Drilling Technology

Preventing Stuck Pipe DrillingEngineering

Fri, 18 May 2012 22:02:46 GMT

If the driller is unable to free the stuck pipe or the force necessary to free the pipe is greater than the force that can be applied by the blocks, then other remedial measures must be used. Normally a lubricating fluid is spotted in the troublesome area and is used to dissolve the filter cake. Spotting procedures and calculations have been mentioned in the Advanced Logging Procedures manual, under Additional Volume Calculations. These spotting procedures are facilitated by pin-pointing the...

Oil And Mud Coating 1 PetroleumEngineering

Fri, 18 May 2012 20:21:08 GMT

DECK DRAINS TO COMMON HEADER EMPTY INTO SLOT ENGINE GENERATOR SET Fig. 5.15. Inland water drilling barge with heavy duty diesel-electric rig. After Rowan,10 Fig. 5.15. Inland water drilling barge with heavy duty diesel-electric rig. After Rowan,10 are available however, all are essentially valves designed for closing the annular passage between two concentric pipes. Most blowout preventers are either hydraulically or pneumatically operated, with manual operation available as a safety...

Results Drilling of Plastics

Fri, 18 May 2012 15:35:13 GMT

Using the capability of the software to save in different formats, a drill was generated and exported into Abaqus and DEFORM using the SAT and STL formats, respectively. The drills were then meshed using the meshing module of these two packages. The resultant meshes along with the original solid model can be seen in Figure 4.14. Figure 4.14 Solid Model left , Meshed in Abaqus middle , and Meshed in DEFORM right . Figure 4.14 Solid Model left , Meshed in Abaqus middle , and Meshed in DEFORM...

Gel Strengthlbs ft secmin DrillingEngineering

Fri, 18 May 2012 08:44:34 GMT

This is a measurement that denotes the thixotropic properties of the mud and is a measurement of the attractive forces of the mud while at rest or under static conditions. As this and yield point are both measures of flocculation, they will tend to increase and decrease together, however a low yield point does not necessarily mean 0 0 gels Gel strength is measured with the viscometer by stirring the mud at high speeds for about 15 seconds and then turning the viscometer off or putting it into...

Selection Of Shale Shakers Drilling Fluid Systems

Fri, 18 May 2012 08:05:07 GMT

The first consideration in selecting a shale shaker is to decide whether or not a gumbo slide, or gumbo-removal device, will be needed. This is often necessary when drilling recent sediments. A scalping shaker must be considered next. Scalping shakers are usually needed when large quantities of drilled solids or gumbo reach the surface. Usually, long intervals of 17 y-in.-diameter holes, with flow rates above 1000 gpm, require scalping shakers in front of fine mesh screens see Chapter 7 . The...

Presurvey Checklist For Magnetic Single Shots DrillingGuide

Fri, 18 May 2012 02:39:25 GMT

An OpCo representative should ensure that the following is carried out. 1. Check that the required length of NMDC is available. 2. Check that the instrumentlanding assembly will seat correctly in the landing ring TOTCO ring , and will not jam or land eccentrically. 3. Check whether the instrument is to be top or bottom landed or used with a mule shoe. 4. Install the landing ring in the proper place when making up the BHA. Avoid landing the instrument directly on top of bit, mudmotor or turbine....

Freeing stuck pipe DrillingOperations

Thu, 17 May 2012 22:20:11 GMT

When the drillstring becomes stuck, immediate action will prove to be most effective in most cases. Prior to taking this action, the cause of the problem must be determined. This is achieved by considering the circumstances leading up to getting stuck and relating this to well conditions and history. Pipe will be stuck, either mechanically, or differentially. Sometimes, mechanically stuck pipe will end up differentially stuck too, but even in the worst hole, this will take time. 3.3.1...

Specific Gravity DrillingFluids

Thu, 17 May 2012 10:33:14 GMT

The density of any material is derived by multiplying the specific gravity of that material by the density of pure water. For example, the specific gravity of barite is 4.2 and its density is equal to 4.2 8.33 lb gal 35 lb gal. Conversely, to convert from density to specific gravity, divide the density of a material or mud by the density of pure water. As an example, a 17.5 lb gal mud has a specific gravity of 2.1. To determine the weight of 1 bbl of barite, determine the density of 1 bbl of...

Junk Baskets Oil Well Drilling

Thu, 17 May 2012 09:06:20 GMT

Many types of junk baskets exist. The three categories are the plain, the reverse circulating, and the pump junk baskets. The operation of the plain junk basket is to run into the hole, circulate, cut a short core to push the object into the barrel of the junk basket, grasp the core and or object with the fingers or grapple of the junk basket. The pipe is usually chained out of the hole not rotated to prevent the dropping of a partially grapped object. Reverse circulating junk baskets are the...

Nozzle Areasqin 1 PetroleumEngineering

Thu, 17 May 2012 07:35:17 GMT

Fig. 7.8. Pressure drop across conventional water course bits. Assuming pm 9.5 lb gal and C 0.80. Courtesy Hughes Tool Company. where n either plastic or apparent mud viscosity nw water viscosity T temperature, F Use of this equation requires knowledge of viscosity at two temperatures, so that linear plots can be established. Water viscosity data were given in Figure 6.8. Yield point at the desired temperature may then be calculated from Eq. 6.4. The average circulating temperature of the mud...

Chapter Footnotes Cfm Horizontal Directional Drilling

Thu, 17 May 2012 03:36:04 GMT

1 Jeffery S. Puckett, PE 2000 . Analysis of Theoretical Versus Actual HDD Pulling Loads. Bending Stress stress bending stress bending 13342psi External Hoop Stress stress hoopexternai stress hoopextemai 470.6psi Thermal Stress k .0000065 Tt 80 T2 50 stress thermal Bk Combined stress and limitations Combined stress is analyzed by calculating the maximum shear stress on a small element In the pipeline. The maximum shear stress should be limited to 45 of he SMYS ASME ANSI B31.4 . The maximum shear...

Systematic And Random Errors Oil Well Drilling

Thu, 17 May 2012 01:07:03 GMT

Wolff and deWardt published the following table which presents their finding in the study of surveying errors in the North Sea area. They also wrote that surveying errors are more systematic rather than random. At the time they worked for Shell

Undergauge Borehole DrillingEngineering

Thu, 17 May 2012 00:22:54 GMT

When drilling long sections of abrasive formations, the gauge protection on the bit and stabilizers can become so worn it becomes ineffective. Any additional hole that is drilled will be undergauge. Preventive measures include 1. Properly gauge the bit and stabilizers after each run 2. Ream back to bottom if an undergauge hole is suspected 3. Never force a new bit to bottom 4. Select bits with good gauge protection 5 amp 7 feature in roller 5. Carefully run fixed cutter bits after roller cone...

Cost Per Foot Calculations Including Downhole Motors DrillingEngineering

Wed, 16 May 2012 19:29:15 GMT

When downhole motors are used and charged at an hourly rate, they can be included in the cost equation C CRig D tf CBit Moto D C d The following example is a case history. The above equation was used to qualify the savings to an operator in the North Sea when drilling a very hard conglomerate formation with an impregnated diamond bit and a turbine. Calculations were made based on all the bit runs through the conglomerate formation on five different wells. The following values were used for the...

Flowline Pullin OffshoreDrilling

Wed, 16 May 2012 17:22:39 GMT

The unique LPS diverless flow-line pull-in system is a significant part of the entire program as flow-line installation is usually expensive and subsea connections normally require diver assistance. As pointed out earlier, the original flow-line connection for Shell Oil Company wets accomplished using a preformed line with external TFL loops pulled by a winch within the service capsule. With the horizontal wellhead cellar design, the flow line approaches the cellar from the ocean floor and is...

Final Refusal Depth DrillingProcedures

Wed, 16 May 2012 12:33:39 GMT

The following procedure details the determination of final refusal depth. 1 When the driving depth of the conductor pipe is not specified in the Drilling Programme, the final depth of the driving is the 'refusal depth'. The refusal value generally used is 1,000-1,100 blows metre. Local experience could dictate a different refusal value. The driving depth can be predetermined by conducting soil boring analysis. Examine offset well data for depths and potential problems in order to determine if...

Bentoniteligno Mud DrillingGuide

Wed, 16 May 2012 10:15:20 GMT

Fresh water bentonite mud is a relatively inexpensive drilling mud which is used widely in drilling operations. The main mud parameters are maintained by careful balancing of clay and lignosulfonate additions. Addition of clay will increase YP and gel values whereas lignosulfonate additions will lower the fluid loss and YP gel values. When mud properties cannot be maintained additions of CMC-LV are required. The PV is kept low by optimal solids removal and dilution. Batchwise dilution...

Appendix A Glossary Drilling Risers Systems

Wed, 16 May 2012 07:13:13 GMT

Accumulator BOP . A pressure vessel charged with gas nitrogen over liquid and used to store hydraulic fluid under pressure for operation of blowout preventers. Accumulator Riser Tensioner . A pressure vessel charged with gas nitrogen generally over liquid that is pressurized on the gas side from the tensioner high-pressure gas supply bottles and supplies high pressure hydraulic fluid to energize the riser tensioner cylinder. Actuator. A mechanism for the remote or automatic operation of a valve...

Jetting Assemblies DrillingEngineering

Wed, 16 May 2012 05:53:22 GMT

A typical jetting assembly used to drill a 12 74pilot hole is This is essentially a strong angle build rotary assembly with a suitable bit for jetting. The upper stabilizer is optional and is often omitted.

Environmental Considerations For Drilling Operations DrillingEquipment

Wed, 16 May 2012 04:20:00 GMT

11.3 Environmental Regulations 571 11.4 Site Assessment and Construction 575 11.4.3 Drilling Fluid Considerations 578 11.5 Environmental Concerns While in Operation 583 11.5.4 Reclamation of the Drill Site 589 11.5.7 Fixation of Reserve Pit Water and Solids 592

Screen Deck Design DrillingFluids

Wed, 16 May 2012 00:45:56 GMT

Hook-strip screens have been mounted with both underslung and over-slung supports. Some previous generations of oilfield shaker designs used screens that were underslung, or pulled up from the bottom of a group of support, or bucker, bars Figure 7.15 . These support bars would divide the flow of material down the screen. Some problem is experienced occasionally when solids are trapped under the rubber bar supports. Some linear motion shale shakers utilize overslung screens Figure 7.16 . With...

Placement DrillingEngineering

Tue, 15 May 2012 21:18:16 GMT

The stabilizer is most commonly run directly above the motor. According to the 3-point geometry, increasing L by moving the first string stabilizer higher in the BHA reduces the Theoretical Geometric Dogleg Severity. This does not always work in practice. It has been found that moving the stabilizer higher can make it harder to get away from vertical in a kick-off. However, once some inclination has been achieved, the rate of build is often greater than the TGDS. For flat turns or for dropping...

Gas Migration When Gas In Solution WellControl

Tue, 15 May 2012 19:04:13 GMT

Well Control problems can result in blowouts because of the solubility of certain gases in specific types of mud e.g. Methane dissolves in oil base mud, and S dissolves in water base mud. This fact makes it more difficult to detect a kick. A large gas influx entering the wellbore may change the pit level very little if the gas dissolves in the mud. The influx is then circulated up the wellbore in the mud column, until the hydrostatic pressure on top of the gas decreases to a certain point then...

Biopolymers DrillingGuide

Tue, 15 May 2012 18:31:04 GMT

Recently several biopolymer X-C Polymer, Rhodopol, Enerflo, Drillam X 84 have found worldwide application in drilling fluids. These polymers are quite expensive. When used in concentrations as low as 2-3 kg m 3 1 Ib bbl a major increase in YP and gel values is normaly obtained. Various salts sodium chloride, magnesium chloride and pottassium chloride are used for drilling through salt sections. The mud is saturated to the salt that is expected in the hole and thus washouts due to the...

Diamond Gauge Protection 1 DrillingGuide

Tue, 15 May 2012 18:27:47 GMT

Typical Part Section through Centre of Bit Typical Part Section through Centre of Bit with Diamonds Low Pressure Collectors with Diamonds Low Pressure Collectors

MakeUp Torque DrillingEngineering

Tue, 15 May 2012 16:29:32 GMT

Part of the strength of the drillstring and the seal for the fluid conduit are both contained in the tool joints. It is very important therefore, that the correct make-up torque is applied to the tool joints. If a tool joint is not torqued enough, bending between the box and pin could cause premature failure. Also, the shoulder seal may not be properly seated, resulting in mud leaking through the tool joint, causing a washout. Exceeding the torsional yield strength of the connection by applying...

Toof Face DirectionalDrilling

Tue, 15 May 2012 15:41:33 GMT

Azimuth is the direction of the wellbore relative to true or grid north in the horizontal plane. We measure this angle by measuring the direction of the earth's magnetic field relative to the tool. Magnetic Declination is the difference in degrees between magnetic north and true north or grid north for a particular location on the earth. This value changes with time and location and must be determined using the software program. On a directional well it is important that the value for magnetic...

Circulation Prior to Tripping DirectionalDrilling

Tue, 15 May 2012 15:25:28 GMT

Hole size and inclination will influence the minimum off-bottom circulation time prior to tripping. The figures in the table below are guidelines based on simple slip velocity considerations and field experience. In practice, some of the section back to surface will not be deviated at the same angle. The overall minimum circulation time prior to tripping should be apportioned in direct relation to the relative lengths of section at each angle. This is shown in Figure 25 for tripping out of 445...

a Diverter System DrillingProcedures

Tue, 15 May 2012 12:47:00 GMT

The subsea diverter system is an integral part of the marine riser system. Diverter mechanism consists primarily of a packing insert that can seal on drill pipe or open hole with an insert plug , a control system, two flow lines, a ball joint and valving. The Regan Hughes Offshore KFD diverter is the most common system used on today's rigs. There are three basic models KFDG Gimble which is used on rigs that do not have an upper ball joint. KFDH Housing used on many vessels having limited room...

Multiple Wells From Offshore Structure DrillingServices

Tue, 15 May 2012 12:36:42 GMT

One of today's more common applications of directional drilling techniques is in offshore drilling. Many oil and gas deposits are situated beyond the reach of land based rigs. To drill a large number of vertical wells from individual platforms is impractical and would be uneconomical. The conventional approach for a large oilfield has been to install a fixed platform on the seabed, from which as many as sixty directional wells may be drilled. The bottomhole locations of these wells can be...

AdvantagesDisadvantages of NonDispersed Polymer Muds DrillingFluids

Tue, 15 May 2012 11:52:13 GMT

Advantages Disadvantages of Polymer Muds Irreversible adsorption of the polymer on clays Easily converted to a deflocculated system Requires more dilution than deflocculated systems More corrosive than deflocculated systems Sensitive to contaminants carbonate contamination difficult to treat Contamination - Non-Dispersed Polymer Muds Contaminant Treating of Non-Dispersed Polymer Muds Increasing retort solids, PV, YP, gels, MBT. Thick mud on bot-toms-up after trips. High flowline viscosity....

Foreword ScientificDrilling

Tue, 15 May 2012 10:48:04 GMT

Scientific drilling is an indispensable tool of modern Earth science research, as it provides the only means of obtaining direct information on processes operating at depth. Drilling allows for the determination of in-situ properties of solid materials and fluids and permits testing of hypotheses and models derived from surface observations. In addition, drill holes may be used as a natural laboratory for experiments and as observatories for long-term monitoring of on-going active processes....

Cement bond logs CBLVDL DrillingOperations

Tue, 15 May 2012 10:04:22 GMT

Cement bond logs are sonic tools which emit sounds and pick up reflections. They are used inside casing as a means of locating the top and the quality of cement behind the casing. Uncemented casing resembles a tubular bell and transmits sound easily. Well-cemented casing will dampen sound vibrations and produce different results which can be interpreted together with well data. The value of CBL VDL is debatable. The author has seen apparently uncemented casing behind which communication was...

Example Lock Up Oil Well Drilling

Tue, 15 May 2012 07:22:25 GMT

In the example problem on drag of the components of the drill string, it was computed that the expected drag from the BHA, the drillpipe in the reach, in the lower build, and the tangent section was 14,853 lb. The available gravity weight for the bit for that same section of drillpipe was computed to be 1,761. In the above example it was learned that the resistance to buckling of 5 drillpipe for the conditions of that example was 24,204 lb. Thus, the maximum weight which can be placed on the...

Beach sand DrillingServices

Tue, 15 May 2012 06:06:04 GMT

The linear zone of sediments marking a former coastline may form a series of sandstone reservoirs. Unlike river sandbars, grain orientation and direction of maximum permeability are across the trend. Information on facies changes is especially useful in locating this type of reservoir. Knowing that limestone and shale usually form some distance offshore, the geologist can determine the direction in which the sediments become coarser and more permeable. The coarsest, best-sorted, most permeable...

Applying a West Declination DirectionalDrilling

Tue, 15 May 2012 06:05:51 GMT

If the magnetic direction is 120 and the declination is 5 west , the true direction would be calculated as True Direction Magnetic Direction Declination Implications of an Incorrect Declination Since declination is a addition of degrees of correction to the magnetic hole direction, any mistakes made to the declination have serious consequences. For example, if you intend to apply a 18 declination but instead input a -18 declination, your reported hole direction will be wrong by 36 This can...

Measurementswhiledrilling Mwd DrillingOperations

Tue, 15 May 2012 06:04:39 GMT

MWD systems allow the following variables to be measured The purpose of these logs is explained on page 164. The range of services provided by MWD are improving and the rate of change is accelerating. If the present rate of development continues, then MWD could effectively replace electric logging for many evaluation applications in the near future,

degree Gyro Compass DirectionalDrilling

Tue, 15 May 2012 05:34:40 GMT

Read from the 0 vernier line horizontally to the intersection of the inclination to determine the inclination to a precision of 0.5 30 always round down Use the 30' vernier scale to increase the precision of the reading to 5'. To use the vernier, look for an alignment of the division markings on both the vernier and inclination scales, read the value on the vernier scale at this intersection point. This is then added to the previous reading Determine the hole direction of the chart as follows...

Example Drillpipe Tension Oil Well Drilling

Tue, 15 May 2012 03:37:19 GMT

The weight indicator shows 230,000 lbs. The block and lines weight 30,000 lbs. A pump pressure gauge in line with the drillpipe shows 7,000 psi. The drillpipe is 5 by 4.276 by 19.5 ppf and the average weight per foot of the steel in the drillpipe is 21.4 lb ft. What is the real tension in the drillpipe at the rotary table and at a depth of5,000 feet The inside end area of 5 drillpipe 0c 4 4.2762 14.360 sq. in. Treal 230,000 - 30,000 7,000 14.360 300,520 lb rotary table Treal 300,520 - 21.4...

Annular Velocity 1 DrillingFluids

Tue, 15 May 2012 00:25:26 GMT

What is the annular velocity at 110 SPM on one pump, opposite a. Drill Collars Open Hole AV0h dc _ft min b. Drill Pipe Open Hole AV0H DP _ft min c. Drill Pipe Casing AVCSG DP _ft min The annular velocity defines the average velocity at which the mud passes through a specific annular space and is normally expressed in units of ft min. The following annular velocities opposite specific intervals will be based on pump output at 110 SPM and 94 volumetric efficiency. a. Drill Collars Open Hole, AV0h...

Mike Hughes and Larry Cushman OffshoreDrilling

Mon, 14 May 2012 23:35:16 GMT

Diving can be defined as a method of transportation that allows a man to perform work in the ocean, or on the ocean floor. There are two basic ways men can work underwater. The first is pressurized or hyperbaric diving. With this method the man goes directly into the ocean, and is therefore continuously subjected to the increasing pressures of depth. The second method of diving is unpressurized or isobaric diving in which the man goes under water in an unpressurized sealed diving bell,...

Pump Output DrillingFluids

Mon, 14 May 2012 21:48:18 GMT

What is the pump output Q in barrels per stroke bbl STK and gallons per stroke gal STK at 94 volumetric efficiency A National 10-P-130 which has a 10-in. stroke with a 5-1 2 in. liner at 100 volumetric efficiency will deliver 3.0996 gal STK. Triplex Single Acting Mud Pump Capacities Per Cycle Barrels per Stroke -100 Volumetric Efficiency Duplex Double-Acting Mud Pump Capacities Per Cycle Barrels per Revolution - 90 Volume Efficiency - Rods Deducted Therefore, at 94 volumetric efficiency a....

aAnnular to Ram Stripping WellControl

Mon, 14 May 2012 19:31:18 GMT

When stripping with ram preventers, the same principle applies to packing element wear as the annular preventers. The lower the closing pressure while stripping, the longer the life of the sealing element. Initially CLOSE the ram preventers, using 1500 psi pressure, and then adjust the regulator to reduce the pressure, depending on the pressure of the well. The annular preventer should also be closed with 1500 psi and the regulator adjusted to sealing pressure with a minimum of 600 psi.

Density Control of Water Soluble Completion Fluids DrillingFluids

Mon, 14 May 2012 18:30:55 GMT

The concept of a water soluble fluid consisting of a saturated brine and ground salt NaCl in combination with polymeric viscosifiers and filtration control agents has been patented by TBC-BRINADD and licensed by a number of workover completion fluid suppliers. In these systems, the ground salt functions as a weighting agent. Figure 5 gives a typical particle size distribution for a ground salt weighting agent. Due to the 2.18 specific gravity, the typical density range for these formulations is...

Austin Chalk Well Dimmit County Texas Usa Oil Well Drilling

Mon, 14 May 2012 17:58:00 GMT

The following is a description of the typical Austin Chalk well in Dimmit county, Texas. Vertical wells in the area produced from no oil to 5 barrels of oil per day. The described well initially flowed 1,660 bopd. The Austin Chalk is a highly, vertically fractured formation with no matrix permeability. The horizontal section of the well was drilled under balanced in order to assess the production rate as the well was drilled and to reduce plugging of fractures with drill solids. The 7 5 8...

List Of Abbreviations WellControl

Mon, 14 May 2012 17:54:56 GMT

Hmud Head of Mud or Hydrostatic Pressure of Mud usually psi . Gmud Pressure gradient of mud usually psi foot . PF Formation Fluid Pressure usually psi . PFB Formation Breakdown Pressure or Formation Fracture Pressure or Formation Breakdown Pressure Gradient usually psi foot . Maximum Equivalent Mud Weight, to produce Formation Breakdown Pressure at Shoe. Maximum Allowable Annular Surface Pressure usually psi . Surface Pressure, which if exceeded may cause leakage of whole mud into formation of...

DRILL COLLAR Nzf DrillingEquipment

Mon, 14 May 2012 17:28:35 GMT

FIGURE 2.9 Practical chart for drill collar selection 3-in. ID. From Drilco, Division of Smith International, Inc. .

Bit Technology 1 DrillingEngineering

Mon, 14 May 2012 17:20:47 GMT

The Advanced Logging Procedures workbook contains information on drill bits, IADC classifications and bit grading, and should be reviewed before beginning this chapter. The first successful rolling cutter rock bit was introduced into the oil field by Howard Hughes Sr. in 1909. Over the next fifteen years, the rolling cutter bit was used primarily in hard formation areas. This rolling cutter bit was a two-cone bit with cones that did not mesh, consequently, the bit had a tendency to balled-up in...

SlantedFace Rock Bits Horizontal Directional Drilling

Mon, 14 May 2012 15:47:01 GMT

Slanted-face rock bits are used in harder ground conditions and soft rock less than 3,500 psi that cannot easily be penetrated with thrust alone. The face of the tool usually has one or more nozzles emitting pressurized drilling fluid. In harder ground conditions, steering is accomplished by techniques such as partial rotation and release, wiggling the bit clockwise counterclockwise fishtailing while thrusting at the desired steering orientation, or by a broader arc of clockwise...

Desilter Suction and Discharge Pits Mud CleanerConditioner TankArrangement

Mon, 14 May 2012 13:35:37 GMT

The desilter suction pit is the desander discharge pit. The desilter will remove smaller particles than the desander, so its operation is downstream of the desander. Setup and operation of desilters are the same as with desanders. The manifold discharge is downstream of the suction, with a low equalizer between the two tanks. It is recommended that the desilter process more volume than the rig is pumping so that there is a backflow through the equalizer, ensuring that all of the drilling fluid...

Pills and Spacers DrillingFluids

Mon, 14 May 2012 08:28:03 GMT

Both direct and indirect displacement procedures utilize pills and spacers for effective hole cleaning and separation of fluids. The primary purpose of a spacer is to provide complete separation of two incompatible fluids. The spacer must be compatible with both the displaced fluid and the displacing fluid. Cleaning pills are used to scour and sweep debris out of the hole. Two types of pills may be used. A basic cleaning pill is composed of viscosified drill water, seawater or brine. A scouring...

Simplified Roller Bit Classification System DrillingGuide

Mon, 14 May 2012 06:33:24 GMT

A new roller bit classification system has been approved by the American Petroleum Institute as a recommended practice and It will be included in the forthcoming edition of RP7G. Recommended practice for drill stem design and operating limits . The system is meant to standardise the nomenclature for roller bits according to the application recommended by the manufacturer and their special features and not to standardise the bit design itself. A 3-digit code is used. The first digit series...

Tapered Bha Oil Well Drilling

Mon, 14 May 2012 03:42:44 GMT

In the make-up of BHA's it is often required that components which have different outside or inside diameters be connected. A rule of thumb which has been published by DRILCO, a manufacturer of BHA components, is that the section modulus ratio SMR of the bodies of the two connected components be 5.5 or less. Section modulus is the cross-section moment of inertia divided by the radius to the outer fiber. DRILCO further claims that a short sub with an intermediate section modulus will not protect...

Advantages of NDS DrillingEngineering

Mon, 14 May 2012 01:31:39 GMT

Elimination of trips for directional assembly changes, saving rig time More complex well paths can be drilled Wells are drilled more closely to the plan at all times Smaller directional targets can be hit Steerable turbines use the side force method by having an eccentric or offset stabilizer at the lower end of the bearing section at the bottom end of the turbine body, quite close to the bit. The three blade version shown below is the one most commonly used, but a single blade version exists...

Critical Buckling Force DrillingEngineering

Sun, 13 May 2012 13:55:00 GMT

Dawson and Paslay developed the following formula for critical buckling force in drill pipe. I is axial moment of inertia. W is buoyed weight per unit length. r is radial clearance between the pipe tool joint and the borehole wall. If the compressive load reaches the Fcr, then sinusoidal buckling occurs. This sinusoidal buckling formula can be used to develop graphs and tables see pages 4-18 through 4-23 . If the compressive load at a given inclination lies below the graph, then the drill pipe...

Magnetic Toolface DirectionalDrilling

Sun, 13 May 2012 13:38:28 GMT

Magnetic toolface is the direction, in the horizontal plane, the bent sub scribe line is pointing with regard to the north reference Grid, Magnetic, or True Magnetic Toolface Dir Probe Mag Toolface Total Correction Toolface Offset Magnetic orientation is used when the inclination of the wellbore is less than 5 to 8 When the inclination is below this amount, the survey instrument cannot accurately determine the highside of the instrument for orientation purposes The toolface will be presented...

How To Determine Cut Point Curves DrillingFluids

Sun, 13 May 2012 12:11:53 GMT

1. If a flow meter is unavailable, determine the flow rate to the solids-control equipment. To calculate the flow rate, one must know the fluid pump's gallons per stroke, strokes per minute, and efficiency. The flow rate can then be calculated by flowrate cylinder volume N spm pump efficiency cylinder volume pump sleeve inner diameter in inches 2 4 pump stroke length in inches 0.00433 in3 gal 2. Take a representative sample from the feed stream and measure the density. 1. Weigh the sampling...

Oil Concentration Per Cent By Volume 1 PetroleumEngineering

Sun, 13 May 2012 12:01:29 GMT

Fig. 8.18. Relative drilling rate vs. oil content West Texas field data. After Eckel,30 courtesy API. which more than compensate for the latter detrimental effects. Density and solid content decreases may be compensating factors in some instances. Laboratory test results showing the effect of oil percentage on the drillability of two Gulf Coast shales are shown in Figure 8.17. Note the optimum oil concentration for shale B which is not evident for shale A. This optimum percentage shale B...

Formation tester DrillingOperations

Sun, 13 May 2012 10:11:09 GMT

Wireline formation testers need to have the following characteristics 1. Selective setting so they can be placed alongside the formation to be tested and then pressed into the formation to provide an effective seal. 2. Sample chambers in which to take formation fluid samples. 3. Pressure measurement by which reservoir pressures build up rates can be recorded. The most commonly used formation test tool is the repeat formation test tool RFT . This can be set and unset gaining information from...

Directional Sensor Components DirectionalDrilling

Sun, 13 May 2012 04:04:05 GMT

Contained inside the assembly is a Single Port MPU, Triple Power Supply and a Digital Orientation Module. The Single Port MPU is a modular micro-controller assembly based on the Motorola MC68HCll microprocessor implementing Honeywell's qMIXTM communications protocol qMIX ll TM . The Triple Power Supply provides regulated power for the complete assembly. The microprocessor provides the control and timing to interface the logic circuit controls the analog power switch. With the analog power...

Discharge DrillingFluids

Sat, 12 May 2012 14:55:35 GMT

Most hydrocyclones are of a balanced design. A properly adjusted, balanced hydrocyclone has a spray discharge at the underflow outlet and Figure 11.2. Solution to common discharge header problem. Figure 11.2. Solution to common discharge header problem. exhibits a central air suction core. Many balanced hydrocyclones can be adjusted so that when water is fed under pressure, nothing discharges at the apex. Conversely, when coarse solids are added to the feed slurry, wet solids are discharged at...

Info Mdd DrillingFluids

Sat, 12 May 2012 12:58:14 GMT

normally pressured formations, which have a self-supporting structure of solid particles so the pore pressure depends only on the weight of the overlying pore fluids , and abnormally pressured or geopressured formations, which are not fully compacted into a self-supporting structure so the pore fluids must bear the weight of some or all of the overlying sediments as well as the weight of the overlying fluids . The hydrostatic pressure gradient of formation fluids varies from 0.43 psi ft to over...

Vibrating Systems Drilling Fluid Systems

Sat, 12 May 2012 08:11:55 GMT

The type of molion imparled to the shaker depends on the location, orientation, and number of vibrators used. In all cases, the correct direction of rotation must be verified. Circular molion shakers use a single vibrator mounted at the shaker's center of gravity. Belt-driven vibrators and hydraulic-drive vibrators are used for this shaker design. Unbalanced elliptical motion shakers use a single vibrator mounted above the shaker's center of gravity. Integral vibrators, enclosed vibrators, and...

Trans Water Water PetroleumEngineering

Fri, 11 May 2012 23:43:40 GMT

Fig. 10.29. Core analysis and productivity interpretation for a predominately silty Cockfield sand. After Elmdahl,28 courtesy AIME. Fig. 10.29. Core analysis and productivity interpretation for a predominately silty Cockfield sand. After Elmdahl,28 courtesy AIME. will bleed oil and gas for several hours after being recovered. The saturations obtained from samples taken near the center of such cores may have undergone relatively little flushing. Highly permeable cores are readily flushed and may...

Shale Inhibition PotentialWetting Characteristics DrillingFluids

Fri, 11 May 2012 22:50:31 GMT

Because the continuous phase in NAFs is nonaqueous, cuttings drilled with NAFs do not hydrate, and they are left oil wet and nearly intact. Invert-emulsion NAFs can actually increase cuttings' hardness by osmotically removing water from the cuttings. WBMs, on the other hand, generally are not very efficient at removing water from the cuttings indeed they may only slow hydration, so that cuttings will still tend to imbibe water, swell, soften, and even disperse. The same phenomenon occurs in the...

Comparative Oil Mud Products by Function DrillingFluids

Fri, 11 May 2012 19:04:04 GMT

VERSA MUL CARBO TEC L INVERMUL EMUL ORGANOLIGNITE VERSA LIG CARBOTROL A9 DURATONE NA VERSA TROL CARBO TROL BARABLOK TRUDRILL S ANCO-MUL FR-G GELTONE II TRUVIS ANCO-MUL GEL-B CARBO GEL BENTONE 38 TRUVISHT ANCO-MUL GEL-H VERSA WET SURF COTE DRILTREAT O.W.

Lignins and Tannins DrillingFluids

Fri, 11 May 2012 11:19:40 GMT

These include sulfonated tannins, quebracho, lignosulfonates, lignites and lignite derivatives. The mechanisms by which they work is by thinning the clays adsorbing on the positive edges of the clay platelets, which leads to repulsion among the platelets , plus plugging action of the particles themselves. These additives improve the distribution of solids within the drilling fluid by deflocculating solids such as bentonite and through the colloidal nature of the chemical, skewing the particle...

Casing Operations With A Top Drive DrillingProcedures

Fri, 11 May 2012 08:33:21 GMT

With the introduction of 500 tons bails and adequately rated swivel, the Top Drive is rated at 500 tons for casing operations. Longer bails 132 or 144 must be used to allow clearance for the casing elevator under the torque wrench in the pipe handler. Also clearance for the cementing head must be taken into consideration when determining casing bails length. By attaching a short piece of hose to the saver sub in the pipe handler, the casing can be filled while lowering by using the remotely...

Hydrostatic Pressure DrillingEngineering

Fri, 11 May 2012 07:48:39 GMT

As mentioned earlier, this is the pressure created by a column of fluid due to its density and vertical height. This type of pressure always exists and may be calculated whether the fluid is static or flowing. It can be calculated using Hp psi MWx 0.0519 x TVD ft Hydraulic Pressure This is the pressure created or needed to move drilling fluid through pipe. In oil field terms, it is the pressure generated by the mud pump in order to move the drilling fluid from the mud pump around the system and...

Table Cement Components and Characteristics DrillingEngineering

Fri, 11 May 2012 07:46:56 GMT

Tricalcium alum nate C,A 3CaO A120 Tetracalcium aluminorerrite C4AF 4CaO Al A Fe,0, Tricalcium silicate C3S 3CaO SiQj Dicalcium silicate C S 2CaO Si02 Affects the initial setting and thickening time of the cement Makes the cement susceptible to sulfate attack Major component and produces most of the strength Responsible for early strength development Hydrates slowly Promotes small, gradual gain in strength over an extended period of time in which the surface of one cement grain reacts while...

Fatigue Of Drillpipe Oil Well Drilling

Fri, 11 May 2012 03:44:50 GMT

In deep holes most drillpipe failures are the direct result of fatigue. Drillpipe fatigues while it is rotated within doglegs. The amount of fatigue damage depends on 1 the tensile load in the drillpipe at the dogleg, 2 the severity of the dogleg, 3 the number of turns of the drillpipe while it is within the dogleg, and 4 the mechanical dimensions and metallurgical properties of the drillpipe. Because tension within the drillpipe is a major factor, the most critical location for a dogleg is at...

Available Torque For The Drill Bit Oil Well Drilling

Thu, 10 May 2012 22:36:33 GMT

Excessive torque may limit the length of the horizontal section. The torque available to turn the drill bit while drilling in the rotary mode will be constrained by one of the following. 1. The maximum torque possible by the rotary table 2. The torsional strength of the weakest connection or tooljoint 3. The torsional strength of the wall of the thinnest pipe The torsional strengths of the drillpipe and tooljoints are written in Tables 2.2 to 2.12 and for rotary shoulder connections in Table...

Density Borehole Compensation Standoff Correction DirectionalDrilling

Thu, 10 May 2012 20:55:25 GMT

Figure 10 - Spine and Ribs Standoff Correction Crossplot Figure 10 - Spine and Ribs Standoff Correction Crossplot In the downhole logging situation, environmental corrections must often be made. In LWD density logging, the most common is a correction for the effect of standoff from the borehole wall. The correction that must be made is dependent on both the amount of standoff and on the density of the drilling fluid that occupies the standoff space between the tool and wall. The spine and rib...

Torque And Drag Oil Well Drilling

Thu, 10 May 2012 19:42:51 GMT

'Torque and drag' is a broad term which refers to the effects which the geometry and other aspects of the drill hole may have on the turning and pulling of the drill string. In regard to the drill string there are two drilling modes sliding and rotating. In the 'sliding' mode the drill string is not rotated and torque is low however axial drag is high and lock-up is possible. Lock-up is the buckling of a section of the drill string within the drill hole and prevents the transmission of force to...

Maxi Rigs Horizontal Directional Drilling

Thu, 10 May 2012 18:53:22 GMT

1. Mobilization and Set Up lt 6 hours 2. Pilot Hole Drilling 100-400 ft hr 3. Prereaming Reaming Per Pass 100-300 ft hr 4. Product Pullback Without Reaming 200-600 ft hr 200-600 ft hr 200-600 ft hr 200-600 ft hr 200-600 ft hr 200-600 ft hr Function of material, diameter, length of sections, crew size and skill, and testing requirements. TABLE 2-5 HDD Production Rates for Various Conditions TABLE 2-5 HDD Production Rates for Various Conditions Pilot Hole Production Rate ft hr for Pipe Diameter...

Rheology DrillingFluids

Thu, 10 May 2012 16:02:40 GMT

Rheology is the study of the deformation and flow of matter. Viscosity is a measure of the resistance offered by that matter to a deforming force. Shear dominates most of the viscosity-related aspects of drilling operations. Because of that, shear viscosity or simply, viscosity of drilling fluids is the property that is most commonly monitored and controlled. Retention of drilling fluid on cuttings is thought to be primarily a function of the viscosity of the mud and its wetting...

Minimizing Errors DrillingServices

Thu, 10 May 2012 15:14:39 GMT

One way to minimize the error caused by the drill string is to eliminate as much of the magnetism as possible. This is done by isolating the magnetometer package with as many non-magnetic drill collars as possible. The length of the non-magnetic collars implies a uniform and non-interrupted nonmagnetic environment. This, however, is not true in practice. Each connection in a drill string, whether magnetic or not, is magnetic due to the effects of the mechanical torque of the pin in the box....

Coefficient of Friction f DrillingEngineering

Thu, 10 May 2012 14:31:06 GMT

Though very seldom quantitatively defined in field operations, f will normally vary between 0.07 for invert emulsion muds and 0.40 for low solids native muds . As the mud density increases, the amount of solids barite, sand, bentonite, etc. also increases, which increases the coefficient of friction. The coefficient can be determined using a specialized mud test apparatus called a stickometer. This test uses a torque plate which is pushed against a filter cake at 500 psi. After a set time...

Factors Contributing to Swab and Surge DirectionalDrilling

Thu, 10 May 2012 14:08:58 GMT

Swab and surge pressures are principally related to the wellbore geometry, mud properties, pipe running speed and circulation. The wellbore geometry and the size of the drill pipe determine the size of the annulus. A larger annulus allows a slower movement of displaced fluid past the moving drill pipe. This reduces the swab or surge pressure effect. Any restrictions such as packoff or swelling of the well bore reduces the annulus size and increases the swab or surge effect. See Figure 11. The...

P Pi Pd P P DrillingGuide

Thu, 10 May 2012 10:19:00 GMT

Introduction to Drilling and Producton Techniques 5w CTC Round I Self Study Examination 1 day CTC Mud and Cement Chemistry 1wj STC Drilling Techniques 5w CTC P133 Well Control Refresher 3d STC P211 Production Chemistry 7d STC PD02 Round II Self Study Examination 3 days CTC P201 Petroleum Engineering 2w CTC P215 Production Techniques 2w STC P230 Drilling Techniquues 3w CTC P231 Mud and Cement Chemistry integral part of P2.30 P290 or Introduction to Business Techniques, Economics and Project P220...

Storm Valve WellControl

Thu, 10 May 2012 09:59:04 GMT

In the event that the string has to be hung-off whilst waiting on weather or pulling the BOP stack for repair, the well can be secured by using a storm valve See Figure 70. This valve is run above a retrievable packer and serves both as a means of sealing off the drillpipe and as a means of releasing the running string. It is a sleeve type valve operated by left hand rotation. As the upper mandrel is backed out of the upper body, it pulls up and closes the valve sleeve. Continued rotation then...

Drilling and Back Reaming Horizontal Directional Drilling

Thu, 10 May 2012 09:01:28 GMT

The following are basic requirements for this stage of the process 1. Drilling mud should be used during drilling and back-reaming operations. Using water alone may cause the bore hole to collapse in unconsolidated soils, while in clays the use of water may cause swelling and subsequent jamming of the product. 2. Heaving may occur when attempting to back-ream too large of a hole. This can be avoided by using several pre-reams to gradually enlarge the hole to the desired diameter. 3. A swivel...

Recommended Flange Bolt Torque 1 DrillingProcedures

Thu, 10 May 2012 04:29:32 GMT

API Specification 6A seventeenth edition 1996 It should be recognised that applied torque to a nut is only one of several ways to approximate the tension and stress in a fastener. The following table 15.c is for the convenience of the user only, and is based on calculations which assume certain friction coefficients for the friction between the studs and nuts, and between the nuts and the flange face. Two coefficients of friction are used in the table 0.13 approximates the friction with...

Compton Scattering DirectionalDrilling

Thu, 10 May 2012 04:08:56 GMT

Compton scattering refers to the particle-like interaction between a gamma ray and a free electron. The outcome of scattering between a gamma ray and an electron is governed by the laws of conservation of energy and momentum. Basically, these laws establish limits on the possible outcomes of the interaction. The best analogy to Compton scattering is that of a collision between two billiard balls. In such a collision, a ball moving at some velocity collides with a second ball that can be...

Lithology Correction DirectionalDrilling

Thu, 10 May 2012 04:06:49 GMT

Corrections are required for lithologies other than limestone. In addition to limestone the main lithologies that are encountered in logging are sandstone and dolomite. Although the presence of hydrogen in the pore space of the rock is the primary variable in neutron porosity measurements, the moderating effects of the rock type can be significant, amounting to several porosity units above or below the porosity that would be computed were the rock a limestone. The sandstone correction is...

API RPlb TB EEC bD Drilling Risers Systems

Thu, 10 May 2012 03:38:53 GMT

inertia effects are not included. Also excluded from the hydrodynamic calculation is the relative velocity of the riser passing through the water. The wave and vessel motion are stepped past the riser, the static solution is calculated for each step, and the maximum values of the critical parameters are observed over one wave period. There are two different approaches for solving the equations while including dynamics and relative velocities. A time domain solution is the more direct and...

Choke Manifold Pressure 1 WellControl

Thu, 10 May 2012 03:00:55 GMT

Ph 5200 psi in annulus PUMP AT KILL RATE HOLDING CONSTANT KILL LINE PRESSURE READING CHANGE IN BHP 0 psi increase SECTION 1 FUNDAMENTAL PRINCIPLES OF WELL CONTROL It is extremely important to note that regardless of which method is used, they both accomplish the goal of maintaining constant bottom hole pressure equal to formation pressure, just as would be the case were CLFL absent. This is done without the need to alter any calculations on the kick sheet. Thus initial and final circulating...

Viscosifying Agents DrillingFluids

Thu, 10 May 2012 00:17:36 GMT

The material used to maintain viscosity in the packer fluid will vary with the type of fluid used. Bento-nite, of course, is a viable and inexpensive choice for use in fresh water fluids. Several polymers are available for use in the clear brines as well as in fresh water. CMC and polyacrylonitriles may be used, but polymers such as xanthan gum, HEC and other starch derivatives are frequently chosen, because they are partially or completely acid soluble. This acid solubility enables the...

Advanced Rheology and Suspension Analysis DrillingEquipment

Wed, 09 May 2012 22:53:58 GMT

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...

api RPib la GTasai dsimase t Drilling Risers Systems

Wed, 09 May 2012 22:35:15 GMT

The tensioner system should be designed to permit one unit to be out of service for maintenance or repair without jeopardizing the ability of the remaining tensioner units to provide the required tension to the marine drilling riser. A unit may be either a single tensioner or a pair of tensioners, depending on specific design. g. Maximum Tension Setting. The maximum tension setting should not exceed 90 of DTL so that the maximum tension, including dynamic variations, will be less than the DTL....

RIGTRAllM Goc WellControl

Wed, 09 May 2012 20:17:16 GMT

Riser Margins. A riser margin is the minimum additional mud weight that can be used to compensate for the loss of mud hydrostatics in the riser being replaced by sea water hydrostatics, if the riser was disconnected, or the connector failed. See Figure 4 If the river was disconnected, bottom hole pressure would be reduced by 64 psi. To compensate for this reduction in pressure a mud weight of 12.17 ppg would be required. Figure 4 Floating Rig, Riser Margin Figure 4 Floating Rig, Riser Margin

Zinc Bromide DrillingEquipment

Wed, 09 May 2012 19:30:44 GMT

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...

Jet Nozzles 1 DrillingEngineering

Wed, 09 May 2012 19:14:53 GMT

There are essentially three types of jet nozzles used in tri-cone bits. Shrouded nozzle jets provide maximum protection against retainer ring erosion, excessive turbulence or extended drilling periods. Standard jet nozzles are easier to install and are recommended for situations where erosion is not a problem. Air jet nozzles see above are used on bits designated for drilling with air or gas. Nozzle sizes play an important role in bit hydraulics. The benefits of the correct selection include...

Info Pzd WellControl

Wed, 09 May 2012 17:47:02 GMT

Flared Orifice entrance reduces erosion on the entrance surface. Accuracy levels are maintained over extended periods of use. Choke beans save time and money because replacement intervals are extended. Cameron K choke beans come in two styles, positive and combination. The positive bean has a fixed orifice diameter. The combination bean has a fixed diameter and a throttling taper at the entry. The combination bean is used with an adjustable choke needle to make incremental changes to orifice...

Abnormal Pressure 1 WellControl

Wed, 09 May 2012 17:05:13 GMT

Abnormally high formation pressure is defined as any formation pressure that is greater than the hydrostatic pressure of the water occupying the formation pore spaces. Abnormally high formation pressures are also termed surpressures, overpressures and sometimes geopressures. More often, they are simply called abnormal pressures. Abnormally high formation pressures are found worldwide in formations ranging in age from the Pleistocene age approximately 1 million years to the Cambrian age 500 to...

General Guidelines Yok DrillingProcedures

Wed, 09 May 2012 17:00:50 GMT

1 The Well programme will define the 30 casing string assembly including the type of connections, mudline landing ring space out and mudline landing ring final position. It is recommended to weld the 30 landing ring in such a way that its final position is at least 5m below the seabed with the squnch joint releasable connection at least 2m above the seabed Refer to figure 15.n . A driveable Remote Releasable Connection may be installed on the landing joint which avoids sending divers to the sea...

Testing The BOP Stack DrillingProcedures

Wed, 09 May 2012 16:55:45 GMT

1 Retrieve the 18 4 nominal seat protector. Do not land the test plug on the seat protector since test pressure will force the protector down, swedging it into the housing. 3 Fill the running string to the top with water. The string must remain open to atmosphere during the entire test. 4 Pressure test the BOP stack as per Eni-Agip Division and Affiliates Well Control Policy using either one of the two pods. A BOP function test must then be performed on the other pod.

I The Chronological Basis Of Field Development DrillingOperations

Wed, 09 May 2012 16:32:52 GMT

The development of a field from initial exploration through evaluation and into subsequent development can vary substantially in length depending upon the size of the field, its complexity and the environment in which the field is likely to be developed. In some cases, particularly onshore, the cost of drilling exploration wells and conducting evaluation activities is relatively low and therefore it becomes Figure 1 Chronological basis of field development sometimes more easy to complete the...

Si Sy PetroleumEngineering

Wed, 09 May 2012 16:10:49 GMT

The following restrictions and assumptions will be made 1. K 2. This means that the cable tension at the start of the pickup stroke is sufficient to give the tools an upward acceleration of g. , 2. The upper limit for G is fixed at 1325 D. This is arbitrarily chosen as the limit imposed by bit life between sharpenings, and must be evaluated for different formations from field experience. 4.18 Work per unit time GN 1325 DN The input horsepower to the formation may therefore be expressed as If it...

Nrms And Krm Model No Shale Shakers Drilling Fluid Systems

Wed, 09 May 2012 15:21:28 GMT

NRM-1M-S or NRM-H5-S. MoJcl uni Mied J-hJe ihaL-cri IncJudt As filitidard cLj ii inlciit Siireen lien with 20 30 njesh r inleM sied ciath and tension nirmlwrt V-belt w'uti vihr tor iheive ne f cemIained, aL'ifi mounlid, tmld c lIrditle failli k IK Iwa-wiy anriet nnJ flow dijtrihiLt iij Sumt with L t i .il 1 MiS'iiiMTt for tltcfric m.M r, stt ,jm tu rliin or enijTnf. Domesti inrj Cn rrittlsn prie irr F. .B- deflgHUd point . E pe gt rt prictl Ar PJL Kl deJigmated peint , p e d for f. iwl. ICI AND...

Pressure Equalizing 1 DrillingGuide

Wed, 09 May 2012 14:45:14 GMT

GRADING OF WORN ROLLER BITS Reporting Wear in Eights Degree of tooth v new dullness Ti tooth height 7a gone tooth height V4 gone tooth height 3 8 gone tooth height 7 gone tooth height gone tooth height 3 4 gone tooth height 78 gone tooth height all gone NOTE If any one row has a majority of teeth broken, add the letters BT BEARING CONDITION check the worst cone B1 bearing life used 7 B2 bearing life used 7, tight B3 bearing life used B4 bearing life used 72 medium B5 bearing life used B6...