Optimization Design Research On Tight Oil Reservoirs Volume Fracturing In Chang6and Chang7Areas

Tight oil is hydrocarbon accumulation of self-generating and self-storage and a typicalunconventional oil-gas resource.For the tight oil reservoirs that have the characteristics ofultra-low permeability and poor connectedness, it is hard to achieve the expected stimulationeffect only on the traditional single fracturing, because of the poor supply ability from thematrix to fracture in the low-permeability reservoirs. Volume stimulating to reservoir,achieving the “short distance” from matrix to fracture because of producing fracture network.Therefore, tight oil reservoirs fracturing should form a complicated network fracture systemwhich realized the comprehensive transformation of reservoir in three-dimensionaldirection-volume fracturing.Based on discrete fracture network (DFN) research methods, this paper studies andsimulates complex fractures for tight oil reservoirs after volume fracturing. First, formedvolume fracturing interval optimization criteria by studing difference of horizontal stress,elastic modulus, poisson’s ratio, natural fracture.Secondly,based on13typical Wells of3blocks production history data matching,we figure out formation and fracture parameters, ithas important guiding significance for oilfield later development research. Taking An83blockas an example, we take single well cumulative production as optimization index and optimizefracture parameters in this block, such as horizontal section length, fracturing stages, clustersand fracture length. At the same time, taking stimulated reservoir volume as an optimizationindex, construction parameters such as displacement, pad fluid percentage, total fracturingfluid volume,are woked out. Finally，we studied relationship between carrying fluid and padfluid volume and stimulated reservoir volume for different fracturing fluid system, themeaningful conclusions that slick water has the strong abilty of building fratures andsubsequent building fratures after carrier are concluded, which may better guide theoptimization design and site construction of volume fracturing.