A more thorough explanation:

A certificate of interest is a document that proves ownership in oil and gas production. It shows the percentage or fraction of ownership that a person or company has in the production of oil and gas.

For example, if a company owns 10% of the oil and gas production in a particular well, they would receive a certificate of interest that proves their ownership. This certificate would show that they are entitled to 10% of the profits from the sale of the oil and gas produced from that well.

Another example would be if an individual owns a small percentage of a group of oil wells. They would receive a certificate of interest that shows their ownership in the production of oil and gas from those wells.

These examples illustrate how a certificate of interest is used to prove ownership in oil and gas production.