Window opening technology of simple casing applied in the deep well;

Tuocan 1 well is the firstφ244 5mm casing window sidetracking horizontal well.

According to the eight casing window sidetracking horizontal wells' conditions in Liaohe Oilfield, the main technical measures are given to improve the milling efficiency, which have important effects on improvements of casing milling technologies.

Duringφ139 7 mm OD casing window sidetracking drilling or deepening drilling, using the smaller size, single cone bit has apparent economic benefit.

A quantitative model was established for the prediction of the residual wall thickness of intermediate casing.

Statistics describe that intermediate casing damages mainly consist of wellhead subsidence, connection failure, broken down or burst, deforming, etc.

Because the mud density was reduced too much when drilling the fifth spudding wellbore at one time, the intermediate casing was weared out.

This article introduces the engineering flow and technical measures for casing side-tracking of complicated accidental wells according to well .