huge.However,the study on the diagenesis of deep reservoir is relatively week.Based on rock cores,this paper provided a comprehensive analysis of the diagenesis and its effects on the reservoir physical property of deep low-permeability sandstone reservoir of Enping Formation in the research area.The result of research shows that the composition maturity of Enping Formation reservoir in Yangjiang Depression is relatively high and the reservoir space is dominated by dissolution pores,accounting for more than 50%.The reservoir is generally porous with low permeability and porosity.The strata of Enping Formation are in the middle diagenetic stage(IIA-IIB).The diagenetic sequence is:Prodiagenetic stage A(IA)-mechanical compaction/chlorite film→Prodiagenetic stage B(IB)-mechanical compaction/tuffaceous alteration/feldspar dissolution→Mesodiagenetic stage A(IIA)-mechanical compaction/calcite cementation/feldspar dissolution/debris dissolution/kaolinite cementation→Mesodiagenetic stage B(IIB)-chemical compaction/dolomite cementation/pore chlorite/quartz enlargement.The reservoir space of deep low permeability reservoir in Enping Formation is obviously affected by diagenesis.Compaction changes the porosity of Enping Formation reservoir significantly,which reduces porosity by 11.8%to 26.3%,with an average of 19.5%,and has a pore reduction of 2.3%to 30.1%,with an average of 12.3%in the pore space by cementation.The porosity of Enping Formation reservoir is increased by 1.3%to 24.8%,with an average increase of 9.4%,due to the dissolution impact.Based on a comprehensive analysis of the matching relationship between oil and gas filling and reservoir pore evolution,it is concluded that the deep reservoirs in this area belong to"tight first and then reservoir formed".

关 键 词：阳江凹陷 深层储层 成岩作用 储层成因 

分 类 号：P618.13[天文地球—矿床学]