摘要
番禺气田含气层为典型的海相三角洲沉积,而主要含气层段MFS18.5层以三角洲前缘沉积为主,而SB13.8层则为三角洲平原沉积。依据岩心、薄片、扫描电镜、X衍射等资料,详细研究该气田储集层特征及成岩作用,按照最新碎屑岩成岩阶段划分标准,SB13.8层处于开启型弱碱性水循环环境(pH>7.5),胶结作用不强烈,成岩作用较弱,属于早成岩B期;MFS18.5层属于中成岩A期,处于相对封闭型弱酸性水循环环境(pH值<6.5),温度的增加催化了有机酸水溶液对硅酸盐矿物的溶蚀进程,为次生孔隙带的发育提供了条件,并据此建立了海相石英砂岩类储集层的成岩模式。从储集层特征上来看,MFS18.5层的结构成熟度与矿物成熟度均高于SB13.8层,而且呈现出由下向上逐渐降低的趋势;同时MFS18.5层比SB13.8层受波浪改造的作用要强,其搬运距离要远。从阴极发光和扫描电镜观察的结果可以看出,MFS18.5层石英次生加大可以到3级,且自生高岭石也相当发育。这是MFS18.5层砂岩与珠江口盆地其它油田同类储层相比,孔隙度差别不大,但渗透率偏低的重要原因。另外,应用精细的单井盆地模拟,在埋藏史的基础上模拟孔、渗的垂向变化,可以直观而较为准确的分析垂向上多个储盖组合的相互差异与特征。
The main gas-bearing layers at Panyu gas field was belong to delta deposits of marine facies. The main bearing gas layer, SB13.8 layer was as main sediments of deltaic plain, but MFS18.5 layer was the depositing product of deltaic front. Based on the data of core, thin section ; scan microscope, X-diffraction, etc. , the reservoir characteristics and diagenesis of Panyu gas field had been studied in detail. According to the latest classified criterion on diagenetic stage of clastic reservoirs, SB13.8 layer, one of the two main gas bearing layers, its stratum water circulating environment was an open type of alkalescence （ pH 〉 7.5 ） , which was belong to stage B in early diagenesis with weak cementation and feeble diagenesis. MFS18.5 Layer, an other gas bearing layer, its stratum water circulating environment was an relative closed type of feeble acid（ pH 〈 6.5） , which was belong to stage A in middle diagenesis. So, the augment of temperature had been catalyzed the dissolution course of organic acid water solution for silicate minerals, which had provided sufficient and indispensable conditions for the development of the secondary porous zones. Hereby, the diagenetic pattern of mavine quartzite sandstone reservoir has been established. As the view of reservoir characteristics, the texture and mineral component mature of MFS18.5 layer was higher than that of SB13.8 layer and it descended from lower to upper. Meanwhile, MFS18.5 layer had been reconstructed by waves and transported with long distance that was much more than those of SB13.8 layer. According to the results on cathode luminescence and scan microscope, the secondary enlargement of quartzs was to be the third degree and autogenetic kaolinite was well developed. This is the reason why the sandstone of MFS18.5 layer has the lower permeability and poor porosity contrasting with other reservoirs in Peal River Mouth basin. On the other hand, using specify basin simulating method of single well, the vertical change of porosity and permeability on the basis of burial history have been simulated, which can intuitively and more accurately analyze one another difference and characteristics of vertical mul-tiply.
出处
《沉积学报》
CAS
CSCD
北大核心
2007年第6期876-884,共9页
Acta Sedimentologica Sinica
基金
高等学校博士学科点专项科研基金(20050491001)资助
关键词
珠江口盆地
番禺气田
成岩作用
盆地模拟
储盖组合
Peal River Mouth basin, Panyu gas field, diagenesis, Basin simulation, mul-tiply
