An Innovation Chart for Key Parameters Calculation of Flowmeter in Production Profile Interpretation

During the production profile logging data processing and interpretation process of oil&gas wells, it is essential to calculate the fluid flow velocity and evaluate the flow rate for each oil layer in the wellbore. Currently, the industry traditional method involves calculating the liquid flow velocity by first selecting certain data points in different steady-flow depth intervals, then creating X-Y space crossplot between logging speed of cable and rotor speed of turbine flowmeter to perform regression analysis on the measured data of each group to calculate the friction coefficient (k) (i.e., the slope of the regressed line in the crossplot) and the startup speed (b) (i.e., the x-axis intercept with the X-axis) of the rotor, which are critical parameters for determining the flow velocity and production accumulative rate of each layer. However, the transitional X-Y coordinates crossplot method has certain limitations: 1) Each group of N measured data points can be regress \(C_{N}^{2}\) straight lines, but the traditional crossplot method only provides one solution and ignores many other reasonable solutions; 2) Among all the measured points of each group, the difference of regression slopes between any two measured points is very small. So, this traditional method cannot obviously show the small changes of friction coefficient (k) and startup speed (b). Thus, it is not sensitive to the parameters calculation of friction coefficient (k) and startup speed(b). Therefore, an innovation chart is proposed for addressing the challenge of determining friction coefficient and startup speed calculation in this paper. The innovative chart method, which employs Hough space transforms to reprocess data points from a flow-stable interval, is newly constructed in this paper. The traditional crossplot derived from X-Y space are replaced by a newly self-invented chart, avoiding issues with missing possible results in traditional X-Y crossplot. By analyzing the intersections of curves within Hough space, the method determines all possible lines’ slopes and x-axis intercepts for all the data points of each group, effectively solving the limitations of conventional X-Y crossplot while providing intuitive access to startup speed and friction coefficient. Based on the innovative chart, a new processing and interpretation procedure for production profile logging data is established. After comparing the results from both methods, two key parameters’ results obtained are consistent. Further, the innovative chart in Hough space demonstrated greater efficiency and following practical advantages: 1) It can display all the possible results for startup speed and friction coefficients, avoiding omission limitations encountered in traditional X-Y crossplot; 2) The key parameters are intuitively displayed as they appear in the visual interface, reflecting the original data directly; 3) The concentration of curve intersections provides insight into the quality of the raw data, which provides a quality control function with the innovative chart.