Fiber probe has been widely used in the field of multiphase gas phase detection because of its anti-electromagnetic interference, easy array and high sensitivity. In this paper, a gas-liquid two-phase flow holdup imaging method based on single-mode fiber probe is proposed. The fusion of single-mode fiber probe measurement technology and Kriging interpolation algorithm can not only provide a more comprehensive and detailed visualization of the holdup distribution in the measurement area, but also effectively overcome the limitations of traditional methods.
:
:For each pair of measuring points, the distance between them (i.e. the lag distance) is calculated, and then the semi-variance of the gas holdup between the pair of points is calculated. The semi-variances of all pairs of measuring points are grouped according to the lag. For each lag interval, the mean value of the semi-variance of all points within the interval is calculated to form the value of the experimental variance function. According to the calculated values of the experimental variation function, the appropriate model is selected for fitting, and then solved by indirect adjustment method, the nugget effect value C0, partial abutement value C and variable range alpha can be obtained, so as to establish the experimental variation function model.
:The variance function between the estimated point and the known point is calculated by using the established experimental variance function. In the search range with the point to be estimated as the center, the variation function value between the point and all known points is calculated, and combined with the semi-variance value between all known points obtained in step 2, the Kriging equations are substituted, m+1 equations are established (where m is the number of all known points in the search range), and m weight coefficients are solved.
:
:Using image processing software, these data points are mapped into a grid in the interpolation region to generate a two-maintenance gas rate image of the column cross section. In the image, different colors or gray levels represent the gas holdup sizes of different interpolation points on the column cross-section, which intuitively shows the spatial distribution of gas holdup.
A
This method not only solves the limitation of traditional array optical fiber probe in gas retention measurement, but also benefits from the excellent stability and durability of optical fiber sensor, which is very suitable for application in complex environment such as oil and gas Wells. By providing an intuitive image of the gas phase distribution, the imaging technology can assist in adjusting production strategies, optimizing water injection schemes, and effectively supporting stimulation. In addition, real-time monitoring and visualizing changes in gas holdup are critical to early identification of safety risks, such as bubble accumulation that could lead to pressure instability or equipment failure. Therefore, this technology has important guiding significance and practical value in preventing potential problems.