辽河盆地大民屯凹陷油水变化规律与油气富集

对辽河盆地大民屯凹陷静安堡西侧低潜山带地层水化学性质特征分析表明,潜山顶部地层水是以NaHCO₃水型为主,局部出现CaCl₂水型,反映了潜山顶部总体上具有一定的自由交替水动力条件的开放性环境,而局部出现封闭性环境;这种局部性的封闭环境主要是由于封堵性断层及上覆欠压实泥岩的封堵造成的。地层水矿化度具有明显的由西向东增加的变化趋势,西部最低值仅为1500mg/L,而东部矿化度最高达9378.69mg/L。高矿化度分布区是油气富集的有利区带。原油的物性与地球化学特征则表明了区内油气的运移距离较短,但在短距离的运移过程中,原油物性发生了明显的变化。潜山顶部地层水与原油的这些变化特征,指示了油气运移的方向及其富集的场所。

VARIETY REGULARITY OF OIL AS WELL AS FORMATION WATER PROPERTY AND HYDROCARBON GATHERING IN THE DAMINTUN SAG OF THE LIAOHE BASIN

According to analysis of formation water and crude oil at the west Jinganpu of Damintun Sag in the Liaohe Basin,type NaHCO_3 formation water on the top of the burial hills in the studied area is dominative,type CaCl_2 appear in local area.The result reflects that environment on the top of the burial hills is open and water can alternate in this environment,but it is closed in local area.This enclosed environment is the result of close faults and overlying undercompacting mudstone.Mineralization degree of formation water has the trend that value increase from west to east and the lowest value in west is only(1 500 mg/L),but in east the value is amount to 9 378.69 mg/L.The zone that presents high degree of mineralization is favorable area that gathers hydrocarbon.Physical property and geochemistry feature of crude oil indicate that migration length of hydrocarbon is short.But in this short distance,the crude property takes place great change.The changes of geochemistry feature show the hydrocarbon migration direction and gathering location.