射孔水平井产能预测方法

为了预测射孔水平井的产能,在Joshi推导水平井产能公式所用模型的基础上,引入了三径向流模型,采用等值渗流阻力法,建立了孔眼未射穿污染带和孔眼射穿污染带2种情况下射孔水平井产能预测模型,考虑了孔深、孔密、孔径、相位、污染带的半径与污染程度、压实带的厚度与压实损害程度、水平井水平段长度等因素对产能的影响,流动机理更加符合油藏实际。利用所建立的产能预测模型进行参数敏感性分析,结果表明,射孔水平井产能随着孔深、孔径、孔密、相位、水平井水平段长度等参数的增大而增大,随着压实带厚度和压实损害程度的增大而减小,对水平井水平段长度、孔深、孔密、压实损害程度的敏感性较大,对相位、孔径、压实带厚度的敏感性较小;孔眼射穿污染带时产能指数对射孔参数的敏感性比孔眼未射穿污染带时低。工程设计时,应尽量增加水平井水平段长度、孔深、孔密,避免过高的压实损害程度。

A new method to forecast the productivity of perforated horizontal well

In order to forecast the productivity of perforated horizontal well, this paper introduced a three radial flow model based on the model used by Joshi in the derivation of horizontal well productivity formula. On the basis of the proposed model, this thesis derived out the productivity formula of perforated horizontal well with the equivalent flow resistance method, when the damaged zone is penetrated or not respectively. The productivity formulas takes many influencing factors into consideration such as the perforation length,shot density, perforation diameter, phasing, the diameter and the pollution degree of the damaged zone, the thickness and compaction damage degree of the crushed zone, the length of horizontal well, making the flowing mechanism more suitable for the real reservoir condition. The sensitivity analysis of the parameters with respect to the derived formulas shows: the productivity of perforated horizontal well rises with the increment of perforation length, shot density, perforation diameter, phasing, and the length of the horizontal well, and decreases as the thickness and compaction damage degree of the crushed zone increases. And, it is sensitive to the length of the horizontal well, perforation length, shot density and compaction damage degree, and is insensitive to phasing, perforation diameter, and thickness of the crushed zone. The perforation parameters is more sensitive with respect to the productivity index when the damaged zone is not penetrated than that penetrated. We should give priority to the length of the horizontal well, perforation length, shot density, and avoid excessive high compaction damage degree during the engineering design.