Logistic Considerations for Safe Execution of Offshore Chemical EOR Projects

Abstract

Chemical EOR technologies used offshore can either be short term reservoir conformance treatments such as Marcit Gels for near-wellbore and BrightWater® for in-depth permeability modifications or long term floods such as mobility control improvements utilizing polymers (latex emulsion or powder). Each offshore EOR technology has significant logistical challenges for successful implementation that ultimately impacts the oil recovery performance. This paper will present a project management plan and logistics using existing offshore facilities, which needs to be considered well in advance of project execution for a successful field implementation for both conformance and mobility control programs. Synthetic polyacrylamides for offshore mobility control applications are limited in practice but interest in offshore applications is increasing rapidly. Polyacrylamides are commercially available in two forms, latex emulsion (liquid) and powder. Each product form has unique benefits and challenges for effective field execution that will be discussed here. The project execution management plan encompasses global supply chain activities (logistics, imports, regulatory) as well as design, construction, and installation of custom facilities. In addition, field execution requires detailed project management including safety and HazID visits, pre-job site visits, pumping services, and surveillance programs. This management plan can be furhter complicated by the type of completion (i.e., dry or wet tree), chemical tie-in location to water injection, neat or slipstream chemical injection, deck space for injection equipment and chemical base tanks, hydration or inversion equipment, and size of transport vessel for chemical transfer offshore. Offshore EOR projects are not generally planned during initial field development. Rather, EOR projects are considered add-on technologies that have to fit existing facilities and operations. This add-on approach increases the complexity and risks of EOR projects and Offshore Operations. Lessons learned and some tools that we have utilized to plan and implement offshore chemical EOR projects are discussed.

Development and Application of Chemical EOR Technologies in China Offshore Oil Fields

“…Heavy oil accounts for 85% of the oil reserves in Bohai oil field, and the main development bottlenecks of these heavy oil fields are high crude oil viscosity, strong reservoir heterogeneity, and poor water drive efficiency. In particular, the viscosity of underground crude oil in some heavy oil reservoirs reaches 200-700 mPa s, and their recovery factor from traditional water flooding could only reach about 12% [5][6][7][8][9]. It could be seen that the research and application of enhanced oil recovery technology in offshore heavy oil reservoirs are of great significance for the stable production and economic efficient development of Bohai oil field.…”

“…6. There is a big difference between offshore oil field and onshore ones in development model and polymer injection timing, so it is necessary to establish evaluation methods and standard for offshore polymer flooding performance [5][6][7][8][9].…”