The Calculation of Pressure Gradients In High-Rate Flowing Wells

Abstract

Work on the calculation of vertical two-phase flow gradients by Cia. Shell de Venezuela has been based mainly on the "energy-loss" method proposed by Poettmann and Carpenter in 1952. The "energy-lass-factor" correlation proposed by Poettmann and Carpenter was based on relatively lowrate flow data. This correlation proved inapplicable to high-rate flow conditions. In an attempt to establish a satisfactory correlation for high rates, a series of experiments was carried out at rates up to 5,000 BID in Cia. Shell de Venezuela's La Paz field in Venezuela, using tubing strings fitted with electronic surface-recording pressure elements.As a result of these experiments a correlation between energy-loss factor and mass flow rate was established which is believed to be applicable to a wide range of conduit sizes and crude types at high flow rates (e.g., above 900 BID for P/S-in. OD tubing). It is anticipated that the resulting gradient calculations will have an accuracy of the order of ± 5 per cent.A t lower flow rates the energy-loss factor cannot be considered as constant for any mass rate of flow, but varies with the free gas in place and the mixture velocity. No satisfactory correlating parameter was obtained. As a practical compromise for low flow rates, a modification of the curve proposed by Poettmann and Carpenter was used. In practice this was found to give gradient accuracies of approximately ± 10 per cent down to flow rates as low as 300 B/ D in 2?/8-in. tubing.

Development of an expert system for selection of multiphase flow correlations

“…Abd El-Moniem (2016) and Abd El-Moniem and ElBanbi (2015) collected bottom-hole flowing pressure data points from both the literature from Ashiem (1986), Baxendell and Thomas (1961), Chierici et al (1974), Hill and Wood (1994), Peffer et al (1988) and Reinicke et al (1987) and actual oil wells covering different well and flow conditions. The current study used around 2730 oil well data points for developing the expert system and 144 different data points for its validation.…”

A Combined Bottom-hole Pressure Calculation Procedure Using Multiphase Correlations and Artificial Neural Network Models

“…Due to the unsuccessful extrapolation of the Poettman and Carpenter correlation from low flow rates to high flow rates, Baxendell and Thomas (1961) suggested some modifications to the Poettman and Carpenter correlation to fit smoothly to the high-rate correlation derived from Cia, Shell de Venezuela's La Paz field in Venezuela.…”

“…The comparison of the three correlations in "Category a" from Table 2.1, i.e. Poettman and Carpenter (1952) correlation, Baxendell andThomas (1961) correlation andFancher andBrown (1963) correlation, is shown in Figure 2.1. Figure 2.1: "Category a" friction factor correlations (Brill and Mukherjee, 1999).…”

“…The three correlations plotted all used the numerator of the Reynolds number ρvd to predict friction factor. Baxendell and Thomas (1961) correlation modified Poettman and Carpenter (1952) correlation at high flow rates and Fancher and Brown (1963) correlation considered gas-liquid ratio as an additional parameter.…”

“…The experimental data to develop this correlation was acquired under the following condi- Hagedorn and Brown performed a statistical analysis on the results of the calculations utilizing the data obtained in their study as well as the data reported by Fancher and Brown (1963), Baxendell and Thomas (1961) and Gaither, Winkler and Kirkpatrick (1963) with a total average percent error of 1.101% and a total standard deviation of the percent errors of 6.469%.…”