Discussion On The Application Of Medium And Long Term Ensemble Forecast In Avoiding Typhoon Of Deepwater Drilling Platform

With the decrease of oil resources on land and offshore,the petroleum development of China will gradually turn to the deep waters of the South China Sea that is rich in resources.The oil and gas exploitation of deepwater drilling in the South China Sea requires particular attention to the challenges of typhoons because the typhoon in the South China Sea is gusty,frequent and changeable in intensity path,etc.Once the typhoon comes,it takes more time to deal with the borehole and to recover the BOP stack and the emergency time of withdrawing the deepwater drilling platform is more pressing than that of offshore drilling.Therefore,there is an urgent need for a more accurate medium and long term typhoon prediction fordrilling platforms in the deep waters of the South China Sea.In order to explore a better forecasting method from the numerical forecast that can apply to deepwater drilling platforms in the South China Sea,this article compares the effects of different time interpolation algorithms on typhoon numerical forecasting and selects the appropriate algorithm for long-term numerical typhoon forecast data for fine treatment by choosing the collection of the ECMWF(European Centre for Medium-Range Weather Forecasts)of typhoon numerical forecast products as the analysis target.On that basis,the long-term(up to 32 days)typhoon forecast deviation of westerly,landing-type and anomalous path typhoons in the Soth China Sea will be calculated by the equal weight average method.And then the diviation will be analyzed and corrected accordinug to the statistical results according which giving deepwater drilling platforms more typhoon forecasts in advance by revising long-term numerical model forecast products will become possible.Finally,this paper will compare the observation data of typhoon paths in China and the determination of a forecasting agency Forecast data and ECMWF mid-and long-term typhoon ensemble forecast data by taking the example that a deepwater drilling platform of China avoided the 1724 tropical storm "Haikui"during the operation of a deepwater well site in southeast of Hainan in early November,2017.In addition,this paper will discuss the traditional climatic typhoon prediction,numerical deterministic and ensemble forecasts at several critical typhoon-avoidance decision points-in-time,and the differences between these results and the actual situation.Comparative analysis suggests that the medium-to-long range ensemble forecasting performs the best,giving warning much earlier,and closest to the actual observation.Finally,combining the revised long-term(up to 32 days)aggregate forecast and mid-and long-term typhoon aggregate forecast,through the actual case of avoiding the "Haikui" and "Ewiniar" typhoon,this paper further verifies the actual value of the revised long-term numerical forecast in maritime safety assurance,and discusses the important role played by refined integration/probabilistic meteorological support in deepwater-drilling typhoon-avoidance and summarizes the valuable experiences.