冀中拗陷古潜山油田水化学研究

冀中拗陷油气田87%的储量产于海相碳酸盐岩古潜山中,在油气生成、运移、集聚和散失的过程中地下水起了重要作用。本文根据50个试样的水化学分析资料,运用对应分析方法对冀中拗陷古潜山油田水进行了分类并初步探讨了水化学成分演化与油气藏形成的关系。

STUDY ON CHEMISTRY OF OILFIELD WATER IN BURIED BLOCK HILL IN JIZHONG DEPRESSION

The block hill consisted with Proterozoic-Paieozoic carbonate rock in Jizhong Depression lies buried under the Cenozoic plain in a depth of 0.7-6 km, in which the oilfield water plays an important role in the formation, migration, accumulation and preservation of oil pools. According to chemical analytical data of 50 samples, using Correspondence Factors Analysis with TDS, Na++K+, Ca2+,Mg2+, SO2-, Cl- and HCO3- as index, the oilfield water in buried hill can be divided into three types: (1) weak admixture water (with about 90% paleolixiviation water (PLW) and 10% Tertiary stratum water (TSW) in high level of buried hill; (2) admixture water (with TSW 20-30% and PLW 70-80%) in hydrodynamic equilibrium area of the slope between high level and low trough; (3) strong admixture water (with TSW 40-50% and PLW 50-60%) in low trough.The properties of crude oil are closely bound up with the compositions and dynamic condition of oilfield water. Based on the composition of oilfield water and relation with forming oilfield water, the author sets up an evolution model of oilfield water in buried hill in Jizhong Depression.