Issue 3

EAGE SUEZ ACADEMY TEAM'S MAGAZINE

Main Sponsor INSIDE SCOOP About us

2 | ISSUE 3 | FEBRUARY2017 0o64 Focus is a magazine prepared by
EAGE Academy committee members,
4d Seismic Time Lapse and two issues were published until
now. The first issue contained three
4D Seismic The time-lapse, or 4D, seismic method involves topics the first was about earthquakes
acquisition, processing, and interpretation of repeated and the second discussed seismic
seismic surveys over a producing hydrocarbon field. The processing. The third topic was about
objective is to determine the changes occurring in the the relationship between geology and
reservoir as a result of hydrocarbon production or injection medicine. The second issue topics are
of water or gas into the reservoir by comparing the repeated environmental geophysics, and how to
datasets. protect ourselves from earthquakes.
It contained also an article to tell
0o68 the students about the main work of
academy committee.
Drilling Problems and Their remedies
Our team
While we drilling a well the are most common problems
that face us such as lost circulation ,stuck pipe, Fishing . Editor in Chief
lost circulation. Its mean that I losses drilling mud in a Mostafa Ahmed Sobhy
permeable layer
stuck pipe. During drilling operations, a pipe is considered Academic Head
stuck if it cannot be freed from the hole without damaging Sara Abd allah
the pipe, and without exceeding the drilling rig’s maximum
allowed hook load. Academic Team
What is the meaning of fishing? Sometimes, something Khloud Hashem
gets into the hole that needs to be recovered .the
processes of recovered any thing that go down to the well Esraa Fawzy
called Fishing. Ahmed Mokhtar
Mosa Mohamed
102 Sameh Hamed

EOR Methods in Carbonate reservoirs Taha Yehia
Mohamed Ramadan
About more 60 % of the discovered reservoirs are carbonate
ones which need from us better studies and researches to IR Head
maximize the recovery of this reservoirs types. Omar Khaled Hassan
The challenge in this reservoir is due to its heterogeneity and
mixed wettability although it has good permeability. IR Team
This article talks about some problems which we face during Sherouk Mohamed Abdel-Razeq
carbonate reservoir stimulation, reasons and solutions.
The case study included shows the results from stimulating Sara khaled Hassan
this reservoir. Sohaila Ahmed Abdel-hady

168 Creative Director
Aya Elgendy
Oil distillation
Graphic designers
Oil is one of the most important natural resources on Noha Mohamed Mahran
which we rely mainly on life, whether in homes, factories Hossam Nasr Mohammed
or as fuel for different means of transport. When crude oil
is extracted, it must pass some separation processes to Mohammed Amr
obtain its derivatives. , In this article we are talking about the
simple stages of distillation process. Oil is one of the most | ISSUE 3 | FEBRUARY2017 3
important natural resources on which we rely mainly on life,
whether in homes, factories or as fuel for different means
of transport. When crude oil is extracted, it must pass some
separation processes to obtain its derivatives. , In this article
we are talking about the simple stages of distillation process.

4D SEISMIC TIME LAPSE Changes in a Reservoir Seen through 4-D Seismic
Source: Schlumberger
edited by: Mohammed Shahin Four-D seismic can determine changes in flow, temperature, pressure and
saturation. By scanning a reservoir over a given period of time, the flow of the
hydrocarbons within can be traced and better understood. For example, as
hydrocarbons are depleted from a field, the pressure and composition of the
fluids may change. Additionally, geologists are interested in understanding
how the reservoir reacts to gas injection or water flooding. Furthermore, 4-D
seismic can help to locate untapped pockets of oil or gas within the reservoir.
Typically, 4-D seismic data is processed by subtracting the data from one
survey from the data of another. The amount of change in the reservoir is
defined by the difference between the two. If no change has occurred over the
time period, the result will be zero

4D surveys are 3D surveys repeated in time, also called a time-lapse survey. It is References •Jump up to: 5.0 5.1 5.2 Johnston, J.H. et al. 2000.
considered best to leave the sensor array permanently in place for this to improve Using Legacy Seismic Data in an Integrated
repeatability. The Time interval can be about 6 months to a year or two, and can go on •Koster, K. et al. 2000. Time-Lapse Seismic Time-Lapse Study: Lena Field, Gulf of Mexico.
for multiple years. Surveys in the North Sea and Their Business The Leading Edge 19 (3): 294. http://dx.doi.
Impact. The Leading Edge 19 (3): 286. http://dx.doi. org/10.1190/1.1438596
By comparing or animating the three-D images rapidly changes in the org/10.1190/1.1438594 •Eastwood, J. et al. 1994. Seismic Monitoring of
formation structure as a result of production can be observed, telling the •Lumley, D.E., Behrens, R.A. and Wang, Z. 1997. Steam-Based Recovery of Bitumen. The Leading
interpreters where and how the hydrocarbons have been drained. Assessing the Technical Risk of a 4D Seismic Edge 13 (4): 242. http://dx.doi.org/10.1190/1.1437015
Used to find oil and gas prospects, there are multiple types of seismic Project. The Leading Edge 16 (9): 1287. http://dx.doi. •Talley, D.J. et al. 1998. Dynamic Reservoir
surveys that can be produced over reservoirs to understand the subsurface org/10.1190/1.1437784 Characterization of Vacuum Field. The Leading
environment. Made up of reflection and refraction mapping, seismic surveys •Wang, Z. 1997. Feasibility of Time-Lapse Seismic Edge 17 (10): 1396. http://dx.doi.org/10.1190/1.1437858
give geologists a better idea of what lies beneath the surface - or even below Reservoir Monitoring: The Physical Basis. •Wang, Z., Cates, M.E., and Langan, R.T. 1998.
thousands of feet of water. The Leading Edge 16 (9): 1327. http://dx.doi. Seismic Monitoring of a CO2 Flood in a Carbonate
One of the most intricate forms of seismic survey, 4-D (four-dimensional) org/10.1190/1.1437796 Reservoir: A Rock Physics Study. Geophysics 63 (5):
seismic, is a type of geophysics. Also known as time lapse seismic, 4-D seismic •Behrens, R., Condon, P., Haworth, W. et al. 2001. 1604. http://dx.doi.org/10.1190/1.1444457
incorporates numerous 3-D seismic surveys over the same reservoir at 4D Seismic Monitoring of Water Influx at Bay •Greaves, R.J. and Fulp, T.J. 1987. Three-
specified intervals of time. Studying multiple time-lapsed 3-D surveys, or three- Marchand: The Practical Use of 4D in an Imperfect Dimensional Seismic Monitoring of an Enhanced
dimensional subsurface images, portrays the changes in the reservoir over World. Presented at the SPE Annual Technical Oil Recovery Process. Geophysics 52 (9): 1175. http://
time. Conference and Exhibition, New Orleans, dx.doi.org/10.1190/1.1442381
Louisiana, 30 September-3 October 2001. SPE-
4 | ISSUE 4| FEBRUARY2018 71329-MS. http://dx.doi.org/10.2118/71329-MS.

| ISSUE 4 | FEBRUARY2018 5

Drilling Problems and Their Remedies : Lost circulation zone and causes :

There are various common problems that might occur during drilling, and Formations that are inherently Cavernous formations are often
there are some uncommon ones, too. This chapter will describe the most fractured, cavernous, or have high limestones with large caverns. This
commonly encountered drilling problems caused by downhole conditions. permeability are potential zones of type of lost circulation is quick,
When any problem is encountered, the drilling staff must identify the root lost circulation. In addition, under total, and the most difficult to seal.
causes of the problem before a proper response to solve the problem can be certain improper drilling conditions, High-permeability formations
formulated. If the root causes are incorrectly identited, it is unlikely that the induced fractures can become that are potential lost-circulation
correct response will be made, and the problem might remain unsolved. It can potential zones of lost circulation. The zones are those of shallow sand
even make the situation worse. Identifying the root causes of problems covered major causes of induced fractures are with permeability in excess of 10
in this article will be described, along with possible responses. excessive downhole pressures and darcies. Generally, deep sand has
setting intermediate casing, especially low permeability and presents no
The main drilling problems: in the transition zone, too high. loss-of-circulation problems. In
Induced or inherent fractures may be noncavernous thief zones, mud level
1- Lost Circulation horizontal at shallow depth or vertical in mud tanks decreases gradually
at depths greater than approximately and, if drilling continues, total loss of
Lost circulation is defined as the 2,500 ft. Excessive wellbore pressures circulation may occur.
uncontrolled flow of whole mud are caused by high flow rates (high
into a formation sometimes referred annular-friction pressure loss) or
to as thief zone. shows partial and tripping in too fast (high surge
total lost-circulation zones. In partial pressure), which can lead to mud
lost circulation, mud continues to losses. In addition, improper annular
flow to surface with some loss to hole cleaning, excessive mud weight,
the formation. Total lost circulation, or shutting in a well in high-pressure
however, occurs when all the mud shallow gas can induce fractures,
flows into a formation with no return which can cause lost circulation.
to surface. If drilling continues
during total lost circulation, it is | ISSUE 4 | FEBRUARY2018 7
referred to as blind drilling. This is
not a common practice in the field
unless the formation above the thief
zone is mechanically stable, there
is no production, and the fluid is
clear water. Blind drilling also may
continue if it is economically feasible
and safe.

6 | ISSUE 4| FEBRUARY2018

Prevention of lost 2- Stuck Pipe 2. Mechanical pipe sticking :
circulation :
During drilling operations, a pipe is The causes of mechanical pipe sticking
The complete prevention of lost considered stuck if it cannot be freed are inadequate removal of drilled
circulation is impossible because and pulled out of the hole without cuttings from the annulus; borehole
some formations, such as inherently damaging the pipe and without ex- instabilities, such as hole caving,
fractured, cavernous, or high- ceeding the drilling rig’s maximum sloughing, or collapse; plastic shale or
permeability zones, are not avoidable allowed hook load. Differential pres- salt sections squeezing (creeping); and
if the target zone is to be reached. sure pipe sticking and mechanical key seating.
However, limiting circulation loss pipe sticking are addressed in this
is possible if certain precautions are section
taken, especially those related to
induced fractures. These precautions Causes of stuck pipe
include maintaining proper mud can be classified into :
weight, minimizing annular-friction
pressure losses during drilling and 1. Differential pressure pipe sticking
tripping in, adequate hole cleaning,
avoiding restrictions in the annular Differential-pressure pipe sticking
space, setting casing to protect upper occurs when a portion of the drill
weaker formations within a transition string becomes embedded in a
zone, and updating formation pore mud cake (an impermeable film of
pressure and fracture gradients for fine solids) that forms on the wall
better accuracy with log and drilling of a permeable formation during
data. If lost-circulation zones are drilling. If the mud pressure, which
anticipated, preventive measures acts on the outside wall of the pipe,
should be taken by treating the mud is greater than the formation-fluid
with lost-circulation materials (LCMs). pressure, which generally is the case
(with the exception of underbalanced
drilling), then the pipe is said to be
differentially stuck The differential
pressure acting on the portion of
the drill pipe that is embedded in
the mud cake can be expressed as.

8 | ISSUE 4| FEBRUARY2018 | ISSUE 4 | FEBRUARY2018 9

3. Fishing : 3- Washover and basket:
Within this class of tool there are three types: the fishing magnet, tools that
Sometimes, something gets into the hole that needs to be recovered. use fluid movement to catch small bits of junk, and tools that use a barrel to go
For instance, a spanner might drop down the rotary table or part of the drill over bits of junk and then close below the junk.
string might break. These items prevent normal operations from continuing.
The item that must be removed from the well is called a fish and activities to 1. Fishing for wireline and slow job because each stand of pipe
remove the fish are termed fishing. There are four main causes for fish in the logging tools has to have the wire fed through it
hole before it can be connected to the
a ) If there is a failure somewhere in the pipe in the hole that causes a break, wireline sometimes breaks, string at the rotary table.
the lower part of the string will drop into the hole resulting in a tricky fishing job.
b) If stuck pipe cannot be freed, it has to be cut or unscrewed downhole. Wireline is fi shed with a spear that 2. Drilling, milling, and
c) Something falls into the well. has barbs on the side The spear is smashing junk :
d) Sometimes wells are worked over; they may require that the existing run into the top of the wire and Finally, In surface holes where
completion is replaced with another completion. Often the completion tubing rotated. The barbs catch on the wire formations are soft, smaller
has to be cut downhole and recovered in pieces. and cause the wire to wrap around bits of loose junk can be drilled
There are five classes of tool that can be used to remove a fish or junk from the the spear so that it can be pulled with a steel tooth bit. Often what
hole. The choice of which one to use will depend on the circumstances. The five out. If a logging tool gets stuck, the happens is that the bits of junk
classes are each briefly described: best way to fish it is by stripping get pushed into the side of the
over the wire. The wire is cut at the hole and are never seen again.
OUTSIDE CATCH TOOLS surface and is fed through a special Steel tooth bits are also capable
If the junk has a round profile at the top, the preferred tool will tool that latches onto a profile at the of breaking up small bits of jun
top of the logging tool. This fishing no other drill bit can do this.
normally be an outside catch tool. These tools are pushed over the top of tool is then run in the hole over
the fi sh. When the fishing tool is moved upwards, it grips the fish and the wire so that the wire guides the
allows force to be applied. fishing tool to the logging tool. It is a
INSIDE CATCH TOOLS
Edit by: Mosa Salama
Sometimes, a tubular fish has a large outside diameter, which
prevents an overshot from going over it. | ISSUE 4 | FEBRUARY2018 11

10 | ISSUE 4| FEBRUARY2018

EOR Methods in luids present in these reservoirs
often contain hydrogen sulphide
Carbonate Resevoirs
Fand carbon dioxide, produced
edited by : Taha Yehia by chemical reactions within
the carbonate reservoirs, this hydrogen
During the past decade, two-thirds sulphide is highly corrosive and toxic.
of new hydrocarbon discoveries Beside that tar mass which is heavy layers
were made in carbonate reservoirs. of hydrocarbons that are highly viscous,
More than 60% of the world’s oil are also found in these reservoirs and
and 40% of the world’s gas reserves are held can form permeability barriers. Because
in carbonates.The Middle East has 62% of carbonate reservoirs have very high seismic
the world’s proved conventional oil reserves; velocities generating multiple reflections,
approximately 70% of these reserves are in obtaining good seismic images can be
carbonate reservoirs. The Middle East also difficult. Also, it is extremely difficult to
has 40% of the world’s proved gas reserves; describe the wetting character of reservoir
90% of these gas reserves lie in carbonate rocks as they have complex structures of
reservoirs. Beside the great importance of a variety of minerals.This makes incorrect
carbonate reservoirs, they have specific assumptions about reservoir wettability
characteristics which make dealing with might result is unexpected formation
them a real challenge. Unlike the relatively damage. Unlike,sandstone reservoirs which
homogenous sandstone reservoirs, in which have strongly water-wet, wettability is a
hydrocarbons are found within sand layers, further heterogeneous characteristic in
carbonate reservoirs (limestone or dolomite), carbonates. The aging of carbonate rock
are made of materials such as shell or coral. containing water and oil turns initially
These reservoirs are characterized by a water-wet rocks into mixed-wet or even oil-
matrix with a low permeability and high wet rocks. This means that oil can adhere
heterogeneity resulting from fractures or to the surface of carbonate rock and it is
dissolution patterns, as carbonates may therefore harder to produce. This article will
dissolve in the presence of water. discuss the main stimulation techniques in
carbonate reservoirs, challenges we face in
12 | ISSUE 4| FEBRUARY2018 the stimulation process and its solutions.

Carbonate Stimulation :

When the productivity of a well in a
carbonate reservoir decreases as a result
of formation damage or low natural
permeability, the production team will
attempt to increase productivity through
intervention and appropriate treatments. If
they decide to work over the well, they must
identify and implement a treatment program
that creates conductive flow paths between
the reservoir and the borehole. This is the
essence of carbonate stimulation.

| ISSUE 4 | FEBRUARY2018 13

Acids play a key role in boosting production or increasing injectivity in oil and gas fields. 2- UNEVEN DISTRIBUTION OF THE TREATING FLUID
Stimulation of carbonate rocks usually involves a reaction between an acid and the minerals
calcite (CaCO3) or dolomite CaMg(CO3)2 that is intended to enhance the flow properties of the When injecting acids into a well with the goal of stimulating the production of a low permeability
rock. reservoir, the acids will naturally go into the more permeable parts of the geological formation.
The solution is Diversion. Diversion is a technique used in injection treatments to ensure uniform
Stimulation methods in carbonate sequences can be divided into two main groups: distribution of the treatment fluid across the treatment interval. Injected fluids tend to follow the path
of least resistance, and this may lead to inadequate treatment of the least permeable areas within
01 Matrix stimulation involves 02 Acid-fracturing stimulations, in the stimulation interval. Using diversion methods, engineers can focus treatment on the areas that
pumping acids, solvents, or contrast, are performed above require more stimulation. To be effective, the diversion effect should be temporary to enable the full
other treatment chemicals the fracture pressure of the productivity of the well to be restored when the treatment is complete. There are two main categories
into the formation- formation. A viscous pad (a of diversion: mechanical and chemical.

hydrochloric acid (HCl) is the most commonly fracturing fluid that does not contain proppant) MECHANICAL METHODS
Mechanical diversion techniques, such as ball sealers,
applied stimulation fluid- at less than the is pumped into the formation at pressures above
packers, and straddle packer assemblies, are used to divert
reservoir fracture pressure. When acids are the fracture initiation pressure, which fractures reservoir treatments to the target zone. Ball sealers and solid-
particle diverting agents incorporated into the treatment
introduced into a carbonate formation, some the rock. Then an acid stage is pumped to etch fluid form a temporary plug in the perforations accepting the
most fluid flow, thereby diverting the remaining treatment
of the minerals in the rock dissolve, which the fracture surfaces. The acid also creates fluid to the less permeable zones (Fig. 3a). Packers and
straddle-packer assemblies function by performing several
creates intricate, high-permeability channels or conductive wormholes at or near the fracture short treatments over a longer interval to help ensure even
treatment over the entire zone (Fig. 3b).
wormholes (Fig. 1). surfaces Figure 2. When the treatment is complete LIMITATIONS

and the fracture closes, the etched surfaces though widely used, mechanical diversion methods may not
always be feasible or recommended. They are often ineffective
provide high-conductivity flow paths from the for stimulation projects in long horizontal or extended-reach
wells.
reservoir to the wellbore.
CHEMICAL METHODS
In sandstones, matrix treatments are used CHALLENGES WE FACE IN THE
to restore or improve the natural formation STIMULATION PROCESS Conventional chemical diversion methods include nitrogen
permeability around the wellbore by removing foam, bridging agents such as benzoic acid flakes, and
formation damage. This is accomplished by 1- WATER-BEARING ZONES crosslinked polymer gels. These create a temporary plug in
dissolving material that is plugging the pores high-permeability carbonate zones so that the stimulation
or by enlarging the pore spaces. In carbonates, ZONES One of the fundamental requirements fluids are diverted into the low-permeability zones that require
matrix stimulation creates new, highly for any stimulation program is that the increase in more treatment. Polymer-based gels are a well-established
conductive channels (wormholes) that bypass conductivity is restricted to the hydrocarbon zone. Acid or chemical diversion technique. These systems use reversible,
the damage. Matrix treatments are often fracture stimulation of water bearing layers adjacent to the pH-triggered cross-linker additives to alter the viscosity of the
applied in zones with good natural permeability reservoir would lead to a sharp rise in water production fluid during the acid treatment. SDA* Self-Diverting Acid is a
to counteract damage in the near-wellbore with the associated issues of fluid handling, separation, polymer system mixed with HCl. When combined with fresh
area. and disposal. In extreme cases, stimulation of the water acid, the SDA fluid has a low viscosity to facilitate pumping.
zone could end the economic life of the well. However, once this fluid enters a carbonate zone and the acid
becomes spent, the polymer crosslinks and the fluid viscosity
14 | ISSUE 4| FEBRUARY2018 increases. The higher gel viscosity restricts the flow of fresh
acid through the wormholes, and diverts it into the zones with
lower permeabilities and, eventually, to all the zones requiring
treatment (Fig. 4).
LIMITATIONS

Modern chemical diversion methods can be very effective,
but may create problems if incorrectly managed. In some wells,
for example, temporary plugs may become permanent, which
damages the formation and reduces production from the zone
that was supposed to be stimulated.

| ISSUE 4 | FEBRUARY2018 15

ADVANCED TECHNOLOGY 5-PREVENTING ACID DAMAGE TO WELL C : s s aCase astsuedys: tsuuCdCyess inusCaCuedsi asrianbia audi rabia
AND SURFACE EQUIPMENT
ClearFRAC polymer-free fracturing fluid, aIn SsaiugIdnniiAfSircaaabunidat,i thAcerhraeabhniaags,ebtheeiennrea cshaigarnsbifoibcnaeanettne grpweraeotrederuthcmatunioctnhhe fagrvoreemraagtee1pr1rotodhfuafcsnteiottnhwferoemallvs1e1 ortafhfgsaeett
which is based on viscoelastic surfactant (VES) The used chemicals and acids in stimulation charnegseervinoircarbsotniamteularteisoenrvoir testcimhnuliaqtuioens, whelalsdthbaetehnadsbtiemenuslatitmeudlawteidthwoituhtoutthteheVVDDAA
technology, and a high-temperature version of treatments can cause damage to the tecwhniitqhueas, swhiitfht aawsahyiftfraowmaypforolymmepro-lbymaseer-d syssytsetme(mFig(.F6i)g. W. a6t)e.rWcuattinerthceuVtDAin-trtehaetedVwDeAll-s
the system that can be used at temperatures completion equipment of the well bassetdimstuimlautliaotniofnlufilduisdstotwowaardrdnnoonn--ddaammaagginingg wtarsematuecdh lwoweellrsthwaansinmwuelclshtrleoawteedrwtihthaonthienr
to 135degC.VES surfactant fluids are polymer- Solution VDAVDsyAstesmyss.teSamusd.i ASraaumdcioAharasmusceod VhEaSsfluuisdesd sywsteelmlss.tTrehiastwedas wbeitchauoseththeer hsiygsht-veimscoss. itTyhgiesl
free, so they do not damage the formation. Corrosion inhibitors prevent acid damage to for VaEraSngfeluoifdsstimfourlataionraanpgpleicaotifonsst,imincululadtiniogn inwtahes bweatcearuzsoenetshreehmiagihne-vdisinctoacsti,twy gheerleiansththee
Their enhanced, drag-reducing properties and equipment both at the surface and in the well. matarpixpalcicidaiztinognasn, dindcivluerdsiinong imn partordixucatcioindiaznindg gewl afotremrezdoinethserheymdraocinaerbdoninztoancets, hwadhebrroekaesn
significantly lower friction pressure enable The initial cost of corrosion inhibitors may seem wataenr dinjedcivtieornswioenllsi,nanpdraocdiducfrtaicotnurianng din whiagthe- r anthdeenagbelel dftohremaecidd toinmitghraete hfuyrdthreorciantrobothne
the stimulation team to reduce the pumping very high—they are the single most expensive preisnsjuerec,thioignh twemelplse,raatunrde gaacsidwefllrsaacntdurwinagteri-n mzaotrnixe.sThhiasdlebdrtookmenoraenedffeecntiaveblsetdimtuhlaetiaonciodf
requirements and treat deeper zones. There is component of the materials used—but the cost injehcitgiohn-pwreells.sSuarued, i AhriagmhcoteanmdpSecrhalutumrbeerggears thteohmydirgorcaatrebofnu-rbtehaerirnginztoonetsheanmd ahitgrhixe.r Trahtiess
a range of VES fluids for various applications. of damage to pumping equipment and tubulars if engwineelelsrs faonundd wthaatethr-einprjeodcutciotinonwraetellsso. fSthaeu5di ofleodil otrogmasoprreodeufcfteiocnt.ive stimulation of the
These include VDA diverting fluid, ClearFRAC they were not to be used would be even higher. welAlsraafmtercsotimaunldatioSncwhiltuhmVDbAerfglueidr weenregimnuecehrs hydrocarbon-bearing zones and higher
hydraulic fracturing fluid, and ClearPAC* gravel
packing fluid. found that the production rates of the rates of oil or gas production.
5 wells after stimulation with VDA fluid
6-STIMULATION THROUGH
3- EMULSIONS AND SLUDGE HORIZONTAL WELLS FORM A REAL
CHALLENGE
During fracturing and matrix acidizing,
the acid may come into direct contact with Long, open hole horizontal wells provide an
produced crude oil or well fluids. This may efficient way to develop complex carbonate
result in the formation of emulsions or sludge. reservoirs, but there are challenges in
Emulsions can be viscous and may block the attempting to stimulate these wells due to the
treated formation and reduce oil production. difficulty of proper distribution of the
Solution stimulation fluid through the well.
Reservoir engineers can add anti-emulsifying Solution
and antisludging agents to prevent these Mechanical isolation and individual
emulsions forming and demulsifiers to break treatments which allow treating each part of the
emulsions once they have formed. well separately.

4-INSOLUBLE REACTION PRODUCTS

When operators anticipate that a formation
will contain large amounts of acid insoluble
silts or other fines that could be released
during acidizing, these solids can cause severe
plugging of pore throats during flow back.
Solution
the acid should be treated with a silt-
suspending agent. By keeping these solids in
suspension, the operators can produce them
out of the formation and avoid damaging the
well’s performance.

16 | ISSUE 4| FEBRUARY2018 | ISSUE 4 | FEBRUARY2018 17

Oil Distillation There are many types of distilleries
used in oil refining, petrochemical
Petroleum is considered one industry, desalination, pharmaceutical
of the most important daily industry and many others such as:
needs. It is used in most
household appliances. 1. Simple or progressive distillation
2. Sudden distillation.
Oil distillation is one of the 3. Frequent distillation using distillation
processes used in preparation towers.
for direct use. Its main idea 4. Steam distillation.
is the process of separating 5. Vacuum distillation.
the liquid from the solution,
depending on the difference | ISSUE 4 | FEBRUARY2018 19
in the boiling point. The
material to be separated has
a boiling point different from
the other substances in the
solution. By evaporation of
a heterogeneous mixture of
water and natural matter, and
then the steam condensation
process is carried out by
cooling process.

18 | ISSUE 4| FEBRUARY2018

How distillation is done ?

1 First Step : 2Second Step :
When crude oil is extracted from After removing water and salts, we move on to the main step
the well, the water and associated in the process of refining oil, which is the process of separating
salts are disposed of in several ways, oil into its components depending on the difference in the
because this water and these salts can boiling point of these components. This separation process
cause serious and serious problems is known as distillation of oil because oil is separated and
when oil distillates in a later step divided into specific components and known and specific
in the distillation tower. The water uses.
accompanying the oil if not removed
, Distillation As the salts if it still This step occurs in a huge tower known as a distillation tower
produced acids in the tower which where the oil is heated to degrees up to 400 degrees Celsius or
leads to erosion. slightly more in a special oven and then pushed with hot oil
at the bottom of the tower.

3 Third Step : We also know that the oil consists of a large mixture of organic
After obtaining these compounds each compound has certain characteristics and has
derivatives, they are not a certain boiling point, the light organic compounds that are
marketed directly because low in boiling will rise to the top of the tower such as methane
they are in fact not valid and ethane. They will condense into special trays inside the
for use so far. In order to be tower and then be pulled out through special openings.
usable, some improvements Thus, the higher components in the boiling point will intensify
have to be made to make slightly below. As we descend to the bottom of the tower, the
them suitable for the boiling points of these components will increase until we
desired use. reach the bottom of the tower, where we will find the heavy
residues, the components with high boiling points.

In general, the products (petroleum derivatives) obtained are
different from refinery to refinery according to the design of
the tower itself, as well as by the quality of oil is it light oil or
heavy oil.

20 | ISSUE 4| FEBRUARY2018 | ISSUE 4 | FEBRUARY2018 21

In general, most of the petroleum | ISSUE 4 | FEBRUARY2018 23
derivatives produced by the oil
distillation tower are as follows:
Gases such as: methane, ethane,
ethylene, propane, butane and
others.
1) Light liquids: mainly gasoline
(automotive fuel).
2) Kerosene: It is used as jet fuel,
and a poor type of cheap fuel is
used in industrial plants and
homes.
3) Diesel: a heavier liquid
than kerosene is used as fuel
in factories, large engines and
trucks.
4) Heavy liquids: An important
source of petroleum industries,
some of which can be converted
to light derivatives such as
gasoline through known oil
operations such as thermal
cracking and catalytic cracking.
5) The pitch: are the residues
gathered at the bottom of the
tower , With high molecular
weight and used in the coating
of concrete constructions, ship
painting, paving and paving of
roads.

Edit by: Ahmed Mokhtar

22 | ISSUE 4| FEBRUARY2018

Other References:
1- Distillation: https://www.eia.gov/todayinenergy/detail.php?id=6970
2- Crude Oil Distillation - nptel.
Journal of Chemical Education.
Fenster
1967 44 (11), p 660
3- Drilling problems
John Martin Shaughnessy (BP plc) | William Thomas Daugherty (BP America) | Rick L.
Graff (Chevron Corp.) | Todd Durkee (Kerr-McGee Oil & Gas Corporation)
PEH:Drilling Problems and Solutions - - PetroWiki
4- SPE-171126-MS_Viscous Fingering Stimulation Option Applied on Heavy-Oil Carbonate
Reservoirs.(Javier Ballinas, Weatherford).
5- SPE 160887_Stimulation Strategies to Guard against Uncertainties of Carbonate
Reservoirs.
6- SPE-169662-MS A Laboratory Study of Ionic Effect of Smart Water for Enhancing Oil
Recovery in Carbonate Reservoirs.
7- Production Doubled in a Saudi Aramco Carbonate Reservoir_slb website.
8- SPE 93413_Stimulation Challenges and Solutions in Complex Carbonate Reservoirs.
9- An overview of hydraulic fracturing and other formation stimulation technologies for
shale gas production (Luca Gandossi).
10- GEOLOGY OF CARBONATE RESERVOIRS_WAYNE M. AHR Texas A&M University.
11- www.researchgate.com.
12- www.onepetro.com.
13- www.slb.com.

Our Academic Team:

Follow us on your favourite social networks

eagesu eagesu eagesu eagesu