井格块等效半径和视表皮系数的计算

CALCULATION OF EQUIVALENT WELL-BLOCK RADIUS AND APPARENT SKIN FACTOR

本文通过精确解和差分方程相结合的方法,导出了拟稳定渗流以及井格块不是内格块时井格块的等效半径;以粘度模型为基础,建立了既适用于假塑型又适用于粘弹性流体的视表皮系数的计算公式。并得到当井格块是内格块时,拟稳定渗流和稳定渗流的等效半径相等的结论;对于稳定渗流方格块,不论位置如何,井格块等效半径都近似地等于0.2Δx。

This paper gives a derivation of equivalent well-block radii for different situations(such as pseudostationary flow,non-inter well-block)by means of analytic solution and method of finite difference.A model of apparent skin factor is established also.The model is also adapted to both pseudoplastic and viscoelastic fluid in addition to newtonian fluid.The following conclusion are drawn:for inter well-block,equivalent radius of pseudosteady state flow is identical to that of steady flow,in case of steady flow and square block, equivalent wen-block radii are approximately equal to 0.2△x independent of well-block position.