古龙地区葡萄花油层沉积微相及油藏特征

Sedimentary microfacies and reservoir characteristics of Putaohua reservoir in Gulong area

古龙地区在构造上由葡西鼻状构造、新肇鼻状构造、新站鼻状构造、他拉哈向斜、古龙向斜和茂兴向斜共6个三级构造单元组成,呈现“凸凹相间、西低东高”的格局。通过测井曲线响应、岩性组合特征等资料对古龙地区葡萄花油层从单井上进行沉积微相划分,发现古龙地区葡萄花油层沉积相主要由浅水三角洲相和浅水湖泊相组成,三角洲相以三角洲前缘亚相为主,湖泊相主要为滨浅湖亚相。三角洲前缘亚相大面积分布,分流河道微相、席状砂微相和河口坝微相分布较广,并且油气显示良好。受构造位置的影响,古龙地区葡萄花油层内既存在滞留型非常规油气藏、半滞留型非常规油气藏,也存在常规油气藏,常规油气藏以复合型油气藏为主。油气藏主控因素主要有古流体压力、砂体类型及空间叠置关系、储层类型、构造类型及分布和断层排列及时间演化等。

Gulong area is structurally composed of six tertiary structural units:Puxi nose structure,Xinzhao nose structure,Xinzhan nose structure,Talaha syncline,Gulong syncline and Maoxing syncline,showing a pattern of“alternating convex and concave,low in the west and high in the east”.The sedimentary microfacies division of Putaohua reservoir in Gulong area from a single well was carried out by logging curve response and lithologic assemblage characteristics,and it is found that the sedimentary facies in Putaohua reservoir in Gulong area are mainly composed of the shallow water delta facies and the shallow water lacustrine facies,with the delta facies mainly dominated by delta front subfacies and the lacustrine facies mainly dominated by shore-shallow lake subfacies.Delta front subfacies are widely distributed,distributary channel microfacies,sheet sand microfacies and mouth bar microfacies are also widely distributed,and oil and gas show well.Influenced by tectonic location,there are detained and semi-detained unconventional reservoirs as well as conventional reservoirs in Putaohua reservoir in Gulong area,and the conventional reservoirs are mainly composed of composite reservoirs.The formation of oil and gas reservoirs is controlled by many factors:paleofluid pressure,sand body type and spatial superimposition relationship,reservoir type,structural type and distribution,fault arrangement and time evolution,etc.