The pulsed neutron-neutron plus logging is applied in cased wells in Tainan gas field to evaluate the water flooding status of the reservoir after water invasion. The effects of main influencing factors such as fluid accumulation in the wellbore, enhanced radioactivity in the flooded zone, and changes in casing size on pulsed neutron-neutron plus logging curves are investigated and correction methods are proposed. A set of quantitative interpretation method of reservoir saturation has been formed based on a stepwise stripping method and SIGMA - RATGN crossplot method. The evaluation criteria of water flooding levels of gas reservoir in Tainan gas field is established further more according to the oil displacement efficiency, water saturation and corrected thermal neutron capture section value. The new method effectively improves the accuracy of gas reservoir identification and reservoir saturation interpretation, and the coincidence rate of water flooding level evaluation reaches 92.3％, providing technical support for stable production of Tainan gas field.
关键词
台南气田/脉冲中子-中子测井/水淹层/饱和度/解释模型/储层评价
Key words
Tainan gas field/pulsed neutron-neutron plus logging/water flooded layer/saturation/interpretation model/reservoir evaluation
维普
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