| Aiming at the sedimentary facies, sedimentary microfacies, reservoir characteristics and other problems of current Permian-Triassic reef-shallow reservoir, this article taking carbonate reservoir sedimentary, reservoir geology and diagenesis theories as guidance, in the basis of the results of previous studies, combining the test data of field investigation samples, conventional and casting thin sections, using outdoor and indoor information, macro and micro observation, studied on its sedimentary microfacies features, reservoir rock characteristics, reservoir physical characteristics, the type of reservoir space, pore structure features, pore evolution process, as well as the impact factors of reservoir development. Based on them, established the reef and oolitic shallow reservoir development model. Through the above research work, the reservoir comprehensive evaluation had been done, and forecasted the favorable reservoir development region. The main achievement understanding are the following points:(1)Based on the previous study results, combining the outcrop, rocks sections and other data, studied on the purpose layer's sedimentary facies and sedimentary microfacies, determined the distribution of sedimentary facies. Changxing formation's principal sedimentary facies include reef, open platform, restricted platform and slope, four-phase in all. Feixianguan formation's sedimentary facies includehe shallow, open platform, restricted platform, evaporite platform, also four-phase in all. The most favorable facies are a shallow, reef, open platform and evaporite platform.(2) According to conventional and casting thin sections observation,and previous research results, combining with sedimentary facies characteristics, a detailed study of the reservoir porosity evolution, pointed out that the rupture and pressure solution during late buried period in reef, Changxing formation, the early dorag dolomitization and dissolution during burial period in oolitic shallow, Feixianguan formation, are the basic conditions of good reservoir.(3) Through the conventional and casting thin sections observation, evolution of porosity research, porosity and permeability samples testing, mercury penetration data collation, reservoir space types and characteristics analysis, determined that the oolitic dolomitic shallow reservoir's developed pore scale was the largest, vug types was abundant, and the reservoir properties was best. Followed by evaporation platform dolomite, the reservoir ability is general. Oolitic limestone and reef limestone's porosity also developed, but poor performance of accumulation, of a certain capacity.(4) On the basis of reservoir characteristics research, established the Permian-Triassic reef-shallow reservoir development models. The reef reservoir of Changxing experienced a period of colonization, colonial period, the Pan-colonization period and the integration period of four stages of colonization, the formation of a certain amount of accumulation capacity; Feixianguan formation's oolitic shallow reservoir experienced growth, oolitic shallow be dolomited, oolitic buried and be dissolution of three stages, forming a high-quality reservoir. And based on this, the favorable distribution of the reservoir region was predicted that the northwestern Jiaoshutang- Pingxiba is the oolitic shallow, evaporation dolomite reservoir's most favorable region, and the eastern Qiaoting - Tiechanghe is reef, lagoon and shallow reservoir's favorable distribution region. |
