Study The Optimization Method Of Perforating Parameters For Horizontal Wells In Heterogeneous Reservoirs

During the course of perforating horizontal well drilling oil field, the interaction of these factors such as fluid viscosity and the roughness of the shaft, it would cause the existence of the pressure drop for the horizontal wellbore. The wellbore pressure drop cause the inflow velocity of heel is far more than toe, so the inflow profile of wellbore is disequilibrium, the earlier water breakthrough will be caused in heel of wellbore, it particularly affect the output of crude oil. In addition, because of the complexity of geological conditions, most of the reservoirs are the heterogeneous permeability in reality. It led to the fluid permeability near the wellbore is different in different paragraphs. The inflow velocity in high-permeability zone is faster than that in low-permeability, so in the high-permeability zone the water can breakthrough earlier, thus very affect the effect of drilling horizontal well. Therefore, the study of horizontal well perforating parameter optimization problems has important guiding significance in the reservoir development. At present, under the condition of homogeneous reservoir, put forward the methods of perforating parameters optimization, that improve the inflow profile of wellbore, and obviously have solved the earlier water breakthrough in horizontal well drilling. But the methods of perforating parameters optimization under the condition of heterogeneous reservoirs still need further study.In this paper, taking the perforation density as the research object, adopting numerical analysis method, a coupling model of the flow in the heterogeneous reservoirs and the horizontal wells is established. At the same time, using this coupling model to optimize the perforating parameters of horizontal well.In this paper, mainly according to the problem of the disequilibrium of inflow profile for perforated horizontal wellbore during the horizontal well drilling, has carried out the following some research work:(1) Under the assumption for homogeneous reservoir conditions, using the continuum theory, according to the basic equations such as the mass conservation equation and the momentum conservation equation, has introduced the coupling model of the flow in homogeneous reservoir and in horizontal wells; this coupling model can be used as a research basis of heterogeneous reservoirs.(2) Using the above mathematical model, combining with the control principle of the inflow velocity, has introduced the coupling model of the flow in heterogeneous reservoir and in horizontal wells.(3) On the basis of the coupling model of the flow in heterogeneous reservoir and in horizontal wells, has introduced the optimization model of perforating parameters of horizontal well, and this model in order to obtain uniform flow profile as a target. In addition, using the optimization model for calculating concrete examples, has contrasted and analyzed the calculation results of before and after the optimization.