Skin factor is a dimensionless parameter that quantifies the formation damage around the wellbore. it also can be negative (which indicates improvement in flow) OR positive (which means formation damage exists). Positive skin can lead to severe well production issues and thus reducing the well revenue
All hydrocarbon reservoirs are surrounded by water-bearing rocks called aquifers which they effect on reservoir performance. it's a key role for production evaluation and therefore it should be managed.
I hope this presentation helps you to understand why we use acidizing process and calculations needed to perform the optimum acidizing .
Any questions contact me at karim.elfarash@std.suezuniv.edu.eg
This presentation tackles one of the problem in oil industry, which is sand that is produced in the oil wells. Brief description about the problem, its causes, effects and solutions are proposed.
Skin factor is a dimensionless parameter that quantifies the formation damage around the wellbore. it also can be negative (which indicates improvement in flow) OR positive (which means formation damage exists). Positive skin can lead to severe well production issues and thus reducing the well revenue
All hydrocarbon reservoirs are surrounded by water-bearing rocks called aquifers which they effect on reservoir performance. it's a key role for production evaluation and therefore it should be managed.
I hope this presentation helps you to understand why we use acidizing process and calculations needed to perform the optimum acidizing .
Any questions contact me at karim.elfarash@std.suezuniv.edu.eg
This presentation tackles one of the problem in oil industry, which is sand that is produced in the oil wells. Brief description about the problem, its causes, effects and solutions are proposed.
it gives you an indetail information about gas formation volume factor formula, derivation, constant information, and a numerical problem for better understanding
Selection of the best artificial lift systems for the well depend on location, depth, estimated production, reservoir properties, and many other factors. Here is an overview on selection criteria for the best results
The problem of water and gas coning has plagued the petroleum industry for decades. Water or gas encroachment in oil zone and thus simultaneous production of oil & water or oil & gas is a major technical, environmental and economic problems associated with oil and gas production. This can limit the productive life of the oil and gas wells and can cause severe problems including corrosion of tubulars, fine migration, hydrostatic loading etc. The environmental impact of handling, treating and disposing of the produced water can seriously affect the economics of the production. Commonly, the reservoirs have an aquifer beneath the zone of hydrocarbon. While producing from oil zone, there develops a low pressure zone as a result of which the water zone starts coning upwards and gas zone cones down towards the production perforation in oil zone and thus reducing the oil production. Pressure enhanced capillary transition zone enlargement around the wellbore is responsible for the concurrent production. This also results in the loss of water drive and gas drive to a certain extent.
Numerous technologies have been developed to control unwanted water and gas coning. In order to design an effective strategy to control the coning of oil or gas, it is important to understand the mechanism of coning of oil and gas in reservoirs by developing a model of it. Non-Darcy flow effect (NDFE), vertical permeability, aquifer size, density of well perforation, and flow behind casing increase water coning/inflow to wells in homogeneous gas reservoirs with bottom water are important factors to consider. There are several methods to slow down coning of water and/or gas such as producing at a certain critical rate, polymer injection, Downhole Water Sink (DWS) technology etc.
Shubham Saxena
B.Tech. petroleum Engineering
IIT (ISM) Dhanbad
it gives you an indetail information about gas formation volume factor formula, derivation, constant information, and a numerical problem for better understanding
Selection of the best artificial lift systems for the well depend on location, depth, estimated production, reservoir properties, and many other factors. Here is an overview on selection criteria for the best results
The problem of water and gas coning has plagued the petroleum industry for decades. Water or gas encroachment in oil zone and thus simultaneous production of oil & water or oil & gas is a major technical, environmental and economic problems associated with oil and gas production. This can limit the productive life of the oil and gas wells and can cause severe problems including corrosion of tubulars, fine migration, hydrostatic loading etc. The environmental impact of handling, treating and disposing of the produced water can seriously affect the economics of the production. Commonly, the reservoirs have an aquifer beneath the zone of hydrocarbon. While producing from oil zone, there develops a low pressure zone as a result of which the water zone starts coning upwards and gas zone cones down towards the production perforation in oil zone and thus reducing the oil production. Pressure enhanced capillary transition zone enlargement around the wellbore is responsible for the concurrent production. This also results in the loss of water drive and gas drive to a certain extent.
Numerous technologies have been developed to control unwanted water and gas coning. In order to design an effective strategy to control the coning of oil or gas, it is important to understand the mechanism of coning of oil and gas in reservoirs by developing a model of it. Non-Darcy flow effect (NDFE), vertical permeability, aquifer size, density of well perforation, and flow behind casing increase water coning/inflow to wells in homogeneous gas reservoirs with bottom water are important factors to consider. There are several methods to slow down coning of water and/or gas such as producing at a certain critical rate, polymer injection, Downhole Water Sink (DWS) technology etc.
Shubham Saxena
B.Tech. petroleum Engineering
IIT (ISM) Dhanbad
The efficiency of enhanced oil recovery method is a measure of the ability to provide greater hydrocarbon recovery than by natural depletion, at an economically attractive production rate.
Facebook Page: https://www.facebook.com/petroleumengineeringz
Blogspot: http://petroleumengineeringsociety.blogspot.com/
Reservoir engineering is the field to evaluate field performance by performing reservoir modeling studies and explore opportunities to maximize the value of both exploration and production properties to enhance hydrocarbon production.
Student information management system project report ii.pdfKamal Acharya
Our project explains about the student management. This project mainly explains the various actions related to student details. This project shows some ease in adding, editing and deleting the student details. It also provides a less time consuming process for viewing, adding, editing and deleting the marks of the students.
Saudi Arabia stands as a titan in the global energy landscape, renowned for its abundant oil and gas resources. It's the largest exporter of petroleum and holds some of the world's most significant reserves. Let's delve into the top 10 oil and gas projects shaping Saudi Arabia's energy future in 2024.
CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptxR&R Consult
CFD analysis is incredibly effective at solving mysteries and improving the performance of complex systems!
Here's a great example: At a large natural gas-fired power plant, where they use waste heat to generate steam and energy, they were puzzled that their boiler wasn't producing as much steam as expected.
R&R and Tetra Engineering Group Inc. were asked to solve the issue with reduced steam production.
An inspection had shown that a significant amount of hot flue gas was bypassing the boiler tubes, where the heat was supposed to be transferred.
R&R Consult conducted a CFD analysis, which revealed that 6.3% of the flue gas was bypassing the boiler tubes without transferring heat. The analysis also showed that the flue gas was instead being directed along the sides of the boiler and between the modules that were supposed to capture the heat. This was the cause of the reduced performance.
Based on our results, Tetra Engineering installed covering plates to reduce the bypass flow. This improved the boiler's performance and increased electricity production.
It is always satisfying when we can help solve complex challenges like this. Do your systems also need a check-up or optimization? Give us a call!
Work done in cooperation with James Malloy and David Moelling from Tetra Engineering.
More examples of our work https://www.r-r-consult.dk/en/cases-en/
Overview of the fundamental roles in Hydropower generation and the components involved in wider Electrical Engineering.
This paper presents the design and construction of hydroelectric dams from the hydrologist’s survey of the valley before construction, all aspects and involved disciplines, fluid dynamics, structural engineering, generation and mains frequency regulation to the very transmission of power through the network in the United Kingdom.
Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
(C) 2024 Robbie E. Sayers
Democratizing Fuzzing at Scale by Abhishek Aryaabh.arya
Presented at NUS: Fuzzing and Software Security Summer School 2024
This keynote talks about the democratization of fuzzing at scale, highlighting the collaboration between open source communities, academia, and industry to advance the field of fuzzing. It delves into the history of fuzzing, the development of scalable fuzzing platforms, and the empowerment of community-driven research. The talk will further discuss recent advancements leveraging AI/ML and offer insights into the future evolution of the fuzzing landscape.
Forklift Classes Overview by Intella PartsIntella Parts
Discover the different forklift classes and their specific applications. Learn how to choose the right forklift for your needs to ensure safety, efficiency, and compliance in your operations.
For more technical information, visit our website https://intellaparts.com
Event Management System Vb Net Project Report.pdfKamal Acharya
In present era, the scopes of information technology growing with a very fast .We do not see any are untouched from this industry. The scope of information technology has become wider includes: Business and industry. Household Business, Communication, Education, Entertainment, Science, Medicine, Engineering, Distance Learning, Weather Forecasting. Carrier Searching and so on.
My project named “Event Management System” is software that store and maintained all events coordinated in college. It also helpful to print related reports. My project will help to record the events coordinated by faculties with their Name, Event subject, date & details in an efficient & effective ways.
In my system we have to make a system by which a user can record all events coordinated by a particular faculty. In our proposed system some more featured are added which differs it from the existing system such as security.
Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
In order to develop an e-commerce website, a number of Technologies must be studied and understood. These include multi-tiered architecture, server and client-side scripting techniques, implementation technologies, programming language (such as PHP, HTML, CSS, JavaScript) and MySQL relational databases. This is a project with the objective to develop a basic website where a consumer is provided with a shopping cart website and also to know about the technologies used to develop such a website.
This document will discuss each of the underlying technologies to create and implement an e- commerce website.
Water scarcity is the lack of fresh water resources to meet the standard water demand. There are two type of water scarcity. One is physical. The other is economic water scarcity.
COLLEGE BUS MANAGEMENT SYSTEM PROJECT REPORT.pdfKamal Acharya
The College Bus Management system is completely developed by Visual Basic .NET Version. The application is connect with most secured database language MS SQL Server. The application is develop by using best combination of front-end and back-end languages. The application is totally design like flat user interface. This flat user interface is more attractive user interface in 2017. The application is gives more important to the system functionality. The application is to manage the student’s details, driver’s details, bus details, bus route details, bus fees details and more. The application has only one unit for admin. The admin can manage the entire application. The admin can login into the application by using username and password of the admin. The application is develop for big and small colleges. It is more user friendly for non-computer person. Even they can easily learn how to manage the application within hours. The application is more secure by the admin. The system will give an effective output for the VB.Net and SQL Server given as input to the system. The compiled java program given as input to the system, after scanning the program will generate different reports. The application generates the report for users. The admin can view and download the report of the data. The application deliver the excel format reports. Because, excel formatted reports is very easy to understand the income and expense of the college bus. This application is mainly develop for windows operating system users. In 2017, 73% of people enterprises are using windows operating system. So the application will easily install for all the windows operating system users. The application-developed size is very low. The application consumes very low space in disk. Therefore, the user can allocate very minimum local disk space for this application.
2. 1. Primary Recovery Mechanisms
A. Rock and Liquid Expansion Drive Mechanism
B. The Depletion-Drive Mechanism
C. Gas-Cap Drive
a. Gas-Cap Drive; Recovery
3. 1. Primary Recovery Mechanisms (Cont.)
A. The Water-Drive Mechanism
B. The Gravity-Drainage-Drive Mechanism
C. The Combination-Drive Mechanism
4.
5. Aquifers
Many reservoirs are bounded on a portion or
all of their peripheries
by water bearing rocks called aquifers.
The aquifers may be
so large compared to the reservoir they adjoin as
to appear infinite for all practical purposes, and
they may range down to those as small as
to be negligible in their effects
on the reservoir performance.
Spring14 H. AlamiNia Reservoir Engineering 2 Course (1st Ed.) 5
6. Types of Aquifers
The aquifer itself may be
entirely bounded by
impermeable rock
so that the reservoir and
aquifer together form a
closed (volumetric) unit.
On the other hand,
the reservoir may be
outcropped at one or
more places where it
may be replenished by
surface water.
Regardless of the source
of water,
the water drive is the
result of water moving
into the pore spaces
originally occupied by oil,
replacing the oil and
displacing it to the
producing wells.
Spring14 H. AlamiNia Reservoir Engineering 2 Course (1st Ed.) 6
7. Aquifer Geometries
It is common to speak
of edge water or
bottom water in
discussing water influx
into a reservoir.
Bottom water
occurs directly
beneath the oil and
edge water
occurs off the flanks of
the structure
at the edge of the oil
Spring14 H. AlamiNia Reservoir Engineering 2 Course (1st Ed.) 7
8. water-driving mechanism;
characteristics
Cole (1969) presented
the following discussion
on the characteristics
that can be used for
identification of the
water-driving
mechanism:
Reservoir Pressure
Water Production
Gas-Oil Ratio
Ultimate Oil Recovery
Reservoir Having Artesian Water Drive
Spring14 H. AlamiNia Reservoir Engineering 2 Course (1st Ed.) 8
9. water-driving mechanism;
reservoir pressure
Reservoir Pressure
The reservoir pressure decline is usually very gradual.
Next slide graph shows the pressure-production history
of a typical water-drive reservoir.
It is not uncommon for
many thousands of barrels of oil [MM bbl]
to be produced
for each pound per square inch drop [1 psi]
in reservoir pressure.
The reason for the small decline in reservoir pressure
is that oil and gas withdrawals from the reservoir
are replaced almost volume for volume
by water encroaching into the oil zone.
Spring14 H. AlamiNia Reservoir Engineering 2 Course (1st Ed.) 9
10. Pressure-production history
for a water-drive reservoir
Although pressure history is
normally plotted versus
cumulative oil production,
it should be understood
that
total reservoir fluid
withdrawals are the really
important criteria in the
maintenance of reservoir
pressure.
In a water-drive reservoir,
only a certain number of
barrels of water
can move into the reservoir
as a result of
a unit pressure drop within
the reservoir.
Spring14 H. AlamiNia Reservoir Engineering 2 Course (1st Ed.) 10
11. Minimizing pressure decline
Since the principal income production is from oil,
if the withdrawals of water and gas can be minimized,
then the withdrawal of oil from the reservoir can be
maximized with minimum pressure decline.
Therefore, it is extremely important to reduce
water and gas production to an absolute minimum.
This can usually be accomplished by
shutting in wells producing large quantities
of these fluids and, where possible,
transferring their allowable to other wells producing
with lower water-oil or gas-oil ratios.
Spring14 H. AlamiNia Reservoir Engineering 2 Course (1st Ed.) 11
12. water-driving mechanism;
Water Production
Water Production
Early excess water production occurs
in structurally low wells.
This is characteristic of a water-drive reservoir, and,
provided the water is encroaching in a uniform manner,
• nothing can or should be done to restrict this encroachment,
• as the water will probably provide
the most efficient displacing mechanism possible.
Spring14 H. AlamiNia Reservoir Engineering 2 Course (1st Ed.) 12
13. Water production
If the reservoir has one or more lenses of
very high permeability, then the water may be
moving through this more permeable zone.
In this case, it may be economically feasible
to perform remedial operations to shut off
this permeable zone producing water.
It should be realized that in most cases
the oil that is being recovered
from a structurally low well will be recovered
from wells located higher on the structure and
any expenses involved in remedial work
to reduce the water-oil ratio of structurally low wells
may be needless expenditures.
Spring14 H. AlamiNia Reservoir Engineering 2 Course (1st Ed.) 13
14. water-driving mechanism;
Gas-Oil Ratio, Recovery
Gas-Oil Ratio
There is normally little change in the producing gas-oil ratio
during the life of the reservoir.
This is especially true if the reservoir does not have an initial free
gas cap.
Pressure will be maintained as a result of water
encroachment and therefore there will be relatively little gas
released from this solution.
Ultimate Oil Recovery
Ultimate recovery from water-drive reservoirs is usually much
larger than recovery under any other producing mechanism.
Recovery is dependent upon the efficiency of
the flushing action of the water as it displaces the oil.
In general, as the reservoir heterogeneity increases,
the recovery will decrease,
due to the uneven advance of the displacing water.
Spring14 H. AlamiNia Reservoir Engineering 2 Course (1st Ed.) 14
15. Effect of reservoir heterogeneity on
recovery of a water drive mechanism
The rate of water advance is normally faster
in the zones of high permeability.
This results in earlier high water-oil ratios and
consequent earlier economic limits.
Where the reservoir is more or less homogeneous,
the advancing waterfront will be more uniform, and
when the economic limit,
(due primarily to high water-oil ratio),
has been reached,
a greater portion of the reservoir will have been
contacted by the advancing water.
Spring14 H. AlamiNia Reservoir Engineering 2 Course (1st Ed.) 15
16. Effect of aquifer activity on recovery of
a water drive mechanism
Ultimate oil recovery is also affected by the degree
of activity of the water drive.
In a very active water drive
where the degree of pressure maintenance is good,
the role of solution gas in the recovery process is
reduced to almost zero,
with maximum advantage being taken of
the water as a displacing force.
This should result in maximum oil recovery
from the reservoir.
Spring14 H. AlamiNia Reservoir Engineering 2 Course (1st Ed.) 16
17. water-driving mechanism;
summary
The ultimate oil recovery normally ranges
from 35% to 75% of the original oil-in-place.
The characteristic trends of a water-drive reservoir
are shown graphically in next slide and are
summarized below:
Spring14 H. AlamiNia Reservoir Engineering 2 Course (1st Ed.) 17
18. Production Data
for a Water-Drive Reservoir
Spring14 H. AlamiNia Reservoir Engineering 2 Course (1st Ed.) 18
19.
20.
21. The mechanism of
gravity drainage illustration
The mechanism of gravity drainage occurs in
petroleum reservoirs as a result of
differences in densities of the reservoir fluids.
The effects of gravitational forces can be simply
illustrated by placing a quantity of crude oil and a
quantity of water in a jar and agitating the contents.
After agitation, the jar is placed at rest, and the denser
fluid (normally water) will settle to the bottom of the jar,
while the less dense fluid (normally oil) will rest on top
of the denser fluid.
The fluids have separated as a result of the gravitational
forces acting on them.
Spring14 H. AlamiNia Reservoir Engineering 2 Course (1st Ed.) 21
22. Equilibrium in the reservoir
The fluids in petroleum reservoirs have all been
subjected to the forces of gravity, as evidenced by
the relative positions of the fluids, i.e., gas on top,
oil underlying the gas, and water underlying oil.
Due to the long periods of time involved in the
petroleum accumulation-and-migration process,
it is generally assumed that
the reservoir fluids are in equilibrium.
If the reservoir fluids are in equilibrium, then the gas-oil and
oil water contacts should be essentially horizontal.
Although it is difficult
to determine precisely the reservoir fluid contacts,
best available data indicate that, in most reservoirs,
the fluid contacts actually are essentially horizontal.
Spring14 H. AlamiNia Reservoir Engineering 2 Course (1st Ed.) 22
23. The Gravity-Drainage-Drive
Mechanism; characteristics
Gravity segregation of fluids is probably
present to some degree in all petroleum reservoirs,
but it may contribute substantially
to oil production in some reservoirs.
Cole (1969) stated that reservoirs operating largely
under a gravity drainage-producing mechanism are
characterized by:
Reservoir Pressure
Gas-Oil Ratio
Secondary Gas Cap
Water production
Ultimate Oil Recovery
Spring14 H. AlamiNia Reservoir Engineering 2 Course (1st Ed.) 23
24. The Gravity-Drainage-Drive
Mechanism; Reservoir Pressure
Variable rates of pressure decline, depending
principally upon the amount of gas conservation.
Strictly speaking, where the gas is conserved and
reservoir pressure is maintained,
the reservoir would be operating under combined
gas-cap drive and gravity-drainage mechanisms.
Therefore, for the reservoir to be operating solely
as a result of gravity drainage,
the reservoir would show a rapid pressure decline.
This would require the up structure migration of
the evolved gas where it later would be produced from
structurally high wells, resulting in rapid loss of pressure.
Spring14 H. AlamiNia Reservoir Engineering 2 Course (1st Ed.) 24
25. The Gravity-Drainage-Drive
Mechanism; Gas-Oil Ratio
Low gas-oil ratio from structurally low wells.
This is caused by migration of
the evolved gas upstructure
due to gravitational segregation of the fluids.
On the other hand,
the structurally high wells
will experience an increasing gas-oil ratio
as a result of the upstructure migration
of the gas released from the crude oil.
Spring14 H. AlamiNia Reservoir Engineering 2 Course (1st Ed.) 25
26. The Gravity-Drainage-Drive
Mechanism; Secondary Gas Cap & …
Secondary Gas Cap
Formation of a secondary gas cap in reservoirs
that initially were undersaturated.
Obviously the gravity-drainage mechanism
does not become operative
until reservoir pressure has declined
below the saturation pressure,
since above the saturation pressure
there will be no free gas in the reservoir.
Water Production
Little or no water production.
Water production is indicative of a water drive.
Spring14 H. AlamiNia Reservoir Engineering 2 Course (1st Ed.) 26
27. The Gravity-Drainage-Drive
Mechanism; Ultimate Oil Recovery
Ultimate recovery from gravity-drainage reservoirs will
vary widely,
due primarily to the extent of depletion
by gravity drainage alone.
Where gravity drainage is good, or
where producing rates are restricted
to take maximum advantage of the gravitational forces,
recovery will be high.
There are reported cases where recovery
from gravity-drainage reservoirs
has exceeded 80% of the initial oil-in-place.
In other reservoirs where depletion drive also
plays an important role in the oil recovery process,
the ultimate recovery will be less.
Spring14 H. AlamiNia Reservoir Engineering 2 Course (1st Ed.) 27
28. oil saturation
in a gravity-drainage reservoir
In operating a gravity-drainage reservoir,
it is essential that the oil saturation
in the vicinity of the wellbore
must be maintained as high as possible.
There are two basic reasons for this requirement:
A high oil saturation means a higher oil flow rate
A high oil saturation means a lower gas flow rate
If the evolved gas migrates up structure
instead of toward the wellbore,
then a high oil saturation
in the vicinity of the wellbore can be maintained.
Spring14 H. AlamiNia Reservoir Engineering 2 Course (1st Ed.) 28
29. The Gravity-Drainage-Drive
Mechanism, well placement
In order to take
maximum advantage of
the gravity-drainage-
producing mechanism,
wells should be located
as structurally low
as possible.
This will result in
maximum conservation
of the reservoir gas.
A typical gravity-drainage reservoir
Spring14 H. AlamiNia Reservoir Engineering 2 Course (1st Ed.) 29
30. The Gravity-Drainage-Drive
Mechanism; ultimate recovery
Factors that affect ultimate recovery from gravity-
drainage reservoirs are:
Permeability in the direction of dip
Dip of the reservoir
Reservoir producing rates
Oil viscosity
Relative permeability characteristics
Cole (1969) presented the following complete
treatment of the above listed factors.
Spring14 H. AlamiNia Reservoir Engineering 2 Course (1st Ed.) 30
31. ultimate recovery parameters
Permeability in the Direction of Dip
Good permeability in the direction of migration of the oil is a
prerequisite for efficient gravity drainage.
For example, a reservoir with little structural relief
that also contained many more or less continuous shale “breaks”
could probably not be operated under gravity drainage
• because the oil could not flow to the base of the structure.
Dip of the Reservoir
In most reservoirs, the permeability in the direction of dip is
considerably larger than the permeability transverse to the
direction of dip.
Therefore, as the dip of the reservoir increases,
the oil and gas can flow along the direction of dip
(which is also the direction of greatest permeability) and
still achieve their desired structural position.
Spring14 H. AlamiNia Reservoir Engineering 2 Course (1st Ed.) 31
32. ultimate recovery parameters (Cont.)
Reservoir-Producing Rates
Since the gravity-drainage rate is limited,
the reservoir-producing rates should be limited to the
gravity-drainage rate, and then maximum recovery will
result.
If the reservoir-producing rate exceeds the gravity
drainage rate,
the depletion-drive-producing mechanism will become more
significant
• with a consequent reduction in ultimate oil recovery.
Spring14 H. AlamiNia Reservoir Engineering 2 Course (1st Ed.) 32
33. ultimate recovery parameters (Cont.)
Relative Permeability
Characteristics
For an efficient gravity-drive
mechanism to be operative,
the gas must flow up
structure
while the oil flows down
structure.
Although this situation
involves counterflow of the
oil and gas, both fluids are
flowing and, therefore,
relative permeability
characteristics of the
formation are very
important.
Oil Viscosity
Oil viscosity is important
because
the gravity-drainage rate
is dependent upon
the viscosity of the oil.
In the fluid flow equations,
the flow rate increases as
the viscosity decreases.
Therefore, the gravity-
drainage rate will increase
as the reservoir oil viscosity
decreases.
Spring14 H. AlamiNia Reservoir Engineering 2 Course (1st Ed.) 33
34.
35. The Combination-Drive Mechanism
The driving mechanism most commonly
encountered is one in which
both water and free gas are available in some degree
to displace the oil toward the producing wells.
Two combinations of driving forces can be present
in combination drive reservoirs. These are:
Depletion drive and a weak water drive and;
Depletion drive
with a small gas cap and a weak water drive.
Then, of course, gravity segregation can play an
important role in any of the aforementioned drives.
Spring14 H. AlamiNia Reservoir Engineering 2 Course (1st Ed.) 35
36. Combination-Drive Reservoir
The most common
type of drive
encountered,
therefore,
is a combination-drive
mechanism
as illustrated in
the Figure.
Spring14 H. AlamiNia Reservoir Engineering 2 Course (1st Ed.) 36
37. Combination-drive reservoirs
recognition factors
Combination-drive reservoirs can be recognized by
the occurrence of a combination of
some of the following factors:
Relatively rapid pressure decline.
Water encroachment and/or
external gas-cap expansion
are insufficient to maintain reservoir pressures.
Water encroaching
slowly into the lower part of the reservoir.
Structurally low producing wells
will exhibit slowly increasing water producing rates.
Spring14 H. AlamiNia Reservoir Engineering 2 Course (1st Ed.) 37
38. Combination-drive reservoirs
recognition factors (Cont.)
If a small gas cap is present the structurally high wells
will exhibit continually increasing gas-oil ratios,
provided the gas cap is expanding.
It is possible that the gas cap will shrink due to production of
excess free gas, in which case
the structurally high wells will exhibit a decreasing gas-oil ratio.
• This condition should be avoided whenever possible, as large
volumes of oil can be lost as a result of a shrinking gas cap.
A substantial percentage of the total oil recovery may be
due to the depletion-drive mechanism.
The gas-oil ratio of structurally low wells
will also continue to increase due to evolution of solution gas
throughout the reservoir, as pressure is reduced.
Spring14 H. AlamiNia Reservoir Engineering 2 Course (1st Ed.) 38
39. Combination-drive reservoirs
recognition factors (Cont.)
Ultimate recovery from combination-drive reservoirs is
usually greater than recovery from
depletion-drive reservoirs
but less than recovery from
water-drive or gas-cap-drive reservoirs.
Actual recovery will depend upon
the degree to which it is possible
to reduce the magnitude of recovery by depletion drive.
In most combination-drive reservoirs,
it will be economically feasible to institute some type of
pressure maintenance operation,
either gas injection, water injection,
or both gas and water injection,
depending upon the availability of the fluids.
Spring14 H. AlamiNia Reservoir Engineering 2 Course (1st Ed.) 39
40. 1. Ahmed, T. (2010). Reservoir engineering
handbook (Gulf Professional Publishing).
Chapter 11
41. 1. The Material Balance Equation
2. Tank-model concept
3. The MBE indices