文昌10区珠海组低渗储层“甜点”控制因素

Factors of controlling the distribution of the low permeability reservoir "sweet spots" from Zhuhai formation of Wenchang 10 area

根据常规物性分析、测井解释、岩石薄片、岩石碳氧同位素等,研究文昌10区珠海组扇三角洲沉积储层厚度与物性分布;考虑沉积环境、成岩作用等,分析不同层段低渗成因及物性影响因素,确定"甜点"储层控制因素与分布.结果表明:胶结强度差异为珠海组一段和二段"甜点"储层控制因素,扇三角洲前缘水下分流河道断裂活动速率较低、略远离南断裂较高压力的低钙质胶结区为"甜点"储层发育区;压实、溶蚀强度与砂岩粒级为珠海组三段"甜点"储层控制因素,水下分流河道/河口坝粗粒度、较弱压实、强溶解带为"甜点"储层发育区.该研究为勘探有利区带预测提供地质依据.

The reservoir is developing in underwater distributary channel and Debouch bar.Reservoir properties are low permeability mainly,moderate permeability partly.By physical property,logging interpretation rock thin-sections and rock carbon/oxygen isotopes,et al,the reasons of low permeability formation and factors of physics quality are analyzed finally from sedimentary facies and diagenesis on the base of understanding reservoir distribution.It is determined that cementation strength is the main controlling factor on reservoir 'sweet spots' from the first and second members of Zhuhai formation,development direction of 'sweet spots' is where are of low velocity of fault moving slightly away from south fault zone and calcareous cement weak developing with higher pressure in underwater distributary channel.Compaction,erosion intensity and sandstone grain size are the factors of the third member of Zhuhai formation,where are coarse size,weak compaction or strong dissolution of submarine distributary channel and river mouth bar are the zones of as the 'dessert' reservoirs.All above are supplying geologic evidence to forecast advantage areas for exploration.