Capacity to Trap Gas

Hydrate forms as cement in the pore spaces of sediment as well as in layers and nodules of pure hydrate. Hydrates also seem to have the capacity to fill sediment pore space and reduce permeability, so that hydrate-cemented sediments act as seals for gas traps.

Gas hydrates are stable at the temperatures and pressures that occur in ocean-floor sediments at water depths greater than about 500 meters, and at these pressures they are stable at temperatures above those for ice stability. Gas hydrates also are stable in association with permafrost in the polar regions, both in offshore and onshore sediments. Gas hydrates bind immense amounts of methane in sea-floor sediments. Hydrate is a gas concentrator; the breakdown of a unit volume of methane hydrate at a pressure of one atmosphere produces about 160 unit volumes of gas. The worldwide amount of methane in gas hydrates is considered to contain at least 1x104 gigatons of carbon in a very conservative estimate). This is about twice the amount of carbon held in all fossil fuels on earth.

Gas hydrate concentration occurs at depocenters, probably because most gas in hydrate is from biogenic methane, and therefore it is concentrated where there is a rapid accumulation of organic detritus (from which bacteria generate methane) and also where there is a rapid accumulation of sediments (which protect detritus from oxidation).

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.

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.