| Based on previous study results, stratigraphic reservoirs are defined and classified byusing geology, well logging, well testing and seismic data. Typical stratigraphic reservoirs inWu-xia area Junggar basin are dissected. Characteristic of unconformity in Wu-xia area arestudied. The conditions and main dominated elements of stratigraphic reservoirs are summedup. Basined on these, numerical simulation on accumulation mechanism of stratigraphicreservoirs are studied by using PetroMod in order to provide theoretical basis for futureexploration of stratigraphic reservoirs in Wu-xia area Junggar basin.Based on characteristic of stratigraphic reservoirs in Wu-xia area Junggar basin,stratigraphic reservoirs are defined as reservoir bodies filled with oil and gas. Reservoirbodies are formed by overlapping, disintegration and leaching, which is caused by tectonicmovements or sea (or lake) level fluctuation. Reservoir bodies are screened by impermeablebarrier on updip direction. Based on the genesis of traps, stratigraphic reservoirs are dividedinto stratigraphic overlap hydrocarbon reservoirs and stratigraphic denudation hydrocarbonreservoirs. There are 6 types of unconformability in Wu-xia area Junggar basin. They aretruncation unconformability of truncation, unconformability of lap, unconformability ofbruchfalten, unconformability of fold. The unconformability can be divided into 3 sections onthe vertical. Respectively, on the bottom of Cretaceous, Jurassic and Triassic, there are 16, 22and 28 lithological collocations. The distribution of stratigraphic reservoirs in Wu-xia areaJunggar basin is controlled by"two zones and one body", which is range overlap zone, planeof denudation and discordant body. The distribution range of stratigraphic overlaphydrocarbon reservoir in Wu-xia area Junggar basin is controlled by range overlap zone. Andthe distribution range of stratigraphic erosion hydrocarbon reservoir is controlled by plane of denudation. Transform system can be offered by basal conglomerate (or transgressive sands)and the weathering leached zone. Cap formation can be offered by the weathered clay layer.The discordant bodies are composed by conglomerate (or transgressive sands), the weatheringleached zone and the weathered clay layer. The characteristic of type stratigraphic reservoirsin Wu-xia area Junggar basin is oil and gas offered by different source rocks and multiphasefluting. The results of numerical simulation on accumulation show that the contribution ofunconformability around the source rocks is more than the far away. The dominant migrationpathway is formed by oil and gas migrating along micro-structural in the weathered clay layerand basal conglomerate developed in unconformability. The distance of oil and gas migrationon horizontal is further in the weathered clay layer than in basal conglomerate.
|
PDF Full Text Request