The Cross-correlation Flowmeter Based On Conductance Senseor Applying To Measure The Flowrate Of Water Injection-well

The main purpose of injection profile logging is to know the zonal water intake conditions for improving the displacement efficiency. The oilfield can keep the long range development only when according to accurate reliable injection profile logging data to carry out efficient exploitation .At present, the flow measurement methods applying to injection profile mainly have: isotope tracer tool, turbine flowmeter, electromagnetic flowmeter, ultrasonic flowmeter, impulse neutron oxygen activation logging,ect. But it still needs a method that is low cost, no radioactive contamination, applying to the low flow injection well.Cross-correlation flowmeter has high repeatability and accuracy; good consistency conformity. It has already succeeded in high water-cut flowrate measurement in Daqing oilfield for more than 200 wells. It would provide a new kind economical flowmeter for the low or medium permeability field that applying conductance cross-correlation with a packed umbrella to injection profile logging. And it would also reduce the radioactive contamination of the isotope to human body and the environment. The conductance correlation method applying to the commingled water injection wells is introduced in this paper. In view to the different flowing noise between production profile and injection profile, cross-correlation principle and tracer are referenced in this article. Conductance sensors have no flowing noise to check because of the uniform distribution of electrical conductivity in water injection well. Therefore, High concentration NaCl solution is ascertained to be the marking solution to obtain flowing noise. The sensors model is established by the finite element analytical method and its flow field is also analyzed. For delaying the diffusion of marking solution and increasing the fluctuation of flowing noise, polymer is added to the NaCl marking solution. The relation of the characteristic between polymer solution concentration and conductance is also analyzed.The experimental loop is also described. The dynamic results are analyzed. They indicate that the correlativity of the flow noise signals is very strong and there is a good linearity existing between the correlation velocity and the standard flowrate. And there is a good resolution to the water flowrate under the low flowrates .Generally speaking, cross-correlation method would provide a new method for measuring injection profile flowrates. It also provides a new reference for measuring production profile flowrates when water is continuous phase. The mechanical drafting for downhole machine is also described to establish a basis for making model machine.