around the perimeter of the circulating sub oil compensation spring 355 oil compensation piston 357 and fail sate spring 367 fig3 b also illustrates drillstring 320 and connecting rod 365 additionally shown are valve sleeve 370 also known as a valve poppet formed to sealably engage valve seat 375 valve seat 375 also called a valve plug may be mounted by use of a screw for example and includes an o ring 378 to form a seal with valve sleeve 270 holes 380 and 381 for mud flow 390 into the center of the circulating sub are formed in the upper portion of valve sleeve 370 holes 382 and 383 in valve sleeve 370 correspond to holes 384 and 385 in the housing and provide an alternate route for the drilling mud when the circulating sub is open and activated the housing is a circulating sub housing that engages with the valve sleeve but may be any appropriate housing such as a section of the drill string in addition many of the advantages of the preferred embodiment may still be obtained even where the valve poppet is not exactly like the configuration shown the valve poppet can therefore be any of a variety of configurations during operation downhole circulating sub electronics 308 receive power from the surface to facilitate power delivery the system may be preferably part of a coiled tubing.