Publications

PHE ONWJ has Zulu offshore complex which contributes 3000 BOPD of oil with major potential and undeveloped reserves. It has been producing highly viscous oil, accompanied with high water cut. The liquid phase is delivered in a subsea pipeline for more than 70 km lengths. In terms of flow assurance, the high viscous oil has led to significantly high backpressure. In addition to that, it has also led to unstable liquid flowing from Zulu to receiving facilities since the water and oil are not coherently arrived at the same time. The oil tends to spend much longer traveling time than water. This water-oil slug phenomenon creates some complexity to operability and daily production measurement. In order to suppress the water-oil slug effect, chemical is continuously injected at Zulu. The chemical is able to create water-oil emulsion (oil dispersed in water) so that the velocity of the oil will be more uniform with water velocity. The objective of this research is to get information of minimum water cut that should be maintained to prevent high backpressure and for chemical effectiveness. Other than that, the result is also intended to provide estimation of traveling time difference between water and oil so that the cycle of production measurement can be estimated. The methodology is using Flow Simulation Software which utilizes the actual field data recording and latest laboratory test. Simulation results have concluded that water cut should be maintained to be more than 80%. Less water cut will lead to high backpressure. In fact, the 60% water cut will be the emulsion inversion point of Zulu liquid which resulting to highest backpressure impact. In terms of no chemical injected, the oil has more than one day traveling time delay from water. These results will be used in Zulu operating philosophy and envelope.