Optimization and infill adjustment of development well patterns in Zhao 10 Block

In Zhao 10 Block, the well patterns were originally designed with small spacing density, and progressive development and concentrated construction were carried out, so at present, the distribution of well patterns is quite uneven. In order to improve the development results of this block, the original well pattern plans were optimized and adjusted by means of multiple methods (e.g. gas reservoir engineering, numerical simulation and economic evaluation) after the geological and dynamic characteristics were newly understood. It is indicated that in the areas where no well is arranged, the spacing density of vertical well patterns can be set at 3.33 wells/ km²with the corresponding spacing of 500 m×600 m. For the well patterns with spacing of 600 m×800 m, regular infilling can, to some extent, increase the recovery factor of gas reservoirs, but it is economically infeasible. Vertical wells are advantageous in vertical reserves producing and horizontal wells are higher in areal reserve producing degree. Besides, horizontal wells can increase individual-well production rate effectively. Therefore, combined well patterns of vertical well+horizontal well can be ultimately used in this block, which can increase the recovery factor to 46.9%.