Ram Blowout Preventers
Ram type BOPs are the most common type of blow out preventers. This section looks at three common types in use Shaffer 'SL', Cameron 'U' and Hydril 'V'. API RP53 requirements state that surface rams must close within 30 seconds. Subsea rams must close within 45 seconds. The Cameron 'U' BOP is a ram type preventer designed for both land and subsea operations. U BOP rams are pressure energising.
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...
Freeing stuck pipe
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...
Hydrostatic Pressure
Hydrostatic pressure is defined as the pressure due to the unit weight and vertical height of a column of fluid. Hydrostatic Pressure Fluid Density x True Vertical Depth Note It is the vertical height depth of the fluid column that matters, its shape is unimportant. Since the pressure is measured in psi and depth is measured in feet, it is convenient to convert mud weights from pounds per gallon ppg to a pressure gradient psi ft. The conversion factor is 0.052.
Shear Rate vs Shear Stress
It describes the thickness or pumpability of the fluid, and is somewhat analogous to the apparent viscosity. The flow behavior index n indicates the degree of non-Newtonian characteristics of the fluid. As the fluid becomes more viscous, the consistency factors k increases as a fluid becomes more shear thinning n decreases. When n is 1 the fluid is Newtonian. If n is greater than 1, the fluid is classed as Dilatant the apparent viscosity increases as the shear rate increases.
SaltBased Muds
To eliminate confusing terminology, any references to the term salt in this manual will herein refer to sodium chloride, unless otherwise stated. Therefore, salt-based muds are muds containing varying amounts of predominantly sodium chloride ranging from 10,000 mg L NaCl up to saturation, 315,000 mg L NaCl. However, when referring to chloride ion concentration which is colorimetrically titrated and reported on the Drilling Mud Report, chlorides will mean chlorides from any source such as...
Kick Detection And Precautions To Take While Drilling
a First indication of a kick while drilling would be an increase in flow rate. b If the increase in flow rate is not picked up then the second indication of a kick would be a pit level increase. c While drilling the horizontal section mixing chemicals or slow addition of mud into the active system should be avoided 5.9.2 KICK DETECTION AND PRECAUTIONS TO TAKE WHEN MAKING CONNECTIONS. a The equivalent circulating density is relatively higher when drilling high angle wells. While drilling, the...
Energy Conversion Factors
Energy conversion efficiency (η) is the ratio between the useful output of an energy conversion machine and the input, in energy terms. The input, as well as the useful output may be chemical, electric power, mechanical work, light (radiation), or heat. We assume that one litre water at 4 °C and 1 Atm.(=101.3 kPa=14.7 psi) equals one dm 3water at 4 2C and 1 Atm. although we know this is not exactly Ihe same. We take this liberty because it helps simplifying our calculations.
Substructurepipe setback load capability
This must be sufficient to take the full drillstring stood back in the derrick whilst the heaviest string of the casing is being run. Again, in most cases, this will be the production string. It is not acceptable to have to lay out drillpipe to allow casing to be run as we never know when the casing might need to be pulled and the hole reconditioned with a bit and BHA. 2.4 BOP size, type, number and rating In chapter 3, we defined minimum BOP requirements for each well type. With this basic...
Drilling and Back Reaming
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...
Abnormal Pressure
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.
The Wait And Weight Method
The Wait and Weight is sometimes referred to as the 'Engineers Method' or the 'One Circulation Method'. It does, at least in theory, kill the well in one circulation. Once the well is shut in and pressures stabilised, the shut in drill pipe pressure is used to calculate the kill mud weight. Mud of the required weight is made up in the mud pits. When ready, kill mud is pumped down the drill pipe. At commencement, enough drill pipe pressure must be held to circulate the mud, plus a reserve...
Drilling or connection tonmiles
The ton-miles of work performed in drilling operations is expressed in terms of work performed in making round trips. These are the actual ton-miles of work involved in drilling down the length of a section of drill pipe usually approximately 30 ft plus picking up, connecting, and starting to drill with the next section. To determine connection or drilling ton-miles, take 3 times ton-miles for current round trip minus ton-miles for previous round trip where Td drilling or connection ton-miles...
Calculating Maintenance and Treatment Requirements for an Active Mud System
A mud system during drilling and circulation is undergoing continual change. Because of the change, the mud must be treated to maintain its desired properties. jn order to make the most economical treatments, it is important to know the current component concentrations, and based on assumed or calculated losses, be able to calculate the amounts of materials required to maintain the system. Utilizing material balance techniques, it is possible to estimate the quantities of materials needed to...
Design Radius of Curvature
Determining the entry and exit points, the depths that must be achieved, and direction changes for the drill path are all major parts of the planning process. One of the keys to these calculations is the bend radius of the drill rod and or the product pipe. Bend radius is often misunderstood. It is often confused with the number of feet needed to make a 90-degree turn.
Gm Power Unit For Centrifuge
Inquire for Rental, Lease, and Purchase DAHLORY standard and custom designed Cuttings Washing Equipment is being used with excellent results in the Gulf of Mexico, off the coast of California - any area where contamination is a problem. Oil and Water Separators can be supplied if required to process the waste water from the Cuttings Washing Unit, the working floor and other hosed down areas. DAHLORY Hi-Angle Shaker, available in single or dual models, incorporates the following advantages and...
Commercial Bentonite
Commercial bentonites used in drilling muds are naturally occurring clays and are mined in many areas of the world. They contain the clay mineral smectite and may contain accessory minerals such as quartz, mica, feldspar and calcite. Smectites are three-layer swelling clays of which the most predominant form is calcium, but also sodium. Because smectites have the ability to swell hydrate in the presence of water, these bento-nites are used to viscosify drilling fluids. Sodium bentonite, found...
Subsea applications
In subsea applications the hydrostatic pressure exerted by the hydraulic fluid must be compensated for in the calculations Example Same guidelines as in surface applications Hydrostatic pressure of hydraulic fluid 445 psi Adjust all pressures for the hydrostatic pressure of the hydraulic fluid Pre-charge pressure 1000 psi 445 psi 1445 psi Minimum pressure 1200 psi 445 psi 1645 psi Maximum pressure 3000 psi 445 psi 3445 psi Determine hydraulic fluid necessary to increase pressure from pre-charge...
Lost Circulation
Lost circulation is potentially one of the most expensive problems in drilling because of the large quantities of drilling fluid that can be lost before losses are cured or reduced to an acceptable level. Lost circulation does not necessarily imply total losses and includes partial or seepage losses. The range of lost circulation problems extends from shallow unconsolidated sands, to well consolidated formations that can be fractured by the hydrostatic pressures imposed upon them by the...
Contractors expenditure
Before looking at how the contractor can make money from a contract, his expenses should be understood. These costs can be broken down into 11 groups. If the contractor can, by manipulating the contract, get the operator to assist in any of the above expenses, then the contractor's profitability will increase. This concept must be fully understood by the operator to ensure that he is aware that what seems a small concession by the operator, could increase the contractor's profitability...
Sample Catcher
Sample catchers are usually required for any air and gas drilling operation. The sample catcher allows small rock cutting samples to be obtained from a well during the drilling operation. The sample catcher is installed in the body of the blooey line usually near the entrance to the blooey line see Figure 2-14 . Figure 2-16 shows a typical sample catcher design. This design has a small diameter 2 inch nominal diameter or smaller transport pipe welded through the blooey line body. A short...
Formation Pressure Tests
Two methods of testing Equivalent mud weight test Precautions to be undertaken before testing 1. Circulate and condition the mud to ensure the mud weight is consistent throughout the system. 2. Change the pressure gauge if possible to a smaller increment gauge so a more accurate measure can be determined. 4. Begin pumping at a very slow rate 1 4 to 1 2 bbl min. 5. Monitor pressure, time, and barrels pumped. 6. Some operators may have different procedures in running this test, others may include...
Basic solids analysis calculations
NOTE Steps 1 4 are performed on high salt content muds. For low chloride muds begin with Step 5. Step 1 Percent by volume saltwater SW SW 5.88 x 10-8 x ppm Cl 12 1 x by vol water Step 2 Percent by volume suspended solids SS SS 100 by vol oil by vol SW Step 3 Average specific gravity of saltwater ASGsw ASGsw ppm Cl 095 x 1.94 x 10-6 1 Step 4 Average specific gravity of solids ASG ASG 12 x MW by vol SW x ASGsw 0.84 x by vol oil Step 5 Average specific gravity of solids ASG ASG 12 x MW by vol...
Gas Kick In Horizontal Section
A Gas will not migrate if hole angle is 90 degrees or greater. b Gas will not migrate if it is dissolved in oil based mud. c Gas maybe trapped in undulations or washouts or in hole sections which are greater than 90 degrees. d If gas cannot be removed from inverted sections then consider bullheading gas into formation. e Slow circulating rates which give a flow rate greater than 130 ft min while circulating gas out of horizontal section should be considered. Flow rates lower than this may not...
Rig Sizing and Selection
Drilling rigs are used to drill the hole, lower and cement casing in the well, and provide a means to perform various auxiliary functions such as logging and well testing. Today's rigs are complicated and require highly experienced, trained personnel for efficient operations. If improperly selected, the rig can be the cause for low penetration rates, formation damage from poor solids control, and high ultimate well costs. In past years, rig selection was often based on footage rating. A...
Optimized rotary drilling performance and minimized bit wear
Schlumberger PowerPak steerable motors offer high performance drilling and predictable trajectories. Over three decades of knowledge and experience in directional drilling were utilized to engineer the motor components with a focus on reliability. The PowerPak motor is composed of four sections including the top sub, power section, surface adjustable bent housing, and bearing section. The top sub can be a standard crossover, dump valve, float sub, or flex sub. Dump valve or float sub features...
Example Drillpipe Tension
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...
Concepts of Petroleum Geology and Basic Rock Properties
Petroleum is not found in underground lakes or rivers, but it exists within the void space of certain rocks. Unfortunately, these oil-bearing rocks are a definite minority, and the determination of their whereabouts is the basic problem confronting geologists and geophysicists. The mechanism of the origin and accumulation of petroleum is not completely understood and is the subject of much controversy. However, a great deal has been learned about the habitat of oil and gas, i.e., the nature of...
Burn Pit Oil And Gas
Figures 2-1 and 2-14 show the burn pit at the exit end of the blooey line. The burn pit should always be located away from the standard mud drilling reserve pit water storage for an emergency mud drilling operation . This design of pit location prevents any hydrocarbon liquids from flowing into the reserve pit, thus, preventing reserve pit fires near the rig. The burn pit is located downwind from the drilling rig. Such a location keeps the smoke and any dust from the drilling operation from...
Weighted Cement Calculations
Amount of high density additive required per sack of cement to achieve a required cement slurry density wt x 11.207983, . ,, n - wt x CW - 94 - 8.33 x CW where x additive required, pounds per sack of cement Wt required slurry density, lb gal SGc specific gravity of cement CW water requirement of cement AW water requirement of additive SGa specific gravity of additive Additive gal 94 lb sk Gravity Example Determine how much hematite, lb sk of cement would be required to increase the density of...
Sand Content
This simple test is used to determine the volume percent sand-sized particles in a mud. The information is used to make adjustments in solids control equipment. Sand causes excessive wear on mixing equipment, drill string, and on pump parts. The sand content in a mud system is estimated by wet screen analysis using a 200-mesh 74-micron screen. It should be recognized that it is a size-classification of particles and other products, such as lost circulation materials LCM , lignite,...
Cable Tool Drilling
The first oil well in the United States was drilled with cable tools in 1859 to a depth of 65 feet. This was the historic Drake well located near Titusville, Pennsylvania it is credited with having started the American petroleum industry. The cable tool also called churn or percussion drilling method, however, did not originate in this country, but is believed to have been employed first by the early Chinese in the drilling of brine wells.1 In this method, drilling is accomplished by the...
Soil Conditions
For HDD purposes there are two broad soil types nonreactive, which consists of sand, silt, and gravel and reactive, which consists of clay and shale. For nonreactive soils and rock the best drilling fluid to use is bentonite clay -based. The bentonite will assist with filtration control, cutting suspension and removal of the slurry, and supporting the bore hole. For reactive soils and rock, use polymer-based drilling fluids. This will slow down swelling, clean the drill bit, and help with the...
Types of Base Oils Used
In many areas, diesel is used to formulate and maintain oil muds. In remote areas where diesel may not be plentiful, crude oil can be used instead of diesel. Crude oils should be tested prior to their use, since they may pose safety problems. Mineral oils and the new synthetic fluids are replacements for diesel, especially because of their lower toxicity compared to diesel. However these fluids are usually higher in cost compared to diesel. There are a wide variety of oils available for use in...
Principal Additives of KCl Polymer Muds
KCl-Polymer Muds with low KCl concentrations typically 3-5 wt and low densities are easy to maintain when drilling harder formations. However, when increased densities are required, mud composition is more complicated and mud properties are more difficult to control. Materials and concentration ranges for KCL-Polymer Muds are listed in Table 32. Not listed is poly propylene glycol , or PPG, such as DCP-208, which is gaining increasing popularity as an inhibitor aid. This low-molecular weight...
Flanges And Ring Gasketsapi A
1.13.1 Flange type connections are 6B or 6BX The flanges are manufactured to meet the API specifications and pressure ratings with a corrosion resistant ring groove machined in the flange face. The 6B type flange is not designed to have face to face make up, but relies on bolt torque to ensure a seal. This type of connection requires periodic bolt torque checking. So it is either through-bolted or stud bolt design. R and RX Gaskets are interchangeable The R or RX type ring gaskets will fit the...
Tiedback liner
For a high pressure well, the intermediate string may simply be unable to withstand the tubing leak at surface pressures, acting in the burst mode. The solution to this problem is to run a full string of pipe to surface. Within the full string choice are two options. Firstly, to run a full string of casing, and secondly, to run a liner and tie it back. The following facts should be considered 1. Running a full string is easier, faster and hardware can be cheaper. 2. If, when running a full...
Density Mud Weight
Density is a measure of the weight of the mud in a given volume, and is frequently referred to as mud weight. The instrument used to measure density is the mud balance (see Figure 1-6). The instrument consists of a constant volume cup with a lever arm and rider calibrated to read directly the density of the fluid in lbs gal (water 8.33 lbs gal) and pressure gradient in psi 1000 ft (water 433 psi 1000 ft) or pounds per cubic foot (water 62.4 lbs ft). Effect of Particle Size and Shape on Surface...
Mud Weight Marsh Funnel Viscosity And pH
A MUD WEIGHT OR DENSITY TEST Theory The density of the drilling fluid must be controlled to provide adequate hydrostatic head to prevent influx of formation fluids, but not so high as to cause loss of circulation or adversely affect the drilling rate and damaging the formation. Normal pressure gradient by water is equal to 0.433 psi ft and equal to 433 psi 1000 ft. The Baroid Mud Balance as shown below is used to determine density of the drilling fluid. The instrument consists of a constant...
Rig Site Preparation
After the geological location for the well has been selected, the surface site for the rig must be acquired and prepared. Rig site preparation will vary for land, marsh, and offshore operations. Some sites require minimum time and effort while others may involve significant costs that often exceed the actual cost for drilling the well. Rig site selection and preparation involve the efforts of many groups within the operating company. A typical scenario of the groups and actions is as follows...
Api Minimum Wall Thickness Requirement Chart
Calculate the internal yield burst pressure for 26.40-ib ft, N-80 grade, 7.625-in. pipe. Assume it has a wall thickness t of 0,328 in. Use the API minimum wall thickness factor of 0,875, Recalculate the results and use 95 wall thickness. 1. The internal yield pressure burst is calculated with Eq. 11.3 2 80,000 psi 0.328 in. 7.625 in, 6,022 psi 6,020 psi 2. Recalculate the results with a 95 wall thickness Where pipe will be used in sour gas service, it often must be rolled wilh a large wall...
Subsea Control Pods
The subsea control pods contain the equipment that provides the actual fluid transfer from the hose bundle to the subsea stack. A typical pod assembly Fig 9.14 consists of three sections - an upper female receptacle block permanently attached to the lower marine riser package a lower female receptacle permanently attached to the BOP stack Control fluid enters the pod at the junction box and is routed either direct to an SPM valve or to one of the two regulators one for the BOP rams and one for...
Blowout Preventer Control Systems
Foreman C. Jim Stewart amp Stevenson, Inc. Next to the blowout preventers, the most important component for well control in floating drilling is the system that monitors and controls the behavior of the subsea BOP s from the drilling rig. From 1955 to 1963, the control system design used in subsea drilling was basically a land rig or closed-type system. A hydraulic power unit provided fluid to a shipboard mounted control valve manifold. Hydraulic power lines were...
Table Common Brine Systems
Potassium chloridc K.Ci Sodium chloride NaCl Calcium chloridc CaCE Calcium bromide CaBr, Three-Salt Brines Calcium chloride calcium bromide zinc The potassium ion is particularly effective at plugging the clay lattice to minimize hydration of formation clays, as shown in Fig. 8-7. A sodium chloride system NaCl is probably the most common brine water used in drilling, completion, and workover operations due to its availability. The maximum density for a sodium chloride brine is 10.0 lb gal at 60...
Nonmagnetic Drill Collars
The primary purpose of non-magnetic drill collars is to reduce the interference of the magnetic fields associated with those sections of the BHA which are both above the below the magnetic compass contained in the survey tool with the earth's magnetic field. The non-magnetic collars reduce this type of interference by moving the BHA sections away from the survey compass. There are four critical factors in selecting non-magnetic collars 1 their total length, 2 the location of the survey compass...
Friction Factors
Coefficients of friction between the drill string and drill hole with unknown cuttings bed packing, which are often called friction factors, have been reported in the range of 0.24 to 0.28 by north sea operators. Gravity pulls pipe and BHA's only toward the center of the earth. Friction between the wall of the hole and the drill string vanishes becomes zero during the rotation of the drill string. All of the weight of any part of the drill string which is in a hole where the inclination is 90...
Cost Per Foot Equation
The cost per foot equation is used for the comparison of alternative equipment, chemicals, and procedures for the drilling of a formation or an interval. The comparisons are often called break-even calculations and are usually between drill bit types or manufacturers however, any of the variables may be compared. Bit Tools Mud Drill Time Trip Lost Rig Support Tool Rental C Drill Rate Drill Time C Cost per foot for the interval of concern ft Bit Cost of delivered bit at the drill site Tools Cost...
Drill Pipe Yield Strength and Tensile Strength
If drill pipe is stretched, it will initially go through a region of elastic deformation. In this region, if the stretching force is removed, the drill pipe will return to its original dimensions. The upper limit of this elastic deformation is called the Yield Strength, which can be measured in psi. Beyond this, there exists a region of plastic deformation. In this region, the drill pipe becomes permanently elongated, even when the stretching force is removed. The upper limit of plastic...
Oil Well Cementing Properties And Functions
The cement used for oil well cementing differs from concrete or masonry work in that it consists of a thin slurry of primarily cement and water. The cement used in oil wells must possess three primary properties. They must possess a proper water-to-cement ratio, a sufficient fluid time to allow placement, and must develop enough strength in a minimum time to bond the pipe to the formation. Hydration reaction with water begins when water is added to cement. The cement slurry gradually sets to a...
Pulling Force
Most HDD crossings are comprised of a combination of straight sections and bends, and Equations 7-4 and 7-5 have to be applied to each straight section and bend in the bore hole. The corresponding loads may be estimated by the following equations. For calculating the estimated peak force on the product pipe the load is calculated at four points, as shown in Figure 7-1. The greatest load will be experienced at point 4. The loads may be estimated by using the following equations T1 exp Va a Va w...
Drill Pipe Classification
Drill pipe class defines the physical condition of the drill pipe in terms of dimension, surface damage, and corrosion. Drill pipe class is indicated by paint bands on the drill pipe according to the following code Class 1 drill pipe is New and therefore the strongest. As pipe is used, the wall thickness will be gradually reduced. This reduction of the drill pipe cross sectional area results in a lower Total Yield Strength in pounds. This yield strength in pounds can be calculated using the...
HDD Risk Identification
Potential risks that are a part of all HDD projects include a failure to complete the bore, safety of the public and workers, environmental issues, damage to surface structures, and striking other underground structures. Risk reduction is the attempt to identify potential risks during the planning and design phase so that they may be eliminated or reduced. A risk contingency plan is often used by the engineer and or contractor to help identify the major risks and develop general plans and...
Waste Management and Disposal
The drilling-fluid program should address environmental issues concerned with the discharge of drilling fluid, products, and removed solids. Personnel managing the solids-separation equipment must be very familiar with this part of the drilling-fluid program and have a good understanding of governmental regulations and operator requirements. Many drilling operations have strategies in place for drilling-fluid recovery and will have established some general guidelines for the disposal of...
Extracting the core
Only coventional coring will be dealt with in this section as other techniques have specialised handling methods. The details of the operation are available in any coring manual. The salient point regarding the core is to ensure that it is placed the right-way-up in the core catching trays, with the minimum of breakage or spillage. Pieces of core should be raked up using a hammer or shovel. The line of vision between the Driller and the Coring Engineer should be uninterrupted at all .times to...
Metamorphic rocks
Metamorphic rocks can be formed from sedimentary, igneous or previously existing metamorphic rocks. Metamorphism is the change from one state to another. Rocks that have been metamorphosed have undergone at least one of two processes. These are change in temperature and change in pressure. The pre-existing rock's chemistry may change due to partial melting and either loss or gain of chemical components. The gain of components usually involves the addition of water, i.e. mineral hydration,...
Annulars Hydril Gk
The 'GK' annular preventer is designed for surface installations and is also used on offshore platforms and subsea. Standard operation requires both opening and closing pressure. Seal off is affected by hydraulic pressure applied to the closing chamber, which raises the piston, forcing the packing unit into a sealing engagement. Main features include Only two moving parts piston and packing unit mean few areas are subjected to wear. The BOP is thus safer and more efficient requiring less...
Accumulator Types
Two types of accumulator are in common use bladder type and float type Figure 47 . They each have a total capacity fluid nitrogen bladder float of 11 gallon although 15 gallon versions are also available. Cameron float type accumulators are available with up to 35 gallon capacity. The volume occupied by the float or bladder is usually taken to be 1 gallon. The bladder type accumulator contains a rubber bladder that separates the nitrogen from the stored hydraulic fluid. The gas is injected into...
Toxic Components in Drilling Fluids
Because formulations for mud additives are continually undergoing change, the Drilling Representative should be aware of certain additives that are considered toxic. EPA priority pollutants include various trade metals zinc, chromium, lead, mercury, cadmium, nickel, asbestos, and various phenol compounds. Chromium is a highly controversial issue the EPA defines toxic chrome as Cr 6 or in a hexavalent state . In drilling fluids, the chrome exists in a trivalent state Cr 3 and the process to...
Authorisation For Expenditure Afe
The AFE is the tool that is used for predicting the cost of a proposed well. The accuracy of the AFE depends on the amount of available information used to construct it. As operators, we need to know how much a well is going to cost if it is dry, tested or completed. Consequently, AFEs should be broken down into sections to fllow us to see at a glance how the various well options compare financially. In this section, we look at the component parts of AFEs for onshore and offshore wells. At Nor...
Well Logging
A well log may be defined as a tabular or graphical portrayal of any drilling condition s or subsurface feature s encountered which relate to either the progress or evaluation of an individual well. The records of core analysis data vs. depth, shown in the last chapter, are often called core logs. This chapter will discuss the following common logs and introduce the general subject of electric and radioactivity log interpretation. 1. Driller's logs including drilling time In the early days of...
Standard Drill String
Figure 3-1 shows a schematic of a standard rotary drill string used to drill deep boreholes with direct circulation. Such a drill string would be used on large drilling rigs. At the bottom of the drill string is the drill bit. The drill bit is threaded made-up to a bit sub. The drill bit has a male thread or threaded pin pointing up. The bit sub is a short thick wall pipe that has a female thread or threaded box on both ends. Above the bit sub are the drill collars. Each of the drill collars...
Rotary Drilling
Rotary drilling is a method used to drill deep boreholes in rock formations of the earth's crust. This method is comparatively new, having been first developed by a French civil engineer, Rudolf Leschot, in 1863 3 . The method was initially used to drill water wells using fresh water as the circulation fluid. Today this method is the only rock drilling technique used to drill deep boreholes greater than 3,000 ft . It is not known when air compressors were first used for the drilling of water...
Functions Of A Drilling Fluid
Functions of a There are a number of functions of a drilling fluid. The more basic of Drilling Fluid these are listed below 2. Carry cuttings and sloughings to the surface 4. Cool and lubricate bit and drill string In addition to these functions, there are several other functions with which the drilling fluid should not interfere Functions of a Clearly, these lists of functions indicate the complex nature of the Drilling Fluid Clearly, these lists of functions indicate the complex nature of the...
Properties of oil base mud
Apart from the standard properties that are also measured for water base muds ref. pag. 2-4 of this section oil base muds require some special properties. The electrical stability of an IOEM is a measure of the voltage required to initiate the flow of an electrical current through the mud. A change in electrical stability normally represents a change in the emulsion stability of the mud. Several parameters determine the absolute value of electrical stability - Total water content and emulsion...
Oil Base and Synthetic Base Muds Nonaqueous Fluids Testing
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...
Drilling Fluids And Reynolds Number In Relation To Marsh Funnel
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...
Oilbase Drilling Fluids Technology
Oil-base drilling fluids have been developed to overcome certain undesirable characteristics of water-base muds. These deficiencies are primarily due to the properties of water specifically, its abilities to dissolve salts to interfere with the flow of oil and gas through porous rocks to promote the disintegration and dispersion of clays and to effect corrosion of iron. In addition to providing a means for avoiding these objectionable features of water muds, oil muds offer potential advantages...
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...
Percent Solids By Weight
Fig. 2.15-Effect of clay concentration on viscosity of fresh water.3 Water is the basic component of most drilling fluids. Many wells are begun using the natural water available in the area. As drilled solids become entrained in the water, a natural mud is formed. Some clays hydrate readily in water and greatly increase the viscosity of the mud. This increase in viscosity enhances the ability of the drilling fluid to carry the rock cuttings to the surface, especially in the larger hole sizes...
PDC Bit Operating Parameters
PDC bits do not have the benefit of the self fluid-cleaning action between rows of teeth like roller cone bits, so they must rely on the bit's hydraulics to flush the cuttings from under the bit to prevent balling. This is accomplished with strategically positioned converging-diverging nozzles which maximize cleaning while minimizing erosion of the body near the nozzle area. Optimum hydraulic range is between 2.0 to 4.0 hydraulic horsepower per square inch. The interchangeable jet nozzles come...
Air Rotary Drilling Kern County California
Solids Content of Drilling Mud Volume Percent Figure 2-9. Effect of solids on drilling performance. From World Oil. Further studies96 led to the introduction of a bentonite extender polymer for the preparation of a low-solids, fresh-water mud. This mud was composed of about 3 by weight of bentonite, 0.01 polymer and 0.05 soda ash. A five-well test program in Wood County, Texas, showed the effect of solids content on drilling progress, as illustrated in Figure 2-9.9 7 In a later report,98 the...
Hollow Stem Auger Sampling in Unsaturated Materials
Core sampling through the hollow-stem auger in unsaturated materials is a relatively simple process. Unlike the problems of loose material left in the hole when solid-stem augers are pulled, the hollow-stem auger remains in the ground to act as a casing and hold out any potential caving materials. The only loose material remaining in the hollow-stem auger-drilled hole is 2-3 in. of material loosened by the pilot bit, that has not been moved up the auger flight. The method for sampling through...
Annular Preventers
API RP53 state that surface annular preventers closing times should not exceed 30 seconds for smaller than 18 3 4 and 45 seconds for 18 3 4 and larger. Subsea annular preveters should not exceed 60 seconds. Shaffer annular BOPs are rugged, compact and will seal on almost any shape or size- Kelly's, drill pipes, tool joints, drill collars, casing or wireline. They also provide positive pressure control for stripping drill pipe into and out of the hole. The annular BOP is one of the first lines...
Fail Safe Valves
These valves are usually mounted in pairs on both the choke and kill lines. They are opened hydraulically from the surface 0.6galls of fluid is typically required but once the opening pressure is released, spring force automatically forces the gate valve closed. In deep water operations, the hydrostatic head of fluid in the opening line tends to open the valve. Some designs counter this be incorporating a system which transmits seawater hydrostatic pressure to an oil chamber on the spring side...
Breakover Point Between Stripping and Snubbing
Example Use the following data to determine the breakover point DATA Mud weight 12.5 ppg Drill collars 6-1 4 in. 2-13 16 in. 83 lb ft Length of drill collars 276 ft Shut-in casing pressure 2400 psi Determine the force, lb, created by wellbore pressure on 6-1 4 in. drill collars Force, lb pipe or collar OD, In 2 x 0.7854 x wellbore pressure, psi Force, lb 6.252 x 0.7854 x 2400 psi Force 73,631 lb Determine the weight, lb, of the drill collars Wt, lb drill collar weight, lb ft x drill collar...
Formulae And Conversion Factors Equation Sheet For Oilfieldfield Units
Mud Weight ppg x 0.052 x True Vertical Depth ft Hydrostatic Pressure in Drill String psi SIDPP psi 8. Initial Circulating Pressure psi 9. Final Circulating Pressure psi 12. Equivalent circulating density ppg Pressure psi True vertical Depth ft 0.052 Pump Output bbls stk x Pump Speed spm Pump Output bbls min Annulus Volume bbls ft SCR psi x Kill Mud Weight ppg Original Mud ppg SIDPP psi TVD ft 0.052 Original Mud ppg Mud Grad psi ft - Influx Grad psi ft x Influx Height ft SIDPP psi Annulus...
Water Base Muds Testing
To accurately determine the physical properties of water-based drilling fluids, examination of the fluid is required in a field laboratory setting. In many cases, this consists of a few simple tests conducted by the derrickman or mud Engineer at the rigsite. The procedures for conducting all routine drilling fluid testing can be found in the American Petroleum Institute's API RPB13B. Density Often referred to as the mud weight, density maybe expressed as pounds per gallon lb gal , pounds per...
Storm Valve
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...
Workshop a Surface
Preventer J Note The well will be killed using the left hand automatic choke. To mud gas separators, pits and diverter lines To mud gas separators, pits and diverter lines i To mud gas separators, pits and diverter lines Remotely operated choke - right hand IP Positive Closing Choke i To mud gas separators, pits and diverter lines Remotely operated choke - right hand IP Positive Closing Choke Questions 1-4 refer to the diagram above. The valves shown are numbered 1 to 15. 1. If all of the above...
Lime Solids and Salinity Calculations
This section describes the calculations for oil mud salinity and solids which only the chloride ion data and which can be used only for oil muds that contain either CaCl 2 or NaCl not both salts mixed together . In the event that a mixed salt type of oil-based mud is to be analyzed, then it is necessary to perform the analysis for the calcium ion and to perform the calculations found in API RP 13B-2, Section 7. The equations used in this procedure can be solved by using a hand calculator, but...
Basics of Shale Shakers
The characteristics of shale shakers are 1 vibratory motion, 2 amplitude and frequency, 3 deck slope and number of decks of screens, and 4 screening area. 1. Vibratory Motion - There are three types of shale shaker screening motion circular, unbalanced elliptical and linear see Figure 11 Each is differentiated by the positioning of the vibrator s with respect to the center of gravity of the deck. Circular motion is produced when the vibrator is placed at the center of gravity of the deck...
Bottoms Up Time
What is the bottoms-up time with one pump operating at 110 SPM a. _min Bottoms up time with one pump operating at 110 SPM is equal to the total annular capacity drill string in the hole divided by the pump output in barrels per minute. In Problem 7, the total annular capacity was calculated to be 802 bbl. .A n n c a p , b b l Q, bb. min
The Whipstock
The whipstock is a steel ramp shaped device which deflects the bit off the cement plug. Two types are popular. One is called a permanent whipstock because it is cemented and left in the hole. The other is called a retrievable because after deflecting the bit off the cement plug it is pulled from the hole. The basic problems which often occur are similar for both types. The first problem is that the whipstock is not set on bottom which allows the bit to drill around the end of the whipstock and...
Buoyed String Weights
Compute the air weight per foot and the total weight of a 8 * 3 * 30' collar. Ws 2.67 * (82 - 32) 146.7 lb ft Ws 2.67 * (82 - 32) * 30 4,400.6 lb The buoyed weight of drill strings is the weight of a drill string which would be indicated if it were attached to a scale and hanging free. The buoyed weight at a point in a drill string is the computed buoyed weight of the components below that point, and is computed as if it were hanging free. It should be noted that tension is not usually equal to...
Non Retrievable
T Tl Electronics Sensors ix Sensors and electronics are integral part of the drill collar. Zero or limited lost-in-hole charges Light, easily transported Lower cost Run or replace on slick line when needed Limited sensors Typically lower reliability Typically multi- High lost-in-hole sensor charges Higher reliability Trip to replace
High Weight Pill
Neal Adams recommended the five steps as depicted in the following sketch for gaining control of an underground blowout. The method is not definitive and the normal kill information will be obscure and un-examinable in most cases. The objective of the method is to use the existing mud in the hole and a high weight pill to terminate gas flow from the kicking formation until the hole is repaired and a higher weight drilling mud is circulated. IIIII1II ' I ' I ' I ' I ' I ' I ' I ' I '...
Casing Tally
An example problem is presented to illustrate the problems encountered in making a casing tally and the subsequent location of centralizers on the casing string. Caution must be exercised in regard to any attempt to set the casing shoe near the bottom of a drill hole. The depth of the bottom of a hole as determined by the strapping of a drill string while in tension or in the derrick may disagree by as much as ten feet with its depth as determined by a casing tally. Logging cables give similar...
Mark C Morgan
Gumbo is formed in the annulus from the adherence of sticky particles to each other. It is usually a wet, sticky mass of clay, but finely ground limestone can also act as gumbo. The most common occurrence of gumbo is during drilling of recent sediments in the ocean. Enough gumbo can arrive at the surface to lift a rotary bushing from a rotary table. This sticky mass is difficult to screen. In areas where gumbo is prevalent, it should be removed before it reaches the main shale shakers. Many...
Sequential Treatment
Solids control equipment should be arranged so that each piece removes successively finer solids as demonstrated in Figure 7-2. Although all the equipment in the following list may not be needed, the most common arrangements are Scalper shakers seldom needed a aaaaaaa a Gumbo is formed in the annulus from the adherence of sticky particles to each other. It is usually a wet, sticky mass of clay, but finely ground limestone can also act as gumbo. Enough gumbo can arrive at the surface to lift a...
A Measuring the pipe stretch under tension
The method is based upon Hooke's Law. Knowing the stretch under a particular tensile load enables the unstretched length to be calculated. This equals the length of pipe between the stuck point and surface. The stretch in the pipe is found with reference to some fixed point which will not move when extra pull is applied where L Length free pipe in metres Wdp Plain end pipe weight in kg m Wdp Plain end pipe weight in lb ft e ins p lbs Reasonable estimates of the depth of the stuck point can be...
Rigsite Determination Of Specific Gravity Of Drilled Solids
If a laboratory balance is not available at the rig site, have a laboratory determine the volume of a pressurized mud balance and stamp the volume, in cubic centimeters, on the cup. For example, assume 240 cc Collect some representative cuttings about 100 g from the shaker screen. Wash the cuttings in distilled water or oil for an oil mud to remove the drilling fluid. Place the shale cuttings in several retorts and remove the liquid from the cuttings. Add the dry cuttings to the cup of the...
Directional Drilling Azimuth Reference Systems
This section discusses the primary azimuth reference systems currently used in directional drilling. This will include True North and Magnetic references with particular detail given to Grid Coordinate systems i.e. UTM, Lambert, Geographic, and Local . A simple field-proven method is also presented to help avoid confusion when converting from one system to another. More than one multi-million dollar directional drilling project has missed its intended target s due to errors and or...
Aqueous Phase Activity AWOM
An oil-based mud which is used to drill water-sensitive shale sections must contain a large amount of salt dissolved in its water phase in order to prevent shale hydration and swelling, otherwise instability of these shales may result. Effective salinity of an oil mud's water phase can be measured as activity by measuring the water's vapor pressure or relative humidity in air. The Activity Test is a simple test that can be used at the rig and is very helpful in oil mud engineering in cases when...
Maximum Safe Dogleg Limits S Drill Pipe
40 60 80 100 120 140 160 180 200 220 240 260 280 300 TENSION IN DRILL PIPE BELOW DOG-LEG, 1000 LB 40 60 80 100 120 140 160 180 200 220 240 260 280 300 TENSION IN DRILL PIPE BELOW DOG-LEG, 1000 LB Safety is the responsibility of everyone associated with the drilling operation. In order to conduct safe operations, contractor and company personnel must clearly understand and effectively discharge their respective responsibilities The drilling contractor is responsible for Implementation of a...
General Types of Additives
Many different products are classified as viscosifiers for clearwater brines, water-based muds, and oil-based muds. The viscosity of a fluid is dependent upon interparticle force size, shape, and number of particles and viscosity of the base fluid. Viscosity Measurements. Fluid viscosities are measured in several different manners at the rig site. The most common procedures utilize the Marsh funnel and the viscosity-gel (VG) meter. These tests evaluate different fluid properties...
Lubricate and Bleed
The lubricate and bleed method involves alternately pumping a kill fluid into the tubing or into the casing if there is no tubing in the well, allowing the kill fluid to fall, then bleeding off a volume of gas until kill fluid reaches the choke. As each volume of kill fluid is pumped into the tubing, the SITP should decrease by a calculated value until the well is eventually killed. This method is often used for two reasons 1 shut-in pressures approach the rated working pressure of the wellhead...
Gaskets Seals And Wellheads Api Type R Ring Joint Gasket
The type 'R' ring joint gasket is not energised by internal pressure. Sealing takes place along small bands of contact between the grooves and the gasket, on both the OD and ID of the gasket. The gasket may be either octagonal or oval in cross section. The type 'R' design does not allow face-to-face contact between the hubs or flanges, so external loads are transmitted through the sealing surfaces of the ring. Vibration and external loads may cause the small bands of contact between the ring...
Depth References
During the course of a directional well, there are two kinds of depths Measured Depth MD is the distance measured along the actual course of the borehole from the surface reference point to the survey point. This depth is always measured in some way, for example, pipe tally, wireline depth counter, or mud loggers depth counter. True Vertical Depth TVD is the vertical distance from the depth reference level to a point on the borehole course. This depth is always calculated from the deviation...
Example Slant Hole Plan
A slant hole is to have a target depth of -5,374 ft mean sea level , a south coordinate of 2,147 ft, and east coordinate of 3,226 ft. The rotary bushing is elevation is 780 ft MSL . The magnetic declination is 6 east. A build gradient of 2 degrees per 100 ft of turn has been selected. Target Depth sub-sea -5,374' Target True Vertical Depth 6,154' Target Departure 2,1472 3,2262 '5 3,875-14' Target Azimuth 90 atan 2,1447 3,226 123,6450 Magnetic Azimuth 123.6450 6.0 129.6450 Select Build Gradient...
Hangoff Procedures During Bad Weather
Whilst 'Waiting on Weather' it might be necessary to hang the drill string off from the wellhead or BOPs. In severe cases, it might also be necessary to disconnect the riser from the BOP stack. The decision to 'hang-off should be taken to allow sufficient time for the bit to be pulled safely into the casing shoe. A natural tendency for the driller to pull up too quickly could perhaps induce swabbing and a possible kick situation later. The preferred method to hang-off the string is to use a...
Stripping
See Figure 1 to Figure 7 1.2.1 General Stripping is an emergency well control procedure. It requires good planning, proper training The primary objective of the stripping operation shall be to maintain a constant bottom hole pressure, thus preventing a build up of excessive borehole pressures or influx from exposed The following are guidelines for carrying out a successful stripping operation a Pressure control is based on a volume balance. This means that for every barrel of pipe stripped in...
Operational procedure stripping
After closing in the well, determine the influx volume and record pressures at two minute intervals. After closed-in pressures have stabilized complete table 1 and further record pressures at five minute intervals or after stripping in each stand. 2. Determine the volume of drilling mud in the OH DC annulus equivalent to one psi one kPa of hydrostatic head i.e. the volume of fluid equivalent to a change of hydrostatic head of one psi kPa . Annular volume per ft bbl ft bbl Mud gradient psi ft...
HDD Design Basics
The planning, design, and construction of HDD projects requires a specialized knowledge of pipeline construction methods and HDD equipment and technology. While Chapter 3 provides information about HDD equipment, this chapter discusses HDD design and installation. The planning and design of a HDD crossing should focus on meeting the requirements of the owner while keeping the project costs as low as possible. Many factors have an impact on HDD costs, but the most important is the crossing...