Abstract:

Shale oil play is continuous petroleum accumulations just like shale gas, both of them are unconventional resources. The A-29 block locates in north of favorable prospecting area of Tuscaloosa Marine Shale（TMS）, which is one of the best shale oil potential areas in North America.
Because of being lack of geologic awareness, the resources potential is not clear, the next step of exploration is hard to deepen. Now, knowing the resources potential and selecting favorable area are very important for next exploration and development. Analyses of lithologic association of TMS formation indicate that upper layer and lower layer are tight rock, and middle rock is shale oil reservoir. OOIP is calculated by volumetric method and the range is from 0.30×10⁸ m³ to 2.56×10⁸ m³,and resources abundance is from 7.36×10⁴ m³/km² to 63.22× 10⁴ m³/km². Based on research of some key geologic parameters which are depth, thickness, TOC, R_o and brittleness, the results show that A-29 block is a good shale oil exploration area, TMS formation is so hard for hydraulic fracturing, and the shale oil favorable area is in southeast of block. But the exploration risk is in existence, the lower layer of TMS is tight sand and tight limestone which contains free water. Once the process of fracture stimulation is not proper and length of fracture is not controlled, the breakthrough will happen. So, high risk of completion should be noticed.

Key words: extra-low permeability reservoir, diagenetic processes, diagenetic reservoir facies classification, log response, GY Oilfield