大宛齐油田地层水化学特征分析

Analysis of the Chemical Characteristics of the Formation Water in Dawanqi Oilfield

大宛齐油田油层连通性差,加之断层切割,是一个多油水系统的断块岩性油藏,各油藏之间没有统一的油水界面。通过对地层水化学特征开展研究,可以为更好地认识与研究该类油藏的形成及分布特征提供相关参考与佐证。地层水的化学特征是受成岩环境以及后期改造作用综合影响的结果,地层水的化学特征的形成过程与油气成藏密切相关;开展地层水化学特征研究,有利于油气的勘探与开发。大宛齐油田地层水总矿化度主要分布在200000mg/L-250000mg/L,属于盐水和卤水;PH值6-8,为弱酸-弱碱性,地层水基本为CaCl2水型。通过对大宛齐油田地层水的PH值、常规成分、主要元素及其组合统计分析,反映了大宛齐油田地层水的特征,并揭示了其与油气分布的关联。对于油层埋深浅,地层水矿化度较大且变化明显的油田水研究具有一定的借鉴意义。

Cut by faults,the reservoir of Dawanqi oilfield which has poor connectivity,is a multiple oil-water system fault lithology reservoir.There is no uniform oil-water interface between each reservoir.Research of the chemical characteristics of formation water can provide relevant reference and evidence for better understanding of reservoir formation and distribution characteristics.The chemical characteristics of formation water are the combined effects of diagenetic environment and late reform.The process has close relationship with reservoir formation.Research of the chemical characteristics of formation water is in favor of oil and gas exploration and development.The formation water in Dawanqi oilfield which total salinity ranges from 200000mg/L to 250000mg/L,belongs to salt water and brine.The PH value is from 6 to 8 which indicates weak acid-alkaline.Formation water is substantially water-CaCl2.Statistical analysis of the PH value,conventional components,main elements and combination of the formation water in Dawanqi oilfield reflectd the characteristics of formation water and reveals its association with oil and gas distribution.It is of reference significance for studying the reservoirs which are shallow and formation water salinity vary greatly and obviously.