准噶尔盆地车排子地区地层水离子参数特征与油气藏的关系

Relationship between water ion parameter characteristics and hydrocarbon reservoirs in Chepaizi area of Junggar Basin

准噶尔盆地车排子地区侏罗系与白垩系地层水矿化度整体较低,以Na HCO3水型为主。根据地层水化学成分特征,计算出多种离子比例系数,分析其与油气聚集的关系。研究表明:离子比例系数有明显的南北分区特征,南部凸起边缘封闭性不好,北部古隆起位于构造高部位,封闭条件较好,南部邻区四棵树凹陷的油气经南部断裂等输导体系运移到北部成藏。侏罗系地层水曾经遭受过比较强烈的大气降水的入渗,使早期油发生水洗氧化作用,形成现今大量的稠油油藏。侏罗系地层水封闭性好于白垩系,更有利于油气聚集和保存。

The formation water of Jurassic and Cretaceous in Chepaizi area of Junggar Basin is low TDS whole- ly and mainly is of the NaHCO3 type. Based on the chemical composition characteristics of the formation water in the Chepaizi area, the authors calculate the ion ratios to analyze the relationship with the oil and gas accumulation. The research shows that the ion ratios have obviously differentiable characteristics in the north and south. The south is on the edge of uplift which has adverse closure property while the north is on the palaeohigh which has good clo- sure property. The oil and gas from Sikeshu sag of southern adjacent area were migrated to the north by petroleum migration pathways such as south faults. The Jurassic formation water had suffered from more strong infiltration of atmospheric precipitation, which led to oxidation of early oil and formed the current heavy oil reservoir. The closure property of the Jurassic formation water is better than that of Cretaceous, which favors oil and gas in accumulation and reservation.