化学生热催化裂解体系对稠油降黏实验研究

Effect of Chemical Heat-Generating Catalytic Cracking System on Heavy Oil Viscosity Reduction

为了更好地提高稠油油藏开发效果,采取化学生热与催化裂解方式来降低稠油黏度、提高地下稠油的流动能力非常必要。选择NaNO_2和NH_4Cl溶液作为化学生热剂,通过正交实验优选出生热剂最佳反应条件为:4 mol/L NaNO_2,4mol/L NH_4Cl,体系pH值为2。该条件下,反应温度和压力在短时间内迅速上升,分别达到峰值204℃和13.6 MPa,达到峰值的时间为6 min,反应基液温度升高149℃。油酸镍催化降黏体系最佳配方为:以反应原油的质量为基准,羧酸盐型油酸镍催化剂0.3%,供氢剂甲酸7%,助剂尿素7%,乳化剂十二烷基苯磺酸钠0.13%。该催化体系的最佳反应温度为280℃。油酸镍催化后,原油黏度由213.8 mPa·s降至74.2 mPa·s,降黏率为65.3%。当化学生热剂与催化裂解剂共同作用时,降黏率可达66.5%,饱和烃和芳烃含量增加,胶质和沥青质含量减小,催化降解效果较好。

In order to improve the development efficiency of heavy oil reservoir, the application of chem-thermogenic and catalytic pyrolysis to reduce the viscosity of heavy oil was particularly important. NaNO2 and NH4C1 solution were chosen as chemical heat-generating agent, and orthogonal experiment was designed. The optimum reaction condition was obtained as follows： 4 mol/L NaNO2, 4 mol/L NH4C1 and 2 system pH value. On this condition, the temperature and pressure of reaction rose rapidly in a short time with peak value 204℃ and 13.6 MPa after 6 min, respectively. The temperature of reaction solution increased 149℃. The best formula of oil-soluble nickel-based catalysts system was established： the mass of reactive crude oil as benchmark, 0.3% oleic acid nickel catalyst, 7% formic acid hydrogen donors, 7% auxiliary of carbamide and 0.13% sodium dodecyl benzene sulfonate. The optimum reaction temperature of the catalytic system was of 280℃. When the crude oil was catalyzed by oleic acid nickel, the viscosity decreased from 213.8 mPa· s to 74.2 mPa· s and the viscosity reduction rate was of 65.3%. When the chemical heat-generating agent and the catalytic cracking catalyst worked together, the viscosity reduction rate was up to 66.5%. The content of saturated hydrocarbon and aromatic hydrocarbon increased, whereas that of colloid and asphaltine decreased. So the catalytic degradation effect was quite well.