Optimum tubing size prediction model for vertical multiphase flow during flow production period of oil wells

Abstract

Optimum tubing size (OTS) selection was traditionally done by using nodal analysis to perform sensitivity analysis on the different tubing sizes. This approach was found to be both cumbersome and time-consuming. This study developed a userfriendly and time-efficient OTS prediction computer model that could allow Petroleum Production Engineers to select the best tubing size for any vertical oil well. The tubing size selection was based on the present operating flow rate, economic considerations and future operating flow rate as defined by the OTS selection criteria of this study. The robustness of the model was tested using tubing sizes ranging from 0.824 to 6.0 inch in a vertical well producing from both saturated and undersaturated oil reservoirs. The 2.750-inch tubing was found the OTS for both scenarios. In the validation, the results obtained from the novel OTS prediction model and Guo et al. (Petroleum production engineering: a computer-assisted approach, Gulf Professional Publishing, Cambridge) spreadsheet program using the Poetmann-Carpenter method were in excellent agreement for operating flow rate but not for operating pressure. Furthermore, the novel OTS prediction model was in excellent agreement with the same spreadsheet program based on modified Hagedorn-Brown correlation for both operating flow rate and pressure. The results showed that the model developed in this study is reliable and can be used in the field for vertical oil wells. The new model could as well inform the Production Engineer when the well would need artificial lift for economic production of the well. It was recommended that Newton-Raphson and modified Hagedorn-Brown methods be used in future study.

Waveguide Analysis of Radiofrequency Transmission in Well Tubulars for Electromagnetic Heating of Heavy Oil

“…The standard casing and tubing sizes in a vertical well producing from both saturated and undersaturated oil reservoirs are presented in 10 and 11 respectively. A predictive model determined the optimal tubing size (OTS) of 73 mm preferable in both cases [41]. The corresponding optimal casing size (OCS) was determined to be 139.7 mm [42].…”

“…At sufficiently high frequencies, Z ∞ in exhibits a real component which is equal to the characteristic impedance of the fictitious line to approximate, according to (41) and shows that matching to ports with impedance Z 0 will be achieved by choosing Z 0 = L u C u . As frequency decreases, the magnitude of the term under the radical sign eventually becomes zero.…”

Tubing System Performance Profiling of Dry Gas Wells Using Newton Raphson Iteration Method

“…Due to the series of complex correlations and equations required in specifying the tubing performance of a nonassociated gas well, it is often necessary to develop an efficient algorithm that will facilitate the determination of pressure variables, show the pressure profile of the tubing in a chart and most importantly, suggest upon comparisons, the best tubing size that would yield optimum performance. In 2020, Nwanwe et al [14] used MATLAB to develop a model that predicts optimum tubing size for vertical oil wells. However, this paper uses C# programming language to profile Tubing System Performance for dry gas wells.…”