Study On Encapsulation And Control-release Of Initiator For Heavy Oil Aquathermolysis

The aquathermolysis is the most effective method about heavy oil recovery in the worldtoday. More and more research suggested that the initiator has promoting effect for hydrothermal cracking of heavy oil in the reaction. However, the activity of initiator was easy to be lost during the process of injection into oid well for its instabililty. In this dissertation, microcapsule technology was used to protect the initiator. Thus, long-distance transportion of the initiator without the loss of activity in the oil well could be expected.Tert-butyl peroxide(TBPB) was chosen as the initiator for the experiment. Two kinds of microcapsule, used β-cyclodextrin and sodium alginate as coating materials, were successfullysynthesized in the dissertation.First, the β-cyclodextrin microcapsule was synthesized. β-cyclodextrin(0.02 mol·L-1) and tert-butyl peroxide(TBPB) was mixed and stirred at 40 ?C for 3h. The microcapsule was obtained after washing and evaporation. Its structure was characterized by techniques of FT-IR, 1H-NMR, TG, and UV.β-cyclodextrin and tert-butyl peroxide(TBPB) formed a type of inclusion complex with the molar ratio of 2:1. The covering rate of microcapsule is 95.5% at the above condition.Second, calcium alginate microcapsule was synthesized using sodium alginate as coating material and calcium chloride as the curing agent. The structure of calcium alginate microcapsule was characterized by Optical microscope and UV. The best reaction condition was tested and confirmed as follows: the concentration of sodium alginate is 1.5%, the concentration of calcium chloride is 6%, the amount of surfactant is 0.2%. The drug cladding rate of microcapsule is 93.6% at the above condition.Third, effect of two kinds of microcapsule on the viscosity reduction of heavy oil was tested. The oil sample of shan 56-9×11 from The Shengli oilfield was used. The aquathermolysis reaction conditions were as follows: the amount of catalyst is 0.2%, surfactant is 0.05%, oil-water ratio is 7:3, the reaction temperature is 150°C, the reation time is 24 h. Both kinds of inclusion compound could promote the viscosity reduction of heavy oil. The alcium alginate microcapsule has much better effect.