Difference between revisions of "JD"

Revision as of 11:30, 11 July 2023

Brief

JD - dimensionless productivity index^[1], inverse of dimensionless pressure (based on average pressure) which contains the type of flow regime, boundary condition, drainage shape and stimulation ^[2].

Math & Physics

{J_D} = \frac{1}{\bar{P}_D}

From the Darcy's law for an unfractured well located in the center of a circular drainage area, the JD is:

Pseudo-steady state:

{J_D} = \frac{1}{ln{\frac{r_e}{r_w}-\frac{3}{4}+S}}

Steady state:

{J_D} = \frac{1}{ln{\frac{r_e}{r_w}-\frac{1}{2}+S}}

	Well in circular drainage area	Well in the drainage area with the shape factor ${C_A}$
Steady state	${J_D} = \frac{1}{ln{\frac{r_e}{r_w}-\frac{1}{2}+S}}$	--
Pseudo steady state	${J_D} = \frac{1}{ln{\frac{r_e}{r_w}-\frac{3}{4}+S}}$	--

Oil

{J_D} = \frac{141.2 B \mu}{kh} \frac{q}{\bar{P} - P_{wf}} = \frac{141.2 B \mu}{kh} J

{q} = \frac{kh}{141.2 B \mu} (\bar{P} - P_{wf}) J_D

Gas

J_D=\frac{1422 \times 10^3\ T_R}{kh} \frac{q_g}{P_{\bar{P}}-P_{P_{wf}}}

Maximum $J_D$

The undamaged unstimulated vertical well potential in a pseudo steady radial flow is:

{J_D}_{max} \approx \frac{1}{ln{\frac{500}{0.1}-\frac{3}{4}+0}} \approx 0.13

The maximum possible stimulated well potential for pseudo steady linear flow is:

${J_D}_{max}= \frac{6}{\pi} \approx 1.91$ , see 6/π stimulated well potential

The maximum possible stimulated well potential for steady state linear flow is:

${J_D}_{max}= \frac{4}{\pi} \approx 1.27$ , see 4/π stimulated well potential

Nomenclature

B

= formation volume factor, bbl/stb

J

= productivity index, stb/psia

J_D

= dimensionless productivity index, dimensionless

kh

= permeability times thickness, md*ft

\bar{P}

= average reservoir pressure, psia

\bar{P}_D

= dimensionless pressure (based on average pressure), dimensionless

P_{\bar{P}}

= average reservoir pseudopressure, psia²/cP

P_{wf}

= well flowing pressure, psia

P_{P_{wf}}

= average well flowing pseudopressure, psia²/cP

q

= flowing rate, stb/d

q_g

= gas rate, MMscfd

r_w

= wellbore radius, ft

r_e

= drainage radius, ft

S

= skin factor, dimensionless

T

= temperature, °R

Greek symbols

\mu

= viscosity, cp

References

↑ Rueda, J.I.; Mach, J.; Wolcott, D. (2004). "Pushing Fracturing Limits to Maximize Producibility in Turbidite Formations in Russia" (SPE-91760-MS). Society of Petroleum Engineers.
↑ Cite error: Invalid <ref> tag; no text was provided for refs named DW

[pushing-1] Rueda, J.I.; Mach, J.; Wolcott, D. (2004). "Pushing Fracturing Limits to Maximize Producibility in Turbidite Formations in Russia" (SPE-91760-MS). Society of Petroleum Engineers.

[DW-2] Cite error: Invalid <ref> tag; no text was provided for refs named DW

[1]

[2]

@@ Line 18: / Line 18: @@
 <table width="100%" border="1" cellpadding="3" cellspacing="1">
 <tr>
-<th><math> {J_D} </math></th>
+<th></th>
 <th>Well in circular drainage area</th>
 <th>Well in the drainage area with the shape factor <math> {C_A} </math></th>
@@ Line 27: / Line 27: @@
 <td>Steady state</td>
 <td><math> {J_D} = \frac{1}{ln{\frac{r_e}{r_w}-\frac{1}{2}+S}} </math></td>
-<td> Calculated with Nodal Analysis using the [[PQplot]] by setting the flowing wellhead pressure (FWHP) equal to the current flowing line pressure (FLP) at the well head. <BR>Use the current value of [[JD]].</td>
+<td> --</td>
 </tr>
@@ Line 34: / Line 34: @@
 <td>Pseudo steady state</td>
 <td><math> {J_D} = \frac{1}{ln{\frac{r_e}{r_w}-\frac{3}{4}+S}} </math></td>
-<td>Calculated the same way as for the '''Gas Flowing''' case</td>
+<td>--</td>
 </tr>

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