松辽盆地北部中央坳陷带异常压力条件下地层水化学特征及其成岩响应

摘要

The pressure system in the central depression of the Songliao Basin was analyzed systematically. A large amount of data about formation water was studied and compared, based on which the ions pattern as well as the dia-genesis reaction of formation water were discussed. It has been concluded that abnormal pressure obviously influences geofluid and diagenesis. Both overpressure and underpressure can increase TDS; however, their influencing mecha-nisms are different. Water type varies in different pressure systems, leading to different diagenesis effects. In over-pressure and normal pressure systems, NaHCO3 and NaCl type water is dominant, and the dissolution of minerals works as the main diagenesis effect. As to underpressure system, CaCl2 type water is dominant, and the main diagene-sis effect is the albitiztion of feldspar.%　　在对松辽盆地中央坳陷带压力系统进行系统分析的基础上，结合研究区大量地层水资料，通过对比，研究地层水离子组合特征及其对异常压力条件下成岩作用的响应。研究表明，异常压力环境对地质流体及成岩作用有明显影响。超压和低压均能使地层水矿化度升高，但是影响机制不同。不同压力体系水型不一样，主要发生的成岩作用也不同。超压和常压体系主要为 NaHCO3型和 NaCl 型水，成岩作用以矿物的溶解作用为主。而低压体系主要为 CaCl2型水，成岩作用以钙长石的钠长石化为主。