A Study On The Structural Evolution And The Control On The Oil Accumulation In The Central Tarim Brush Zone

The brush structure is located in the central uplift of Tarim Basin, and it has huge oil resource and exploration prospect in this area. But the exploration result of the central Tarim area is not good, with discovered industrial oil and gas flow only in Ordovician system of TZ 4 oil field. The constraints cause mainly by the insufficient research on the structure development and evolution and its controls on reservoir and hydrocarbon accumulation. Therefore, the thesis was based on the tectonic deformation characteristics and structural stress measurement in central Tarim area, then author simulated the stress field of this area by means of FEM. Further author discussed the relationship between stress field and exploration and development of the oil-gas.The ground structural features in Tarim area develop well. The thesis discussed the development character of the fault and folds in the area, and made an emphasis on the brush structure by field investigations. Moreover, based on the analysis of tectonic characteristics and combined with the evident epoch of mountain folding in Central Tarim area, author analyzed the progress of the structure evolution in this area, and further discussed the relationship between tectonic characters and the oil-gas.With regard to the tectonic stress study, making use of many methods such as magnetic fabric, archaeomagnetism and combining with tectonic analysis, author discussed the paleo-stress field characteristics in this area. Based on the stress measurement data, GPS data, well logging data and geological materials, author discussed the present stress field. Author set up four geological models based on recovered paleo-tectonics, and numerically simulated the tectonic stress by use of FEM to gain the stress distribution characteristics of Central Tarim area in different geological age. Finally revealed the fault closure and its opening extent in each age and the predominant direction of hydrocarbon migration, which supplyed the important reference and guidance for hydrocarbon reservoir' exploration.The thesis used the stress simulation results to find out the stress areas which were advantage for hydrocarbon accumulation, and analyzed these stress areas to outline the advantage traps of each age. Baesd on the results of stress, author concluded the favorable target for further prospecting in central Tarim area of Tarim Basin.According to the prediction and the evaluation of reservoir in Central Tarim area, author suggests that there should be 4 important favorable areas for next exploration, which are the following areas: Ordovician system of Z44-24-26area with carbonatite reservoir bed; Silurian period prospect areas are Z47-10-11 area; Late Ordovician- Devonian period prospect areas are Z49,Z45,Z201-11,Z23,Z12,Z44-16,Z24,Z26; Carboniferou-Early Permain Period prospect area is Z18.