In recent years, offshore exploration efforts were extended into deeper and deeper water located further and further from shore in less and less hospitable enviomments. Consequently, not all of the fields discovered were feasible – economically and/or technologically – to develop and to produce using established methods. To improve this situation, a transportation system was developed which allowed crude-oil tankers to be loaded via a single-point mooring buoy, SPM, located near a producing platform – thus, the need for expensive, deep-water pipelines was reduced.
Despite this innovation plus additional improvements, many discovered fields still remain in the marginal category for conventional evaluation. Therefore, it is necessary to optimize the total production/storage/transport system before consistently rational decisions can be made regarding field development.
This paper presents a method for predicting the behavior of an SPM system – considering the effects of tanker size, number of tankers, deviations from schedule, weather, loading rate, storage capacity and production rate( The primary descriptive factor determined by this approach is the operating efficiency of the storage/transport system which constitutes a constraint on the production system. Since the production system can be optimized on an economic basis while recognizing well productivity and reservoir performance, it is possible to specify the optimal configuration for the entire system – and to assure the compatibility of the upstream and downstream elements.
The analysis of the SPM system, a procedure for optimizing the production system and a discussion of the upstream-downstream coupling – and its effect on the optimization of the entire system – are presented in this paper. A simple, but complete, example is also included.