Mechanical/Geometrical Skin If a reliable skin value is available from transient well testing, then this value should be directly entered by selecting the “Enter by hand” option. In addition, PROSPER provides 3 methods of estimating skin factor using input parameters such as perforation geometry, depth of damage etc. The required input parameters are often difficult…

# Category: Basic Petroleum Engineering

## Z Factor

Read All Detail | Discussion

## Shut-in Well Head Pressure

Read All Detail – Discussion

## Well Inflow Performance

Well Inflow Performance represents the relationship between pressure and flow rate at the well face of an individual well. The scientist Darcy was the first studied extensively the relationship between pressure and flow rate. His experimental studies consist on creating a pressure differential across a porous media and measured the resulting flow rate. Darcy’s experiments…

## Introduction to IPR and VLP

Read All Detail – Discussion The productivity of the well depends on an efficient use of the compressional energy available in the reservoir allowing the reservoir fluids to flow toward the production separator. As an introduction to IPR…

## Vogel’s inflow performance relationship

In 1968, Vogel established an empirical relationship ( Vogel’s inflow performance relationship )for flowrate prediction of a solution gas-drive reservoir in terms of the wellbore pressure based on reservoir simulation results. Vogel’s Model compared to PI Model… The PI model works very well for single phase fluid (water, oil, or water/oil) flowing into a wellbore, even though…

## The Composite Inflow Performance Relationship

The Composite Inflow Performance Relationship is based on the combination of PI model, presented in the previous articles “Well Inflow Performance”, and “Vogel’s inflow performance relationship”. As per the aforementioned articles, PI model could be used if the well producing a single phase flow with no gas in the solution (Pwf > Pb). In the other…

## Pressure Gradient

Pressure and depth: “Pressure and Depth” is the FUNDAMENTAL relationship in the oil industry. Your understanding of the concept is crucial. The easiest way to calculate pressure from depth is to use the pressure gradient of the given fluid. Pressure gradients for incompressible fluids have units of pressure/depth. For example, psi/ft, bar/m. Pressure gradient seems difficult, but it…

## Pressure drawdown & Skin Factor

Pressure Drawdown: Pressure Drawdown (∆P) is defined as the difference between the static bottom hole pressure (SBHP) and the flowing bottom hole pressure (Pwf). Thus, the drawdown is the differential pressure that drives fluids from the reservoir into the wellbore. ∆P= Pressure drawdown = SBHP – Pwf Example: If SBHP = 200 bar, and Pwf =…

## Multiphase Flow Properties & Pressure Gradient Calculation

For oil wells, the main component of pressure loss is the gravity or hydrostatic term. Calculation of the hydrostatic pressure loss requires knowledge of the proportion of the pipe occupied by liquid (holdup) and the densities of the liquid and gas phases. Accurate modeling of fluid PVT properties is essential to obtain in-situ gas/liquid proportions, phase densities,…

## Multiphase flow correlations

The primary purpose of a multiphase flow correlations is to predict the liquid holdup (and hence the flowing mixture density) and the frictional pressure gradient. This article details the most widely used correlations for the prediction of the Vertical Lift Performance. The oil and water are lumped together as one equivalent fluid. Thus flow correlations in common…

## Outflow Performance Correlation Selection

There is no universal rule for selecting the best flow correlation for a given application. When an outflow performance simulator is used, it is recommended that a Correlation Comparison always be carried out. By inspecting the predicted flow regimes and pressure results, the User can select the correlation that best models the physical situation. Refer…