Since it was introduced some years ago, Conductor Supported Platform (CSP) has been widely utilized as one of the cost-effective solutions for developing Oil and Gas marginal fields. However, cost efficiency of this system compared to conventional jacket system is still debatable among the stakeholders due to lack of real experience based studies that address the constraints and limitations of the system.
This paper addresses some constraints and concerns that should be taken into consideration when adopting the CSP system, these constraints and concerns are based on real experience, which started from the engineering phase up to the installation phase of one the projects that involved two wellhead platforms having the same topside facilities configuration, the substructure of one platform was CSP system while the other one was decided to be conventional jacket. The selected development plan allowed the opportunity to analyse the CSP system and evaluate it against the conventional one.
The cost efficiency of the CSP system was found sensitive to many parameters, mainly the topside weight and extra offshore work inherent in this system, although the advantage of being installation by rig which cuts down the installation cost, these parameters should be thoroughly investigated in feasibility studies involving this system as one of the evaluated options.
The international codes and recommended practices should address some design requirements specifically for this type of structures such as the effect of subsequent drilling on the pile capacity and consideration of threaded connection in the pile installation.
A case study based on real experience, which started from the early engineering phase up to the installation phase of two wellhead platforms (NAO & HH) in the same water depth, the two platforms have the same topside facilities configuration, NAO is a conductor supported platform whilst HH-due to the development plan constraints- was decided to be conventional jacket platform, the CSP system was deeply analysed and compared to the conventional one.
For the sake of objectivity, the comparative study has been based on preselected factors, these factors were selected based on their impact on both cost and schedule of the field development execution, the selected factors are: the engineering of the platform, substructure size, topside size, foundation piles and offshore installation operations.
