东营凹陷下第三系深层成岩作用及次生孔隙发育特征

通过钻井取心分析测试、岩石薄片和扫描电镜观察等手段,对东营凹陷下第三系深层成岩作用和次生孔隙发育特征进行研究。结果表明,东营凹陷下第三系深部碎屑岩地层经历了强烈的压实压溶作用和胶结作用、复杂的交代作用和多期次的溶解作用,原生孔隙消失殆尽。胶结作用是降低深层孔渗性能的主要因素,方解石类、黄铁矿、高岭石、绿泥石等成岩矿物的大量析出与次生孔隙发育密切相关;溶解作用使深层碎屑岩产生粒间溶孔、溶缝、溶蚀填隙物内孔隙和铸模孔等次生孔隙。从晚成岩A期到晚成岩C期,有机质成熟过程、粘土矿物转化、烃类与硫酸盐矿物的热化学氧化还原反应等造成的酸性地层水介质,使东营凹陷下第三系深部碎屑岩储层在不同构造部位分别发育2~4个次生孔隙发育带。

Diagenesis and secondary pore development in Paleogene deep formation in Dongying Sag

Based on the measurements of drilling,coring,microscopic and microscanning,the diagenesis and secondary pore development in Paleogene deep formation in Dongying sag are researched.The results indicated that the clastic rock strata buried in deep depth,they came through strong compaction,cementation,complex metasomatism and dissolution,so the primary pores are few.In all of these diagenesises,cementation is the main factor to decreasing stratum porosity and permeability.Abundance outputting of calcite,pyrite,kaolinite and chlorite were well corresponding with secondary pores growth.The dissolution developed sorts of pores.The acid stratum liquid caused by the organic matter maturation,clay minerals transformation and thermo chemistry oxidation deoxidation reactions of hydrocarbon and sulfate minerals developed 2 to 4 secondary pores zones in the deep formation of Dongying sag in Paleogene on different tectonic block from late diagenesis A stage to late diagenesis C stage.