Billy P. Morris, W.A.C.O. Logging Services
Ranking high among conditions that reduce well productivity is the deposition of scale and/or precipitant in and around the well bore. These deposits occur in both producing and injection wells and range from silts and soft asphaltines to extremely hard and brittle scales such as calcium or barium sulphate. Methods of removal of the deposits include solvents of all types, chemical converters, mechanical scrapers, high pressure fracturing or wash, and several variations of explosive devices. These various methods, successful to some degree, all have some undesirable side effects and most are significantly ineffective when used on the more resistant scales. A tool for use specifically on these harder, more brittle deposits has been developed, utilizing sonic energy and shock waves to pulverize these scales and facilitate their removal from the well bore. Effectiveness varies with conditions, but results have been more gratifying in areas where other techniques and tools have been the least successful. The tools are in operation in limited supply at present, with a history of approximately 60 operations. Tools, principles, applications, current results, and projected improvements are discussed in this writing. Subsequent results will be made available to the industry as service and histories progress