Such cases may be caused by drilling holes cut with seams between layers app nahai daira (Marker Bed) or may be drilled into the rocks the mud. Thus, using the drill pressure is missing.
Such cases may be caused by holes drilled to intersect the boundaries between layers anhydride Sprite (Marker Bed) or drill into shale mud. The pressure used to penetrate.
Such cases may be caused by drill holes to cut with the interface between the layers anhydrite (Marker Bed) or may penetrate into layers of mudstone. The pressure used to break away.