基于数值模拟的径向井压裂布孔方案

Radial Perforation Scheme of Multi Radial Wells Fracturing Based on Simulation

目前多径向井压裂的裂缝形态尚无合适的评价指标,缺乏针布孔方案设计的理论依据,限制了该技术的发展。结合某低渗稠油油藏实际参数相应的地层模型,分析不同布孔方案下裂缝形态的变化规律,并提出“最大缝控面积”理论作为布孔方案优化的依据;在明确裂缝形态的基础上进行产能模拟,并对“最大缝控面积”理论进行验证。结果表明,多径向井压裂可形成沿各径向井扩展的主裂缝;多径向井应沿水平最大主应力方向对称布孔,且在水平面内应均匀分布;优化后的布孔方案为四径向井所形成的裂缝正交且与水平最大主应力方向呈45°夹角。研究结论为现场径向井压裂联合蒸汽吞吐技术开采低渗稠油油藏提供理论依据,对该技术的推广应用具有重要的指导意义。

At present,the fracture morphology of multi radial wells fracturing is not clear,and there is no proper evaluation method.Therefore,the lack of theoretical basis for the design of field radial perforation scheme has greatly restricted the development of the technology.Based on parameters from a low permeability heavy oil reservoir,the model of extend finite element is established in order to research the fracture morphology of multi radial wells and analyze the influence of different scheme parameters on fracture morphology.Also the maximum sweep area theory is proposed to evaluate the scheme.On the basis of the definite fracture morphology,the productivity simulation is carried out,and the change rules of productivity under different schemes and development modes are analyzed,also the theory of maximum sweep area is verified.The results show that the main cracks along each radial well are formed;Radial wells should be symmetrical along the direction of maximum principal stress,also should be uniform distribution in-plane.Combined with the production capacity of the simulation results determining the optimal scheme:four cracks formed by each radial well are orthogonal,also the angle of them and the maximum horizontal principal stress should be 45°angle.The conclusion is significant and important for the field.