Imaging deeply buried, ultrathin sandstone reservoirs using geostatistical inversion: A case study in Yudong area, Tarim Basin, China

Prediction of deeply buried (5,000-6,000 m), ultrathin (1–4 m) sandstones is critical to successful exploration and development of a large, subtle hydrocarbon accumulation in the Yudong area of the Kuqa Depression, Tarim Basin, China, as well as other basins. In this study, a geostatistical inversion approach was applied to improve areal mapping of very thin sandstone reservoirs in a Paleocene depositional sequence. We used a high-quality 3D seismic data set with sparse well control. Reasonable stratigraphic and depositional facies analysis established the framework necessary for the inversion workflow. A realistic statistical model (variogram type and range) was selected using a stochastic simulation of multiple combinations of parameters. Results were a significant improvement over those of the previous spark-spike inversion and have been used successfully in local exploration.