川口油田延长组沉积古地理研究及其数字化方法的实现

【作者】 陈杰；

【导师】 崔智林；

【作者基本信息】 西北大学 ， 古生物学与地层学， 2003， 硕士

【摘要】 鄂尔多斯盆地是我国十分重要的中生代内陆盆地，厚逾千米的上三叠统延长组是区内主要的含油岩系，其岩性特征表现为河流-湖泊相的陆相沉积。根据岩性特点以及含油性本文将川口油田延长组分成5个岩性段和10油层组，其中根据岩性标志将长6油层组进一步划分为长6~1、长6~2、长6~3与长6~4，并根据时间岩性标志在等时地层格架内进行了地层对比。 通过古生物、沉积结构与构造、沉积韵律、沉积厚度与沉积旋回特征和测井相分析等，在延长组中识别出河流、三角洲、湖泊沉积体系，以及长6油层组的沉积微相，并对长6油层组各小层的沉积微相进行了精细描述，反演出其古地理的演化历程。研究表明，沉积微相的平面展布规律控制了储集层的分布特征，而储集相带的分布控制了油气的富集。 在区域沉积背景的墓础上，结合地质相特征与测井相分析，对地层厚度、砂体厚度以及砂地比(砂岩含量)等在平面上的分布规律进行了综合分析，并结合沉积序列与沉积特征等，判别了沉积微相在平面上的分布格局，恢复出长6油层组各沉积期的古地理环境。 在局部地区尝试运用数字化的方法对长6油层组沉积微相进行了定量描述，实现了数字化沉积微相研究。其理论依据是：等时地层单元内，由某一地质历史时期所形成地层厚度与沉积时间具有一一对应的关系，据此对某一等时界面上的沉积特征进行数字化的描述。数字化沉积微相的方法在油田中为提高油气勘探程度与开发提供了新的思路。更多还原

【Abstract】 The Ordos basin is an important terrestrial basin that came into being during Mesozoic in our country. The Yanchang Formation more than one kilometer in thickness is the main oil-bearing beds in the study area. Its lithology characteristic indicated that the formation was deposited in fluvial-lacustrine environment. The Yanchang Formation was divided into five lithologic segments and ten oil-bearing packages according to the features of lithology. The Chang-6 oil-bearing beds was subdivided into Chang-61, Chang-62, Chang-63 and Chang-64. And the time correlation in sequence stratigraphic unit was realized according to the temporal rock maker.The fluvial, delta, and lacustrine sedimentary system was realized according to the analysis of the fossils, sedimentary structure, sedimentary cycle, rhythmic bedding and other criteria in the Yanchang Formation. The sedimentary microfacies of the Chang-6 oil-bearing beds was identified through its fine description, and the evolution of palaeogeography was revealed. My research also indicates that the sedimentary microfacies of the Chang-6 oil-bearing beds controls the characteristic of the reservoir distribution, and the reservoir distribution controls the oil enrichment mainly.On the basis of areal geological background, the distribution pattern of sedimentary microfacies in the Chang-6 oil-bearing beds was distinguished and the palaeogeographic environment was reconstructed by the analysis of geology facies, logging facies, stratum thickness, sandstone thickness and sandstone percent and other sedimentary characteristic.The method of digital sedimentary microfacies was applied in part of the research area for the first time, and acquired the satisfying effect. The digital sedimentary microfacies realized the description of the sedimentary evolution from Chang-62 to Chang-61. The principle of this method is that we can regard the time stratum unit as three-dimension sedimentary body, when the stratum formed in a certain geological epoch, there was a definite proportion relationship between the thickness of the stratum and the thickness of the time stratum unit. The method realized the transformation between the sedimentary thickness and sedimentary time. The method of digital sedimentary microfacies offers new conception of exploration and development in oil field.更多还原