Drilling fluid là cuốn sách hay được sử dụng trong phòng thí nghiệm cũng như trên khoan trường. Dung dịch khoan đóng vai trò vô cùng quan trọng trong quá trình khoan, vì vậy hiểu biết những đặc trưng nhất của nó có ý nghĩa vô cùng lớn. Sở hữu cuốn sách này các khoan sĩ sẽ cảm thấy tự tin hơn rất nhiều khi ra ngoài thực tế
Drilling Fluids Manual Amoco Production Company Drilling Fluids Manual Drilling Fluid Classifications 1-1 Pneumatic Fluids 1-1 Oil-Based Fluids 1-2 Water-Based Fluids 1-3 Non-Inhibitive Fluids 1-3 Inhibitive Fluids 1-3 Polymer Fluids 1-3 Major Functions 1-4 Control Subsurface Pressure 1-4 Transport Cuttings 1-5 Support and Stabilize Wellbore 1-5 Minor Functions 1-6 Support Weight of Tubulars 1-6 Cool and Lubricate the Bit and Drill String 1-6 Transmit Hydraulic Horsepower to Bit 1-6 Provide Medium for Wireline Logging 1-7 Assist in the Gathering of Subsurface Geological Data and Formation Evaluation 1-7 Additional Benefits 1-7 Minimize Formation Damage 1-7 Reduce Corrosion 1-8 Minimize Lost Circulation 1-8 Reduce Stuck Pipe 1-8 Reduce Pressure Losses 1-8 Improve Penetration Rates 1-8 Reduce Environmental Impact 1-8 Improve Safety 1-8 Cost 1-12 Application and Performance 1-12 Production Concerns 1-12 Logistics 1-12 Exploration Concerns 1-12 Environmental Impact and Safety 1-13 Basic Engineering Calculations 2-1 Specific Gravity 2-1 Volume, Capacity and Displacement 2-1 Volume 2-2 Capacity (Mud Pits) 2-3 Capacity and Displacement (Drill String and Hole) 2-3 Annulus Capacity and Multiple-Pipe Annulus Capacity 2-4 Conversion to Other Units 2-4 Tabulated Capacity and Displacement Data 2-5 Annular Velocity 2-5 Mud Circulation Time 2-5 -3 “Proprietary - for the exclusive use of Amoco Production and other wholly owned subsidiaries of Amoco Corporation.” Rev 6/94 Amoco Production Company Drilling Fluids Manual Pressures 2-6 Hydrostatic Pressure 2-6 Pressure Gradient 2-6 Annular Pressure Loss 2-6 Equivalent Circulating Density (ECD) 2-6 Weight-Up and Dilution 2-7 Weight-Up 2-7 Density Reduction 2-7 Concentrations - Weight Percent and Volume Percent 2-8 Volume Percent Solids 2-8 Weight Percent Solids 2-8 Parts Per Million and Milligrams Per Liter 2-9 Material Balance 2-9 Weight-Up of Water-Based Muds 2-10 No Volume Increase 2-10 Volume Increase 2-11 Dilution of Water-Based Muds 2-12 Density Reduction/No Volume Increase 2-12 Density Reduction - Volume Increase 2-13 Mixing Two Fluids 2-14 Example Calculations 2-14 System Building 2-17 Example Calculations 2-17 Solids Analysis 2-22 Example Calculations 2-22 Daily Maintenance of Polymer Systems 2-33 Given Data 2-36 Mud Pit Capacity 2-37 Mud Volume in Pits 2-37 Hole Volume 2-38 Drill String Displacement 2-38 Drill String Capacity 2-39 Mud Volume 2-39 In Pits/Pipe Out of Hole 2-39 In Hole/Closed End Pipe 2-39 In Pits/Closed End Pipe 2-39 In Hole/Open Ended Pipe 2-40 Total Circulating Volume 2-40 Bbl/STK, Gal/STK 2-41 Bbl/Min, Gal/Min 2-43 Annular Velocity 2-43 Bottoms-Up Time 2-44 Total Circulation Time 2-45 Surface-to-Bit Travel Time 2-45 Rev 6/94 -4 “Proprietary - for the exclusive use of Amoco Production Company and other wholly owned subsidiaries of Amoco Corporation.” Amoco Production Company Drilling Fluids Manual Hydrostatic Pressure 2-46 Bottom Hole Circulating Pressure 2-46 Equivalent Circulating Density 2-46 Water-Based Drilling Fluids Testing Procedures 3-1 Mud Density 3-1 Marsh Funnel Viscosity 3-1 Rheology 3-2 Plastic Viscosity (PV) and Yield Point (YP) 3-2 Gel Strength (10-sec/10-min) 3-3 Static Filtration Tests 3-4 Low-Temperature/Low-Pressure Filtration 3-4 High-Temperature/High-Pressure Filtration (HTHP) 3-6 Retort -Water, Oil and Solids 3-14 Retort Test Procedure 3-14 Retort Cup Verification Procedure 3-15 Sand Content 3-18 Methylene Blue Capacity 3-19 pH 3-20 Alkalinity and Lime Content 3-22 Mud Alkalinity (PM) 3-22 Filtrate Alkalinity (PF) 3-23 Filtrate Alkalinity (MF) 3-23 Lime Content 3-24 Chloride 3-25 Lightly-Colored Filtrates [Table 4] 3-26 Dark-Colored Filtrates [Table 5] 3-28 Total Hardness [Table 6] 3-29 Calcium and Magnesium [Table 7] 3-30 Sulfide 3-32 Carbonate/Bicarbonate 3-36 Potassium 3-39 Centrifuge RPM Calibration 3-39 Standard Potassium Calibration Curve Procedure 3-40 Test Procedure - Potassium Ion 3-41 Oil-Based Drilling Fluids Testing Procedures 3-42 Mud Density 3-42 Marsh Funnel Viscosity 3-42 Rheology 3-43 Plastic Viscosity (PV) and Yield Point (YP) 3-43 Gel Strength (10-sec/10-min) 3-43 Static Filtration Tests 3-44 Low-Temperature/Low-Pressure Filtration 3-44 High-Temperature/High-Pressure Filtration (HTHP) 3-45 Retort - Water, Oil and Solids 3-47 -5 “Proprietary - for the exclusive use of Amoco Production and other wholly owned subsidiaries of Amoco Corporation.” Rev 6/94 Amoco Production Company Drilling Fluids Manual Retort Test Procedure 3-47 Retort Cup Verification Procedure 3-48 Whole Mud Alkalinity (VSA) and Lime Content (LimeOM) 3-49 Whole Mud Chloride (ClOM) 3-50 Whole Mud Calcium (CaOM) 3-50 Electrical Stability (ES) 3-51 Sulfide 3-52 Aqueous Phase Activity (AWOM) 3-56 Introduction 3-56 Equipment 3-56 Procedure 3-57 Water-Wet Solids 3-60 Causes of Water-Wet Solids 3-60 Visual Indicators of Water-Wet Solids 3-61 Mud Test Indicators of Water-Wet Solids 3-61 Special Tests and Indicators of Water-Wet Solids 3-61 Lime, Solids and Salinity Calculations 3-62 Total Lime Content (LimeOM) 3-62 Whole Mud Salinities (ClOM, CaCl2OM, NaClOM) 3-62 Aqueous Phase Salinity (Weight Percent) 3-63 Aqueous Phase Salinity - Parts per Million 3-64 Aqueous Phase Salinity (Milligram per Liter) 3-64 Oil/Water Ratio (O/W) 3-64 Oil/Brine Ratio (O/B) 3-64 Solids Content 3-65 Examples of Calculations for Oil Mud Analysis 3-66 EXAMPLE A - Oil Mud with CaCl2 Aqueous Phase: 3-66 Example B — Oil Mud with NaCl Aqueous Phase 3-68 Permeability Plugging Test (PPT) 3-72 Introduction 3-72 PPT Principles 3-73 Permeability Plugging Test Procedure 3-77 Pilot Testing 3-80 Introduction 3-80 Designing Pilot Tests 3-80 Pilot Testing Equipment 3-82 Interpretation of Pilot Test Results 3-82 Basic Chemistry 4-1 Introduction 4-1 Chemical Analysis - Mud Check 4-6 pH 4-6 PM 4-7 PF 4-8 MF 4-8 Rev 6/94 -6 “Proprietary - for the exclusive use of Amoco Production Company and other wholly owned subsidiaries of Amoco Corporation.” Amoco Production Company Drilling Fluids Manual Total Hardness As Calcium 4-8 Chlorides 4-8 Carbonates 4-8 Methylene Blue Capacity (MBT) 4-9 Mud Chemistry 4-9 Saltwater Mud 4-9 Seawater Mud 4-9 Saturated Salt Mud 4-10 Calcium-Based Mud 4-10 Potassium Mud 4-11 Structure of Clays 4-12 Kaolinites 4-13 Illites 4-13 Chlorites 4-14 Smectites (Montmorillonites) 4-15 Attapulgite and Sepiolite 4-16 Clay Properties 4-16 Clay Particle Size 4-16 Cation Exchange 4-16 Clay Interactions 4-19 Commercial Bentonite 4-20 Drilling Fluid Bentonites 4-20 API Bentonites 4-22 Introduction 4-23 Polymer Types 4-23 Polyacrylate, Polyacrylamide, and PHPA 4-23 Cellulose Derivatives 4-24 Starch 4-26 Guar 4-26 Xanthan Gum 4-26 Polymer Uses 4-26 Viscosity 4-26 Bentonite Extension 4-26 Flocculation 4-26 Deflocculation 4-27 Filtration Control 4-27 Shale Stabilization 4-27 Filtration Fundamentals 4-28 Types of Filtration 4-28 Static Filtration 4-28 Dynamic Filtration 4-29 Problems Caused by Poor Filtration Control 4-29 Factors Affecting Filtration 4-29 Time 4-29 -7 “Proprietary - for the exclusive use of Amoco Production and other wholly owned subsidiaries of Amoco Corporation.” Rev 6/94 Amoco Production Company Drilling Fluids Manual Pressure 4-30 Temperature 4-31 Permeability 4-33 Filtration Measurement 4-33 Filtration Control Additives 4-33 Bentonites 4-34 Lignins and Tannins 4-34 Starches 4-34 Sodium Carboxymethylcellulosics (CMC) 4-34 Polyanionic Cellulosics (PAC) 4-34 Sodium Polyacrylates (SPA) 4-34 Contamination of Water-Based Drilling Fluids 5-1 Introduction 5-1 Salt Contamination 5-2 Calcium Contamination 5-4 Cement Contamination 5-4 Anhydrite-Gypsum Contamination 5-6 Magnesium Contamination 5-6 Carbonate/Bicarbonate Contamination 5-7 Solids Contamination 5-9 Treatment 5-11 Dilution 5-11 Mechanical Separation 5-11 Principles of Mechanical Solids Control 5-11 Acid Gases 5-12 Contamination Due to Bacteria 5-13 Introduction 5-14 Unweighted Water-Based Mud 5-14 Weighted Water-Based Mud 5-14 Oil-Based Mud 5-14 Mud Test Data for Solids Calculations 5-16 Mud Balance (MW) 5-16 Retort (VW,VO) 5-16 Chlorides (CL-) 5-16 Density (ρ) 5-16 Methylene Blue Capacity (MBT) 5-16 Densities Required to Perform Solids Calculations 5-17 Salinity Corrections 5-17 Correction of Retort Water 5-17 Correction of the density of the Water 5-17 Solids Calculations - Water-Based Muds 5-18 Unweighted Freshwater Muds (No Retort Data Needed) 5-18 Weighted and Unweighted Muds (Retort Data Required) 5-19 Differentiating Drill Solids from Bentonite by CEC Ratio 5-19 Rev 6/94 -8 “Proprietary - for the exclusive use of Amoco Production Company and other wholly owned subsidiaries of Amoco Corporation.” Amoco Production Company Drilling Fluids Manual Assumed 9:1 CEC Ratio 5-20 Measured CEC Ratio 5-20 Drill Solids/Bentonite Ratio 5-20 Example - Solids Calculations for Water-Based Muds 5-21 Introduction 5-24 Characteristics of Solids 5-24 Types of Solids 5-24 Size of Solids 5-25 Shape of Solids 5-27 Concentration and Size Distribution of Solids 5-27 Methods for Solids Control 5-28 Dilution Method 5-28 Gravity Settling Method 5-28 Mechanical Separation Method 5-28 Chemical-Mechanical Separation Method 5-29 Principles of Mechanical Solids Separation 5-29 Processing in Sequence 5-29 Total Flow Processing 5-29 No Bypassing 5-29 Sequence of Solids Control Devices 5-29 Solids Removal Region 5-30 Addition Region 5-32 Mud Check (Suction) Region 5-36 Basics of Solids Removal Devices 5-36 Basics of Shale Shakers 5-36 Basics of Hydrocyclones 5-39 Basics of Centrifuges 5-40 Basics of Centrifugal Pumps 5-42 Dewatering and Zero-Discharge Solids Control 5-42 Rheology 6-1 Introduction 6-1 Velocity Profile 6-1 Shear Stress (t) 6-2 Shear Rate (g) 6-2 Viscosity (m) 6-3 Bingham Plastic Fluids 6-6 Pseudoplastic Fluids 6-13 Dilatant Fluids 6-14 Thixotropic Fluids 6-14 Flow Regimes 6-14 Laminar Flow 6-15 Transition Flow 6-16 Turbulent Flow 6-16 -9 “Proprietary - for the exclusive use of Amoco Production and other wholly owned subsidiaries of Amoco Corporation.” Rev 6/94 Amoco Production Company Drilling Fluids Manual Yield-Power Law Rheology, Hydraulics, and Hole Cleaning 6-16 Introduction 7-1 Dry Gas Drilling Fluids 7-2 Air 7-3 Natural Gas 7-4 Mist Drilling Fluids 7-4 Foam Drilling 7-5 Stiff Foam 7-5 Stable Foam 7-6 Gasified (Aerated) Mud Drilling Fluids 7-7 Air Application 7-8 Nitrogen Application 7-8 NON-INHIBITIVE FLUIDS 8-1 Introduction 8-1 Clear Water 8-1 Native Muds 8-1 Bentonite-Water Muds 8-2 Lignite-Lignosulfonate (Deflocculated) Muds 8-2 Principal Additives of Lignite/Lignosulfonate (Deflocculated) Muds 8-2 Typical Properties of Lignite/Lignosulfonate (Deflocculated) Muds 8-4 System Conversion/Maintenance 8-4 Advantages/Disadvantages of Lignite/Lignosulfonate (Deflocculated) Muds 8-4 Troubleshooting and Contamination 8-5 INHIBITIVE FLUIDS 8-7 Introduction 8-7 Calcium-Based Muds 8-7 Lime Muds 8-7 Principal Additives of Lime Muds 8-8 Typical Properties of Lime Muds 8-9 System Conversion/Maintenance 8-9 Advantages/Disadvantages of Lime Muds 8-12 Troubleshooting and Contamination - Lime Muds 8-13 Lime/MOR-REX Muds 8-13 Principal Additives of Lime/MOR-REX Muds 8-14 Typical Properties of Lime/MOR-REX Muds 8-15 System Conversion/Maintenance 8-15 Advantages/Disadvantages of Lime/MOR-REX Mud 8-16 Troubleshooting and Contamination - Lime/ MOR-REX Muds 8-17 Gyp Muds 8-17 Principal Additives of Gyp Muds 8-18 Typical Properties of Gyp Muds 8-19 Rev 6/94 -10 “Proprietary - for the exclusive use of Amoco Production Company and other wholly owned subsidiaries of Amoco Corporation.” Amoco Production Company Drilling Fluids Manual Glossary of Environmental Terms API ASTM American Petroleum Institute American Society for Testing and Materials BAT BCT BPT BPJ BOD BIA BLM Best Available Technology Economically Achievable Best Conventional Pollutant Control Technology Best Practical Control Technology Best Professional Judgment Biochemical Oxygen Demand Bureau of Indian Affairs Bureau of Land Management CASRN COD CWA CFR CERCLA Chemical Abstracts Service Registry Number Chemical Oxygen Demand Clean Water Act Code of Federal Regulations Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (SUPERFUND) DOE DOI DOT DMR DO Department of Energy Department of Interior Department of Transportation Discharge Monitoring Report Dissolved Oxygen EPA EHS Environmental Protection Agency Extremely Hazardous Substance LEPC DEQ DNR Local Emergency Planning Committee Louisiana Department of Environment Quality Louisiana Department of Natural Resources Office of Conservation MSD MSDS EC50 LC50 Marine Sanitation Device Material Safety Data Sheets Median Effective Concentration Median Lethal Concentration MOGA MMS Mid-Continent Oil and Gas Association Minerals Management Service NPDES NSPS NOW OSHA OOC OCS -A -G National Pollutant Discharge Elimination System New Source Performance Standards Nonhazardous Oilfield Waste Occupational Safety and Health Administration Offshore Operators Committee Outer Continental Shelf Outer Continental Shelf - Atlantic Outer Continental Shelf, Gulf Rev 6/94 12-18 “Proprietary - for the exclusive use of Amoco Production Company and other wholly owned subsidiaries of Amoco Corporation.” Amoco Production Company Drilling Fluids Manual -P RCRA RRC Outer Continental Shelf, PacificRQ Reportable Quantity Resources Conservation and Recovery Act Texas Railroad Commission SDS SP SRT SERC SARA SPP Sodium Dodecyl Sulfate Solid Phase Standard Reference Toxicant State Emergency Response Commission Superfund Amendments and Reauthorization Act Suspended Particulate Phase TCLP TPQ TDS TOC TSCA TSS USCG USGS Toxicity Characteristic Leaching Procedure Threshold Planning Quality Total Dissolved Solids (filterable residue) Total Organic Carbon Toxic Substances Control Act Total Suspended Solids (nonfilterable residue) United States Coast Guard United States Geological Survey Definitions Acute Toxicity - Any poisonous effect produced within a short time period following exposure, usually up to 24-96 hours, which results in severe biological harm or death Bioaccumulation - The process where toxic substances accumulate in tissues and pose a substantial hazard to human health or the environment Bioassay - A toxicity test that measures the effect of a chemical or effluent on a test population of organisms Effluent - Anything discharged into a receiving body of water Generic Mud - One of eight general mud classifications used to characterize drilling fluids Hazardous Materials - A substance or material which has been determined by the Secretary of Transportation to be capable of posing an unreasonable risk to health, safety and property when transported in Commerce Hazardous Substances - Elements or compounds other than oil, when discharged in any quantity into or upon the navigable waters of the United States or adjoining shorelines, or the waters of the contiguous zone or in connection with activities on the outer continental shelf, or which may affect natural resources, or present or imminent and substantial LC50 - Lethal concentration at which 50% of the bioassay test population dies Toxicity - The degree of danger posed by a substance to animal or plant life Wetlands - Areas that are inundated or saturated by surface or groundwater and support a prevalence of vegetation adapted for life in saturated soil conditions 12-19 “Proprietary - for the exclusive use of Amoco Production and other wholly owned subsidiaries of Amoco Corporation.” Rev 6/94 Amoco Production Company Drilling Fluids Manual Rev 6/94 12-20 “Proprietary - for the exclusive use of Amoco Production Company and other wholly owned subsidiaries of Amoco Corporation.” Amoco Production Company Drilling Fluids Manual Section 13 Appendix 13-1 “Proprietary - for the exclusive use of Amoco Production and other wholly owned subsidiaries of Amoco Corporation.” Rev 6/94 Amoco Production Company Drilling Fluids Manual Rev 6/94 13-2 “Proprietary - for the exclusive use of Amoco Production Company and other wholly owned subsidiaries of Amoco Corporation.” Amoco Production Company Drilling Fluids Manual 13-3 “Proprietary - for the exclusive use of Amoco Production and other wholly owned subsidiaries of Amoco Corporation.” Rev 6/94 Amoco Production Company Drilling Fluids Manual Rev 6/94 13-4 “Proprietary - for the exclusive use of Amoco Production Company and other wholly owned subsidiaries of Amoco Corporation.” Amoco Production Company Drilling Fluids Manual Settling Plug Mixing Procedure Cementing Equipment Clean and flush all mixing lines to and from cement mixing equipment Arrange for weight material to be mixed rather than cement This may require the use of sacked weight material If sacked weight material is to be used, be sure that weight material sufficient for the plug can be placed near the mixing hopper Estimate manpower and barite moving requirements (forklift and/or crane) Measure mixing water for plug volume (take into account line volumes) into tank If possible, mix caustic soda and lignosulfonate into mixing water This may be done by using mud system slugging pit and pumping mixing water to cement mixing equipment Mix 1-1/2 lb/bbl of caustic soda and lb/bbl of chrome lignosulfonate in mix water Mix plug and pump “on the fly” using weight material and mixing water Avoid mixing slurry below 16 lb/gal for barite weight material and below 20 lb/gal for hematite material as too rapid settling could occur and plugging of equipment or lines can occur Avoid chasing plug with water Use mud instead to prevent premature settling of plug Mud Tank Slugging Pit Empty and clean slugging pit If unable to dump pit, fill with water and agitate Pump out dirty water Repeat, if necessary, to get pit clean Put just enough mixing water in pit to obtain mixing pump suction Add the total calculated amount of caustic soda and chrome lignosulfonate to the mix water Note quantity required and calculate remaining amount of water to be added to bring to total volume mix water Begin mixing weight material Slurry should begin to look viscous when the density nears 16 lb/gal for barite and 20 lb/gal for hematite When slurry density approaches 18 lb/gal for barite and 21 lb/gal for hematite, begin adding remainder of mix water Add mix water in steps with additional weight material to avoid both too light and slurry that will settle or too heavy a slurry that will lose pump suction After adding the calculated volume of mix water, bring slurry to final desired density Allow to mix until weight material is mixed thoroughly Pump plug to mud pump, avoiding water ahead or behind plug Avoid chasing plug with water Use mud instead to prevent premature settling of plug The following are recommendations for composition and application of barite plugs Formulation Plug Density (ppg) 16 17 18 19 Water bbl 71 68 64 60 Chrome Lignosulfonate lb 5.7 5.4 5.1 4.8 Caustic Soda lb 1.1 1.0 1.0 0.9 Barite lb 422 477 533 588 Composition per final bbl 13-5 “Proprietary - for the exclusive use of Amoco Production and other wholly owned subsidiaries of Amoco Corporation.” Rev 6/94 Amoco Production Company Drilling Fluids Manual Preparation of Oil-Base Plugs Plug slurries can be prepared with oil and barite A certain sequence of mixing of products is desirable for optimum performance Always mix the wetting agent with the oil thoroughly before adding the weight material This will aid in keeping the slurry pumpable and tie up any stray water that may be present High density slurries settle more slowly than low density slurries because of the high solids concentration and gel strengths Therefore, the lowest appropriate weight should be chosen, keeping in mind that the slurry volume should be no longer than the distance between the loss zone and the active zone Variations and contaminates in weight material, variations in the viscosities and physical properties of available base oils, and the type of wetting agent will require different concentrations of wetting agent to insure an optimum settling rate It should be kept in mind that too much wetting agent can be just as detrimental as to little wetting agent Therefore, pilot testing should be done with available materials before use It is highly recommended that samples of the oil, barite, and available wetting agent be sent to the DTC for testing to determine optimum concentration The amount of oil and barite required to make a one-barrel pumpable slurry of desired weight can be estimated from the following table Mud Weight (ppg) Oil (bbl) Barite (lb/bbl) 14 0.729 362.9 15 0.691 415.4 16 0.653 467.9 17 0.615 520.4 18 0.577 572.9 19 0.539 625.5 20 0.501 678.0 Again, the amount of wetting agent required for optimum settling will depend upon the characteristics of the barite, oil, and type of wetting agent It cannot be emphasized enough PILOT TEST Recommended Plug Procedures Length of Plug Barite plugs are designed to control formation pressures by providing an immovable, impermeable seal at the point of influx Success depends entirely on the ability to mix the plug slurry with optimum settling properties, spotting the slurry by the recommended displacement procedures, and minimizing the amount of contamination that may adversely affect the settling rate and prevent the formation of a firm plug In some cases, several attempts must be made to successfully seal off the influx of formation fluids The length of the barite plug is a wellsite determination and should be based on the severity of the situation The maximum slurry length should not exceed the distance between the influx and the lost circulation zone Long barite plugs are not desirable because of the distance the drill string has to be pulled to withdraw it completely from the slurry Rev 6/94 13-6 “Proprietary - for the exclusive use of Amoco Production Company and other wholly owned subsidiaries of Amoco Corporation.” Amoco Production Company Drilling Fluids Manual In cases where formation pressure can be estimated, the length of the plug can be calculated to balance this pressure Under these circumstances, he plug is used as both a kill fluid and an immovable seal The length of the plug required to balance a given pressure can be calculated using the following equation P L = -1.8228 where L = Required length of plug (ft) P = Pressure to be balance (psi) 1.8228 = Pressure gradient of compacted barite (psi/ft) S.G of barite (4.2) x 0.434 Mud Density The density (ppg) selected should be 0.5 to 1.0 ppg greater than the fluid in the hole This will ensure that once the plug is spotted, there will be no movement or migration Determine Maximum Slurry Length Determine maximum slurry length (distance between loss zone and zone of influx) if applicable Calculate Total Slurry Volume The volume of slurry can be calculated using the following equation L × Vr × 1470 V = WTM where V = Volume of slurry L = Plug length 1470 = Weight of bbl of barite Vr = Hole volume (bbl/ft) WTM = Barite required to formulate bbl of slurry (from table) Materials Calculate amount of material required to formulate plug Mixing There are two different mixing procedures that can be used when mixing the slurry The first is a mix and displace method, very similar to a cementing operation The barite is added “on the fly” to the premixed oil and wetting agent and immediately pumped downhole The alternate method is to “batch mix” the slurry in a tank with sufficient circulation and agitation to prevent settling and then displace downhole 13-7 “Proprietary - for the exclusive use of Amoco Production and other wholly owned subsidiaries of Amoco Corporation.” Rev 6/94 Amoco Production Company Drilling Fluids Manual Displacement Displacement techniques are similar to those of cementing in that the slurry should be underdisplaced When calculating the volumes of displacement, adjustments should be made so that the height of the slurry is bbls greater in the drill pipe than in the annulus This allows the drill string to be pulled with a natural slug It should be kept in mind that if the slurry is underdisplaced and the drill string left in place, barite will settle, plugging the string and will settle in the annulus, sticking the string Contamination caused by slurry movement is also minimized A 2-5 bbl spacer before and after the slurry will minimize contamination by in-situ drilling mud The following calculations are required to efficiently displace a barite plug Find the height at which the total slurry volume (less than barrels) is equalized in the hole Determine the volume inside and outside the drill collars Subtract this volume from the total slurry volume and determine the height the remaining volume would occupy inside and outside the drill pipe Remaining Volume Height = Capacity DP (bbl/ft) Find the height that barrels of slurry will occupy in the drill pipe Height = -Capacity DP (bbl/ft) Add this to the length of the drill collars and the height of the slurry equalized around the drill pipe Once the total height of the slurry inside the drill string has been determined, the remaining length of the drill string represents the volume of mud required to displace the slurry Rev 6/94 13-8 “Proprietary - for the exclusive use of Amoco Production Company and other wholly owned subsidiaries of Amoco Corporation.” Amoco Production Company Drilling Fluids Manual Conversion Tables Multiply By To Obtain PPG 119.286 kg/m3 PPG 052 psi/ft PPG 1198 gm/cm3 PPG 7.48 lb/ft3 Kg/m3 06243 lb/ft3 PPB 2.853 kg/m3 PPB 2857 mg/l Mg/L 00035 ppb PPM SG Mg/L Ft 0.3048 m M 3.281 ft BBL 5.615 ft3 BBL 15899 m3 BBL 42 gal 7.48 gal 0283 m3 Gal 003785 m3 Lbs 454 kg Lbs 453.6 gm Kg 2.2046 lb PSI 06804 Atm PSI 703.1 kg/m2 °C (°Cx1.9) + 32 °F °F (°F-32) x 556 °C Ft Ft Common Contaminants and Treating Agents Contaminant Calcium Treating Agent lb/bbl of Treating Agent to React with 100 mg/l of Contaminant Soda Ash 0.093 Sodium Bicarbonate 0.074 Magnesium Caustic Soda 0.058 Carbonate Gypsum (if high pH) 0.118 Lime 0.043 Bicarbonate Lime Sulfide Zinc Carbonate 0.14 Zinc Oxide 0.089 13-9 “Proprietary - for the exclusive use of Amoco Production and other wholly owned subsidiaries of Amoco Corporation.” Rev 6/94 Amoco Production Company Drilling Fluids Manual Common Oilfield Screens Wire Diameter (in) inches microns % Open Area 8x8 028 097 2464 60.2 8x8 (2464x2464, 60.2) 10x10 025 075 1905 56.3 10x10 (1905, 1905, 5613) 12x12 023 060 1524 51.8 12x12 (1524x1524, 51.8) 14x14 020 051 1295 51.0 14x14 (1295x1295, 51.0) 16x16 018 0445 1130 50.7 16x16 (1130x1130, 50.7) 18x18 018 0376 955 45.8 18x18 (955x955, 45.8) 20x20 017 033 838 43.6 20x20 (838x838, 43.6) 20x8 020/.032 030/.093 762/2362 45.7 20x8 (762x2362, 45.7) 30x30 012 0213 541 40.8 30x30 (541x541, 40.8) 30x20 015 018/.035 465/889 39.5 30x20 (465x889, 39.5) 35x12 016 0126/.067 320/1700 42.0 35x12 (320x1700, 42.0) 40x40 0.10 015 381 36.0 40x40 (381x381, 36.0) 40x36 010 0178/015 381/592 42.5 40x30 (381x592, 42.5) 40x20 014 012/.036 310/910 36.8 40x20 (310x910, 36.8) 50x50 009 011 279 30.3 50x50 (279x279, 30.3) 50x40 0085 0115/.0165 292/419 38.3 50x40 (292x419, 38.3) 60x60 0075 0092 234 30.5 60x60 (234x234, 30.5) 60x40 009 0077/.016 200/406 31.1 60x40 (200x406, 31.1) 60x24 009 007/.033 200/830 41.5 60x24 (200x830, 41.5) 70x30 0075 007/.026 178/660 40.3 70x30 (178x660, 40.3) 80x80 0055 007 178 31.4 80x80 (178x178, 31.4) 80x40 007 0055/.018 140/460 35.6 80x40 (140x460, 35.6) 100x100 0045 0055 140 30.3 100x100 (140x140, 30.3) 120x120 0037 0046 117 30.9 120x120 (117x117, 30.9) 150x150 0026 0041 105 37.4 150x150 (105x105, 37.4) 200x200 0021 0029 74 33.6 200x200 (74x74, 33.6) 250x250 0016 0024 63 36.0 250x250 (63x63, 36.0) 325x325 0014 0017 44 30.0 325x325 (44x44, 30.0) Mesh Rev 6/94 Opening API Designation 13-10 “Proprietary - for the exclusive use of Amoco Production Company and other wholly owned subsidiaries of Amoco Corporation.” Amoco Production Company Drilling Fluids Manual 13-11 “Proprietary - for the exclusive use of Amoco Production and other wholly owned subsidiaries of Amoco Corporation.” Rev 6/94 Amoco Production Company Drilling Fluids Manual Rev 6/94 13-12 “Proprietary - for the exclusive use of Amoco Production Company and other wholly owned subsidiaries of Amoco Corporation.” [...]... Company Drilling Fluids Manual Rev 6/94 -18 “Proprietary - for the exclusive use of Amoco Production Company and other wholly owned subsidiaries of Amoco Corporation.” Amoco Production Company Drilling Fluids Manual Section 1 Introduction Drilling Fluid Classifications a Drilling fluids are separated into three major classifications (Figure 1): • • • Pneumatic Oil-Based Water-Based Figure 1 Drilling Fluids... Fluids Classification DRILLING FLUIDS Oil-Based Fluids Water-Based Fluids Pneumatic Fluids Diesel Non-Inhibitive Dry Gas Mineral Inhibitive Mist Non-Petroleum Hydrocarbon Polymer Foam Gasified Mud Pneumatic Fluids Pneumatic (air/gas based) fluids are used for drilling depleted zones or areas where abnormally low formation pressures may be encountered An advantage of pneumatic fluids over liquid mud... Amoco Corporation.” Rev 6/94 Amoco Production Company Drilling Fluids Manual Large volumes of drilling fluid filtrate, and filtrates that are incompatible with the formation or formation fluids, may destablize the formation through hydration of shale and/or chemical interactions between components of the drilling fluid and the wellbore Drilling fluids which produce low quality or thick filter cakes... reaching the formation at the bit Since the drilling fluid flow rate sets the system pressure losses, and these pressure losses set the hydraulic horsepower across the bit, it can be concluded that the drilling fluid is as important in determining drilling costs as all other “man-controllable” variables combined Considering these factors, “an optimum drilling fluid is a fluid properly formulated so that the... materials can result in a reduction in the drilling fluid density, which in turn can lead to kicks and a potential blowout The drilling fluid must also be capable to transporting cuttings out of the hole at a reasonable velocity that minimizes their disintegration and incorporation as drilled solids into the drilling fluid system At the surface, the drilling fluid must release the cuttings for efficient... subsidiaries of Amoco Corporation.” Amoco Production Company Drilling Fluids Manual Water-Based Fluids Water based fluids are the most extensively used drilling fluids They are generally easy to build, inexpensive to maintain, and can be formulated to overcome most drilling problems In order to better understand the broad spectrum of water-based fluids, they are divided into three major subclassifications:... Corrosion Control 10-17 Fluid Losses to the Formation 10-18 CORING FLUIDS 10-19 Filtration 10-20 Other Considerations 10-20 Oil Mud Coring Fluid 10-21 PACKER FLUIDS 10-21 Water-Based Drilling Muds 10-21 Clear Fluids 10-22 Viscosifying Agents 10-23 Bridging and Fluid Loss Agents 10-23... well The drilling fluid must overcome both the tendency for the hole to collapse from mechanical failure and/or from chemical interaction of the formation with the drilling fluid The Earth’s pressure gradient is 0.465 psi/ft This is equivalent to the height of a column of fluid with a density of 8.94 ppg, which is approximately the density of seawater In most drilling areas, a fresh water fluid which... Corporation.” Amoco Production Company Drilling Fluids Manual Provide Medium for Wireline Logging Air/gas-based, water-based, and oil-based fluids have differing physical characteristics which influence log suite selection Log response may be enhanced through selection of specific fluids and conversely, use of a given fluid may eliminate a log from use Drilling fluids must be evaluated to assure compatibility... Environmental Impact Fluid selection and engineering can reduce the potential environmental impact of a drilling fluid In the event of a spill, reclamation and disposal costs, as well as pollution associated problems are greatly reduced by proper fluid selection and control Improve Safety A drilling fluid should be engineered for safety It should have sufficient density to control the flow of formation fluids and