Drilling Fluid Definitions and General Functions

Results of research has shown that penetration rate and its response to weight on bit and rotary speed is highly dependent on the hydraulic horsepower reaching the formation at the bit. Because 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 controllable variables combined. Considering these factors, an optimum...

Info

FIGURE 2.9 Practical chart for drill collar selection 3-in. ID. (From Drilco, Division of Smith International, Inc.). FIGURE 2.10 Practical chart for drill collar selection 3-in. ID. (From Drilco, Division of Smith International, Inc.). The second best group of connections are those that lie in the unshaded section to the left of the shaded section. The third best group of connections are those that lie in the unshaded section to right of the shaded section. The nearer the connection lies to...

Calcium Chloride

Toxicity Three to five ounces of calcium chloride may be a lethal dose for a 45-kg (100-pound) person. However, calcium chloride is not likely to be absorbed through the skin in toxic amounts. Strong solutions are capable of causing severe irritation, superficial skin burns, and permanent eye damage. Normal solutions cause mild irritation to eyes and skin, and dust may be irritating. Safety Precautions Contact with eyes and prolonged skin contact should be avoided. Clean, long-legged clothing...

Preventing Contamination

Filtration is a critical step if a well is to produce at its full potential and remain on line for a longer period. Although filtering can be expensive and time consuming, the net production can be enough to pay the difference in only a matter of days. Filtration can be defined as the removal of solids particles from a fluid. Because these particles are not uniform in size, various methods of removal must be used (Table 1.11). Filtration has evolved from the surface filtering systems with...

Stabilize the Wellbore and Control Subsurface Pressures

Borehole instability is a natural function of the unequal mechanical stresses and physical-chemical interactions and pressures created when supporting material and surfaces are exposed in the process of drilling a well. The drilling fluid must overcome the tendency for the hole to collapse from mechanical failure or from chemical interaction of the formation with the drilling fluid. The Earth's pressure gradient at sea level is 0.465 psi ft, which is equivalent to the height of a column of salt...

Suspend Solids and Transport Cuttings and Sloughings to the Surface

Drilling fluids must have the capacity to suspend weight materials and drilled solids during connections, bit trips, and logging runs, or they will settle to the low side or bottom of the hole. Failure to suspend weight materials can result in a reduction in the drilling fluids density, which can lead to kicks and potential of a blowout. The drilling fluid must be capable of transporting cuttings out of the hole at a reasonable velocity that minimizes their disintegration and incorporation as...

Properties and Characteristics of Completion and Workover Fluids

Although the properties required of a completion or workover fluid vary depending on the operation, formation protection should always be the primary concern. Density The first function of a completion of workover fluid is to control formation pressure (Table 1.8). The density should be no higher than necessary to accomplish that function. Increased density can be obtained by using weighting materials such as calcium carbonate (CaCO3), iron carbonate (FeCO3), barite (BaSO4), or by using soluble...

Completion And Workover Fluids

Viscosity In many cases, the viscosity of the fluid must be increased to provide lifting capacity required to bring sand or cuttings to the surface at reasonable circulating rates. A popular viscosifier for completion and workover fluids is hydroxyethylcellulose (HEC). It is a highly refined, partially water soluble, and acid-soluble polymer with very little residue when acidized. Other materials used as viscosifiers include guar gums and biogums (xanthan). Although these materials are...

Calcium Chloride Calcium Bromide Zinc Bromide Solutions

CaCl2 CaBr2 ZnBr2 solutions using 15.0 ppg (1.80 SG) CaCl2 CaBr2 brine and 19.2 ppg (2.28 SG) CaBr2ZnBr2, the proper order of addition is as follows 1. Start with the 15.0 ppg (1.80 SG) CaCl2 CaBr2 brine. 2. Add the 19.2 ppg (2.28 SG). CaBr ZnBr2 brine. Rules of thumb for blending of brines 1. DO NOT CUT SACKS. Exception CaBr2 brines from 11.6 to 15.1 ppg. 2. An increase of CaBr2 decreases the crystallization temperature for CaBr2 brines. 3. An increase of ZnBr2 decreases the crystallization...

Drilling Muds And Completion Systems

1.1 Functions of Drilling Muds 1 1.1.1 Drilling Fluid Definitions and General Functions 1 1.1.2 Cool and Lubricate the Bit and Drill String 2 1.1.3 Clean the Bit and the Bottom of the Hole 2 1.1.4 Suspend Solids and Transport Cuttings and Sloughings to the Surface 2 1.1.5 Stabilize the Wellbore and Control Subsurface Pressures 3 1.1.6 Assist in the Gathering of Subsurface Geological Data and Formation Evaluation 3 1.2.1 Freshwater Muds Dispersed Systems 4 1.2.2 Inhibited Muds Dispersed Systems...

Chapter Air And Gas Drilling

3.2 Minimum Volumetric Flow Rate 200 3.3 Drill Bit Orifices or Nozzles 200 3.8 Suppression of Hydrocarbon Combustion 205 3.9 Aerated Drilling Gasified Fluid Drilling 207 3.9.1 Minimum Volumetric Flow Rate 209 3.9.3 Drill Bit Orifices and Nozzles 215 3.10.3 Minimum Volumetric Flow Rate 221 3.10.4 Drill Bit Orifices and Nozzles 222 3.11 Completions Operations 222 3.11.2 Casing and Cementing 223 3.12 Compressor and Inert Air Generator Units 226 3.12.2 Allowable Oxygen Content 228 3.12.3 InertAir...

Advanced Rheology and Suspension Analysis

FANN 50 A laboratory test for rheology under temperature and moderate pressure up to 1,000 psi and 500 F . FANN 70 Laboratory test for rheology under high temperature and high pressure up to 20,000 psi and 500 F . FANN 75 A more advanced computer-controlled version of the FANN 70 up to 20,000 psi and 500 F . High-Angle Sag Test HAST A laboratory test device to determine the suspension properties of a fluid in high-angle wellbores. This test is designed to evaluate particle setting...

Zinc Bromide

Toxicity There are no published data indicating that zinc bromide is a hazardous material to handle. It is considered toxic when ingested in large amounts. Zinc bromide is also a severe irritant to the skin and eyes. Inhalation results in irritation of mucous membranes in the nose and throat. Because of an exothermic reaction, zinc bromide fluid can burn bare hands if sacked materials have been added. Never expose eyes to zinc bromide blindness can occur. Safety Precautions Contact with skin...

Water Base Muds

A water-base drilling fluid is one that has water as its continuous or liquid phase. The types of drilling fluids are briefly described in the following sections. Freshwater muds are generally lightly treated or untreated muds having a liquid phase of water, containing small concentrations of salt, and having a pH ranging from 8.0 to 10.5. Freshwater muds include the following types. Spud Muds These muds are prepared with available water and appropriate concentrations of bentonite and or...

The basic ingredient of calcium chloridecalcium bromide brines

CaCl2 CaBr2 is a calcium bromide solution that ranges in density from 14.1 to 14.3 ppg 1.72 SG the pH range is 7.0 to 7.5. The density of CaBr2 brine can be increased by adding calcium chloride pellets or flakes. However, a 1.81 S.G. CaCl2 CaBr2 solution crystallizes at approximately 65 F 18 C . CaCl2 CaBr2 brine can be diluted by adding a CaCl2 brine weighing 11.6 ppg 1.39 SG . The corrosion rate for CaCl2 CaBr2 is no more than5 mm per year on N-80 steel coupons at 300 F 149 C . If a...

Drilling Fluid Additives

Each drilling fluid vendor provides a wide array of basic and specialty chemicals to meet the needs of the drilling industry. The general classification of drilling fluid additives below is based on the definitions of the International Association of Drilling Contractors IADC A. Alkalinity or pH control additives are products designed to control the degree of acidity or alkalinity of a drilling fluid. These additives include lime, caustic soda, and bicarbonate of soda. B. Bactericides reduce...

Shale Characterization Testing

Capillary Suction Time CST Inhibition testing looks at the inhibitive nature of a drilling fluid filtrate when exposed to formation shale samples. The CST is one of many tests that are run routinely on shale samples to optimize the mud chemistry of a water-base fluid. Linear-Swell Meter LSM Another diagnostic test to determine the inhibitive nature of a drilling fluid on field shale samples. The LSM looks at long-term exposure of a fluid filtrate to a formation shale sample. Test times for LSM...

Drill String Composition And Design

2.1.1 Selecting Drill Collar Size 57 2.1.2 Length of Drill Collars 60 2.1.3 Drill Collar Connections 63 2.1.4 Recommended Makeup Torque for Drill Collars 68 2.1.6 Rig Maintenance of Drill Collars 80 2.2.1 Classification of Drill Pipe 169 2.2.2 Load Capacity of Drill Pipe 174 2.2.5 Heavy-Weight Drill Pipe 181 2.2.6 Fatigue Damage to Drill Pipe 184 2.3 Drill String Inspection Procedure 186 2.3.1 Drill String Design 187

Specialized Filtration Testing

FANN 90 Dynamic filtration testing of a drilling fluid under pressure and temperature. This test determines if the fluid is properly conditioned to drill through highly permeable formations. The test results include two numbers the dynamic filtration rate and the cake deposition index CDI . The dynamic filtration rate is calculated from the slope of the curve of volume versus time. The CDI, which reflects the erodability of the wall cake, is calculated from the slope of the curve of volume time...

Chapter Fishing Operations And Equipment

7.2 Pipe Recovery and Free Point 341 7.3.3 Internal Mechanical Cutter 344 7.3.4 Outside Mechanical Cutter 344 7.3.7 Washover Back-off Safety Joint Washover Procedures 347 7.4 Jars, Bumper Subs and Intensifiers 349 7.4.1 Drill Collars in a Jarring Assembly 350 7.4.2 Fluid Accelerator or Intensifier 351 7.5.2 Skirted Screw-in Assembly 354 7.5.3 External Engaging Devices 355 7.5.4 Series 150 Releasing and Circulating Overshot 355 7.5.5 High-Pressure Pack-Off 356 7.5.6 Oversize Cutlip Guide 359...

Chapter Tubing And Tubing String Design

10.1 API Physical Property Specifications 509 10.1.1 Dimensions, Weights and Lengths 509 10.1.2 Performance Properties 520 10.2 Running and Pulling Tubing 520 10.3 Preparation and Inspection before Running 520 10.3.1 Stabbing, Making Up and Lowering 525 10.3.4 Causes of Tubing Trouble 531 10.3.5 Selection of Wall Thickness and Steel Grade of Tubing 532 10.3.6 Tubing Elongation Contraction Due to the Effect of Changes in Pressure and Temperature 533 10.3.7 Packer-To-Tubing Force 535 10.3.8...

Drill Collar

The term drill collar derived from the short sub originally used to connect the bit to the drill pipe. Amodern drill collar is about 30 ft long, and the total length of the string of drill collars may range from about 100 to 700 ft or longer. The purpose of drill collars is to furnish weight to the bit. However, the size and length of drill collars have an effect on bit performance, hold deviation, and drill pipe service life. Drill collars maybe classified according to the shape of their...

Environmental Aspects of Drilling Fluids

Brine Drilling Fluids

Much attention has been given to the environmental aspects of the drilling operation and the drilling fluid components. Well-deserved concern about the possibility of polluting underground water supplies and of damaging marine organisms, as well as effects on soil productivity and surface water quality, has stimulated widespread studies on this subject. Drilling Fluid Toxicity There are three contributing mechanisms of toxicity in drilling fluids chemistry of mud mixing and treatment, storage...

And Operations

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Oil Base and Synthetic Base Muds Nonaqueous Fluids Testing

Hpht Fluid Loss Testing Device

The field tests for rheology, mud density, and gel strength are accomplished in the same manner as outlined for water-based muds. The maindif-ference is that rheology is tested at a specific temperature, usually 120 F or 150 F. Because oils tend to thin with temperature, heating fluid is required and should be reported on the API Mud Report. Sand Content Sand content measurement is the same as for water-base muds except that the mud's base oil instead of water should be used for dilution. The...