东营凹陷古近系砂岩储层成岩耗水评价

成岩作用过程中会发生流体浓缩现象,对油气成藏具有重要影响。综合岩石薄片、测试分析及地质统计资料,在成岩矿物蚀变耗水作用研究的基础上,对东营凹陷古近系砂岩储层成岩耗水进行了整体评价。结果表明,东营凹陷古近系砂岩储层成岩过程中普遍发生了耗水作用,耗水反应主要为长石高岭石化,砂体总耗水量平均为383亿t。纵向上,砂岩的长石转化率和耗水量明显存在浅部和深部2个高峰区段,即1200~2000 m和2000~3500 m。平面上,东营凹陷不同区带砂岩耗水量有差异,南部缓坡带和北部陡坡带的浅部区段长石转化率和单位体积耗水量大,洼陷带的长石转化率和单位体积耗水量则以深部区段为主,由于深部区段砂体体积大,造成深部区段尤其是洼陷带砂体耗水量大。

Water Consumption Appraisal of Sandstone Reservoir of Paleogene in the Dongying Sag

Fluid-rock interaction accompanied by inspissation of fluids can make significant effects on hydrocarbon formation.According to integrated data of rock section,test analysis,geostatistics,on the basis of study on water consumption of main mineral alteration during diagenetic stage,water consumption of sandstone reservoir of Paleogene during diagenetic stage in the Dongying sag is integrally evaluated.Research results show that water consumption function is general phenomenon in the Dongying sag.Kaolinization of feldspar is mainly water consumption reaction.Average quantity of total water consumption is 38.3 Gt.Vertically,there are obviously two peak sectors of feldspar transformation ratio and water consumption quantity,namely shallow sector(from 1,200 to 2,000 m) and deep sector(from 2,000 to 3,500 m).Horizontally,different districts of the Dongying sag vary in water consumption quantity;feldspar transformation ratio and water consumption quantity per unit sandstone volume of shallow sector in southern gentle slope and northern steep slope are greater than those of deep sector;on the other hand,those of deep sector in subsag are greater than those of shallow sector.Since sandbody volume of deep sector is bigger,its water consumption quantity,especially in subsag,is great.