Abstract: Reservoir properties in Fengcheng oilfield are commonly poor, and their heterogenity is strong. SAGD fishbone multilateral wells can address the issue of limited steam chamber expansion of conventional SAGD by lateral penetrating deeply into the reservoir. In order to achieve the best development effect, it is necessary to optimize the lateral morphology of SAGD fishbone multilateral wells and grasp the law that affects the recovery variation. To this end, reservoir numerical simulation and orthogonal test design are used to determine the sensitivity of the lateral parameters to enhance oil recovery and optimize the lateral parameters. As a resunt, the influence of the lateral parameters on enhanced oil recovery is analyzed in reservoirs with different physical properties. The research results are applied to Fengcheng Oilfield, and the optimal well deployment scheme for the target block is as follows: lateral length is 120 m, the number of laterals is 4, the angle of laterals is 75 °, the laterals are asymmetrically distributed, and the spacing between laterals are 100 m. The research showed that the influence weights of each lateral parameter take the reservoir permeability of 2.0 D as the obvious cutoff point: the main influencing factors are lateral length, lateral angle, and lateral spacing when the reservoir permeability is less than 2.0 D, and the influence of lateral parameters on the increase of recovery, the impact of lateral angle and lateral spacing starts to become stronger when the reservoir permeability 2.0 D The Study results are of great significance for further enhanced oil recovery of the recovery of SAGD drive in Fengcheng Oilfield.

Key words: SAGD fishbone multilateral well, lateral morphology optimization, numerical simulation, enhanced oil recovery, Fengcheng Oilfield