The Amin Field in Southern Oman is an excellent example of how multi-lateral technology catapulted an oil field from being an unattractive development to a highly attractive investment in the budget constrained late nineties. Despite being discovered in the mid seventies, development of the Amin Field did not really take off until horizontal drilling had secured a firm foothold, and only then with the assistance of multi-lateral technology. During the development of the Field the multi-lateral design was continually technically and economically optimized. This optimization, however, led to the unexpected plugging of the lower lateral by shale which ingressed through the milled casing window from the overlying cap rock. This in turn led to unsatisfactory economic performance of the streamlined multi-laterals and prompted immediate action. The Tieback Junction Sleeve (TBJS) was developed and tested primarily to combat the shale ingression and to provide a sealing multi-lateral junction. To date, extensive yard testing of the system has been undertaken and three complete TBJS systems have been run and tested in the Amin Field. All indications suggest that shale ingression have halted and that the junction is truly sealing.