National Assessment of Oil and Gas Project - Sacramento Basin Province (009) Assessment Units

The Assessment Unit is the fundamental unit used in the National Assessment Project for the assessment of undiscovered oil and gas resources. The Assessment Unit is defined within the context of the higher-level Total Petroleum System. The Assessment Unit is shown here as a geographic boundary interpreted, defined, and mapped by the geologist responsible for the province and incorporates a set of known or postulated oil and (or) gas accumulations sharing similar geologic, geographic, and temporal properties within the Total Petroleum System, such as source rock, timing, migration pathways, trapping mechanism, and hydrocarbon type. The Assessment Unit boundary is defined geologically as the limits of the geologic elements that define the Assessment Unit, such as limits of reservoir rock, geologic structures, source rock, and seal lithologies. The only exceptions to this are Assessment Units that border the Federal-State water boundary. In these cases, the Federal-State water boundary forms part of the Assessment Unit boundary.

评价单元（Assessment Unit）是未发现油气资源评价国家项目（National Assessment Project）中用于实施未发现油气资源评价工作的基本单元。评价单元是在更高层级的含油气系统（Total Petroleum System）框架下进行定义的。本次展示的评价单元为由辖区责任地质学家解释、界定并绘制的地理边界，其涵盖该含油气系统内一组地质、地理与时间属性相似的已知或推测油气藏，具备烃源岩、成藏期次、运移路径、圈闭机制以及烃类类型等共性特征。评价单元边界在地质学上被定义为构成该单元的各类地质要素的分布范围，例如储集岩边界、地质构造范围、烃源岩范围以及盖层岩性边界。唯一的例外情况为与联邦-州水域边界接壤的评价单元，此类情形下，联邦-州水域边界将作为评价单元边界的组成部分。