近临界特性的地层水及其对烃源岩生排烃过程的影响  

Formation Water of Near-Critical Properties and Its Effects on the Processes of Hydrocarbon Generation and Expulsion

作　　者：郑伦举[1,2] 何生[1] 秦建中[2] 马中良[2] 

机构地区：[1]中国地质大学构造与油气资源教育部重点实验室,湖北武汉430074 [2]中国石油化工股份有限公司石油勘探开发研究院,无锡石油地质研究所,江苏无锡214151

出　　处：《地球科学（中国地质大学学报）》2011年第1期83-92,共10页Earth Science-Journal of China University of Geosciences

基　　金：国家重点基础研究发展“973”计划项目(No.2005CB422102);中国石油化工股份有限公司前瞻性基础理论研究课题(No.P05038)

摘　　要：研究利用特制的地层孔隙热压模拟实验装置,开展了模拟地层孔隙空间高压液态水热体系烃源岩生排烃模拟实验.模拟实验施加的流体压力为38±2MPa,温度为290～390℃.模拟实验结果显示了有关高压液态水及其与之相联系的流体压力和孔隙空间等因素对烃源岩生排烃影响作用的一些重要现象,实验发现高压液态水介质条件有利于液态油的生成和保存,不利于液态油向气态烃的转化,而且干酪根的生烃潜力和排油效率有一定的提高.这些新的实验现象可能主要与近临界特性的高压液态地层水的作用有关,进一步推断近临界特性的高压液态水参与干酪根向油气的转化反应,增加了水对油气的溶解能力.在地下实际烃源岩生排烃的温压(100～200℃,30～120MPa)条件下,岩石孔隙中的地层水是一种相对低温高压压缩液态水,这种地层水可能具有近临界特性,对烃源岩生排烃过程有重要影响.但目前对这种现象的机理和石油地质意义还知之较少.因此,加强高压地层水近临界条件下烃源岩生排烃热压模拟实验研究,对进一步深入理解地层条件下的近临界水介质、流体压力、孔隙空间因素对生排烃过程的影响,深化烃源岩生排烃机理的探讨,建立地质尺度上的烃源岩生排烃动力学模型,都具有重要的理论和实际意义.A special simulation experimental device using a high pressure liquid water system in the similar geological pore space with fluid pressures around 38±2 MPa and temperatures ranging from 290 ℃ to 390 ℃ is used to simulate hydrocarbon generation and expulsion from source rocks in this study. The new experimental results show many important phenomena about the generation and expulsion influenced by high-pressure liquid water linking with fluid pressure and pore space. It is found that high-pressure liquid water medium condition facilitates the generation and preservation of liquid oil and improves the potential of hydrocarbon generation from kerogen and the efficiency of oil expulsion but it is not conducive to the conversion of liquid hydrocarbon to gaseous hydrocarbon. It is considered that these new experimental phenomena may be mainly related to the effects of high-pressure liquid water of near-critical properties. It is further inferred that the high-pressure liquid water of near-critical characteristics is involved in the conversion of kerogen to oil and gas reactions,to increase the solubility of the oil and gas in water. Under the appropriate geological conditions,hydrocarbon generation and expulsion from source rocks occur at temperatures ranging from 100 ℃ to 200 ℃ and pressures ranging from 30 MPa to 120 MPa in most cases,suggesting that actual formation pore water could be a compressed state liquid water with near-critical properties at a relatively low temperature and high-pressure environment. This high-pressure liquid water of near-critical characteristics may have important effect on the processes of petroleum generation and expulsion. However,the mechanism and geological significance for petroleum exploration of these phenomena are still not clear. Further studies are necessary for such simulation experiments under high pressure liquid water condition for better understanding of the actual roles of the factors such as the near-critical water medium,fluid pressure and pore space. It is beli

关 键 词：热压模拟实验 高压液态水 流体压力 烃源岩生排烃过程 石油地质 

分 类 号：P618[天文地球—矿床学]