Applying Log-Constrained Seismic Inversion Technique To Optimize the Development of an Offshore Marginal Oil Field

Abstract

Abstract Chengdao Oilfields is located in Bohai Bay of East China. The Oil-bearing sandstones are fluvial sediments of Tertiary upper Guantao Member. The sand bodies change rapidly both in thickness and lithology. It results in quite different productivity between the wells. Development of the oilfield needs high investment with low economic efficiency, and will be full of risks. In order to predict the distribution of the sandbodies and its petrophysical properties to optimize the well locations, a stratigraphic research using log-constrained seismic inversion technique was conducted. By means of improving the processing methods, the stratigraphic wave impedance data with high resolution and accuracy were obtained. According to the relationship between the wave impedance data and the reservoir properties, the lateral changes of the reservoir and it's petrophysical properties were disclosed. Based on this results, 86 wells have been successfully drilled in areas with thick reservoir. Comparing with expected number and thickness of the layers in individual wells, the well numbers with errors less than 20% are 74 (86%) and 67 (78%) respectively. It makes the previous marginal oilfield to be a cost effective recoverable oilfield. This paper presents the research concerned and it's results. P. 557