Crude oil specification refers to a set of characteristics that define the quality and properties of crude oil. These specifications are important for ensuring that crude oil can be safely transported, refined into various products, and meets regulatory requirements. The common crude oil specifications include:

• API gravity: This refers to the measure of how heavy or light crude oil is, and is determined by its density relative to water. The API gravity scale ranges from less than 10 (very heavy) to more than 50 (very light).
• Sulfur content: Sulfur is a common impurity in crude oil that can cause environmental and health problems when burned. Therefore, the sulfur content in crude oil is often limited to a certain level (usually less than 0.5-3.5% depending on the region and regulations).
• Distillation range: This refers to the range of temperatures at which different components of crude oil evaporate. The distillation range is important for determining the yield and quality of different refined products.
• Pour point: This refers to the lowest temperature at which crude oil will flow, and is important for ensuring that crude oil can be safely transported and stored in cold climates.
• Viscosity: This refers to the resistance of crude oil to flow, and is important for determining the pumping requirements and ease of transportation.
• Asphaltene content: Asphaltenes are complex organic compounds that are a natural component of crude oil. High asphaltene content can lead to fouling and corrosion in refining equipment, so it is often limited to a certain level.
• Water and sediment content: Crude oil can contain water and sediment, which can cause operational problems during transportation and refining. Therefore, the water and sediment content is often limited to a certain level.

Overall, crude oil specification can vary depending on the region and the type of crude oil being produced. Oil producers, refiners, and traders must ensure that crude oil meets the required specifications to ensure safe and efficient transportation and processing.