珠江口盆地深层高温高压下的水岩作用

地层中的酸性流体是含油气盆地内部物质迁移和能量交换的主要介质，是形成次生孔隙、改善储层物性的重要物质基础。通过对珠江口盆地岩心样品进行高温高压水岩反应实验，结合扫描电镜、铸体薄片、储层物性、XRD及ICP-OES等分析测试手段，揭示了深层碎屑岩储层溶蚀作用和次生孔隙发育机理。研究结果表明：①高温高压条件下有机酸性流体对岩石矿物具有溶蚀作用，且发生了离子迁移现象，释放出K⁺，Ca²⁺，Na⁺，Mg²⁺等阳离子，反应后样品孔隙度平均提高了5.6%，提升幅度达31.5%，岩石中的易溶组分含量及易溶矿物的原生结构可影响次生孔隙的发育；②选取具有代表性的样品对少井或无井区域进行深部地层条件下的水岩反应模拟实验是科学有效的储层评价途径，实验可模拟溶蚀过程和刻画溶蚀机理，现今在深部油气勘探成本高、风险大的背景下，高温高压实验结果对深部储层预测和勘探目标优选具有重要参考价值。

Water-rock interaction in deep strata under high temperature and high pressure in Pearl River Mouth Basin

Acidic fluid is the main medium of material migration and energy exchange in petroliferous basins and an important material basis for forming secondary pores and improving reservoir physical properties. Through high temperature and high pressure water-rock reaction experiment on the core samples from the Pearl River Mouth Basin, combined with the analysis and test methods of scanning electron microscope,cast thin section, reservoir physical properties,XRD and ICP-OES,the dissolution of deep clastic reservoirs and the development mechanism of secondary pores were revealed. The results show that:(1)Organic acid fluid has the effect of dissolution on rocks minerals Under high temperature and high pressure, and ion migration occurs, releasing cations such as K⁺,Ca²⁺,Na⁺ and Mg²⁺. After the reaction, the porosity of the samples was increased by 5.6% on average,and the increase was 31.5%. The content of soluble components in rocks and the primary structure of soluble minerals can affect the development of secondary pores.(2)Using representative core samples to conduct experiments of deep water-rock reaction is an effective way for reservoir evaluation in areas with less well or without well. Under the current tendency of high cost and risk for oil and gas exploration,it is a meaningful way to predict and explore resources in deep reservoir. The experiment can simulate the dissolution process and characterize the dissolution mechanism. Nowadays, under the background of high cost and high risk of deep oil and gas exploration,the experiment results have important reference value for deep reservoir prediction and exploration target optimization.