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柴达木盆地涩北气田为第四系疏松砂岩储层气田,气田构造平缓,储层岩性疏松,气层含气饱和度较低,气水关系复杂。涩北气田的出水模式有边水水侵、泥质隔层内水的窜流、水层水窜流和储层束缚水转化为可动水等。其中,储层束缚水转化为可动水产出是一种新的出水形式。在气田开发过程中,天然气不断采出,地层压力逐步下降,储层在上覆地层压力作用下被压缩,孔隙度降低,地层含水饱和度增加,当储层压力下降到一定程度时,部分束缚水逐步变成可动水产出,从而影响气田生产。根据涩北气田储层地质特征,结合气田出水规律,分析了涩北气田气井出水原因及类型。从开发实验、数据分析入手,建立了储层束缚水变可动水产出预测图版,该图版中储层含水饱和度曲线与束缚水饱和度曲线交点对应的压力即为气藏层内可动水临界出水压力,研究表明随气藏压力下降,气层束缚水可转变为可动水产出。
The Sebei gas field in the Qaidam Basin is Quaternary unconsolidated sandstone reservoir gas field. The structure of the gas field is gentle, the reservoir lithology is loose, the gas-bearing gas saturation is low, and the gas-water relationship is complex. Sebei gas field water outflow patterns have edge water intrusion, the intercepting of water in the mud compartment, water channeling and reservoir bound water into movable water. Among them, the conversion of bound irreducible water into a movable aquifer is a new form of effluent. In the process of gas field development, natural gas is continuously extracted and the formation pressure gradually decreases. The reservoir is compressed under the pressure of the overburden formation, the porosity decreases, and the water saturation of the formation increases. When the reservoir pressure drops to a certain extent, the partial restraint Water has gradually become movable aquatic products, thus affecting gas field production. According to the reservoir geological characteristics of the Sebei gas field and the water law of the gas field, the causes and types of gas wells in the Sebei gas field are analyzed. Starting with the development of experiments and data analysis, a preliminary map of the reservoir bound water was established. The pressure corresponding to the intersection point of the reservoir water saturation curve and the irreducible water saturation curve is the movable water in the reservoir Critical discharge pressure, studies have shown that with the pressure drop of gas reservoirs, bound irreducible water can be converted into a movable aquatic product.