The Unconformity Structural Characteristics And Effectiveness Evaluation In Chunguang Block,Chepaizi Uplift

Based on a lot of core observation, the basis of field exploration, analysis and application of a large number of experimental data.The thesis had detailed analysis the prospective unconformity characteristics in Chunguang block,Chepaizi uplift,and by combing with the typical unconformity fine anatomical reservoirs,finally achieved the following main conclusions and understanding:At the bottom of Shawan Formation,the top of Cretaceous and the bottom of the Cretaceous, the top of Carboniferous,there distributed unconformity distribution and truncated unconformity with overlying unconformity over two unconformity type in Chunguang block.which accounted for most of the unconformity truncation. Four unconformity can better be done on hydrocarbon migration pathway.According to the lithological profile and logging curves and seismic data to identify unconformity structure and division of work area at the bottom of Shawan, Cretaceous top, bottom and Carboniferous Cretaceous unconformity top four unconformity obvious three-tier structure that the unconformity rocks, weathered clay, semi-weathered rock.Integration four unconformity lithology juxtaposition surface layer structure, for transporting ability thickness of each layer, lithology and lithology provided evaluated. Shawan bottom unconformity that exist 21 kinds of lithology configuration, the top Cretaceous unconformity exist 14 kinds of lithology configuration, the bottom of the Cretaceous unconformity exist 13 kinds of lithology configuration, and Carboniferous top, due to weathering of rocks are unconformably half tuff, lithology configuration is only seven types. Which DFM (fine sandstone-mudstone-tuff), DFK (fine sandstone-fine sandstone-mudstone) are widely distributed, can provide efficient transporting layer of oil and gas.Analysis of the effectiveness of three-layer structure unconformity structure shows that:(1) at the bottom of Shawan unconformity under effective range mainly in most areas northeast, southwest and central, but mainly in the upper part of the effective range of the Middle East and Southeast Asia. Most of the work area in the northwest region due to lack of weathered clay layer formed above the unconformity unconformity conducting layer and semi-weathered rock unified migration pathways. Top (2) Cretaceous unconformity at the southwest corner of the work area and most of the eastern, middle made for transporting characteristics of shale barrier, down from the unconformity above the conducting layer and the unconformity semi-weathered rock composed of double migration aisle. In the work area extending to the southeast and central parts of the small, oil and gas along the unconformity surface transport semi-weathered rock. In the middle of the north east, south east work area and work area small area, oil and gas along the unconformity conducting layer migration in the eastern and southeastern row a small area in the vicinity of 206 wells, under the unconformity are mudstone, Oil barrier. (3) the bottom of the work area at the bottom of the Cretaceous Cretaceous unconformity effectiveness in three. In the work area to the east of the central region, oil and gas along the unconformity unconformity conducting layer and semi-weathered rock composed of dual-channel migration migration, most of the eastern part of the work area in the region, oil semi-weathered rock formations along the unconformity migration, in central work area, oil and gas along the unconformity above the unconformity transporting layer and semi-weathered rock in the middle of no weathered clay separated channels, the conduct migration double migration channels. (4) work area at the top of the Carboniferous hydrocarbon migration better, most of the work area in areas of oil and gas along the unconformity conducting layer and semi-weathered rocks unconformably dual transport channel migration, in southwestern and eastern small some areas of oil and gas along the unconformity transport semi-weathered rock.The results show that the typical reservoir:Changji depression Permian hydrocarbon source rocks generated nearly north-west migration; Sikeshu Jurassic, Anjihaihe hydrocarbon source rocks generated nearly north-south migration. (1) Spring 50 oil and gas from the well area Sikeshu depression Jurassic source rocks, and oil and gas well area for spring 110E Sikeshu Jurassic source rocks and Anjihaihe source rocks mixed oils. Spring area of hydrocarbon accumulation process Paleogene should be: the early Paleogene sedimentary, from four trees sag Jurassic hydrocarbon source rocks along by Cretaceous or Jurassic unconformity migration when raised to the West Wing Chepaizi slope, oil and gas transportation to move along a vertical fault Aika Cretaceous and older strata, and then along the bottom of the Cretaceous unconformity Chepaizi projections for migration. (2) Jurassic to Early Cretaceous, the four trees Jurassic source rocks began to hydrocarbon generation, oil and gas along the Cretaceous unconformity at the bottom of the transportation system to move Chepaizi region and fault car red car 87,84 cars,88 cars well area. At this point, Chepaizi Cretaceous thin, resulting in the spring of 17 wells Cretaceous is oxidized to become heavy. In contrast, the thickness of the Cretaceous red car fault zone area was significantly greater than the spring of 17 wells, reservoirs are effectively preserved, resulting in the red car fault zone Cretaceous oil more dilute form. Filling period (3) Shawan light oil should be 5ma so far, this time Anjihaihe of hydrocarbon source rocks into the threshold, with crude oil Jurassic Anjihaihe source of crude oil occurred after mixing along the sand the bottom of the Gulf Group unconformably migrated to Chepaizi raised, due to better storage conditions, the formation of light oil reservoir.