Because petroleum industry complexity is increasing exponentially with time, many management problems cannot be solved by traditional methods. An objective, total system analysis may help management make the best decision.
The use of total system analysis to solve complex management problems is new. Because it is new it is not well defined and not well understood by many managers. Simply put, it is the analysis of a total system, but this means nothing unless we know what a total system is. There are many kinds of systems: natural, physical, abstract, man-made, military and industrial, to name a few. But for convenience we will limit this paper to business systems. All of our examples will be from the oil industry.
We use the following terms to define a total system.
Total System an on-going process composed of a set of entities with given relationships between the entities and their attributes and with the objective of producing a specific result, given a number of constraints.
Subsystem a component process of a total system. Subsystems may be further subdivided into more detailed subsystems.
Entity a class of objects described by a fixed collection of parameters called attributes. Entities "exist" and have numerical values that describe the state of the system.
Attribute property of an entity -the external manifestation of the way the entity is known. Attributes "describe".
Set a collection of individual entities.
Relationship bonds that link entities and attributes in the system process.
State the complete description of a system's entities, attributes, and relationships at a point in time. System dynamics are represented by changes of state.
Events a change of state that occurs instantaneously at a distinct point in time.
Environment the set of all entities that can influence the system. For practical reasons environments are arbitrarily limited by specified boundaries or otherwise they might be infinite.
Constraint a limitation on the operation of a system.
We can illustrate a total system by a refinery containing such subsystems as an atmospheric distillation unit, a vacuum distillation unit, and a catalytic cracking unit. Some entities of the subsystem "atmospheric distillation unit" are towers, a furnace, heat exchangers, pumps and motors. Attributes of the entity "pumps" are horsepower, rpm and up-time-ratio. A relationship between the furnace and tower T-1 might be, "When the fuel rate to the furnace is increased from 700 to 770 B/D, the inlet temperature of the tower feedstock is increased from 734 to 752F." A system constraint might be, "Throughput is limited to 49,000 B/D by the T-1 bottom pumps."
Business systems that hold interest have several common properties.
1. They are large and composed of many entities.