New advances in the assessment of tight oil resource in China

The research on tight oil becomes another hotspot in the field of unconventional oil and gas after the boom of shale gas. The global recoverable resources of tight oil are estimated to be around 47.3 × 109 t. In recent years, significant progress has been made in the technologies of tight oil exploration and development in North America, thus stimulating the dramatic increase of tight oil production. Meanwhile, China has also acquired remarkable achievements in tight oil exploration. Mature assessment methods have been established for tight oil resources by the US, generally dominated by analogy and statistical methods with their own advantages and disadvantages as well as applicable conditions. In China, improvement of resource evaluation techniques becomes an urgent issue in increasing tight oil reserve and production. This study mainly discusses the resource evaluation methods and resource enrichment characteristics of tight oil. Seven kinds of assessment methods in three categories (i.e., analogy, statistical and genetic method) and evaluation parameters have been preliminary established, and are specifically applied in the Sichuan, Ordos, Songliao, Junggar, Bohai Bay and other tight oil basins through the newly hierarchical resource abundance analogy method, the estimated ultimate recovery (EUR) analogy method and the small-cell volumetric method. The preliminary evaluation results reveal that China has great potential in tight oil resource, and the geological resources amount to 20 × 109 t, providing a resource base for large-scale development.