E.R. West, The Pure Oil Company
Casing design, basic cementing practices, and problems that can occur for deep Delaware Basin wells are presented. Pipe inspection is discussed and recommendations are made as to type and amount of inspection required. Because of extreme depths, many deep wells are terminated or completed shallower than anticipated when unforeseen problems dictate that additional casing strings be set. To overcome this problem, integral joint casing is often installed in a relatively tight hole. This operation presents other problems which are explained. The importance of picking good casing points is stressed and is considered the most important single factor in drilling a deep well. Extremely difficult liner cementing jobs where high pressure gas zones are to be cased are discussed. Gas cutting of fresh cement is one of the more serious problems. Green cement has been circulated off the top of deep liners 24 to 36 hours after placement. Possible answers and proposed solutions for better cement jobs are presented. Loss of circulation in the presence of high pressure gas can be one of the most dangerous and expensive problems in deep drilling. Views are expressed on ways to handle lost circulation. If lost circulation is severe, wireline surveys should be made to determine their zones. In certain cases, casing should be run and cemented without regaining circulation. Reference is made to several deep casing strings cemented without circulation.