WELL-LOG CONSTRAINED INVERSION FOR LITHOLOGY CHARACTERIZATION: A CASE STUDY AT THE JZ25-1 OIL FIELD, CHINA

摘要

With an estimated total reserve of over 800 million barrels of oil equivalent (BBOE), JZ25-1 field is the largest light oil field in the Bohai Bay Basin, Eastern China. The reservoir rocks are mainly sandstones in the Paleocene Shahejie Formation (Es). Thus, a deep understanding of sand distribution is crucial to the efficient development of the field. In this paper, we performed lithology characterization using the well-log constrained inversion. Through seismic-well tie, initial modeling and simulated annealing, we obtained an acceptable inversion result. Using the wave impedance model as a constraint, we created sand thickness map with Kriging interpolation. The result indicates that sand bodies in the lower Es3 were thicker than those in the upper formation, and the thickness of sandstones varies laterally in the study area.