Oil companies spent billions of dollars to get various services necessary for their business. Orders and contracts are awarded. Contractors and service providers got paid for their services. Terms and conditions have to be iron out and agreed upon. Centrifugal pumps used in the operating units have to be purchased from manufacturers. Selection of the right manufacturer will involve both technical and commercial considerations.
Comparison buying is common practice. If engineers deal with the technicalities, buyers will need to look at the commercial terms. Sometimes prices of goods or services are way too expensive to justify the purchase. However, we do not necessarily pick the cheapest thing either. Balancing act needs to come in. Sometimes we need to single source instead of going through multiple bidders to buy something.
Commercial has their own words to describe things. Force majeure is a popular clause to be inserted in contract. This provide the escape in the event things go really bad, things that we cannot reasonably foresee. Buying things from abroad is typical in oil company. There will be tax implications when goods are crossing the borders. Permits and licences from relevant authorities need to be in place. Commercial things like this has be factored into project plan. It can cause unnecessary delay to project installation and start up. Ad valorem is some Latin word that you may find in a contract.