Design and Experimental Study of New-Type Supercritical Steam and Flue Gas Generator for Offshore Oilfield

Liu, Yigang (CNOOC China Ltd, Tianjin Branch) | Zou, Jian (CNOOC China Ltd, Tianjin Branch) | Han, Xiaodong (CNOOC China Ltd, Tianjin Branch) | Wang, Qiuxia (CNOOC China Ltd, Tianjin Branch) | Zhang, Hua (CNOOC China Ltd, Tianjin Branch) | Liu, Hao (CNOOC China Ltd, Tianjin Branch) | Wang, Hongyu (CNOOC China Ltd, Tianjin Branch) | Wu, Wenwei (China University of Petroleum, Beijing) | Wang, Cheng (China University of Petroleum, Beijing)



Steam and flue gas stimulation technology has been applied for heavy oil exploitation in Bohai Oilfield for almost ten years. For the special fuel and water requirement of the current thermal generator, large amount of diesel and desalinated seawater are needed during the thermal injection process. Besides, treatment of the produced oily wastewater on the platform becomes more difficult as the oil output increases.

Aimed at solving the existing problems and taking the advantage of characteristics of the supercritical water, a new type of supercritical steam and flue gas generator for offshore oilfield is proposed and studied. The newly proposed generator is mainly consisted of two sections, which are the supercritical water gasification reactor and combustion reactor, respectively. The produced oily wastewater could be directly used for steam generation. A series of experiments are carried out for its feasibility research and structure optimization.

A prototype of the generator is made for indoor experiment. During the gasification process, wastewater and the organic material mixed inside is placed in the supercritical conditions in the gasification reactor whose temperature and pressure are about 600-700°C and 23MPa, respectively. And the reaction product would be mainly H2, CO2 and water. Gasification Experiments of both the diesel and oily wastewater are conducted. And the combustion experiment is also conducted and the gasified gas is reacted with O2 under conditions of 25MPa and 500-550°C. Composition of the produced fluid in each experiments are analyzed. Besides, the structure of the generator is also designed and optimized for improving its working efficiency.

The proposed new-type supercritical steam and flue gas generator has the characteristics of high efficiency, waste water treatment and higher temperature and pressure delivery capacity. And there would be a promising perspective for its application on offshore platform.