海上废弃气藏改建地下储气库可行性——以琼东南盆地H气田为例

Feasibility of rebuilding abandoned offshore gas reservoir into underground gas storage:Case study of H gas field in Qiongdongnan Basin

目前离岸远、水深较深的海上废弃气藏改建地下储气库的研究尚处于起步阶段。为此,以琼东南盆地H气田岩性气藏为例,以气藏构造特征、密封性评价、储层特征及气藏特征等静态特征研究为基础,结合气藏开发过程中产能评价、动储量评价、连通性分析研究,开展储气库库容参数、注采能力、工作气量、井数及井网等储气库运行参数设计论证,最后以数值模拟为手段,依据设计注采方案,模拟储气库运行指标。分析及模拟结果表明:(1)该区块是一个圈闭封闭性好,储层内部连通,属于高渗—特高渗气藏,圈闭内充满气,无可动水的常压高温岩性气藏,区块储气规模大,产能高,不产地层水,低含凝析油;(2)储气库运行压力介于23~34.5 MPa之间,库容量75.1×10^(8)m^(3),工作气量26.1×^(8)m^(3),注采井数仅需10口,最低外输压力15.3 MPa,区块日均采气量2094×10^(4)m^(3),调峰日采气量达3200×10^(4)m^(3)。结合海上配套工艺技术,认为其设计井数少、工作气量大、外输压力大,与国内已运行的陆地储气库地质气藏条件相比,H气田非常适合建设地下储气库。

At present,the research on transforming offshore abandoned gas reservoir into underground gas storage is still in its infancy.Taking the lithologic gas reservoir of H gas field in Qiongdongnan Basin as an example,based on the study of static characteristics such as gas reservoir structural characteristics,sealing evaluation,reservoir characteristics and gas reservoir characteristics,combined with productivity evaluation,dynamic reserve evaluation,dynamic reserve evaluation and so on in the process of gas reservoir development,connectivity analysis and research are performed to carry out the design and demonstration of gas storage operation parameters such as storage capacity parameters,injection production capacity,working gas volume,number of wells and well pattern.Finally,numerical simulation is used to simulate the operation indexes of gas storage according to the designed injection production scheme.The analysis and simulation results show that:(1)The block is a lithologic gas reservoir with good sealing performance,internal connectivity,high permeability and ultra-high permeability,full of gas and no movable water;in addition,the block has large gas storage scale,high productivity,no formation water and low condensate content.(2)The operation pressure of the gas storage is 23-34.5 MPa,and the storage capacity is 75.1×10^(8)m^(3),working gas volume 26.1×10^(8)m^(3),only 10 injection and production wells are needed,the minimum export pressure is 15.3 MPa,and the average daily gas production of the block is 2 094×10^(4)m^(3),peak shaving daily gas production reached 3 200×10^(4)m^(3).Combined with the understanding of offshore supporting process technology,it is concluded that h gas field is very suitable for the construction of underground gas storage compared with the geological conditions of domestic onshore gas storage.