测井方法识别南八仙油气田N22-N1储层的油气

柴达木盆地南八仙油气田N₂²-N₁油气藏储层分布不稳定，横向上岩性变化大，进行地层对比和细分层工作存在着很大的困难；油气藏无统一的油气水界面和统一的压力系统，油气性质及油气比也存在较大差异，用常规的处理手段和处理程序无法计算和预测储层的产油气比例，导致解释结果符合率低。为此，采用CONGAS凝析油气藏解释评价软件，根据三孔隙测井曲线对天然气的响应特征，通过计算三孔隙测井响应方程，计算出地面条件下的气油比和可动油气密度等参数，将计算的油气饱和度与气油比进行交绘，形成综合测井解释图版。通过对该图版的综合分析，结合储层物性，得到N₂²-N₁油气藏储层油、气、水层的综合定量区分解释标准。应用该标准的综合解释符合率达到94.8%。

Logging identification of oil/gas layers in N22-N1 in the Nanbaxian oil and gas field

The N22-N1 reservoirs in the Nanbaxian oil and gas field of Qaidam basin are featured by in unstable distribution, large lateral variation of lithology, challenging stratigraphic correlation and subdivision. The reservoirs have no unified water/oil/gas contact surface or pressure system, and the oil/gas properties and oil/gas ratio also change greatly, thus conventional processing methods and procedures are not applicable to the calculation and estimation of oil/gas ratio. To solve this problem, we selected CONGAS condensate oil/gas reservoir evaluation software to establish a tri porosity logging response equation based on the tri porosity logging response of natural gas. It was used to calculate the gas/oil ratio and movable hydrocarbon density. The calculated oil/gas saturation and gas/oil ratio were crossplotted to obtain a comprehensive logging interpretation chart. Comprehensive qualitative interpretation criteria for oil, gas and water layers in the N22-N1  reservoirs were defined through comprehensive analysis of the chart and in combination with the physical properties of the reservoirs. The interpretation coincidence rate reaches 94.8 % by using comprehensive qualitative interpretation criteria.