低阻水淹层地化录井识别技术在南海北部A油田的应用

Application of geochemical logging identification technology of low resistivity water⁃flooded zones to A oilfield in the northern South China Sea

在油田开发过程中,常采用注水方式为地层提供能量。由于储层的非均质性,通常物性好、连通性好的层位被快速水淹,剩余油较少,而物性差、连通性差的层位因注入水未波及,则留存较多剩余油。部署调整井开发剩余油需避开水淹层射孔,因此需要对水淹层进行准确识别。通过优选S_(1)、nC_(24)/nC_(29)、∑(C_(1)-C_(5))/∑(C_(1)-C_(9))等地化录井优势参数进行有机组合,建立了基于地化谱图对比识别方法、热蒸发烃气相色谱参数nC24/nC29比值法,以及轻烃组分∑(C_(1)-C_(5))/∑(C_(1)-C_(9))比值与岩石热解S1交会图板法用于低阻水淹层地化录井识别。该技术在南海北部海域A油田的应用表明,水淹层识别符合率达到87.5%,取得了较好的应用效果,为油田开发避开水淹层提供了科学依据。

In the process of oilfield development,water injection is often used to provide energy for the formation.Because of the heterogeneity of the reservoirs,the strata with good physical properties and good connectivity will be generally flooded quickly,resulting in less remaining oil,while the layers with poor physical properties and poor connectivity retain more remaining oil.To develop the remaining oil by deploying adjustment wells,it is necessary to avoid the water⁃flooded zones for perforation,so it is necessary to accurately identify the water⁃flooded zones.By optimizing the dominant parameters of geochemical logging such as S_(1)、nC_(24)/nC_(29)、∑(C_(1)-C_(5))/∑(C_(1)-C_(9)),and combining them organically,the geochemical logging identification method based on geochemical spectrum comparison,the nC_(24)/nC_(29) ratio method of thermal evaporation hydrocarbon gas chromatographic parameters,the light hydrocarbon component∑(C_(1)-C_(5))/∑(C_(1)-C_(9))ratio and the rock pyrolysis S_(1) intersection chart method are established for the geochemical logging identification of low resistivity water⁃flooded zones.The application of the technology to A oilfield in the northern South China Sea shows that the coincidence rate of identifying water⁃flooded zones is 87.5%,and has achieved good application results,which provides a scientific basis for oilfield development to avoid water⁃flooded zones.