板桥断裂构造带油气成藏组合特征

RESERVOIR CHARACTERIZATION OF BANQIAO RUPTURE STRUCTURAL BELT

板桥断裂构造带位于板桥凹陷的东侧,受板桥凹陷和大张坨断层控制。该带富集的天然气除来源于自身烃源岩外,主要来源于板桥凹陷。板桥凹陷气源丰富(有机质丰度高,母质类型好,具有较完整的烃源岩演化序列)、圈闭形成时间早(为天然气早日成藏提供了场所)、油气充注时间晚(前后有4个油气充注期)、盖层封盖能力强(最好的烃源岩同时又是区域盖层)。将板桥凹陷油气藏分为3套成藏组合:①沙一段中部自生自储型咸藏组合;②沙三段生气、沙二段和沙一段下部储气的下生上储型成藏组合;③沙三段自生自储型成藏组合。

Banqiao rupture structural belt is located on the eastside of Banqiao sag, which is controlled by Banqiao and Dazhangtuo faults. This belt is abundant in natural gas which is generated from in-situ hydrocarbon source rocks, but is mainly from Banqiao sag. In this sag, the gas supply is abundant with high abundance of organic matter, good types of parent materials and complete evolution series of hydrocarbon source rocks. The sag is characterized with the early trap-generation time (which provides good settings for formation of reservoirs ), the late hydrocarbon-charging time (there are four hydrocarbon-charging periods) and the strong sealing ability of cap rocks (the best hydrocarbon source rocks are also the regional cap rocks). The oil and gas reservoirs in Banqiao sag are divided into three sets of combination of reservoir formation: I combination of in-situ source rocks and in-situ reservoir rocks for middle Sha 1; II combination of Sha 3 (which generates gas), Sha 2 and lower Sha 1 (which store gas); III combination of in-situ source rocks and in-situ reservoir rocks for Sha 3.