Application of Modern Technology to a Multi-position Down Hole Drilling Electronic Circulating Valve and Integral Disconnect Mechanism

Abstract

Abstract There are several areas where modern technologies can be applied to improve hole conditions reducing the chances of tight hole and stuck pipe. Hole cleaning has always been a key issue in inclined and horizontal wells where cuttings bed form and can lead to time consuming, difficult hole conditions and sometimes stuck pipe when attempting to trip out the hole. Annular velocity is one of the critical parameters that can improve cuttings bed removal but power hungry BHA's and bit hydraulics can sometimes compromise the ability to provide sufficient flow rate to clean the hole. A circulating sub is often installed above the BHA that can be opened to bypass the BHA and provide maximum flow rate to clean the hole. It can also be used to dump high concentrations of LCM in a lost circulation situation that would otherwise block the BHA and bit nozzles. Almost all circulating subs are of a drop ball/dart type that has a limited number of cycles, usually 6 to 9. Balls have to be dropped to open and separate balls dropped to close. These subs have limitations when it comes to hole angle, as the balls require gravity to reach their seats. They are unreliable in inclinations above 65 deg, require surface intervention and are usually only two positions i.e. open or closed. In a packed off situation where the annulus is sealed around the BHA and circulation is prevented, the balls or dart sometimes do not reach their seat and the sub cannot be opened to try and relieve the pack off. This paper discusses the development of a multi-position electronic circulating valve that can be set to multiple positions by surface down linking. The circulating valve can be configured as a standalone tool or combined with a unique motorized disconnect clutch mechanism that is activated by sensing its environment, working through internal logic modes before being in a position to receive a surface signal to disconnect. This has application in a stuck pipe situation where the tool can be commanded to disconnect and the drillstring recovered avoiding the need for surface intervention and any form of wireline and explosives. This tool has application in any well but particularly high angle wells where the circulating valve can be down linked to the first position for partial BHA bypass increasing annular flow and the final, maximum bypass, position can be used for dumping LCM or fast wellbore clean up at section TD or at any point in the well. Deepwater operations with spread rates in excess of $1M per day can benefit from the time savings in wellbore clean up, response to lost circulation and flexibility and control in a stuck pipe situation without waiting for wireline crews or explosives to perform a disconnect.