Density Cutting Volume Fracturing Technology for Horizontal Wells in the Ultra-Low Permeability Reservoirs: a Case Study of the Yuan284 Area in the Huaqing Oilfield Ordos Basin, China

The ultra-low permeability reservoir in Huaqing oilfield presents the characteristics of obvious non Darcy seepage, difficult matrix displacement, channeling of injected water along the waterflooding-induced fracture, and low production of single well in horizontal well development. Conventional water injection development is difficult to adapt to the current economic development. It is urgent to explore the effective development mode of horizontal well in ultra-low permeability reservoir, that is, to transform water-flooding development mode. Based on the mechanism of imbibition oil recovery, through indoor numerical simulation and field test, this paper innovatively puts forward large-scale volume fracturing of horizontal wells, and establishes a new development model of "makeup pressure tightness production" integrating "comprehensive energy supplement, old fracture plugging, synchronous transformation and volume fracturing" for the first time, which breaks through the traditional water drive characteristics and is successfully applied to yuan284 block of ultra-low permeability reservoir in Huaqing oilfield. Through the three-dimensional transformation of the reservoir, this model increases the complexity of fractures, realizes the transformation of seepage from linear flow to complex fracture network, establishes the development mode of imbibition displacement + differential pressure mass transfer, changes from well controlled reserves relying on water drive to fracture controlled reserves relying on seepage, and finally greatly improves the production and recovery of single wells. It is concluded that changing the water injection development mode provides new ideas and technical support for the development of horizontal wells in other similar ultra-low permeability reservoirs.