Suspended solids transport simulation for Siakap North Petai oil and gas platform: Cost-effective and environmentally sustainable offshore disposal of wastes

Abstract

Offshore oil and gas exploration in deep water is more expensive compared to onshore. Strained by current low prices of crude oil, cost rationalization is essential for economic viability of oil and gas exploration offshore. Offshore exploration involves costly activities such as well drilling, well completion and testing as well as installation of flow lines and subsea facilities. Well drilling generates drill cuttings which may be disposed either onshore or offshore. Onshore disposal is not cost-effective and operationally complicated, and should be the option of last resort. More cost-effective offshore disposal of drill cuttings should therefore be utilized if it can be proven to be environmentally sustainable to the marine environment and ecosystems. This research was initiated to assess the environmental sustainability of offshore disposal of drill cuttings by means of model simulations. A critical concern in drill cuttings offshore disposal is the suspended solids (SS) created that might pose adverse impact to marine ecosystems. This paper presents the results of a simulation study by means of AQUASEA, developed by Vatnaskil Consulting Engineers, on the transport and fact of SS at an offshore oil and gas exploration platform in Siakap North Petai Field, off Sabah in the South China Sea. Simulated SS plumes subject to the dominant semi-diurnal tidal flows in the South China Sea and local eddies will be presented. Simulation results indicate that this offshore disposal of drill cuttings is environmentally sustainable at the current rates of well drilling.