摘要
射孔完井是石油天然气开采过程中最常用的完井方式之一。对于确定的油气储层,完井方式决定了单井产能大小。一般常用二维裸眼井模型来进行射孔井的试井资料解释及单井产能的确定,但这种方法分析的结果可能存在较大的误差。因此根据射孔完井的特征以及储层渗透率各向异性特征,建立了一种适合于射孔井的三维数值试井模型。利用三维有限元数值方法求解该模型,获得了射孔井的试井理论曲线和压力分布场。通过分析试井理论曲线的特征及压力分布场中的流体三维流动特征,明确了试井理论曲线的6个流动阶段:井筒储存阶段;第一过渡阶段;早期局部径向流阶段;第二过渡阶段;系统径向流阶段;外边界作用阶段。其中,围绕射孔的早期局部径向流阶段是该类井的主要特征。分析了射孔完井参数射孔密度、射孔长度、射孔相位角以及渗透率各向异性等因素对试井理论曲线的影响,为射孔完井设计以及射孔井的试井分析提供理论指导。射孔井的总表皮系数计算结果表明,在一定参数条件下,射孔井可以成为超完善井,深度射孔是提高产量较有效的手段。
Perforated completion is one of the most commonly used completion methods in oil and gas development. The single well, productivity is largely determined by the completion method for a given oil gas well. The well test analysis and single well productivity calculation are normally realized by using a 2 D open hole model, however, this approach may cause large errors. Based on properties of perforated completion and permeability anisotropy of reservoirs, a three dimensional numerical well test model was proposed to analyze the transient flow in perforated vertical wells. With the model, well test type curves and pressure fields of perforated wdls are obtained by using the 3-D finite demnet method （FEM）. Through analyses of well test type curves and the three-dimensional flow in the pressure field, six flow phases can be recognized on well test type curves of perforated wells, i.e. wellbore storage, the first transition, early-time partly radial flow around the perforation, the second transition, late- time system radial flow and boundary dominated flow. Among them the early time partly radial flow around the perforation is the most important characteristic of perforated wells. Effects of perforated completion parameters, such as perforation density, length, phase angle and permeability anisotropy, on the transient pressure and derivative responses were studied, which provides theoretical guidance to design perforating types and analyze well test data of perforated wells. The calculation result of the total skin factor of perforated wells showed that the productivity of a perforated well may he higher than that of an open hole if the per foration is long enough or the perforation density is high enough, Increasing the perforation length is an effective way to enhance the productivity of a perforated well.
出处
《石油学报》
EI
CAS
CSCD
北大核心
2013年第3期528-534,共7页
Acta Petrolei Sinica
基金
国家重大科技专项"煤层气井生产测试技术"(2011ZX05038-003)资助
关键词
射孔井
数值试井
表皮系数
三维有限元
射孔密度
射孔长度
渗透率各向异性
perforated well numerical well test skin factor 3 D FEM perforation density perforation length~ permeability anisotropy
