| In the past few years, there have been a great of progresses in oil-gas exploration of lower Paleozoic, southern Tabei uplift. The progresses show a bright future. Yingmaili low uplift, the important oil & gas exploration area, is located in the west of Tabei uplift. So, it is necessary to study this area for both oil-gas production and tectonic deformation analyses.Based on the latest seismic profiles, the geology profile, and also the drilling, this paper build a geological structure in study area through the fine interpretation of the seismic profiles, and analyses the geological attribute and formation mechanism of the carbonate uplifts in the southern. At last, this paper analyses the petroleum accumulation in Yingmaili low uplift. This paper has reached the following conclusions:1. There is a notable character of superimposed structure in study area, which comprise two parts:the Paleozoic structural stage and the Mesozoic and Cenozoic structural stage. Paleozoic structural was mainly affected by the large basal thrust faults. The northern of study area was uplifted, and then eroded; in the Major Cenozoic there are normal faults, detachment structures, and multiple thrust imbricate structure near the piedmont structural. The Plastic rock of Middle Cambrian and Jidike layer plays an important role in the development of Detachment structure.2. There are two strong left-lateral extrusions in Study area:1, Hercynianis the significant age that Yingmaili area developed. Affected by the close of the South Tianshan Ocean, stress direction has changed from NE to NW, and generated two groups of fracture (300°-310°&2°-12°).2, late Paleocene-Today, In this stage, Yingmaili area has been uplifted by the enormous stress from the organic belt from west to east, and tectonic deformation developed from organic belt to basin, These characteristics shows in this stage the role of pressure torsion.3. It is of great significance to reveal the formation mechanism of the regional tectonic evolution of multiple insider carbonate anticline in the south of Yingmaili area through the research of Yingmai 2 anticline-- fixed-wing length detachment fold. The detachment surface located in the bottom of the middle Cambrian. The anticline began to uplift at the end of the Ordovician and shortened 400-700m. The uplift has been denuded in the late Hercynian. In this stage, there are two stages of growth caused by fault propagation fold, the flank of growth strata has the character of limb rotation, the other growth strata has the character of on lap, which shows Yingmaili 2 anticline had experienced different sedimentary rates and sustained tectonic activities in the late times.4. The study area evolution process can be summarized as five stages:1).flat envelope gradient; 2).slopes northward; 3).tectonic thrusting; 4).settlement developing; 5).adjustment and reconstruction.5. The Oil and gas accumulation in southern of study area shows the characteristics of Marine Origin Petroleum and Continental oil and gas in northern. Accumulation system can be divided into the Paleozoic reservoir system and Cenozoic reservoir system. There are mainly buried hill traps, structural traps in the Northern and the buried hills trap in the southern region. Along the distribution of unconformity, there are, stratigraphic traps. Superimposed structure played an important role in the research area of oil and gas gathering, the tectonic uplift control the karst process.6. Lower Paleozoic in the southern part of the Yingmaili Cambrian - Ordovician (Ordovician limestone reservoir and dolomite below the salt strata) reservoirs are well developed due to the development of fractures and the bottom of the hot role, and there are rich oil source, the development of multi-reservoir-cap combination of favorable zones of oil and gas exploration. So, this area will be important oil & gas exploration area. |
PDF Full Text Request