水平井水力压裂真三维物理模拟实验

A TRUE 3-DIMENSIONAL PHYSICAL MODELING OF HYDRAUFRACTURING IN A HORIZONTAL WELL

本文介绍了水平井水力压裂真三维物理模拟实验。其结果表明,初破裂压力及初裂缝形态,与钻孔水平段相对于水平主应力方向的取向明显相关。通过改变水平段取向可以影响初破裂压力和控制初裂缝形态。钻孔水平段与水平主应力方向不相合时,裂缝通常不沿原来的裂缝面扩展。有些裂缝呈现出Ⅰ、Ⅱ型复合裂纹扩展的一些特点,如出现“S”型裂缝面。此类裂缝扩展,裂缝面最终将转向垂直于最小水平主应力方向。套管射孔模拟实验表明,如果钻孔方位和射孔位置、密度合适,则可以形成多裂缝。裂缝面最终也将垂直于最小水平主应力方向。

This paper gives some experimental results obtained on a true 3-dimensional physical model for hydraufracturing in a horizontal well. It is demonstrated that initial fracturing pressure and initial fracture configuration is obviously correlated to the orientation of the horizontal hole relative to the direction of the maximum horizontal stress. The initial fracturing pressure and initial fracture configuration can be affected and controlled by a change of the orientation of the horizontal hole. Progress of the fracture will not along the original fracturing plane usually in case that the orientation of the horizontal hole is not coincide with the direction of the maximum horizontal stress. Some fractures exihibit the characteristics of the progress of type Ⅰ and Ⅱ composite fractures, such as a S-shaped fracturing plane. As it progress continuously, the fracturing plane will turn to a direction perpendicular to that of the maximum horizontal stress.