| Gasi oil field, which was developed in 1978, is now in the high water-cut period now. It needs accurate understanding as well as classification about the water.There have been lots of sophisticated logging methods that can be used in new wells' accurate evaluation. However, for these old wells, only open hole well logging is not enough. Further, due to complex geological characteristics of sedimentation and structure, different degree of mineralization, the rule of water flooding is complicated. Moreover, lacking of effective logging data about the water flooded layer makes the explanation of new wells difficult.PNN logging technology conducts evaluation after well logging. It takes the difference of formation capture cross section to identify water flooded layer. Compared with the conventional logging technology, PNN logging is more accurate.The PNN logging technology is combined with the existing logging data of Gasi E3'oilfield in this paper, to analyze the reason why the interpretation accuracy of water flooded layer is relatively lower and to summarize the influence factors of the application of PNN technology. After ruling out the disturbing factors, formation capture cross section is used to calculate the casing saturability and the inversion of electric resistivity. Then combine the PNN logging response with the conventional logging response. Finally, locally suitable qualitative identification method of water flooded layer is got, which including ? curve response, GRPNN response and inversion of electric resistivity, etc. Water saturation is used to calculate the oil displacement efficiency as well as to divide the different level of water flooding. The accuracy of the conclusion is proved by the comparison of the result and the field production data. Draw the combined well profile and ground plan through the conclusion of evaluation to understand the distribution of water flooded layer, and improve the interpretation accuracy of regional water flooded layer. |
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