Drilling fluid technique in southwest wei

Geology in southwest Wei is very complicated,and it is relatively difficult to drill wells there.Shale of Wei and Liu formation 2 series is quite easy to collapse.Also,because of their different deposition conditions,physical property and collapsing degree of the rock vary from each other.Unexpected conditions happened often in the process of drilling in Weizhou12-1N and Weizhou11-4D block.Nowadays,hi-strength sealing petroleum based hydraulic fluid is still used when drilling in southwest Wei zone.With the development of drilling fluid technology,returns ratio of drilling exploration well with hi-strength sealing water base drilling fluid becomes higher and higher by the technique improvement.The techniques of drilling exploration well with hi-strength sealing water base drilling fluid in southwest Wei zone were summed here to supply experience for its further use in field.