Automatic Production and Seismic History Matching by Updating Locally and by Geological Environment in the Nelson Field

Abstract

Abstract It is becoming common to use automatic or assisted techniques for history matching of oil and gas reservoirs. These techniques are complicated by the need to update the properties of the model that are linked to the geological representation of the reservoir but also affect the misfit between observations and prediction. In this work we compare updating of regional properties for the former while updating local properties to satisfy the latter. We apply an automatic history matching approach to the Nelson field, a channelized turbidite reservoir, in order to better match the production rates of oil and water by well. We also integrate time lapse seismic data and we compare the result with production history matching output. We control the shale distribution within and between the major channel complexes by updating on the basis of geological environment variables which are regionally distributed. We compare this approach with more local updating by using pilot points with Kriginig. By updating the reservoir properties by environment variables we reduce the total production history match misfit by 22% for six years of data. We also improve the forecast of a further three years by 20%. By updating locally after by environment, this improvement is 60% and 30% in the matching and forecasting periods respectively. By integrating time lapse seismic data in history matching to update by environment, the production misfit is reduced by an equivalent amount while forecasting is improved by 19%. Seismically we reduce the misfit by 7%. Appropriate updating of the reservoir model is very important for reservoir management to reduce risk in development and to select appropriate models for forecasting. By updating the reservoir based on honouring the geological information or by using the geostatistical tools we can obtain a better representative of the reservoir with stronger prediction capability.