东营凹陷北部永921地区渐新世沙三段和沙四段扇三角洲沉积

东营凹陷北部永 92 1地区沙三段和沙四段广泛发育扇三角洲沉积 ,从中可以识别出砾岩相、砂岩相、粉砂岩泥岩相和泥岩相等 4种岩相类型。根据本区的沉积特征 ,扇三角洲沉积是一个典型的退积型层序 ,沉积边界和扇三角洲砂砾岩体的分布主要受湖平面变化的影响。该区湖相暗色泥岩为主要的烃源岩和盖层 ,扇三角洲前缘的砂砾岩体是较好的储集层。本区生、储、盖发育齐全 ,有着良好的勘探开发前景

FAN DELTA DEPOSITS OF SHA-3 AND SHA-4 MEMBERS AT OLIGOCENE SHAHEJIE FORMATION AT YONG 921 AREA IN THE NORTH OF DONGYING DEPRESSION

Fan delta deposits is widely developed in Sha\|3 and Sha\|4 members of Oligocene Shahejie formation at Yong 921 area in the north of Dongying depression. Four types of facies are recognized according to lithology, texture and structures of rocks, including conglomerate facies, sand\|stone facies, siltstone\|mudstone facies and mudstone facies. Based on analyses of sedimentary characteristics, it is considered that fan delta is a typical set of retrograding ingression lacustrine sequence. The sedimentary boundary and distribution of sandy conglomerate are controlled by the lake level fluctuation in this area, and a complete source\|reservoir\|cap rock assemblage is developed. Dark mudstone of lake containes hydrocarbon source rocks and good cover rock, and sandy conglomerate bodies of fan delta front are good reservoirs. It is proved that fan delta deposits in Sha\|3 and Sha\|4 members have good potentials for oil and gas exploration.