The Experimental Research Of CBM Displacement Under Double Well Convection

With the rapid development of global economy, The demand for energy resources is becoming more and more big, while the non-renewable resources, for example oil, coal reserves, are gradually reducing, In order to realize the sustainable development, the new type of alternative energies are needed urgently to reduce the consumption of non-renewable resources such as the oil and coal. At the same time, the waste gas pollution, which was produced by industry production, is becoming more and more serious to the environment, especially carbon dioxide and other greenhouse gas emissions, has a significant impact on global climate change. Recently, the research about the sequestration of greenhouse gases such as carbon dioxide has been researched largely, and a lot of constructive conclusions have been obtained. At the same time, in order to cope with the impact of climate change on the global economy, the global climate conference was convened in Copenhagen in2002and reached broad consensus.The coalbed methane is also considered an alternative strategic resources. Coalbed methane (CMB), a product in the process of coal metamorphism associated, is also one of the main component of greenhouse gases. As an alternative strategic resources, coalbed methane occupies an important position in the energy structure in our country. During the "11th five-year plan" and "12th five-year", our country made clear the strategic position and proposes the exploration target. Recently there are lots of means to exploit to increase the coal-bed methane output, the way with carbon dioxide to displacing coal seam methane is regarded as a kind of important method with both social significance and economic benefits. In recent years, many studies about carbon dioxide displacing coal seam methane are being proceeded, not only can improve the recovery of coalbed methane, also can increase co2sequestration, reduce greenhouse gas emissions.This paper has carried on the carbon dioxide displacing coal samples of nitrogen in the experimental study in the basis of predecessors’research, and studied the displacement efficiency in the model of single well displacement and double Wells displacement, the studis have been consided as a important guiding significance in engineering.In this paper, mainly including the following several parts:One. At first, this paper mainly introduced the current energy situation of our country, the dangers of greenhouse gases and carbon dioxide displacing coalbed methane strategic significance.Tow. This paper Introduced the coal and coalbed methane adsorption mechanism, competition mechanism and molecular layer adsorption theory and so on, these theory provides a theoretical guidance for carbon dioxide displacing coal seam methane.Three. This paper introduced the the working principle of GC-950and instruments in detail, in order to ensure the accuracy of the experiment, the error analysis should be carried, this error analysis used common mixed in proportion of nitrogen and carbon dioxide, in the mixed gas, nitrogen percentage were10%,30%,50%,70%and90%of five kinds of mixed gas, and each of the mixed gas is600ml in total volume, each of the mixed gas were measured five times, than we can conclude that when the nitrogen concentration in the mixed gases is very high, the test error is bigger, while the concentration of nitrogen is small, the experiment error is smaller.Four. This paper studied the single-well displacement and double Wells displacement with the same condition that the confining pressure is8.5MPa, nitrogen adsorption pressure0.8MPa and carbon dioxide is1.0MPa under the displacement pressure. In the first50minutes, the total nitrogen displacement volume was1336.43ml in the double well displacement mode, while the single well displacement volume was352.63ml under the same condition. So we can include that the double well displacement effect is superior to single well displacement effect.Five. This paper have carried on the carbon dioxide displacing coal seam methane adsorption experimental research in different confining pressure, impassability, displacement pressure in double well displacement mode, and got the optimal scheme of displacement under the each condition.