LW3-1 gas field is located approximately 310 km southeast of Hong Kong in water depths ranging from 1300 to 1500m. It was first discovered in August 2006. The development of this field aims to achieve optimum recovery factor by concurrent depletion strategy and meet the peak gas nomination of downstream demand. This paper is to present the philosophy and methods used in the overall development plan and the practices during the field production period.
LW3-1 has developed 3 main sands with 9 subsea directional wells including two appraisal wells. Each well has been perforated in single sand to avoid interference among the sands through the wellbore. Balanced depletion strategy has been used to optimize ultimate recovery factor, which was estimated by reservoir simulation, analogue and empirical methods for this field. Before all the wells were put on line, the clean-up operation was carried out to determine the well deliverability after completion. LW3-1 first gas was on March 31, 2014, almost 8 years after its discovery.
The reservoir and production teams have worked closely to generate and implement the initial start-up procedures to meet flow assurance and safety requirements. In order to monitor reservoir and production performance, two down-hole gauges and wet gas flow-meters were installed in each well. A real time production surveillance system and database have been also set up to help efficient reservoir management. The actual reservoir and production data so far has met the expectations in the overall development plan. Good communications within Sand 1 and between Sand 2 and Sand 3 have been observed.
LW3-1 is the first deepwater gas field in China and this paper provides valuable information and experiences of the reservoir management and production monitoring of this field.