Study on water injection intensity classification of irregular horizontal-vertical well groups

Horizontal wells with artificial fractures have been proven to be an effective method to develop tight reservoirs. However, inappropriate water injection might lead to non-uniform waterflooding in the group of horizontal producers and vertical injectors. Therefore, the objective of the current study is to optimize the flowrate of vertical injectors in the combination of horizontal and vertical wells. First, a series of numerical models with different relative positions of horizontal and vertical well were built in a tight reservoir. Through numerical simulation and three-dimension (3D) visualization technique, the controlling area of the horizontal well was divided into three areas where injectors follow different flowrates to increase the sweep area and avoid water breakthrough. Then, a numerical model with one horizontal well and three vertical wells was established to study the flowrate ratio between the injectors from different controlling areas. Simulation results show that three injectors with 6:3:1 of flowrate ratio can obtain an extra 2997.6 m 3 cumulative oil production than that with 1:1:1 of flowrate ratio.