陈中红等。陆相断陷咸化湖盆地层水化学场响应及与油气聚集关系——以渤海湾盆地东营凹陷为例。地质科学,2010, 45(2):476-489.

摘　要　东营凹陷古近系水化学场分布与湖盆演化有着良好的对应关系，矿化度从深到浅逐渐降低，体现出沉积环境开放性的增强。剖面上可以划分为四种水文环境：强开放性水文流畅带（地表到1.1 km）、弱开放性水文流畅带（1.1～2.0 km）、水文阻滞过渡带（2.0～2.5 km）和封闭性水文迟缓带（2.5 km以下），水化学场剖面的分带性与压力场分布有着良好的对应关系。高矿化度分布是咸化湖盆重要特征，盐岩溶解、扩散、运移和断裂沟通是其主要成因。在这种高矿化度地层水化学场中主要发育CaCl₂型水，在盆地边缘低矿化度地层水中，以NaHCO₃水型为主，同时发育有少量低－较高矿化度的Na₂SO₄水型和MgCl₂水型。研究结果表明，在东营凹陷断陷咸化湖盆中，含NaHCO₃水型的地层环境更能代表地层水交替强烈的开放性沉积环境，而Na₂SO₄水型分布多与硫酸盐有关；在断陷咸化湖盆中，油气藏分布具有广泛性，油气藏不仅仅存在于高矿化度的地层水环境中，在具低矿化度的各类地层水环境中也分布有油气藏。

关键词　地层水化学场　矿化度　油气成藏　断陷湖盆　东营凹陷

Chen Zhonghong, et al. Response of Formation Water Chemical fields and Its Relation to the hydrocarbon Accumulation in the saline Faulted-basin. Chinee Journal of Geology, 2010, 45(2):476-489.

The formation water chemical characteristics in the Eogene System had good response to the sedimentary conditions and its evolution in Dongying sag. The content of total salinity and chloride ion decreased from the deep depth to the lower, which was good response to the evolution of the Dongying sag from salted basin to fresh water basin. According to the vertica1 characteristics of the formation water four hydrological environments can be classified: stronger formation water frequency alternation belt(0~1.1km), feeble formation water frequency alternation belt(1.1~2.0km), formation water alternate blocking belt (2.0~2.5km) and formation water alternate tardy belt (>2.5km), in every belt the total salinity, ions and ion composition ratio had different responses, and the belts corresponded to the distribution of formation pressure. High salinity displayed the main characteristics of the saline lake-basin, and dissolution of salt rock, diffusion and migration of formation water, and the communication by faults were main reasons.   In the formation water with high salinity, there mainly developed CaCl₂ water type, and in the formation water with low salinity, there mainly developed NaHCO₃ water type, and the NaHCO₃ water type was substituted by the CaCl₂ water type with the content of total salinity increased. There were also developed some Na₂SO₄ and MgCl₂ water types with low~higher salinity. The study demonstrated that, In the saline faulted lake-basin of Dongying basin, NaHCO₃ water type can representative the openly sedimentary conditions with strong alternation of formation water, and Na₂SO₄ was relative to the distribution of sulphate; and some oil reservoirs were found in every condition with low salinity although most oil reservoirs formed in the formation water conditions with high salinity, which displayed the unique relation of formation water chemical field in salted basin with hydrocarbon accumulation.

Key words: formation water chemical field, oil accumulation, salinity, faulted basin, Dongying sag