4 Goals of Well Analysis Determination of the flowrate To determine under what flow conditions well will cease to produce.To select the most economical time for the installation of artificial liftTo optimize the well conditions and system geometryTo analyze each component in the well system
5 production system Sales Gas surface facility Separator Stock tank vertical wellporous media5
6 Inflow Performance Relationship (IPR) Inflow performance relationship (IPR) is defined as the relation between the surface flowrate (q) and bottomhole flowing pressure (Pwf).IPR curves are used to analyze the deliverability of wells by estimating the production rate for a given bottomhole flowing pressure and vice versa and also reflect the ability of the reservoir to deliver fluid to the wellbore.
7 IPR Curve 1) Straight line (Constant PI) 2) A curve which shows that the PI is decreasing with rate3) A combination of 1 and 2.
8 Constant PI Occurs for single phase liquid flow Production rate is proportional to the pressure drawdown
9 IPR Equation for Multiphase Flow Vogel’s EquationFetkovich’s EquationKlins and Majcher EquationPudjo Sukarno’s Equation
10 Fetkovich’s EquationUsing data from multirate tests on 40 different oil wells in six fields, Fetkovich showed that the following approach was suitable for predicting performance:where ≤ n ≤ 1.0LogThis can be expressed in a form similar to Vogel’s IPR.(Pr2 – Pwf2) psia1/nFlowrate ( q ) STB/dLog
12 Effective Parameters on Inflow Performance Dow point and bubble point pressureReservoir pressure depletionSkin effect
13 Tubing Performance Relationship (TPR or VFP) Tubing performance may be defined as the behavior of a well in giving up the reservoir fluids to the surface.relation between the surface flowrate (q) and tubing intake ressure(Pwf).Flowing bottomhole pressure (tubing intake pressure) for each production rate equals total pressure drop through the tubing and any bottomhole restriction and wellhead pressure.PwhPwfQ
14 Pressure Drop In the Vertical Well Hydrostatic pressure dropFriction pressure drop
17 Change in phase behavior in the production tubing
18 Natural flowAccrue when the wellbore flowing pressure and tubing intake pressure (at perforation depth) are equal, TPR and IPR curves intersect together. The intersection of TPR and IPR curves called natural flow point.
19 Variables that Effects on Natural Flow Wellhead pressureGas/liquid ratioTubing sizeStatic pressure &…
28 Choke PerformanceThe main function of a choke is to dissipate large amounts of potential energy (i.e., pressure losses) over a very short distance.Two types of two-phase flow can exist in a choke :P2/P1 ≤ %50 = RCCritical flowSubcritical flowP2/P1 > %50 = RCP1 = Wellhead ( upstream) pressureP2 = downstream pressure
29 CPR and WPRThe intersection of the WPR and choke performance curve defines the rate of natural flow for the given choke size.
31 RecommendBasic requirement for well performance analysis is the ability to determine , so it is required to determine BHP using surface dataDetermine the best correlation to predict the fluid behavior in well column same as culender smite or duckler &…Examine the quality of separator tests using daly reports of SPGC