地化录井技术在渤中19-6构造潜山储集层凝析气层识别中的应用效果分析

Application of geochemical logging technology in identification of condensate gas-bearing formation in buried hill reservoir of BZ 19-6 structure

位于渤中凹陷西南部的渤中19-6构造在潜山已发现渤海湾盆地最大的凝析气田,在录井过程中,由于荧光显示微弱,快速准确识别储集层含油气性难度很大,通过地化录井资料统计分析,总结出适用于该构造凝析气藏准确识别和评价的方法。根据轻烃丰度、∑(C 6-C 9)和热解气相色谱∑nC 21-/∑nC 22+等参数建立交会图板,可有效识别太古界变质岩潜山储集层凝析气层、湿气层与干层,利用岩石热解P g、(S 0+S 1)/S 2、地化亮点、热解气相色谱谱图形态识别凝析气层与湿气层。实践证明,地化录井技术有效地解决了储集层含气性判识的难题,为该凹陷储集层的录井解释评价提供了可靠的技术手段,为下步选择录井方案及决策提供了参考依据。

BZ 19-6 structure is located in the southwest of Bozhong sag.The largest condensate gas field in Bohai Bay Basin has been discovered in the buried hill of this structure.During mud logging,it is difficult to quickly and accurately identify the hydrocarbon bearing property of reservoir because of the weak fluorescence show.Based on the statistical analysis of geochemical logging data,the methods suitable for accurate identification and evaluation of condensate gas reservoirs in this structure were summarized.According to the light hydrocarbon abundance,∑(C 6-C 9),and∑n C 21-/∑nC 22+of pyrolysis gas chromatography,the crossplot charts were established,they can effectively identify condensate gas-bearing formation,wet gas layer and dry layer of buried hill reservoir of Archean metamorphic rocks.The condensate gas-bearing formation and wet gas layer are identified by P g and(S 0+S 1)/S 2 of rock pyrolysis,geochemical bright spot and pyrolysis gas chromatography spectrogram pattern.The practice has proved that geochemical logging technology effectively solves the problem of reservoir gas-bearing identification,provides a reliable technical means for mud logging interpretation and evaluation of the reservoirs in the sag,and provides a reference for the next selection of mud logging scheme and decision-making.