In a flat-layered earth, the reflection points associated with a zero offset VSP occur close to the vertical line passing through the source and receiver coordinates. Thus, the image made from these data will illuminate the subsurface in only a narrow vertical corridor passing through the receiver location. However, if there is structural [[dip]], the reflection points associated with a zero offset VSP can occur at significant horizontal distances from the vertical line passing through the source and receiver. When properly processed, such data can produce high resolution images extending from the receiver position to the farthest reflection point coordinate. | In a flat-layered earth, the reflection points associated with a zero offset VSP occur close to the vertical line passing through the source and receiver coordinates. Thus, the image made from these data will illuminate the subsurface in only a narrow vertical corridor passing through the receiver location. However, if there is structural [[dip]], the reflection points associated with a zero offset VSP can occur at significant horizontal distances from the vertical line passing through the source and receiver. When properly processed, such data can produce high resolution images extending from the receiver position to the farthest reflection point coordinate. |