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معالجة مياه البويلرات بالتبادل الأيوني

Ion Exchange Water Treatment for High-Pressure Boilers

المجال صناعة البتروكيمياء

التطبيق البويلرات الصناعية

الموقع —

المعيار < 0.2 μS/cm

📋 فهرس المحتويات

📋 Table of Contents

الناقلية الكهربائية وعلاقتها بدرجة الحرارة
مبدأ التبادل الأيوني
الراتنج الكاتيوني
الراتنج الأنيوني
عملية التجديد (Regeneration)
أنظمة المعالجة المختلفة
نظام Mixed Bed
جدول مقارنة شامل

Electrical Conductivity and Temperature
Ion Exchange Principle
Cation Exchange Resin
Anion Exchange Resin
Regeneration Process
Different Treatment Systems
Mixed Bed System
Comprehensive Comparison Table

الناقلية الكهربائية النوعية وعلاقتها بدرجة الحرارة Electrical Conductivity & Temperature Specific Electrical Conductivity & Temperature Relationship الناقلية الكهربائية وعلاقتها بالحرارة

الناقلية الكهربائية النوعية هي مقياس لقدرة الماء على توصيل التيار الكهربائي، وهي مرتبطة مباشرة بتركيز الأيونات الذائبة فيه. في وحدات الأمونيا، يُشترط أن تكون الناقلية أقل من 0.2 ميكروسيمنز عند 25°C لضمان سلامة مراجل البخار عالية الضغط.

العلاقة الأساسية: الناقلية الكهربائية تزيد بزيادة درجة الحرارة، لأن الحرارة تزيد من سرعة وحركة الأيونات في الماء مما يسهّل توصيل التيار الكهربائي.

Specific electrical conductivity measures water's ability to conduct electric current, directly related to dissolved ion concentration. In ammonia plants, conductivity must remain below 0.2 μS/cm at 25°C to protect high-pressure boilers.

Key relationship: Conductivity increases with temperature because heat increases ionic mobility, facilitating current flow.

σ_T = σ₂₅ × [1 + α(T − 25)] حيث: α ≈ 0.02 لكل درجة مئوية (2% لكل °C) | σ = الناقلية | T = درجة الحرارة where: α ≈ 0.02 per °C (2% per degree) | σ = conductivity | T = temperature

⚠️ لماذا 25°C كدرجة مرجعية؟ لأنها الدرجة الدولية القياسية للمقارنة. أجهزة القياس تحتوي على دائرة تعويض تلقائية (Temperature Compensation) تُرجع القراءة إلى 25°C مهما كانت درجة الحرارة الفعلية للماء.

⚠️ Why 25°C as reference? It is the international standard for comparison. Conductivity meters include automatic temperature compensation circuits that normalize readings to 25°C regardless of actual water temperature.

مقارنة الناقلية بين أنواع المياه المختلفة

Conductivity Comparison Across Water Types

ماء مقطر نظري | Pure Distilled Theoretically Pure Water 0.055 μS/cm

نظري

مياه البويلر (وحدتنا) | Our Boiler Water Boiler Feed Water (Our Unit) < 0.2 μS/cm ✅

<0.2

ماء الصنبور | Tap Water Tap Water 200–800 μS/cm

200–800

ماء البحر | Seawater Seawater ~50,000 μS/cm

~50,000

💡 حقيقة مهمة: H⁺ و OH⁻ وناقليتهما

💡 Important Fact: H⁺ & OH⁻ Conductivity

H⁺ و OH⁻ يملكان أعلى ناقلية مولية بين جميع الأيونات (349.8 و 198.6 S·cm²/mol على التوالي)، لكن تركيزهما في الماء النقي ضئيل جداً (10⁻⁷ mol/L فقط)، مما يجعل الناقلية الكلية منخفضة جداً. هذا يُثبت أن: الناقلية = قوة الأيون × تركيزه

H⁺ and OH⁻ have the highest molar conductivity of all ions (349.8 and 198.6 S·cm²/mol respectively), yet their concentration in pure water is only 10⁻⁷ mol/L, resulting in very low total conductivity. This proves: Conductivity = Ionic strength × Concentration

الأيون	Ion	Ion Symbol	الناقلية المولية (S·cm²/mol)
هيدروجين	Hydrogen	H⁺	349.8 🏆
هيدروكسيد	Hydroxide	OH⁻	198.6
كالسيوم	Calcium	Ca²⁺	59.5
صوديوم	Sodium	Na⁺	50.1
كلوريد	Chloride	Cl⁻	76.4
كبريتات	Sulfate	SO₄²⁻	80.0

مبدأ التبادل الأيوني Ion Exchange Principle Ion Exchange Principle مبدأ التبادل الأيوني

التبادل الأيوني هو عملية كيميائية تتم داخل راتنج اصطناعي (Resin) حيث يُزيل الأيونات الضارة من الماء ويستبدلها بأيونات غير ضارة. الراتنج عبارة عن حبيبات بوليمرية صغيرة تحتوي على مجموعات وظيفية نشطة قادرة على التبادل.

في عملية إنتاج الأمونيا (High-Pressure Steam Plants)، تُعالج المياه قبل دخولها إلى مراجل البخار لإزالة جميع الأملاح المعدنية التي قد تسبب:

Ion exchange is a chemical process occurring within synthetic resin beads that remove harmful ions from water and replace them with harmless ones. The resin consists of small polymer beads containing active functional groups capable of exchange.

In high-pressure boiler plants, water is treated before entering boilers to remove all mineral salts that could cause:

🧱

الترسبات (Scale)

Scale Formation

تراكم كربونات الكالسيوم والمغنيسيوم على جدران الأنابيب مما يقلل كفاءة نقل الحرارة

Calcium and magnesium carbonate buildup on tube walls reducing heat transfer efficiency

⚡

التآكل (Corrosion)

Corrosion

الأيونات الكلوريدية والكبريتية تهاجم المعادن وتسبب تآكلاً خطيراً في الأنابيب

Chloride and sulfate ions attack metals causing serious pipe corrosion

💥

خطر الانفجار

Explosion Risk

الترسبات تؤدي إلى ارتفاع غير متحكم في درجة الحرارة وزيادة الضغط

Scale leads to uncontrolled temperature rise and pressure increase

📉

خسارة الكفاءة

Efficiency Loss

طبقة ترسب بسماكة 1mm تقلل كفاءة التسخين بنسبة تصل إلى 10%

A 1mm scale layer reduces heating efficiency by up to 10%

الأيونات الموجودة في المياه الخام

Ions Present in Raw Water

⊕ كاتيونات | Cations (+)

كالسيوم | CalciumCalciumCa²⁺

مغنيسيوم | MagnesiumMagnesiumMg²⁺

صوديوم | SodiumSodiumNa⁺

بوتاسيوم | PotassiumPotassiumK⁺

حديد | IronIronFe²⁺

منغنيز | ManganeseManganeseMn²⁺

⊖ أنيونات | Anions (−)

بيكربوناتBicarbonateHCO₃⁻

كبريتاتSulfateSO₄²⁻

كلوريدChlorideCl⁻

نتراتNitrateNO₃⁻

سيليكاتSilicateSiO₃²⁻

كربوناتCarbonateCO₃²⁻

الراتنج الكاتيوني Cation Exchange Resin Cation Exchange Resin (R-H) راتنج تبادل الكاتيونات (R-H)

الراتنج الكاتيوني يحتوي على أيونات H⁺ مرتبطة بهيكله البوليمري. عندما تمر المياه الخام، يحدث تبادل: الراتنج يأخذ الكاتيونات المعدنية ويُطلق H⁺ في مقابلها بكمية مكافئة كيميائياً (نفس عدد الشحنات).

The cation exchange resin contains H⁺ ions bound to its polymer structure. As raw water passes through, an exchange occurs: the resin captures metallic cations and releases H⁺ ions in chemically equivalent amounts (equal charge balance).

R−H⁺ + Ca²⁺ → R−Ca²⁺ + 2H⁺
R−H⁺ + Mg²⁺ → R−Mg²⁺ + 2H⁺
R−H⁺ + Na⁺ → R−Na⁺ + H⁺

💡 مبدأ التكافؤ الكيميائي

💡 Chemical Equivalence Principle

Ca²⁺ له شحنتان موجبتان → الراتنج يُطلق 2 أيون H⁺ في مقابله. هذا هو معنى "كمية مكافئة من أيونات الهيدروجين": نفس عدد الشحنات الكهربائية، وليس نفس عدد الجزيئات.

Ca²⁺ has two positive charges → the resin releases 2 H⁺ ions in exchange. This is the meaning of "equivalent quantity of hydrogen ions": the same number of electrical charges, not the same number of molecules.

الراتنج الأنيوني Anion Exchange Resin Anion Exchange Resin (R-OH) راتنج تبادل الأنيونات (R-OH)

الراتنج الأنيوني يحتوي على أيونات OH⁻ مرتبطة بهيكله. المياه الخارجة من الراتنج الكاتيوني تحتوي على H⁺ وأنيونات (Cl⁻, SO₄²⁻...). عند مرورها في الراتنج الأنيوني يحدث التبادل التالي:

The anion exchange resin contains OH⁻ ions bound to its structure. Water leaving the cation resin contains H⁺ and anions (Cl⁻, SO₄²⁻...). As it passes through the anion resin, the following exchange occurs:

R−OH⁻ + Cl⁻ → R−Cl⁻ + OH⁻
R−OH⁻ + SO₄²⁻ → R−SO₄²⁻ + 2OH⁻
R−OH⁻ + HCO₃⁻ → R−HCO₃⁻ + OH⁻
R−OH⁻ + SiO₃²⁻ → R−SiO₃²⁻ + 2OH⁻

✅ النتيجة النهائية: H⁺ المُطلق من الراتنج الكاتيوني + OH⁻ المُطلق من الراتنج الأنيوني يتحدان ليكوّنا ماءً نقياً: H⁺ + OH⁻ → H₂O

✅ Final Result: H⁺ released from the cation resin + OH⁻ released from the anion resin combine to form pure water: H⁺ + OH⁻ → H₂O

عملية التجديد (Regeneration) Regeneration Process Regeneration Process عملية التجديد

بعد فترة تشغيل، تمتلئ مواقع التبادل في الراتنج بالأيونات المعدنية ويفقد قدرته. نحتاج حينها إلى التجديد (Regeneration) لإعادته إلى حالته الأصلية.

After a period of operation, the resin's exchange sites become saturated with metallic ions and lose capacity. Regeneration is then needed to restore the resin to its original state.

⊕ تجديد الكاتيوني | Cation Regen.

المادة المستخدمة: حمض HCl أو H₂SO₄
Reagent: HCl or H₂SO₄ acid
R-Ca + 2HCl → R-2H + CaCl₂
R-Mg + 2HCl → R-2H + MgCl₂
الحمض يُعيد H⁺ للراتنج
Acid restores H⁺ to resin
الأملاح تُطرد مع محلول التصريف
Salts expelled in drain effluent

⊖ تجديد الأنيوني | Anion Regen.

المادة المستخدمة: هيدروكسيد NaOH
Reagent: NaOH (caustic soda)
R-Cl + NaOH → R-OH + NaCl
R-SO₄ + 2NaOH → R-2OH + Na₂SO₄
NaOH يُعيد OH⁻ للراتنج
NaOH restores OH⁻ to resin
الأنيونات تُطرد مع محلول التصريف
Anions expelled in drain effluent

دورة حياة الراتنج الكاملة | Complete Resin Life Cycle

Complete Resin Life Cycle

راتنج جديد R-H Fresh Resin R-H

→

تشغيل: إزالة الكاتيونات Service: Remove Cations

→

إنهاك R-Ca/Mg Exhausted R-Ca/Mg

→

تجديد بـ HCl Regen. with HCl

→

راتنج مُجدَّد R-H Regenerated R-H

أنظمة المعالجة المختلفة ومتى تُستخدم Different Treatment Systems & When to Use Them Different Treatment Systems أنظمة المعالجة

يعتمد اختيار نظام المعالجة على نوعية المياه الخام والهدف من المعالجة وضغط البويلر المستخدم.

The choice of treatment system depends on raw water quality, treatment objective, and boiler operating pressure.

① راتنج كاتيوني فقط | Cation Only

عندما المشكلة هي العسرة فقط (Ca²⁺, Mg²⁺)
When the problem is hardness only (Ca²⁺, Mg²⁺)
HCO₃⁻ يختفي تلقائياً: H⁺ + HCO₃⁻ → H₂CO₃ → H₂O + CO₂↑
HCO₃⁻ disappears automatically: H⁺ + HCO₃⁻ → H₂CO₃ → H₂O + CO₂↑
📍 التطبيق: مراجل ضغط منخفض، مصانع أغذية، مشروبات
📍 Applications: Low-pressure boilers, food & beverage plants
الناقلية النهائية: 50–200 μS/cm
Final conductivity: 50–200 μS/cm

② راتنج أنيوني فقط | Anion Only

عندما المياه تحتوي على أنيونات ضارة فقط
When water contains harmful anions only
مثال: إزالة NO₃⁻ الزائدة أو SiO₃²⁻ أو F⁻
Example: Removing excess NO₃⁻, SiO₃²⁻, or F⁻
📍 التطبيق: محطات مياه الشرب، الصناعات الغذائية
📍 Applications: Drinking water stations, food industry
الناقلية النهائية: 50–200 μS/cm
Final conductivity: 50–200 μS/cm

③ كاتيوني + أنيوني معاً | Cation + Anion (Full DM)

إزالة كاملة لجميع الأملاح المعدنية
Complete removal of all mineral salts
ضروري لمراجل البخار عالية الضغط ✅ للبويلرات الصناعية
Essential for high-pressure boilers ✅ for industrial boilers
📍 التطبيق: وحدات الأمونيا، الأدوية، أشباه الموصلات
📍 Applications: High-pressure steam plants, pharma, semiconductors
الناقلية النهائية: < 0.2 μS/cm
Final conductivity: < 0.2 μS/cm

⚡ القاعدة الأساسية

⚡ The Fundamental Rule

ضغط البويلر منخفض → تليين يكفي → راتنج كاتيوني فقط
ضغط البويلر عالٍ → تنقية كاملة → كاتيوني + أنيوني + Mixed Bed

Low boiler pressure → Softening sufficient → Cation resin only
High boiler pressure → Full demineralization → Cation + Anion + Mixed Bed

نظام Mixed Bed (السرير المختلط) Mixed Bed Ion Exchange System Mixed Bed Ion Exchange نظام السرير المختلط

نظام Mixed Bed هو وعاء واحد يحتوي على خليط متجانس من الراتنج الكاتيوني والأنيوني بنسبة تقريبية 40%:60%. يُستخدم كمرحلة أخيرة للتلميع (Polishing) بعد نظام الكاتيوني/الأنيوني المنفصل.

A Mixed Bed system is a single vessel containing a homogeneous mixture of cation and anion resins at approximately 40%:60% ratio. It is used as a final polishing stage after the separate cation/anion system.

🔬 لماذا يعطي نقاءً أعلى؟ في النظام المنفصل، التبادل يحدث على مراحل. في Mixed Bed، كل جزيئة ماء تمر بآلاف التبادلات المتتالية في نفس اللحظة ونفس المكان، مما يُعطي ناقلية تصل إلى أقل من 0.06 μS/cm

🔬 Why higher purity? In a separate system, exchange happens in stages. In a Mixed Bed, every water molecule undergoes thousands of consecutive exchanges simultaneously in the same vessel, achieving conductivity as low as 0.06 μS/cm

R−H⁺ + R−OH⁻ + NaCl → R−Na⁺ + R−Cl⁻ + H₂O التبادل يحدث في نفس اللحظة — التعادل فوري Exchange occurs simultaneously — neutralization is instant

مراحل تجديد Mixed Bed | Mixed Bed Regeneration Steps

Mixed Bed Regeneration Steps

① الفصل (Backwash Separation)

① Backwash Separation

ضخ الماء من الأسفل للأعلى. الراتنج الأنيوني (أخف كثافة) يطفو فوق، الكاتيوني (أثقل) يترسب أسفل

Water pumped upward. Anion resin (lighter density) floats to top, cation resin (heavier) settles to bottom

② التجديد المتزامن (Simultaneous Regeneration)

② Simultaneous Regeneration

NaOH يُضخ من الأعلى لتجديد الأنيوني. HCl يُضخ من الأسفل لتجديد الكاتيوني. يخرجان من المنتصف

NaOH pumped from top to regenerate anion resin. HCl pumped from bottom to regenerate cation resin. Both exit at the middle interface

③ الشطف (Rinse)

③ Rinse

شطف كل راتنج بماء نقي لإزالة بقايا الحمض والقاعدة

Each resin rinsed with pure water to remove acid and caustic residues

④ إعادة الخلط (Air Remixing)

④ Air Remixing

ضخ الهواء المضغوط من الأسفل لخلط الراتنجين معاً بشكل متجانس. ثم الشطف النهائي وإعادة التشغيل

Compressed air injected from bottom to thoroughly mix both resins uniformly. Final rinse then return to service

جدول مقارنة شامل لأنظمة المعالجة Comprehensive System Comparison Comprehensive Comparison Table جدول مقارنة شامل

المعيار	Parameter	كاتيوني فقط	Cation Only	كاتيوني + أنيوني	Cation + Anion	Mixed Bed
أيون العمل	Working Ion	H⁺	H⁺	H⁺ + OH⁻	H⁺	H⁺ + OH⁻
ما يُزيل	Removes	كاتيونات فقط	Cations only	كل الأيونات	All ions	الأثر المتبقي	Residual trace ions
الناقلية النهائية	Final Conductivity	50–200 μS/cm	50–200 μS/cm	< 0.2 μS/cm	< 0.2 μS/cm	< 0.06 μS/cm
مادة التجديد	Regenerant	HCl / H₂SO₄	HCl / H₂SO₄	HCl + NaOH	HCl + NaOH	HCl + NaOH
صعوبة التجديد	Regen. Complexity	سهل	Easy	متوسط	Moderate	معقد	Complex
التطبيق النموذجي	Typical Application	ضغط منخفض، أغذية	Low pressure, food	بويلرات الضغط العالي ✅	Petrochemical, high-pressure steam ✅	تلميع نهائي	Final polishing

خط المعالجة الكامل في منشآت البويلرات | Complete Treatment Train in High-Pressure Steam Plant

Complete Water Treatment Train — High-Pressure Steam Plant

مياه خام Raw Water

→

راتنج كاتيوني R-H Cation Resin R-H

→

راتنج أنيوني R-OH Anion Resin R-OH

→

Mixed Bed Mixed Bed

→

ماء نقي <0.2 μS/cm ✅ Pure Water <0.2 μS/cm ✅

oil drilling

After discovering the potential of the existing oil fields, the drilling begins A drilling rig puts the first bit in the ground, the hole will be about 13 meters deep the first section of steel pipe(casing); is placed in the hole and cemented in place it’s a one-day process to bring in and set up the rig and wouldn’t be possible without the use of heavy equipment this well will be drilled to a depth 3 crew shifts will work 24/7 in all weather conditions until drilling is complete.

The worker is mixing” drilling mud” which is crucial for lubrication in the hole Workers constantly monitor the lubricant as it circulates in & out of the well Each section of the drilling pipe. to drill the length of one depending on what they are drilling through. Once a section of the pipe is close to the end, the driller suspends the weight and the bit stops. ‘roughnecks’ at work making a pipe connection to continue drilling downward

rig floor

This process will take place many times during the day and night The graph that shows where the drill bit is beneath the surface reaches its destination, but the work has only started at this point First, the holes are flushed out with circulating water for several hours all the pipes are pulled out of the hole A logging crew arrives to start connecting probes and wires so they can begin the computerized analysis of the well, A logging probe is lowered into the well to the bottom the data were analyzed and fortunately, this oil well had good results so it will move on to completion.

A new set of pipes is installed but this time they will stay in place After meters of pipe are pulled out, and the same length of the new pipe is put in place, the cement trucks roll in one thing are ready, this becomes a robust pumping operation as you’ve never seen before after drilling and casing the well must be (completed)

Acids and fracturing fluids may be pumped into the well to fracture, clean, or otherwise prepare and stimulate the reservoir rock to release oil and gas it is common that the natural pressure of the subsurface reservoir is high enough for the oil or gas to flow to the surface If the pressure is too low then pump jacks is the solution and a common sight in the oil field Once crude oil is extracted from the ground, it must be transported and refined which happens in an oil refinery, In this case, crude oil is transferred from oil tankers directly into a long pipeline system

oil well

petroleum test methods

Petroleum is classified according to several criteria and tests, starting from crude oil to the final products. These tests determine the classification of petroleum from light to heavy and know the percentage of containing types of hydrocarbons (paraffin - naphthene’s - aromatics), impurities, and minerals, which affect The reactions and material used, and for this reason, these tests are very important to know the quality of oil and to determine the variables of the process and determine the final products that can come out of it, and its price in the market.

We can classify these tests as follow:

1. APPEARANCE: (Visual, Color, Particulate Contamination)

2. COMPOSITION: (Acidity, Aromatics, Olefins, Sulfur)

3. VOLATILITY: (Density, Distillation, Vapor Pressure, Flash Point /Fire Point)

4. COMBUSTION:(Antiknock Quality (Ron / Mon), Ignition Quality (Cetane No), Burning Quality (Calorific Value))

5. FLUIDITY: (Viscosity, Viscosity Index, Penetration)

6. STABILITY:(Induction Period, Gum Content)

7. CHANGE OF STATE:(Freezing Point, Pour Point, Cloud Point, Drop Point for Grease, Softening Point)

8. CORROSIVITY: (Total Sulphur, Doctor Test, Acidity / Alkalinity, Copper / Silver Corrosion)

9. OTHERS:(Ash / Sediments/ Carbon Residue, Asphaltenes, water Tolerance Metal Content, Benzene/Aromatics, Olefins/PAH)

A most important test of crude oil:

In this paragraph we going to talk about the most important tests of crude oil that determined the quality and the price:

API GRAVITY:

API is a gravity measuring parameter for all petroleum oil. This is related as:

API = 141.5/s − 131.5

where “s” is the specific gravity of oil at 15.5°C (60°F) with respect to water at the same temperature. The greater the specific gravity, the lower the API gravity. For water, API gravity becomes 10 and for oil, it is greater than 10. Crude oil having an API gravity as low as 9 has been found, which is heavier than water but most commonly it is always greater than 10. Thus, high API gravity crude oil is rich with lighter fractions and thus costlier. The price of oil is fixed depending on the API gravity as it is an easily measured entity and is directly related to the presence of lighter hydrocarbons.

CHARACTERISATION FACTOR

The next entity is the characterization factor (CF), which is most commonly used with API gravity to judge the quality and many physical properties of crude oil and its products. This is defined as the ratio of cubic root of the mole average boiling point (Tb, in Rankine) of oil to its specific gravity (s) at 15.5°C. Thus, it is expressed as:

CF = (Tb)1/3/s.

BOTTOM SEDIMENT AND WATER

Bottom sediment and water (BSW) is a measure of the quantity of residual sediment mostly settleable from the crude oil (if sufficient time is allowed for settling) and water. This may contain both heavy asphaltic hydrocarbon oil and non-hydrocarbon, such as inorganic salts. An amount of BSW is routinely tested for every batch of crude oil received in a refinery. Water, salt, and sediment are removed from the storage tanks, followed by electrical desalting. Throughout the world, petroleum products are tested according to the methods and equipment specified by the American Standard for Testing Materials (ASTM).

Initial Boiling Point (IBP):

heating and vaporizing the crude oil by a gradual increase in temperature followed by collection after condensation. When crude oil is heated in a distilling flask, vapors start emanating

as the temperature rises and these vapors are collected after condensation using ice-cold water. The temperature of vapor giving the first drop of condensate is reported as the initial boiling point (IBP), which may be above or below 0°C depending on the presence of the lowest boiling hydrocarbon in crude. This vaporizing phenomenon is so fast at the beginning that temperature measurement is quite uncertain as the vapor of the first drop is immediately followed by the mixture of vapors with increasing boiling points hence this must be noted in the shortest possible period (within 5–10 min) after the charge is heated.

True Boiling Point (TBP):

Usually, the composition of crude oil varies from well to well and it is essential to have a separate TBP analysis for each batch of oil purchased before refining. Hence, the yields of light to heavy fractions will vary from crude to crude. A small variation in TBP analysis may have a wide variation in the chemical constituents of the boiling fractions. This analysis indicates the maximum possible yields of raw cuts of products that could be obtained by distillation. In a refinery, a distillation column is used to separate these cuts at large rates continuously, where the yields of the raw cuts are slightly different from the TBP analysis. In fact, a distillation column is designed based on the TBP analysis of crude oil. Crude oils having wide differences in TBP analysis cannot be distilled in the same column without sacrificing the yields and quality of the products. It is, therefore, inevitable that the design of a distillation column of a refinery must be done judiciously, depending on the availability of the crude oils, which may have little difference in TBP analysis.

The experience is heating 100 ml and vaporizing the crude oil by a gradual increase in temperature followed by collection after condensation. When crude oil is heated in a distilling flask, vapors start emanating as the temperature rises, and these vapors are collected after condensation using ice-cold water as heating is continued, more and more hydrocarbon vapors with increasing boiling temperature are separated from crude and collected as condensates. This process is continued with gradual heating until no further vaporization takes place. The vapor temperature and the volume of liquid condensates (fraction boiling point FBP) collected are measured and reported as the distillation analysis of crude oil.

Crude oil production:

Having established the size of the oil field, the subsequent wells drilled are called ‘development’ or ‘production’ wells. A small reservoir may be developed using one or more of the appraisal wells. A larger reservoir will require the drilling of additional production wells. Multiple production wells are often drilled from one pad to reduce land requirements and the overall infrastructure cost. The number of wells required to exploit the hydrocarbon reservoir varies with the size of the reservoir and its geology. Large oilfields can require a hundred or more wells to be drilled, whereas smaller fields may only require ten or so.

The drilling procedure involves similar techniques to those described for exploration; however, with a larger number of wells being drilled, the level of activity obviously increases in proportion. The well sites will be occupied for longer, and support services— workforce accommodation, water supply, waste management, and other services—will correspondingly increase. As each well is drilled it has to be prepared for production before the drilling rig departs.

oil rig

OIL FIELD DEVELOPMENT:

Drilling is done to fracture and penetrate the rocky layers to reach the oil formation below the Earth’s surface. A hollow steel pipe containing the drill bit with perforations at its mouth is used for drilling. Mud fluid is pumped through the top end of the drill pipe through a hose which moves down with the pipe as the drilling progresses. The drill pipe and the hose are suspended from the crown of a pyramidal structure called a rig. depicts a typical rig for drilling operations.

Schematic diagram of an oil rig for exploration.

A high-pressure pump is employed to pump the mud solution from the mud pit through the hose such that the cuttings at the drill bit are washed out through the mouth of the drill bit and returned to the top surface through the annular space between the drill pipe and the hole developed. Cuttings with the mud solution are collected and separated from each other. Clarified mud along with fresh mud is pumped back to the drill pipe continuously. Mud is consumed due to absorption and seepage through the pores and crevices of the layers. Monitoring of the level in the mud pit is essential to assess the consumption and generation pattern of cuttings and water.

An alarming decrease in the level indicates leakage through the layers due to seepage in crevices or channels. While an increase in the level indicates ingress of underground water. Samples of drill cuttings are useful for surveying and assessing the direction of the drilling operation as they carry valuable information about the layers and formation. Continuous well logging is then carried out using a modern system of data acquisition and analysis. After drilling to a depth of 30–40 ft, a steel pipe is introduced into the hole to protect the wall of the hole formed.

This is called the casing string, which is then cemented to the wall of the hole by pumping a fast-setting cement solution (usually Portland cement without sand) to the annular space between the pipe casing and the wall of the hole. This casing helps prevent the caving of the wall and seepage of water from the layers.

An additional drill pipe is then joined of sufficient strength to withstand the various static and dynamic stresses for the increasing dead weight of piping, torsional stresses due to rotation, for upward and downward movement, abrasion from sand, fluid friction from mud fluid with cutting and corrosion, etc. The drilling operation is then continued and an additional casing pipe of a reduced diameter from the previous one is inserted and cemented at strategically located positions (for easy recovery of casing pipes after the well life is exhausted) until the target depth is reached. The final casing diameter may reach as small as 5–8 in.

At this stage, the top of the well (well-head) along with the casing hanger is fitted with the necessary piping and collection headers. A pipe riser is inserted in the well to lift the oil and is connected to the well-head piping and valves. The diameter and design of the pipe riser (tubing) may differ depending on the facility of the oil lifting mechanism. The well-head connection consists of a tubing header and a Christmas tree header for the collection of oil, gas, and water to the respective storage tanks.

The surface of the casing pipe at the desired target depth is punctured by bullet or missile firing by experts. The hydrostatic pressure of the mud fluid in the well hole balances the reservoir pressure, thereby preventing spouting of the well from the formation.

drilling operation in well

WELL LOGGING:

Well, logging is a continuous recording process of the activities during drilling, well development, and production until the closure of the well. Thus, the record identifies the history of the well. Well, logging is carried out during the drilling operation using special probes (electrical resistivity, inductance, or magnetic resonance), physical sampling of the drilled soils and rocks, core samples, monitoring drilling fluid, etc.

Various parameters, such as porosity, permeability, and water saturation in oil, of the formation are also obtained by the resistivity probes. During the drilling operation, information about the drill bit, its movement, and direction are determined by these probes. The direction of drilling is ascertained by the dipole sharing investigation tool (DSI). Information is also gathered to release drill bits stuck in the well, monitoring the perforation operation of the casing to communicate with the formation, the properties of oil and gas in the formation, etc. At various stages of production, well probing is used to inspect the casing, the wall of the uncased well, etc., for necessary maintenance operation of the well.

OIL PRODUCTION PROCESSES:

The gas lift method employs high-pressure gas, usually, air or carbon dioxide, which is introduced into the well through the annulus, and oil is carried through the inner tubing, leading to the well-head piping. Initially, the well is filled with the mud fluid and the oil cannot move up owing to the hydrostatic head of the mud fluid. As the gas enters the annulus and piping; the density of the mud column decreases and the hydrostatic head decreases, and as a result, the mud fluid is lifted by the oil pressure. A mud–oil mixture is collected and separated on the surface tanks. When complete displacement of mud takes place from the well and from the pores of the layer near the borehole by the oil pressure, oil production starts increasing.

gas lift method

A sucker rod lift well: contains a piston (or a plunger) pump lowered into the inner tubing. The piston is operated by a metallic wire or rod leading through the tubing and above the well-head and connected to a wire rope from a hanger attached with a reciprocating driving system at the base of the well-head. The piston is contained in a cylinder with non-return valves fitted at both ends.

During the upstroke of the piston, the bottom valve opens, keeping the top valve closed and, as a result, the cylinder pressure falls below the reservoir pressure, forcing oil to enter the cylinder. While during the downstroke of the piston, the upper valve opens and the bottom valve closes and oil in the cylinder is pushed up to the tubing through the upper valve. Thus, the volume of oil displaced upward in the tubing is proportional to the stroke length of the piston. When the tubing is filled with oil after repeating the reciprocating operation, oil starts flowing upward and is collected.

a sucker rod lift

A submersible pump well contains a centrifugal or screw pump installed in the tubing lowered into the borehole. Both the electric motor and the pump are submersed in the well bottom. Electric cable sealed in a flame-proof arrangement is lowered into the well hole through the tubing. The motor is usually kept below the pump in the tubing. Pumps are small in diameter (3–6 in), multistage centrifugal or screw pumps. Since entrainment of sand particles and gas may cause problems to the centrifugal pumps, modern wells are using high-capacity multistage screw pumps that can carry slurries, viscous oil, and even gas.

In fact, future wells will deliver more viscous oil contaminated with sand and clay materials, therefore, increasing use of submersible screw pumps will take place in modern and existing wells. Modern screw pumps with a diameter as small as 6 in with a capacity of 100 m3 or more per day and with a head of 1000 m are being used in wells. The number of stages of a pump may be more than 100 tightly fitted in a tubing.

pumping for oil lifting

The hydraulic pumping method: employs a special type of tubing that consists of two tubes. The inner tube is of a larger diameter in which the plunger or the diaphragm pump is lowered into the borehole. The plunger or the rod of the diaphragm is forced by pumping a liquid over it in a reciprocating manner. Oil is discharged through the outer pipe through its annular space and is delivered to the surface tank. This method does not require lowering any electrical cable and no wire for actuating the plunger.

A high-pressure reciprocating surface pump delivers the liquid forced up and down the plunger of the pump in the borehole in a reciprocating manner. The plunger pump can be withdrawn on the surface from the inner pipe by forcing liquid through the annular outer pipe.

hydraulic pumping for oil lifting

The rate of production from a single well may not be large. Hence, a good number of wells, varying from 100 to 1,000 wells depending on the rate of production, are drilled in the area where the formation is spread. Excitation (stimulation) of the wells by gas or water injection from the surrounding injection wells (judiciously located) is extremely necessary to increase reservoir pressure to the flowing wells.

Modern methods also employ combustion of oil in the surrounding wells to push the oil in the formation by heat effect on reducing viscosity in the porous channels of the formation. A proper temperature gradient is essential from the channels of the combustion zone to the target well. Crude oil from all these wells is collectively routed to storage and conditioning.