Geotechnical Order: A Step-by-Step Guide to Preparing and Implementing a Well Program
The guide is designed to assist professionals involved in the planning and execution of geotechnical projects, including geologists, geotechnical engineers, project managers and drilling contractors. It serves as a valuable reference for both beginners and experienced practitioners, providing a systematic approach to streamlining the process of good program development.
The book begins by introducing the basic concepts of geotechnical engineering and the importance of good programs in collecting accurate and reliable data. It covers various aspects of good planning from project scoping, site characterization and preliminary investigation. This emphasizes the importance of understanding project objectives, site conditions and regulatory requirements in order to design the well program accordingly.
The guide provides a step-by-step approach to well design, including selection criteria for drilling techniques, casing and cementing processes, and geophysical logging methods. It provides practical guidance on factors such as wellbore stability, drilling fluid selection and well construction materials. Additionally, it addresses the challenges associated with a variety of soil and rock formations, providing recommendations for effective drilling and sampling techniques.
In addition, the guide delves deeper into the implementation phase of the well program, with a focus on drilling operations, well completion and data management. It outlines best practices for well monitoring, quality assurance and quality control during the drilling process. The guide also highlights the importance of maintaining accurate records and data documentation for future reference and analysis.
Throughout the book, case studies and real-world examples are included to illustrate key concepts and demonstrate the application of geotechnical principles in a variety of scenarios. These practical insights enhance the reader's understanding and enable them to deal with common challenges faced during good program implementation.
"Geotechnical Orders: A Step-by-Step Guide to the Preparation and Implementation of a Good Program" serves as a comprehensive reference manual for professionals involved in geotechnical engineering and related disciplines. By providing a systematic approach and practical insight, the guide equips readers with the knowledge and tools needed to plan and execute successful geotechnical well programs.
The term "Geo Technical Order, Well Program" typically refers to a set of instructions and guidelines used in the field of geotechnical engineering for planning and executing drilling operations in relation to well construction. Geotechnical engineering involves assessing the physical properties and behavior of the earth materials such as soil and rock to understand their impact on construction projects, including wells.
A Geo Technical Order, Well Program consists of a comprehensive plan that outlines the necessary steps to be followed during the drilling process to ensure the integrity and stability of the well. It serves as a roadmap for the engineers and technicians involved in the drilling operation, providing them with detailed instructions and technical specifications to achieve the desired outcomes.
The contents of a Geo Technical Order, Well Program can vary depending on the specific project requirements and objectives, but it typically includes the following elements:
Before spudding-in of any well, tentative geological and technical programme of the well is prepared by geologist, drilling-in-charge, chemist, nearby wells. For preparation of GTO (Geo Technical order ), Geologist generally incorporates into the GTO, the lithology, stratigraphy, coring/logging policies, expected hydrocarbon shows, temperature, formation pressure, zones of expected mud loss, and other anomalies, dip of the formation etc. Subsequently others also provide all relevant data and GTO becomes completed. It is worth to mention that mud casing and cementation polices vary from area to area, depending on the geological conditions. To avoid complication, correct polices are require smooth drilling of a well.
WELL DATA
Prior to spudding in of a new, the following information are to be provided
(A) Actual location
(B) Kelly Bush level
(C)water depth/Ground level.
MASTER LOG
Al the details regarding the well should be systematically recorded with proper indexing of events. It helps in writing of various types if reports.
Lag time calculation required for collecting the cutting samples during drilling
LAG TIME CALCULATION
Annular Volume
Lag time = --------------------
Mud Flow Rate
Annular Vol = (Voh + Vc) - (Vdp + Vdc)
Voh = Open hole volume
Vc = Casing Volume
Vdp = Drilling Pipe volume
Vdc = Drilling Collar Volume
Mud flow rate = VS x SPM
VS = Vol. of mud pumped per stroke of the mud pump.
SPM = the number of stroke per minutes.
DEVIATION DATA
Directional drilling of a well bore along a predetermined course to a target depth located at a distance from the surface position.
To achieve the TVD ( True Vertical Depth ) and direction, constant monitoring during directional drilling is required for which calculation of directional data is very important which involves a fundamental mathematical procedure. It involves the following data
1. The true Vertical Depth.(Total depth of the hole projected into a vertical plane).
2. The Kick off Point depth (Depth at which deviation is stated).
3. The Deviation ( Horizontal deviation ) which is mainly calculated with respected to the surface
location.
4. The rate of inclination build up and drop off which is normally expressed in degress per 100 ft or
degrees per 30mts.
DIFFERENT TYPES OF INCLINOMETER SURVEYS
There are several method of recording data from deviated wells to know the course of the well. The Important inclinometer surveys are
1. Magnetic Single Shot
2. Multi Shot Survey
3. Gyroscopic Survey
Generally we are using both single and multi shot survey data for calculation purpose. Multi shot survey is more accurate owing to more data control.
LEAK OFF TEST/PRESSURE INTEGRITY TEST
- : Generally carried out in sand, if it is tight &in loose sand only filtrate test.
-: If carried in shale -- gives fracture pressure
Shoe 1/2m drill -- SIT (Shoe Integrity Test)
Formation fresh & Test -- LOT
Require Pressure MWE ( Mud Wight Equivalent ) achieved without LOT--PIT
(Pressure Integrity Test ).
LEAK OFF TEST PROCEDURE
1. Drilling out cement in casing.
2. Circulate and condition the mud.
3. pull out to shoe
4. Using Cementing unit pump, establish circulation and test lines.
5. Close BOP (Blow out preventer)
6. Pump at constant rate between 1/4 to 1/2 bbl per minutes
7. Record and plot pressure versus each 1/2 bbl pumped.
8. When pressure increases. cease to be linear with volume pumped them pump one barrel and shutdown pump.
9. Record maximum pressure observed and pressure change thereafter every minute to ten minuts.
10. Bled pressure off and measure amount of mud bled off .
11. Report to Office the Following
-: MW Viscosity, Shoe depth Open hole depth
-: Pump rate
- : Amount of mud bled off.
-: Pump Shout down pressure
- ; Pressure at the end of test
-: LOT in Equivalent Mud Weight as determined from LOT pressure unit.
1. Gas collection and recording system must be checked to see if they are operative &
calibrated.
2. Lag time must be correct.
3. Check the shale shaker, that they are not allowing small particles through screen. If this
is the case, check the use and operation of desilters.
4. Try to ensure that as constant a circulation as possible is being maintained and that a of change mud pits and systems will not be carried out near prospective zones.
5. Check mud loggers equipment such as pump stroke counter, pit level, weight and ROP
are in good working condition.
6. Check that a representative and uncontaminated sample is collected.
7. Check with the driller that he will notify you drilling break.
8. Ensure that drillers and mud loggers know their reporting procedures and
responsibilities on hydrocarbon shows and drilling breaks.
9. Assemble all possible artificially introduced materials that can be mistaken for the show.
10. Assemble locale local crude for comparison.
OIL FLUORESCENCE
Florescence is checked by fluoroscope. The type of fluorescence is dependent upon specific gravity of oil.The heavier oils have dark brown stains while light oils tend be colorless, The intensity range is taken as bright, dull,pale and faint.
API GRAVITY COLOR
Below15 Brown
15 to 25 Orange Gold
25 to 35 Yellow /Cream
35 to 45 White
Over 45 Blue / White / Violet
FLUORESCENCE SCALE
1 to 2 PICES Trace
1 to 5% Weak
5 to 20% Medium
20 to 50% Good
50 to 70% Very good
70 to 100% Excellent
Mineral Fluorescence is Normally
- Bright and of light color
- Bluish , whitish of pale yellow
- Not soluble in solvent (-ve)
Organic Fluorescence is normally
- Less luminous
- Yellowish green , Yellowish Gold or slightly Orange in colour sometimes these colours
appear to be opaque.
- Soluble in solvent
GEO / MUD LOGGING UNIT
Most of the Logging units have an automatic recording gas detector, which is a combination of dual gas detectors (a) Catalytic (b) Thermal or ( c ) Flame ionization type.
(a) Catalytic detector can record 10% methane
(b) Thermal Conductivity detector Provides linear response up to 100% methane.
Mud logging Unit Record gas concentrations by the combination of both the detectors,
resulting in a continuous recording of all gases concentrations.
GAS-CHROMATOGRAPHY
In the process a sample of gas from the return drilling mud is mixed with inert gas ( helium, nitrogen or air ) and flows through a partition column. The column is placed with absorbent material like charcoal, which absorbs hydrocarbon gases. These hydrocarbon gases are then released to the inert gas system in order of their boiling point. Changes in the composition of gas emerging from column may be detected by measuring the thermal conductivity of the gas or by burning the gas on a platinum filament.
Gas-Chromatography records the percentage of each gas in the air gas mixture from the gas trap. During drilling of an exploratory well, the gas shows encountered should be seen for percentage of lighter hydrocarbon, which gives a clue to the presence of oil. It also automatically identifies the gas component present in the drilling mud, by continuous degassed. Gas chromatography requires an interpretation to identify and measure the gas components.
CHART
Generally from chart, gas percentage is identified from the chromatography to know the components of gases present i.e. , percentage of C1, C2, C3..... etc.
CORE REPORTS
After cutting cores, the following procedure is followed for its proper evaluation:
(1) Proper recovery of cores with marking ( indicating original deposition of the sequence).
(2) Keeping the core boxes with care if Hydrocarbon shows present.
(3) Hydrocarbon shows record.
(4) Systematic details description of cores.
(5) Take decision if bottom portion with Hydrocarbon bearing sand/sandstone /limestone
etc.
MUD LOSS/LOST CIRCULATION
When a very porous and permeable formation is encountered in subsurface, the drilling mud flows into the formation without building up filter cake. Severe mud loss is called lost circulation. During lost circulation, more mud is being pumped down the well than is flowing back. The level in the mud pit falls.
WAYS TO CONTROL LOST-CIRCULATION
(1) Density of drilling fluid is reduced
(2) The flow velocity of drilling fluid is brought down
(3) Mud fluid with high gel strength and viscosity is squeezed into the loss zone and well is kept under observation for sometime.
(4) Loss circulation material is added.
(5) Certain volume of quick setting cement slurry of some low-density plugging mixtures
are pumped into the loss zone.
(6) High molecular compounds capable if becoming polymerized on contact with
formation water.
(7) Loss zone are overlapped with casing liner pipes.
LOCATING LOSS ZONE
(1) Temperature log.
(2) Radioactive tracer.
(3) Hot wire.
(4) Pressure transducer surveys.
DAILY PROGRESS REPORT
It is essential to prepare a daily progress report at site and sent to the conceded authorities.
MASTER LOG
All the parameters indicated in the proforma should be plotted in every shift to keep an updated record depth wise. Important input parameters are mud, ROP ( Rate of penetration), lithology (Cutting %) with description and hydrocarbon shows.
PRESSURE LOG
Prediction of over pressure / High Pressure.
High Pressure encountered in well due to many geological reasons. High pressure areas can be envisaged prior to drilling, based ob some anakysis.
PRIOR TO DRILLING
(1) Decrease in d-exponent trend.
(2) Shale density studies ( decrease in shale density trend).
(3) Flow Line Temperature ( Increase).
(4) Mud Conductivity / Resistivity ( increase in conductivity & decrease in resistivity).
(5) Drag/Torque, ( both increase).
(6) Change of size & shape of cutting ( cuttings are large, angular and splintery).
(7) Mud Volume ( increase).
(8) Chromatograph Charts ( increase in background/connection gas).
(9) Formation fluid (presence of contaminated formation fluid).
AFTER DRILLING
(1) Long evaluation, decrease in shale resistivity and increase in shale transit time on sonic
log.
(2) DST / RFT / MDT, high bottom hole temperature.
(3) Water analysis from DST / RFT /MDT, high sulphate and carbonate content in water.
WORK ORDER FOR CARRYING OUT ELECTROLOGGING OPERATION IN THE WELL
(1) GTO carries information about the types of logs to be recorded.
(2) Normal set of logs.
(3) Special logs.
(4) Interpretation of logs for lithological boundary, pay sands, structural position, sand Oil contain, /gas shows etc.
(5) Suggestion for testing interval and submit the proposal.
COMPOSITE LOG
Data incorporated composite logs are as follows .
(1) Resistivity, Caliper, SP/GR logs.
(2) Lithology with formation boundaries and age.
(3) Casing shoe.
(4) Coring intervals with gross lithology and hydrocarbon indications, both conventional
and SWC.
(5) RFT, DST, MDT data.
(6) Testing result.
WELL LOGGING
A set of minimum logs run in a well, in open hole just after the drilling , to know the ( sand/shale /limestone etc). type of fluid in the formation ( water, Oil or gas) and its porosity ( how porous a rock) is called standard logs. The standard logs consist of DIL/DLL-MSFL-SP-GR- CALIPER-LDL-CNL-SONIC. Special logs such as FMS,CMR,NGS,are also recorded depending upon the nature of the formation. Other logs recorded are CBL-VDL (Cement bound log- Variable Density Log) for understanding the cement bound behind casing. Production Logging is carried out to know the behaviour and to understand remedial measures. From these logs we know.
(1) The depth of the formation tops.
(2) The environment suitable for accumulation of hydrocarbon
(3) Evidence of hydrocarbon in the well
(4) The types of hydrocarbon
(5) Hydrocarbon present in commercial quantities of not
(6) Bore hole geometry
(7) About the reserves
CASING AND CEMENTATION REPORTS
It consists of casing and cementation details to record all the relevant event in a tabulated from. This is required for final well completion report.
WELL INCLINOGRAM
The plotting is done simultaneously along with drilling. It is important to see while drilling a deviated hole whether well is being drilled as per plan. If the well is drifted from the planned direction and drift, remedial measures should be immediately taken up.
FORMATION TEST REPORT
RFT / MDT carried out in most of the well to evaluate pressure of particular sand interval at particular depth and also to collect the fluid/gas samples. This report is made immediately after the test is conducted. This report is very important to decide the testing intervals of the well.
PRODUCTION TESTING
The typical proforma of a testing plan, which is jointly prepared by driller, geologist, production and reservoir engineer for smooth and hazardless testing of the object. Plan may differ from object to object depending upon the nature of sands, casing types etc.
WELL CONSTRUCTION
A typical well construction for a vertical and inclined well is shown in the GTO. This is required for final well completion reports.
WELL COMPLETION REPORTS
After the well is drilled to the desired depth and completed, the well site geologist submits a final well completion report. Report consists of all the data collected from release of location, spudding, during drilling, testing and up to the Rig release phase.
गाइड को भूवैज्ञानिकों, भू-तकनीकी इंजीनियरों, परियोजना प्रबंधकों और ड्रिलिंग ठेकेदारों सहित भू-तकनीकी परियोजनाओं की योजना और निष्पादन में शामिल पेशेवरों की सहायता के लिए डिज़ाइन किया गया है। यह शुरुआती और अनुभवी अभ्यासकर्ताओं दोनों के लिए एक मूल्यवान संदर्भ के रूप में कार्य करता है, जो अच्छे कार्यक्रम विकास की प्रक्रिया को सुव्यवस्थित करने के लिए एक व्यवस्थित दृष्टिकोण प्रदान करता है।
पुस्तक की शुरुआत भू-तकनीकी इंजीनियरिंग की बुनियादी अवधारणाओं और सटीक और विश्वसनीय डेटा एकत्र करने में अच्छे कार्यक्रमों के महत्व को पेश करने से होती है। इसमें प्रोजेक्ट स्कोपिंग, साइट लक्षण वर्णन और प्रारंभिक जांच से लेकर अच्छी योजना के विभिन्न पहलुओं को शामिल किया गया है। यह परियोजना के उद्देश्यों, साइट की स्थितियों और नियामक आवश्यकताओं को समझने के महत्व पर जोर देता है ताकि तदनुसार वेल कार्यक्रम को तैयार किया जा सके।
गाइड कुएं के डिजाइन के लिए चरण-दर-चरण दृष्टिकोण प्रदान करता है, जिसमें ड्रिलिंग तकनीक, आवरण और सीमेंटिंग प्रक्रियाओं और भूभौतिकीय लॉगिंग विधियों के लिए चयन मानदंड शामिल हैं। यह वेलबोर स्थिरता, ड्रिलिंग द्रव चयन और वेल निर्माण सामग्री जैसे कारकों पर व्यावहारिक मार्गदर्शन प्रदान करता है। इसके अतिरिक्त, यह विभिन्न प्रकार की मिट्टी और चट्टान संरचनाओं से जुड़ी चुनौतियों का समाधान करता है, प्रभावी ड्रिलिंग और नमूनाकरण तकनीकों के लिए सिफारिशें प्रदान करता है।
इसके अलावा, गाइड कुआं कार्यक्रम के कार्यान्वयन चरण में गहराई से उतरता है, जिसमें ड्रिलिंग संचालन, कुआं पूरा करने और डेटा प्रबंधन पर ध्यान केंद्रित किया जाता है। यह ड्रिलिंग प्रक्रिया के दौरान अच्छी निगरानी, गुणवत्ता आश्वासन और गुणवत्ता नियंत्रण के लिए सर्वोत्तम प्रथाओं की रूपरेखा तैयार करता है। गाइड भविष्य के संदर्भ और विश्लेषण के लिए सटीक रिकॉर्ड और डेटा दस्तावेज़ीकरण बनाए रखने के महत्व पर भी प्रकाश डालता है।
संपूर्ण पुस्तक में, प्रमुख अवधारणाओं को स्पष्ट करने और विभिन्न परिदृश्यों में भू-तकनीकी सिद्धांतों के अनुप्रयोग को प्रदर्शित करने के लिए केस अध्ययन और वास्तविक दुनिया के उदाहरणों को शामिल किया गया है। ये व्यावहारिक अंतर्दृष्टि पाठक की समझ को बढ़ाती हैं और उन्हें कार्यक्रम के अच्छे कार्यान्वयन के दौरान आने वाली सामान्य चुनौतियों से निपटने में सक्षम बनाती हैं।
"जियोटेक्निकल ऑर्डर: एक अच्छे कार्यक्रम की तैयारी और कार्यान्वयन के लिए एक चरण-दर-चरण मार्गदर्शिका" भू-तकनीकी इंजीनियरिंग और संबंधित विषयों में शामिल पेशेवरों के लिए एक व्यापक संदर्भ मैनुअल के रूप में कार्य करता है। एक व्यवस्थित दृष्टिकोण और व्यावहारिक अंतर्दृष्टि प्रदान करके, गाइड पाठकों को सफल भू-तकनीकी अच्छी तरह से कार्यक्रमों की योजना बनाने और निष्पादित करने के लिए आवश्यक ज्ञान और उपकरणों से लैस करता है।
किसी भी कुएं के स्पिडिंग-इन से पहले, कुएं का अस्थायी भूवैज्ञानिक और तकनीकी कार्यक्रम, भूवैज्ञानिक, ड्रिलिंग-इन-चार्ज, केमिस्ट, पास के कुओं द्वारा तैयार किया जाता है। जीटीओ (भू तकनीकी आदेश) की तैयारी के लिए, भूविज्ञानी आम तौर पर जीटीओ, लिथोलॉजी, स्ट्रैटिग्राफी, कोरिंग / लॉगिंग नीतियों, अपेक्षित हाइड्रोकार्बन शो, तापमान, गठन दबाव, अपेक्षित मिट्टी के नुकसान के क्षेत्र और अन्य विसंगतियों में शामिल होते हैं, गठन की डुबकी इसके बाद अन्य लोग भी सभी प्रासंगिक डेटा प्रदान करते हैं और जीटीओ पूरा हो जाता है। यह ध्यान देने योग्य है कि मिट्टी के आवरण और सीमेंटेशन पॉलिसियां भू-स्थितियों के आधार पर एक क्षेत्र से दूसरे क्षेत्र में भिन्न होती हैं। जटिलता से बचने के लिए, सही पॉलिस के लिए एक अच्छी तरह से चिकनी ड्रिलिंग की आवश्यकता होती है।
