A Study On The Preparation Of Catalyst System For The Downhole Upgrading Under The Steam Injection Conditions For Liaohe Heavy Oil And Its Application

The main production method currently used in the heavy oil production is the steam injection. The reactions happened between the steam injected and the heavy oil at the high temperature in the subsurface porous media can improve the quality of the heavy oil in-situ, decrease the viscosity of the heavy oil permanently, and improve the effect of the steam huff and puff and recovery efficiecy. The production of the heavy oil using the downhole catalytic upgrading method is a latest technique and it has a broad future. So it is valuble in practice to study the fundamental theory concerned with the downhole catalytic upgrading reactions under the steam injection condition and the peparation of the relative chemical agentsThe mechanism of the downhole catalytic upgrading heavy oil under the steam injection conditions is intensely studied in this paper. The downhole catalytic upgrading system is developed and prepared for Liaohe oil heavy oil; the prelimentary operation plan is porposed according the laboratory research resultsand the relative satisfactory results are got through experiments in situ.The degradation mechanism of the resin and the asphlatene in Liaohe heavy oil during the steam injection process is studied, in which the content of S in Liaohe heavy oil is relatively low (-0.5%). The breackings of the aliphatic chains on the congested aromatic hyracarbons and the bridge aliphatic chains between the congested aromatic hyracarbons in the resin and the asphaltene molecles play very important roles during the downhole catalytic upgrading heavy oil reaction under the steam injection conditions, besides the desulphuration. It is proved by the experiment that the main mechanism of the alphatic chains is based on the ipso substitution mechanism.The downhole catalytic upgrading system is developed and prepared for Liaohe heavy oil in this paper. The transition metal ions are put on the framework of organic acid to become oil soluble. The upgradng reaction can happen under the homogeneous catalysis using the organic metal compounds as catalyst. The catalystic sysetem has the low cost, the simple preparation method, the high heat stablity and the high catalystic effect. The catalystic sysetem is effectiv at about 200℃.The viscocity reductin of the upgrading heavy oil and the viscocity reductin of the emulsion are combined in this paper. The organic transition metal compounds act as cayalysts during the upgraing reaction which make the heavy oil partly degrade and viscosity reduce and then, the organic transition metal compounds composited with the surfactant as emulsifers after the upgrading reaction. The heay oil is changed into the O/W eniulson after the upgrading reaction, the viscosity reduction goes farther through the emulsion after the viscocity reductin of the upgrading heavy oil. The composited vicosity reduction rate can reach over 90%.The principle of toluene as an additive for the catalystic upgrading reaction is studied in this paper.As the heavy oil updrading is a reversible reaction between the polymerization and the degration of heavy oil, the radicals H·and benzyl which is produced by toluene under the stean injection condiyions can eliminate the radicals which produced by the heavy degration and block the polymerization among the radicals produced by the heavy oil. In another side, toluene as solvent makes the intercalative aggregation of asphaltene decompcsite in the heavy oil and the asphaltene molecules can fully contact with the catalysts.The prelimentary operation plan is porposed according to the laboratory research results to guide the production in situ for oil recovery in Liaohe oil field.The research results were applied to six heavy oil wells in different districts of Liaohe oil field from 2003 to 2004. The production history shows that the cumulative oil recovered during the production period increased 11009.4 tons, on the average, each well increased oil recovery of 3742.8 tons. The ratio of cost to benefit is 1:7.0. It was observed that the viscosities of heavy oils reduced dramatically after the recovered. In the recovered heavy oil, the amount of saturate and aromatic components increased; meanwhile, the amount of resin and asphaltene components decreased. This indicates that the improvement in the downhole catalystic upgraing reactions significantly enhances the quality of the heavy oil and reduces the viscosity of the heavy oils. Furthermore, the improvement in catalystic upgrading reactions in this paper can facilitate the recovery of heavy oil reservoir economically more efficient.