Posted: May 22, 2010 9:11 pm
JaxonCO wrote:Further to the liquid nitrogen concept, it is routinely used for the purpose you describe. The problem here is the inability to introduce the LN into the outflow at sufficient depth into the well bore to generate an ice plug of sufficient length to withstand the well pressure which will begin to build the instant the ice plug is put in place. Further, the LN-induced ice plug would likely transient.
What is conceptually required is a method to first staunch the outflow of oil, gas and water from the well; secondly to place a "platform" of some form of viscous material well into the well-bore upon which to stand a column of cement; thirdly introduction of a cement slurry of sufficient volume to guarantee an effective cement plug, when set up; fourthly the cement slurry must possess appropriate chemistry to set up within a rather short time interval (due to the well building pressure upon stoppage of outflow), attaining sufficient compressive strength to withstand the final well-bore pressure, likely in the neighborhood of 15.0 lbs/gal *0.052*18,000', or about 14,000 psi. Due to the rate of outflow and the depth of the well, I would guess that you would have about 2 3 hours in which to complete this process.
thanks Jax, for the great info
with an LN injection, there's also the issue of thermo stress to the metal of the casing, which is likely close to its burst pressure in some of the larger diameter sections of the tapered string
since i don't think it would do a lot of good to inject LN into the riser above the BOP and take advantage of the adiabatic cooling of the oil, we are talking about injecting a supercold liquid into hot oil/gas coming up the hole at something like 230C, and we are talking about doing it at something close to reservoir pressures
if you drop the casing temperature to -50C by pumping in LN @ ~-200C, it could well shatter what's probably stainless steel under the pressure/temperature stresses