Abstract:

A computer program (included as an EXCEL spreadsheet) was generated to model flow in capping, containment, and collection system and evaluated using available data from the Macondo well incident. Flow modeling is essential to determine the pipe and component sizes needed or conversely, the flow rate and pressure capabilities required, when applying a capping system to a particular set of conditions. The program consists of 10 multiphase correlations and 5 PVT correlations that have been published over the years. The computational technique used by multiphase correlations is an iterative algorithm, one length increment at a time. The pipe is divided into equal length intervals (50 in the case of the computer program), and the pressure is iterated in each interval until self-consistency is achieved, using the pressure calculated in the interval directly above as a starting point. Once pressure and temperature are predicted as a function of depth, the question of whether hydrates could form in the pipe at any interval of depth is evaluated. A limitation of the computer program is it is a black oil model, that is, the oil in the reservoir has gas in solution and this gas is liberated as pressure and temperature decrease, yielding a multiphase flow of fluids in whatever pipe is in use.

Suggested Citation:

Smith, John Rogers. 2014. Model flow in a capping, containment, and collection system and comparison to available data from the Macondo well incident.. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/N7DJ5CKQ

Purpose:

To model flow in capping, containment, and collection system and evaluated using available data from Macondo well incident.

Data Parameters and Units:

Twophase-LSU capping stack project.xlsm-- Example Two Phase Flow Problem, 2 ph pgm: Depth (ft), Pressure (psi), Regime, Convergence/Indicator, Temperature (C), elemental pressure gradient for two-phase flow (dp/dL), frictional pressure gradient for two-phase flow (dp/dL), pressure gradient due to acceleration for two-phase flow (dp/dL), angle (degrees), Bo Bond number (unitless measure of the importance of surface tension forces compared to body force), Viscosity (kg/m*s), Hydrate (Yes, No), Temperature for each interval (C). Metadata on the input to the two-phase flow pgm (pragmatic general multicast), data def. Graph: pressure (psi) verses depth (feet). DP annulus: computation of single fluid frictional pressure losses for concentric annular flow. hydrate data: Methane (0.7, 0.8, 0.9, 1) hydrate chart: Temperature (Fahrenheit and Celsius) verses Pressure for Hydrate formation (psi).

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