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完井是产层和井筒之间形成有效通道的措施。有效的完井必须保持井筒的机械完整性,以及确保井筒内流体的流动性。本文概述了一种用于优化水平井设计的方法,该方法使用了适于所有类型完井(包括地层伤害和湍流效应)的表皮因子模型。在水平井中使用割缝衬管、带眼衬管、射孔、套管或砾石充填等完井方法来增强井壁的稳定性及防砂效果。但是与裸眼完井相比,这些完井方式油井的产能较低(表现为正表皮),这是由于流向射孔孔眼和割缝的汇聚流会增大近井地带的流体速度。而且,任何渗透率降低的区域(由钻井、完井和其他过程引起的地层伤害)都会增强液流汇聚效应,结果产生相当大的表皮因子。本模型考虑了完井对周围地层伤害的联合效应,如由射孔或割缝堵塞引起的压实带、湍流以及这些效应的相互作用。本文阐述了如何用表皮因子模型筛选套管射孔完井和割缝衬管完井类型。这些筛选方法把地层渗透率、渗透率各向异性、流体性质、地层伤害、岩石机械性能等作为主要参数。本文还给出了能够为该模型提供生产参数的完井类型。割缝或射孔衬管完井模型应用的结果表明,表皮引子的变化幅度可达40%,这取决于炮眼和割缝的性质。应用实例表明,优化完井性能能够在低投入甚至没有投入的情况下提高油井产能,而且不会降低衬管的机械强度。
Well completion is a measure to create an effective channel between the pay zone and the wellbore. Effective completion must maintain the mechanical integrity of the wellbore and ensure fluid flow within the wellbore. This article outlines a method for optimizing horizontal well design that uses a skin factor model that is suitable for all types of completions, including formation damage and turbulence effects. In horizontal wells, wellbore liners, perforated liners, perforations, casing or gravel packings, are used to enhance wellbore stability and sand control. However, compared with open-hole completion, these completion wells have lower productivity (expressed as positive epidermis) because the converging flow to the perforation and kerf increases the fluid velocity near the wellbore. Moreover, any region of reduced permeability (formation damage caused by drilling, completion, and other processes) enhances the fluid pooling effect, resulting in a considerable epidermal factor. The model takes into account the combined effect of well completions on surrounding formation damage, such as compaction belts, turbulence and the interaction of these effects caused by perforations or kerf plugging. This article describes how to use the epidermal factor model to screen casing perforation completions and slotted liner completion types. These screening methods take the formation permeability, permeability anisotropy, fluid properties, formation damage, rock mechanical properties as the main parameters. This article also gives the type of completion that can provide the model with production parameters. The results of the application of kerf or perforated liner completion models indicate that the variation of the epidermal index can reach 40%, depending on the nature of the blasthole and kerf. Application examples show that optimizing well completion performance can increase well productivity with or without input, without reducing the mechanical strength of the liner.