Research And Application Of A Comprehensive Treatment Agent In Injection Wells

The crude oil is water-flooding in an oil filed, it has high wax content、 high viscosity and high pour point. During the injection process, the routine test can not be accomplished because of deposits on the wall. Concerning this problem, the samples taken from blocked injection wells are analyzed. On this basis, the appropriate wax depressing and removal component and scale inhibitor are selected by haplo-factor method、orthogonal test method and uniform design method. With the use of appropriate emulsifiers, the formulation of comprehensive treatment agent is obtained, and the field test is carried out in this oil field. The main research results and conclusions are as follows:1、The deposits and the water samples are analyzed, the results shows that main component of the deposits is hydrocarbon compound and minerals which is called dead oil. The wax content of two oil samples is over 20%, the carbons distribution of paraffin mainly distributes from C20 to C28 and the main ions are Ca2+、Mg2+、Ba2+、SO42-、CO32- and HCO3- and so on in three water samples. The main component of scales is CaCO3.2、The basic formula of components for wax depressing and removal including 9#compound organic solvent、AR-36、compound EVA and butylcellosolve is obtained through orthogonal test. At the same time, the anti-scaling efficiency of ATMP and PESA is over 99.89% when their mass ratio is 1:2. And the emulsifying effect of O-30 and O-3 is the best, the stability coefficient is 72.45% when standing for 80h.3、With the use of appropriate emulsifiers, the comprehensive treatment agent is obtained by mixing the wax depressing and removal component and the aqueous solutions including scale inhibitors. The results of experiments in laboratory shows that wax dissolution rate is 26.9mg/min, the anti-scaling rate is over 98.90% and the wax inhibiting rate is over 56.00%. It also reduces the viscosity of crude oil and has little corrosion to the rubber of packer in injection wells.4、The test result shows that the agent can solve the plugging of injection wells which are caused by dead oil、wax deposition and scaling, and it is easy to operate and the price is low, so it has high field application value.