Study On New Analytical Method Of Polymer Using In Flooding

Polymer flooding has been one of the most maturational and economic chemistry flooding in current enhanced oil recovery technology all over the world because of the apparent mechanism, the simple process and gradually maturing technique. At present, China has profited from polymer flooding and become the main nation large-scale using polymer flooding. Polymer flooding has become the important technical method to our country to keep on high and steady petroleum production. Along with the extension of the chemistry flooding, reservoirs with good conditions got less and less, development of residual oil reservoirs proved to be difficult due to such high temperature and high salinity, so it is necessary to research and apply the heat-resistant and salt-tolerant polymer. As the variation of the molecular structure and composition, methods that evaluated the performance and characterization of the common polymer were unsuitable for the heat-resistant and salt-tolerant polymer. Thus, the primary methods of evaluation should be revised, or new evaluation of the particular parameter should be built for meeting new type polymer's needs.The new analytical method for the new type— heat-resistant and salt-tolerant polymer being used in the Shengli oil-field including hydrolysis degree, HPAM concentration determination, interfacial properties etc are established. Mainly conclusions and innovations drawn form studies were as following:1. Studied the affecting factors of the acid-base titration, the results shows that dissolve is a prior condition to measure the hydrolysis degree. Dissolve more bad, the error more big. These heat-resistant and salt-tolerant polymers which are hard to be dissolved can't depend on salt to dissolve, so other method should be found to determine the hydrolysis degree. Thus on the base of the acid-base titration, the potentiometric titration is established with the potentiometer as an assistance instrument. It has advantages of high precision and good reproducibility. The advantages of two methods are described in comparison with shortcoming and adaptabilities. Two kinds of titration methods are used totally to measure the hydrolysis degree of the polymer solution perfectly. 2. By making use of Size-Exclusion Liquid Chromatography, a method of HPLC todetermine the concentration of HPAM which average molecular weight was up to 15 million was founded. The linear range was 10-500mg /L and threshold 30mg/L. Without any interference from coexisted lignin, BES-3, sodium carbonate, salt and a little amount of crude oil.3. The methods of evaluation are established including bulk shear rheology, interfacial rheology and elongational rheology. All kinds of polymer solutions have diverse rheologic properties. Particularly using the TRACKER fully automated drop tensiometer to measure the interfacial rheology in dilatation or contraction. A measurement of the interfacial viscoelasticity modulus as a token of the membranes' intensity is founded. The different effects by various factors including the volume of the drop, the duration of each measurement, the period of the oscillation are discussed. The ultimate experimental conditions are located.4. The interfacial viscoelasticity is increased while testing time is lasted at the interface between HPAM and dodecane for the same HPAM concentration and the characteristics, which viscoelasticity is smaller at beginning and gets larger along with the increase of time until the equilibrium is obtained, were observed. The various viscoelasticity was found when HPAM concentration was changed. The more the HPAM concentration, the higher the initial and equilibrium viscoelasticity are at HPAM/dodecane interface and the shorter the time is that equilibrium viscoelasticity are obtained. The real part (E') contributes to viscoelasticity (E) much more than that of imaginary part (E").The contribution of real part always plays main role in viscoelasticity. After aging of the HPAM solutions, the interfacial viscoelasticity modulus decreases. Moreover different viscoelasticity at different interfaces for HPAM solution was also found. It seems that viscoelasticity between two phases is lessened while the density difference between these two phase is decreased. In addition, measurement of interfacial rheology is a useful method to evaluate polymer solution.