黄骅坳陷古近系沙河街组一段下部湖泊碳酸盐沉积相及其对油气分布的控制作用?

黄骅坳陷王徐庄油田古近系沙河街组一段下部厚40-50m，由碳酸盐岩与泥页岩互层组成，为湖泊中的碎屑岩-碳酸盐岩混积台地沉积。碳酸盐岩主要为石灰岩，其中包括亮晶颗粒石灰岩、泥晶颗粒石灰岩和泥晶石灰岩。颗粒主要为腹足类，也有鲕粒和内碎屑。根据沉积特征，混积台地可进一步划分为亮晶颗粒石灰岩滩、泥晶颗粒石灰岩滩和滩间等三种相。亮晶颗粒石灰岩滩为高能持续动荡环境，水深在正常浪基面之上，以亮晶颗粒石灰岩沉积为主；泥晶颗粒石灰岩滩为间歇动荡环境，水深在正常浪基面附近，以泥晶颗粒石灰岩沉积为主；滩间为安静低能环境，水深在正常浪基面之下，以泥晶石灰岩和页岩沉积为主。滩主要分布在台地边缘。同生断层的活动控制了台地的形成及滩的展布。亮晶颗粒滩是最好的储集相带，泥晶颗粒滩次之，滩间最差。油气分布主要受沉积相控制，高产井并不是位于构造高部位的滩间，而是位于低部位的亮晶颗粒石灰岩滩。

LACUSTRINE CARBONATE SEDIMENTARY FACIES OF THE SHAHEJIE FORMATION OF PALEOGENE IN HUANGHUA DEPRESSION

The Lower Member of Shahejie Formation in the Wangxuzhuang Oilfield of Huanghua Depression is 40-50 m thick, and mainly consists of carbonate rocks and shales. It is a carbonate-clastic intermixed platform in a lake. The carbonate rocks are mainly limestones, which can be further divided into sparry grainstones, limemud grainstones and limemud limestones. The grains are mainly gastropods as well as some ooids and intraclasts. Based on sedimentary characteristics, the platform can be divided into sparry grainstone bank, limemud grainstone bank and interbank. The sparry grainstone bank is persistently agitated high-energy environments, its water depth is above normal wave base, and deposits are mainly the sparry grainstones. The limemud grainstone bank is intermittently agitated environments, water depth is around normal wave base, and deposits are mainly the limemud grainstones. The interbank is quiet low energy environments, water depth is below normal wave base, and deposits are mainly the limemud limestones and shales. Both the limemud grainstone bank and sparry grainstone bank mainly occur at the edge of the platform. The activity of contemporaneous fault controls formation of platform and distribution of the banks. Sedimentary facies control distribution of oil and gas. the sparry grainstone bank is the best reservoiring facies for oil and gas, the limemud grainstone bank is the second, and the interbank can not form good reservoirs. High productivity wells are not located at structural highs where the interbank facies occur, but at structural lows where there are the sparry grainstone banks.