Interpretation Method Of Water Flooded Layers Of Saturated Hydrocarbon And Light Hydrocarbon Mud Logging In Jiangsu Oilfield

Jiangsu oilfield has stepped into a high water cut stage under years of water flood development, and there are great differences in the use of various types of reservoirs, so the evaluation of water flooded layers has become more and more important. Compared with well logging technology, mud logging technology is based on the analysis of rock samples, and it is not affected by water salinity and reservoir heterogeneity. Mud logging technology can obtain lithology, physical properties, oiliness of reservoirs directly, and it has obvious advantages in qualitative identification of water flooding grades of reservoirs.This paper is according to the reservoir characteristics of ZW oilfield, WZ oilfield and GJ Oilfield, and mud logging physical experiment of water flooded layers is designed, and non-steady state method of oil displacing water is used to making 81 oil samples of different water production rate, then saturated hydrocarbon parameters and light hydrocarbon parameters of core samples can be obtained. Through the analysis of the saturation and light hydrocarbon parameters with the variation of water production rate, saturated hydrocarbon peak shapes change from normal to flat with the increase of water production rate, and peak intensity, amount of peaks and peak area of light hydrocarbon component also decreases. Based on the feature of the spectrum, the water flooding parameters are analyzed and extracted. Saturated hydrocarbon total area decreases, and the parameters of Pr+Ph and Pr/nC17 increase with the increase of water production rate; Light hydrocarbon total area and amount of peaks decrease with the increase of water production rate. Based on the experimental analysis, Pr/nC17, Pr+Ph and saturated hydrocarbon total area are selected to be the sensitive parameters of water flooded layers in saturated hydrocarbon mud logging technology, and light hydrocarbon total area and amount of peaks are selected to be the sensitive parameters of light hydrocarbon technology. Then, sidewall cores of oil testing wells and brought-in wells are used to build qualitative identification charts of water flooded zones with the plot of Pr/nC17 versus total area and the plot of Pr+Ph versus total area in saturated hydrocarbon mud logging technology, and the plot of amount of peaks versus total area is built in light hydrocarbon technology, and the division standard of these charts is showed, too. These charts can distinguish oil/weak, middle and high flooded layers, and the accuracy of the charts is over 85%. Based on the research above, saturated hydrocarbon technology and geochemical pyrolysis technology are combined to build chart of identification of flooded grades, and the charts can distinguish oil/weak, middle and high flooded layers, and the accuracy of the charts is over 90%. Then, a comprehensive evaluation technique for water flooded layers in Jiangsu oilfield is built. The method mentioned in this paper is applied to actual well data, the result shows that the identification results of charts are consistent with the test results, and the comprehensive evaluation technique for water flooded layers mentioned in this paper can be used in Jiangsu oilfield.