关键词: 连续轻烃, 储层, 流体性质, 解释方法, 油水关系

Abstract: At present, the conventional gas logging widely used in domestic oil and gas well drilling operations detects only the light hydrocarbon components lower than nC₅, and has limited capacity to identify reservoir oil-bearing and water-bearing properties. Meanwhile, headspace light hydrocarbon analysis is characterized by great artificial error and long analysis period, which is not applicable for on-site gas detection. Therefore, the GW-OLS online light hydrocarbon logging instrument is developed to continuously and quantitatively acquire the light hydrocarbon data and real time and accurately interpret reservoir fluid property, which achieves the rapid detection and effective analysis of 15 light hydrocarbon components of C₁-nC₈ in 60 seconds by applying the dual quantitative control on drilling fluid extraction and light hydrocarbon component detection, as well as parallel connection design of double capillary columns. In the aspect of reservoir fluid property interpretation, the characteristic chromatogram shape of light hydrocarbon with various reservoir fluid properties is determined, and the online light hydrocarbon chromatogram method is developed which is confirmed by single layer well test results; The oil index-water index interpretation chart is established based on the light hydrocarbon parameters distribution of different reservoir fluids; The online light hydrocarbon multi parameter curve matching method is developed to identify gas layer, oil layer, and water layer by analyzing curve variation characteristics of key parameters such as Σ(C₁-nC₅ ), Σ(nC₆-nC₈ ), and Σ(BZ+TOL). Field application in Liaohe, Jidong, and Changqing oil fields indicates that the online light hydrocarbon analysis method enables to continuously and rapidly detect the light hydrocarbon and interpret fluid property on drilling fluid samples, which plays an important role in fluid property interpretation of low resistivity and tight reservoir, oil-water contact identification of complicated reservoir, and water-bearing property evaluation in condensate oil reservoir, showing promising application prospect.