The Research On Heavy Oil Viscosity Reduction Of Sulfonate Waste Liquor Distribution System

The reserves of conventional crude oil reduce gradually in the worldwide, however the reserves of heavy crude oil is far greater than conventional crude oil, so the development of heavy crude oil is more and more meaningful. Heavy crude oil has the characteristics of high solidifying point, high viscosity and poor liquidity. Sulfonate is widely used in oilfield as viscosity agent. The raw material is accessible and low cost. Sulfonate is also very common and plays a very important role in oil displacement chemicals. The mechanism of the high viscosity of heavy oil is restructuring colloid in heavy oil and asphalt form strong hydrogen bonding interaction. And asphaltene formed is neat flake molecular layer, make a dramatic increase in the viscosity of heavy oil. The orderly structure must be broken in order to reduce the viscosity of heavy oil. Sulfonate has excellent characteristics of resistance to temperature and salt resistance as viscosity agent. Screening suitable viscosity agent and sulfonate base fluid distribution is the recycle of sulfonate downstream products, has the practical value. It opens a new way for the development and utilization of sulfonate base.We have screened suitable viscosity reducer for SHAN 56 heavy oil,moreover have improved the performance and done distribution of research. Through the experimental research, the main conclusions are as follows:(1) Determination of viscosity-temperature curve for SHAN 56 heavy oil:When the temperature increased from 50℃ to 70℃, the viscosity of crude oil reduced sharply. When the temperature increased from 70℃ to 90℃, the viscosity of crude oil changed little, tends to be stable.(2) The conditions of the determination of viscosity reduction rate for sulfonate distribution system:When the mass ratio of oil/water is 7:3, the viscosity of emulsion reduced to minimum(50 degrees Celsius).The emulsion time for water bath was 1 hour, and the stirring speed was 200r/s, and the mixing time was 2 minute.(3) Sulfonate distribution system’s evalution of viscosity reduction.① The most effective viscosity reducers were Sodium hydroxide and sodium dodecyl benzene sulfonic acid for stage 1 heavy oil. Sodium hydroxide dosage was 0.5% in the mass fraction of adhesive solution and viscosity-reducing rate reached 99%. Sodium dodecyl benzene sulfonic acid(SDBS) dosage was 1%-1.5% and viscosity-reducing rate reached 93%. The dosage of two kinds of vicosity reducer was relative low and the formation of O/W emulsion has certain stability, but does not affect its demulsification.② The most effective viscosity reducers were AES (fatty alcohol polyoxyethylene ether sodium sulfate) and AEO (fatty alcohol polyoxyethylene ether) for stage 3 heavy oil. The lowest dosage of AES was 0.05%, the lowest dosage of AEO is 0.5%. The viscosity-reducing rate of sulfonate distribution system(0.04%AES and 10% sulfonate solution) reached 99% and the interfacial tension of combined systems reached 10-2 mn/m, better proved sulfonate and AES blendsed with effect.(4) The mechanism research on heavy oil viscosity reduction of sulfonate complex distribution systemThe type of emulsion was W/O after surfactant. GC-MS oil fingerprint analysis results show that surfactant role after sample did not change component and just changed state of aggregation of crude oil. Through the infrured spectra analysis of asphaltene, asphaltenes in 3000-4000 on the absorption peak intensity decreased after viscosity reducer. Proved that viscosity reducer and asphaltene flake molecules layer formed stronger hydrogen bonding interaction. Through the analysis of particle size, the particle size decreased before and after the asphaltene viscosity viscosity agent role, and thus it could be seen that asphaltene molecules of sheets molecular layer of neat structure had a certain degree of dividing, thus the viscosity of heavy oil was also reduced.(5) Heavy oil displacement efficiency research of sulfonate distribution system The displacing fluid of sulfonate solution(10%) improved recovery ratio 1.09%. The mixed displacing fluid of sulfonate solution(10%) and AES (0.04%) improved recovery ratio 5.23%. The mixed displacing fluid of sulfonate solution(10%) and AEO (0.5%) improved recovery ratio 2.8%.