U.S. patent application number 16/043867 was filed with the patent office on 2018-11-15 for method and apparatus for evaluating the potential effectiveness of refracing a well.
This patent application is currently assigned to Tech Flo Consulting, LLC. The applicant listed for this patent is Tech Flo Consulting, LLC. Invention is credited to William J. Jackson, James L. Miller, II, Erik J. Reissig.
Application Number | 20180328169 16/043867 |
Document ID | / |
Family ID | 58051028 |
Filed Date | 2018-11-15 |
United States Patent
Application |
20180328169 |
Kind Code |
A1 |
Jackson; William J. ; et
al. |
November 15, 2018 |
Method and Apparatus for Evaluating the Potential Effectiveness of
Refracing a Well
Abstract
A method for evaluating the potential effectiveness of refracing
a previously fracked oil/gas well is accomplished by isolating a
plurality of previously fracked zones of an oil/gas well in a
formation and measuring the fluid flow rates from the isolated
zones using a three phase flow meter positioned within the well at
or near the previously fracked zones. The zones may be isolated by
an isolation assembly which includes two packers connected by a
perforated pipe and attached to a tubular positioned within the
well.
Inventors: |
Jackson; William J.;
(Conroe, TX) ; Reissig; Erik J.; (Conroe, TX)
; Miller, II; James L.; (Willis, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Tech Flo Consulting, LLC |
Conroe |
TX |
US |
|
|
Assignee: |
Tech Flo Consulting, LLC
Conroe
TX
|
Family ID: |
58051028 |
Appl. No.: |
16/043867 |
Filed: |
July 24, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
14829602 |
Aug 18, 2015 |
|
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|
16043867 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E21B 47/10 20130101;
E21B 43/14 20130101 |
International
Class: |
E21B 47/10 20060101
E21B047/10; E21B 43/14 20060101 E21B043/14 |
Claims
1. A method of evaluating the potential effectiveness of refracing
a producing oil/gas well that has already been fracked at a
plurality of zones along the length of the well comprising: a)
isolating a first producing, previously fracked zone in the well,
b) measuring the oil, water, or gas flow rate, from the producing
zone while the zone is being produced, c) calculating a production
index for the isolated previously fracked zone, and d) determining
the previously fracked zones that are most likely to exhibit
increased productivity due to a refracing procedure based upon the
production index.
2. The method of claim 1 further including the step of isolating
two or more previously fracked zones and measuring the oil flow
rate flow from each previously fracked zone.
3. The method of claim 1 wherein the previously fracked zone is
isolated by placing a packer within the well at the beginning and
end of the zone.
4. The method of claim 3 wherein the oil, water, or gas flow rate
is obtained by placing a three phase flow meter in tubing located
within the well, the tubing including a perforated pipe positioned
between the packers.
5. The method of claim 4 wherein the oil, water, or gas is produced
using a jet pump positioned within the production tubing.
6. The method of claim 5 wherein the packers are either of the
inflatable type or mechanical type and a portion of power fluid for
the jet pump is diverted to set the packers.
7. The method of claim 1 wherein the well is a horizontal well.
8. The method of claim 1 further including measuring the
temperature and pressure of fluid within the previously fraced
zone.
9. The method of claim 1 further including measuring an initial
static bottom hole pressure and a flowing bottom hole pressure of
the previously fraced zone, measuring a production rate of the
previously fraced zone, wherein the production index is calculated
by subtracting the flowing bottom hole pressure from the static
bottom hoe pressure and dividing the production rate by the result
of subtracting the flowing bottom hole pressure from the static
bottom hole pressure.
10. The method of claim 1 further including the step of refracing
the previously fraced zones that are determined to be most likely
to exhibit increased productivity.
Description
[0001] This application is a continuation of U.S. application Ser.
No. 14/829,602 filed Aug. 18, 2015 the entire contents of which is
hereby incorporated herein by reference thereto.
BACKGROUND OF THE INVENTION
Field of the Invention
[0002] This invention relates to a method and apparatus for
evaluating the potential effectiveness of refracing an oil/gas
well. Individual production zones are tested for flow rates of gas,
water and oil to determine which previously fracked production
zones are the most productive and consequently the best candidates
for refracing.
Description of Related Arts Invention
[0003] Currently when refracing a well the overall productivity of
the well is considered before a decision to refrac is made. Little
is known about which of the many perforated zones are productive in
a well. Therefore, a method of determining which of the zones could
benefit from refracturing is very important.
[0004] Furthermore, while some efforts have been made to measure
the total production of fluids within a well, very little effort
has been made to monitor the individual production rates for gas,
water, and oil as well as pressure and temperature at various
stages of frac zones for the purpose of evaluating the
effectiveness of refracing an individual zone using the proposed
method and tool configuration in this application.
[0005] Consequently there is a need to for a more precise method of
measuring the oil output of individual frac zones in order to
evaluate the potential effectiveness of refracing a given
production zone.
BRIEF SUMMARY OF SOME OF THE PREFERRED EMBODIMENTS
[0006] These and other needs in the art are addressed in one
embodiment by isolating individual frac zones of a previously
fraced formation and measuring the Static Bottom Hole Pressure and
Flowing Bottom Hole Pressure, so a productivity index can be
calculated and the ratio of Oil, Gas and Water can be measured
through the use of a three phase flow meter, such as a Doppler flow
meter. The production index is a measure of well's potential or
ability to produce fluids as a function of reduction in pressure.
The production index (PI) is calculated by subtracting the flowing
bottom hole pressure (PF) from the static bottom hole pressure (PS)
to get a drawdown pressure. The production rate in barrels per day
(bpd) is divided by the drawdown to arrive at the PI. Thus if the
drawdown pressure is 500 psi and the producing rate is 500 bpd,
then the PI is 1.
[0007] The foregoing has outlined rather broadly the features and
technical advantages of the present invention in order that the
detailed description of the invention that follows may be better
understood. Additional features and advantages of the invention
will be described hereinafter that form the subject of the claims
of the invention. It should be appreciated by those skilled in the
art that the conception and the specific embodiments disclosed may
be readily utilized as a basis for modifying or designing other
embodiments for carrying out the same purposes of the present
invention. It should also be realized by those skilled in the art
that such equivalent embodiments do not depart from the spirit and
scope of the invention as set forth in the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] For a detailed description of the preferred embodiments of
the invention, reference will now be made to the accompanying
drawing in which:
[0009] The FIGURE illustrates a schematic showing of a horizontal
well having a plurality of frac zones with an embodiment of
equipment for carrying out the invention placed within the
well.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0010] The FIGURE shows a well 10 within formation 11 including a
casing having a horizontal portion 41 and a vertical portion 40 and
a tubular string 12 which may be coiled tubing or jointed pipe
tubing.
[0011] As shown the well includes a vertical section and a
horizontal portion which terminates at 42. However it is understood
that the well may consist of a vertical section only surrounded by
a plurality of vertically spaced frac zones.
[0012] In a typical horizontally fraced well, there are a plurality
of fracked zones 30, 31, 32, 33, 34, 35 wherein the casing 41 has
been perforated at 14, 15, 16, 17, 18, and 19. As is known in the
art, fracing fluids are introduced sequentially into the formation
through the perforations in the casing to fracture the formation
adjacent the casing to facilitate the flow of oil and other fluids
from the formation to the interior of the well.
[0013] According to an embodiment of the invention, coiled or
jointed pipe tubing 12 is lowered into the well and includes a jet
pump section 20 and, a pup joint 27 having a three phase flow meter
21 located within the pup joint.
[0014] An isolation assembly which includes a first packer 26, a
perforated sub 25, and a second packer 28 is attached to the tubing
12 at an end thereof via meter 27 and jet pump 21. When positioned
within the well as shown in the FIGURE the isolation assembly will
permit only fluid from previously fracked zone 34 to enter the
interior of flow meter 21 via the openings in perforated sub 25.
When inflatable packers are used, power fluid from the jet pump may
be diverted to the packers via a conduit 61 for inflating the
packers.
[0015] To measure the flow rate of fluids from zone 34, power fluid
is delivered to jet pump 20 which will draw fluid from zone 34
through perforated sub 25, packer 26 and pup joint 27. Consequently
the three phase flow meter 21 in pup joint 27 will record the oil,
gas and water flow rates from the previously fraced zone 34. Flow
meter 21 also includes temperature and pressure gauges.
[0016] According to an embodiment of the invention, once the flow
rate of a fluid in a given frac zone has been measured, the flow
rates of fluid in an different normally adjacent zone can be
measured by moving the isolation unit to isolate a different frac
zone such as frac zone 33 shown in the FIGURE.
[0017] The Initial Bottom Hole Pressure will be measured before
each zone is tested and the straddle packers isolate that zone. The
Flowing Bottom Hole Pressure will be measured when the jet pump is
engaged and drawdown is achieved. Consequently the production index
for each frac zone in a producing well can be calculated. Based
upon the calculation a determination can be made as to the original
frac zones that are most likely to exhibit increased productivity
due to a refracing procedure.
[0018] Although the present invention and its advantages have been
described in detail, it should be understood that various changes,
substitutions and alterations may be made herein without departing
from the spirit and scope of the invention as defined by the
appended claims.
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