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To address the problems of low recovery rate and poor water injection huff-n-puff effect in the depleted development of Jimsar shale oil. A study on the applicability of CO2 huff-n-puff technology in shale oil reservoirs was carried out by means of hydrocarbon phase experiments and numerical simulation methods for reservoirs to guide the implementation of CO2 huff-n-puff technology in the field. The results show that Compared with CH4, CO2 interacts better with Jimsar shale oil. Under the conditions of formation pressure and formation temperature, the solution gas-oil ratio of CO2 in crude oil is 497. 83 m³ / m³, the crude oil viscosity is reduced by 70. 65%, and the crude oil volume is expanded by 2. 05 times; for typical shale oil wells, multi-cycle CO2 huff-n-puff can improve the recovery rate by 9. 43 percentage points and crude oil production by 31 472. 40 t. With the shortening of frac- ture spacing and the increase of reservoir porosity, the effect of CO2 huff-n-puff on oil enhancement gradually becomes better, and the influence of permeability and oil saturation on the effect of CO2 huff-n-puff is relatively small. The results of the field test show that CO2 huff-n-puff can effectively enhance the recovery rate of shale oil, and the oil enhancement effect is better under the condition of no fracture disturbance. The research results have some implications for the efficient development of shale oil. [ABSTRACT FROM AUTHOR]

In response to the problems of low recoverable reserves and poor commercial benefits of single well with vertical well fracturing in low-permeabilitv conglomerate reservoir in Well Block Ma18, Aihu Oilfield, the parameter design and productivity prediction of multi-stage fractured horizontal wells were investigated bv numerical reservoir simulation, reservoir engineering method, economic limit method and mine field test method. The results indicated that the " sweet spot" depth in Well Block Ma18 was 3 876 to 3 881 m, the horizontal well strike should be in north-south direction, the recommended length of horizontal interval in horizontal well was 1 200 to 1 400 m, the well spacing was 500 m, the fracture half-length was 150 m, and the fracture spacing was 50 m. Six multistage fractured horizontal wells were designed with optimized parameters, achieving an average daily oil production of 29. 0 t/d in the first year, which was consistent with the predicted production of 25. 0 to 33. 0 t/d. This study developed an oil saturation prediction method for conglomerate reservoir, and developed a method of parameter design and productivity prediction for multi - stage fractured horizontal wells in conglomerate reservoir, providing a reference for similar reservoirs. [ABSTRACT FROM AUTHOR]