State-of-the-art cuttings transport in horizontal wellbores

In the ever-growing use of, directional and horizontal drilling, hole clean ing is a common and costly problem. It can become particularly critical in the case of extended reach drilling where larger and longer wellbores are d rilled. During the past two decades, especially in recent years, many labor atory studies as well as held observations have been directed towards addre ssing the cuttings transport problem. This has resulted in better understan ding of the subject and some remedies to the problems. Several correlation/ models have also been developed that give the field engineer a tool to bett er specify the hydraulic requirements in cleaning the hole. However, becaus e of the complexity of the subject, a comprehensive and proven model, which does not exist at this time, requires much more laboratory research and he ld studies.