济阳坳陷青东凹陷油藏特征及分布规律

Characteristics and distribution of reservoirs in Qingdong Sag,Jiyang Depression

青东凹陷是济阳坳陷勘探程度较低地区,同时也是近期勘探重点和热点地区。综合地质、地震和分析化验等资料,对该区油藏特征和分布规律进行了系统研究。结果表明,该区发育了咸化低熟、咸化成熟、正常成熟3类原油。咸化低熟、咸化成熟原油都来自于沙四段烃源岩,正常成熟原油来源于沙三段烃源岩。该区具有馆陶末期和明化镇期—第四纪2期成藏的特点,晚期充注范围较大,为主要成藏期。青东凹陷发育了构造、地层、岩性和复合类4种油藏类型。纵向上,油气主要分布于沙四上亚段;平面上,青东凹陷共发育东北部走滑断裂构造带、西北部斜坡构造带、中央地垒构造带和青东—青南过渡构造带4个油气富集区带。西北部斜坡构造带可作为近期海上现实的重点勘探区域。

Locating in the Jiyang Depression, the Qingdong Sag, with low exploration degree, is a recent explo-ration focus. Reservoir characteristics and distribution regularities were studied based on geological, seismic and chemical data. The results showed that, 3 types of crude oils developed in the study area, including salty low-mature, salty mature and normal-mature ones. The salty low-mature and salty mature crude oils both originated from source rocks in the 4th member of the Shahejie Formation, and the normal-mature crude oils originated from source rocks in the 3rd member of the Shahejie Formation. The process of petroleum accumulation was divided in-to 2 major phases：the first one at the end of Guantao and the second one from Minghuazhen to Quaternary. Dur-ing the second phase, hydrocarbon charging was widespread, and it was the main phase for accumulation. 4 types of reservoirs generated in the Qingdong Sag, including structural, stratigraphic, lithologic and composite ones. Vertically, oil and gas mainly distributed in the upper section of the 4th member of the Shahejie Formation. On plane chart, oil and gas are abundant in the northeastern strike-slip fault zone, the northwestern slope belt, the central horst belt and the Qingdong-Qingnan transition belt, among which the northwestern slope belt was regar-ded as the key target for future exploration.