Well-Test Horizontal Well, Student Presentation Ppt

8/13/2019 Well-Test Horizontal Well, Student Presentation Ppt

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Well-Test Analysis of Horizontal

Wells


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Group No:----

Students Name:

Salah Kamal Korany

Mohamed Hamed Abd El Gaid


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Introduction

Testing horizontal wells is sill challenging in terms ofmeasurements and interpretation.

For horizontal wells, the early-time transient data arethe most sensitive to the vertical permeability and skin

if the wellbore storage effect is minimized. Recently, production logging and downhole shut-in

have been combined to acquire reliable pressure/ ratedata during drawdown and buildup tests.

Cleanup process are difficult, especially in snakelikecompleted wellbore. so, it is important to obtain flowprofiles and the effective well length(


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The Different Phases in Horizontal

Wells Transient Test Let us consider a horizontal well

completed in an anisotropicreservoir, which is infinite in thexand y directions. The formationpermeabilities in the principal

directions are denoted by kx =ky=kH and kz = kv, with a thickness,h, porosity, , compressibility, Ct,and viscosity,,u. The well half-length is 4. the radius is rw, andthe distance from the wellbore to

the bottom boundary is z..Theboundary conditions at the topand bottom (in the z direction) ofthe system are either no flowand/or constant pressure.


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Wells Transient Test

First flow regime Initially flow occurs

radially in a verticalplane toward the well,

indicated by a plateauon the derivative curveof the log-log plot. Thisregime is termed early-time pseudoradial flow

because of the ellipticalflow pattern resultingfrom the vertical tohorizontal permeabilityanisotropy.


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Second flow regime

The second flow regimebegins when the transientreaches the upper andlower boundaries of theproducing interval andflow becomes lineartoward the well within a

horizontal plane. Thisintermediate-time regimeis characterized by a half-slope trend in thederivative curve.


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Third flow regime

The third flow regime

occurs as the transient

moves deeper into thereservoir and the flow

becomes radial again,

but in the horizontal

plane. This late-time

regime is indicated by a

second plateau in the

derivative curve.


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Effect of Kh/Kv or h/Lp


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Interpretation

The first radial flow regime yields the mechanicalskin factor and the geometric average of thevertical and horizontal permeabilities.

The intermediate-time linear flow regime can beanalyzed to estimate the length of the producinginterval, as long as the horizontal plane can beconsidered isotropic.

The late-time radial flow yields the average

permeability in the horizontal plane and the totalskin factor (mechanical and geometrical skinfactors).


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Interpretation

The identification of the first pseudoradial flow is crucial for acomplete interpretation because it provides the formation

damage. This regime is often masked by the unavoidably large

wellbore storage effects in horizontal wells.

The key to successful horizontal well testing is full control ofthe downhole environment. Full control can be achieved by

using simultaneous measurements of flow rate and either

pressure or downhole shut-in or both.

Moreover, the identification of all three flow regimes is not

always possible from one transient. Combining drawdown

tests in which the flow rate and pressure are measured

simultaneously with buildup tests using downhole shut-in

maximizes the likelihood of identifying all three flow regimes.


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Interpretation

STEPS:

First, the pressure response and its derivative are analyzed to

diagnose the characteristic behavior of the system and dentify

specific flow regimes.

Second, specialized plots are used to extract the effectiveparameters for each flow regime, typically the values of k and

s.

Third, these reservoir parameter estimates are refined by

history matching the measured transient response to thatpredicted by a mathematical model for the well and reservoir

system.


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Finally, The information obtained from this

horizontal well test analysis enhanced theoperators knowledge of the reservoir, which

was used to improve the design of future

horizontal wells in the field.

Well-Test Horizontal Well, Student Presentation Ppt

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