海上复杂气藏储量品质评价及应用

Reserves quality evaluation and application for complex gas reservoirs in the offshore area

东海盆地西湖凹陷天然气储量规模较大,但气藏类型复杂,不同气藏物性、储量规模、驱动类型差异大,要实现气藏的经济有效开发,需对气藏储量品质进行分类评价。以西湖凹陷平北区典型气藏为研究对象,以经济效益为核心评价指标,结合动、静态特征进行储量品质评价分类,建立储量品质与物性、饱和度、地质储量规模、驱动类型的关系式。研究表明:①根据生产动态特征和经济效益,可以将气藏分为四类,对应4种储量品质类型;②基于经济效益建立了一套多参数综合的储量品质评价方法,通过打分可以对各个气藏储量品质进行排序;③效益较好的Ⅰ类和Ⅳ气藏可以优先单独开发,效益较差的Ⅲ类Ⅳ类气藏,建议兼顾动用或者小成本侧钻等方式开发。本次研究将储量品质分类从定性描述提升到定量描述阶段,为海上复杂气藏合理、经济开发提供了依据。

Gas reservoirs in the East China Sea Basin are characterized by their complexity,strong heterogeneity,and large differences in productivity.Even though their reserve scale is large,it is necessary to evaluate the reserve quality for long-term stable production and efficient development.To this end,this study considered typical gas reservoirs in pH area of the West Lake sag as the research object to determine the relationship between reserve quality,physical properties,water saturation,drive type,reserve scale,and the economic performance and key evaluation index,combined with the dynamic and static characteristics.The following results were obtained:(1)according to their dynamic production characteristics and economic performance,gas wells are classified into four reserve types.(2)A set of multi-parameter comprehensive reserve quality evaluation methods was established,and the reserve quality of each gas reservoir was ranked by scoring.(3)Class I and IV gas reservoirs with good benefits should be developed independently with priority,while Class III and IV gas reservoirs with poor benefits should be recommended to be developed considering production or low-cost sidetracking.The results promote the classification of reserve quality from qualitative to quantitative description and provide a base for the reasonable and economic development of offshore complex gas reservoirs.