1. What's IPR and uses of IPR?
IPR stands for Inflow Performance Relationship. The relation between the movement rate (q) and the flowing bottom-hole pressure (Pwf) expresses the inflow performance marriage. For your gas well to move there has to be a pressure differential from the reservoir to the well bore and the smooth characteristics and changes with time. There is a linear relationship between your reservoirs producing at the pressures above the bubble point pressure, this is actually the pressure when Pwf is better or add up to bubble point pressure.
Inflow Performance Relations
The linear form associated with an IPR presents the Production Index (PI), which is the inverse of the slope of IPR. The gas reservoir is deliberately evaluated using the well inflow performance romance (IPR). Gas well IPR also depends on the move conditions, that is, transient, continuous point out or pseudo express flows which can be determined by reservoir boundary conditions.
Uses of IPR:
- It is special kind of dimension property which is used to evaluate life and productivity of reservoir.
- Inflow performance marriage pays to as a tool screen well performance and predicts the simulation and manufactured lift up requirements of lots of wells.
- In order to check on or correct the size of a proper to an accurate value IPR of the well must be known.
2. List three main factors affecting IPR?
The three important factors affecting IPR are:
- Pressure inside the tank.
- Nature of reservoir fluids.
- Types of stones.
3. Explain inflow and outflow performance?
Inflow performance of any reservoir is thought as the functional romance between the streaming bottom-hole and the causing flow rate. It is the rate at which fluid will move towards the wellbore and will depend on the viscosity of the liquid, the permeability of the rock, and the driving force. For any gas well to stream there must be a pressure difference from reservoir to the well-bore at the reservoir depth. In case the well-bore pressure is equal to the tank pressure there can be no inflow. In case the well-bore pressure is zero, the inflow would be a maximum possible i. e the Absolute Open Flow (AOF).
For intermediate well-bore stresses, the inflow will change. For each reservoir, you will see unique relationship between the inflow rate and wellbore pressure. For just a heterogeneous reservoir, the inflow performance might change from one well to some other. The performance is often described in term of an storyline of surface production rate (stb/d) versus streaming bottom opening pressure (pwf in psi). Several models are for sale to determining the several types of Inflow performance Relation; they are Straight line movement, Vogel's method, Future IPR flows, The Fetkovich method and so many more.
Outflow Performance requires fluid circulation through circulation through the creation tubular, the wellhead and the surface flow line. Generally the fluid flow entails the pressure difference across each segment of the substance flow. Calculating the pressure drop at each portion is serious problem as it consists of the simultaneous movement of olive oil, gas and drinking water(multiphase stream), which indicates the pressure drop dependent on many variables in which a few of them are inter-related.
Due to the, it's very difficult to acquire an analytical solution. Instead, empirical formulas and numerical models have been developed and used for predicting the pressure drop in multiphase movement. To be able to obtain the sensible results, hence, it is important to establish the input variables carefully, through close co-operation with development engineers and also to check the results of the Vertical Circulation Performance which is also known as as the Outflow Performance.
4. Talk about and explain Darcy's Equation?
Darcy's Law suggests the fundamental regulation of fluid movement in the porous multimedia. It can be used to spell it out the move of fluid contaminants, which includes essential oil, water & gas, through petroleum reservoirs. It also governs the circulation of the debris through the porous mass media and describes the relationship between the movement rate, pressure drop and smooth resistance.
The mathematical expression produced by Henry Darcy in 1865 expresses that the substance visiting in a the velocity of any homogeneous smooth in a porous medium is proportional to the pressure gradient and inversely proportional to the substance viscosity.
For a horizontal linear system, this romance is:
where:
Are the elevations at the very top and bottom of the porous materials or porous medium.
Gives the space of the sand filter and it is given by the equation ?l = z1 - z2 p1, p2 May be the pressure due to the water flow, measured by manometers above and below the sand filter.
H1, H2 Represents the hydraulic mind at the inlet and wall socket of the fish tank and portrayed as the sum of pressure mind and elevation head.
By a series of experiments, Darcy set up that, for the same fine sand, the release Q is:
- proportional to the cross-sectional area A: Q ~ A;
- Proportional to the difference in the elevation of this particular: Q ~ (H2 - H1); observe that because H2 < H1, the head drop H2 - H1 < 0.
- Inversely proportional to the move span through the porous material: Q ~ 1/?l.
Darcy printed the results of his experiment, and its legislations in 1856, starting the age of the groundwater hydrology. The exact same conclusions can be drawn no matter if the flow is vertical, horizontal, or in virtually any other course
Different porous marketing models to demonstrate Darcy's experiment
n is the visible velocity in centimeters per second and is also add up to q/A, where q is the volumetric flow rate in cubic centimeters per second and A is total cross-sectional area of the rock and roll in square centimeters. Quite simply, A includes the region of the rock and roll material as well as the region of the pore channels. The smooth viscosity, , is indicated in centipoises devices, and the pressure gradient, dp/dx, is atmospheres per centimeter, taken in the same route as nand q. The proportionality constant, k, is the permeability of the rock and roll expressed in Darcy units. The negative indication is because the pressure gradient is negative in direction of flow.
- Laminar (viscous) flow
- Steady-state flow
- Incompressible fluids
- Homogeneous formation
For turbulent flow, which occurs at higher velocities, the pressure gradient boosts at a greater rate than will the stream rate and a particular modification of Darcy's formula is needed. When turbulent circulation exists, the application of Darcy's equation can result in serious errors
References:
- Standard Handbook of Petroleum and Natural Gas Engineering (2nd Release) Edited by: Lyons, William C. ; Plisga, Gary J. 2005 Elsevier
- Natural Gas Executive Handbook By: Guo, Boyun; Ghalambor, Ali 2005 Gulf Posting Company
- Gas Well Deliquification (2nd Release) By: Lea, James F. ; Nickens, Henry V. ; Wells, Mike R. 2008 Elsevier
- http://books. google. co. uk/catalogs?id=AkjWIut5Ll0C&pg=PA28&dq=outflow+performance#v=onepage&q=outflow%20performance&f=false
