Articles

Volume Capacity and Displacement

Mud System Volume - The total mud system volume may be calculated with the drill string either in or out of the hole. Total Mud Volume Pit Volume Hole Volume 2. Pump Output Volume - Pump output tables must be adjusted for estimated or measured pump efficiencies. Triplex pumps usually have an efficiency between 90-98 . Double action duplex pumps usually have an efficiency between 85-95 . The following two equations calculate pump output at 100 volumetric efficiency. The constant, K, may be...

Oil Base and Synthetic Base Muds Nonaqueous Fluids Testing

Hpht Fluid Loss Testing Device

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

Conductor Pipe Connections

Conductor pipe joints installed on land rigs, are usually connected by welding bevelled prepared ends of the pipes together. This is a time consuming operation that requires an average of three hours per joint. On a Jack-up, to reduce the time of the operations and when it is practicable, driveable threaded quick connectors i.e. the RL-4 and driveable squnch joint connectors such as the Fast Realising Joint i.e. the ALT-2 , should be used. a A Squnch Joint Refer to figure 4.c is a threadless...

Identification of Risks

Horizontal Drill Path Design

An important part of the planning and design phase of a HDD project is to identify and avoid or at least reduce possible risks. If potential risks cannot be avoided or reduced, the crossing alternative should be closely evaluated and other alternatives considered. A decision has to be made as to whether to accept the risks or select another crossing option. Even with the best planning and design efforts unexpected risks can occur. Experienced and qualified contractors are well equipped to solve...

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...

Blowout Preventer Control Systems

Drilling Rig Panel

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...

Design Radius of Curvature

Hdpe Pipe Curve Radius

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. Bend radius is defined as the forward distance required for a drill string to make a 90-degree turn see Figure 4-2 ....

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...

Anhydrite Gypsum Contamination

Anhydrite and gypsum are calcium sulfate compounds CaSO4 which are sometimes encountered while drilling. Gyp is calcium sulfate with water of crystallization CaSO4 2H2O , while anhydrite is the anhydrous waterless form of calcium sulfate CaSO4 . These may occur as thin stringers or massive beds. Calcium sulfate contamination is similar to cement contamination because both liberate calcium ions, which in turn cause flocculation. Unlike cement, calcium sulfate does not cause a pH increase since...

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...

Water Base Muds Testing

Mud Balance Used For Drilling

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...

Calculating the Pull Loads

Horizontal Directional Drilling Crossing

The first step in calculating the estimated pulling loads is to develop the input data that will be used in the calculations. This data includes the product-pipe material properties, the drilling-fluid properties, and any code or design factors that are applicable. An example of the input data required for calculating estimated pulling loads is provided in Example 6-1 later in this chapter. Defining the Bore Path The next step is to define the bore path for the crossing. Figure 6-1 defines a...

Carbonate Bicarbonate Contamination

The most common source of soluble carbonate accumulation in muds is CO2 intrusion from formations being drilled. As CO2 enters an alkaline mud, it reacts with OH- ions and soluble carbonates accumulate. Another common carbonate source is thermal degradation of organic additives such as lignite and lignosulfonate at temperatures in excess of 300 F. CO2 is liberated at temperature by alkaline decarboxylation of organic acid groups such as found in humic acid. Lignite is a more potent source of...

Authorisation For Expenditure

How Many Site Office Personnel

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...

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...

Standard Drill String

Drill Pipe Tool Joint Diagram

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...

Subsea Bop Control Systems

Subsea Lubricator Valve Umbilical

As the indirect hydraulic control system is the most common system in use on semi- submersible rigs, the examination focuses exclusively on this system. Therefore, it is necessary to be conversant with this type of control. In particular, the examination 1 Position of equipment in the control system. You should be familiar with the equipment shown in Figure 50 and be able to located specific items by name. You should also be able to determine where individual items are located such as SPM...

Frictional Resistance

Pipe Bending Formula

Pipe resistance to pullback in the bore hole depends primarily on the frictional force created between the pipe and the hole or the pipe and the ground surface in the entry area, the frictional drag between pipe and drilling slurry, the capstan effect at bends, and the weight of the pipe. Equation 7-4 gives the frictional resistance or required pulling force for pipe pulled in straight, level bores or across level ground Figure 7-2 . FP pulling force in pounds coefficient of friction between...

Well Planning Process

The well planning process can be broken down into stages. Each stage is discussed in more detail later on in this chapter. Chapters 13 and 14 show how the well planning process fits into the overall drilling operation. Why is the well to be drilled Will it be a wildcat exploration well or an appraisal or development well 2. Obtaining consent to drill from authorities All relevant data from seismic surveys and offset well reports must be scrutinised to ensure that the optimum drilling programme...

Diverter Procedure While Drilling Fixed

Annular Bop Diverter

1 Where shallow casing strings or conductor pipe are set, fracture gradients will be low. It may be impossible to close the BOP on a shallow gas kick without breaking down the formation at the shoe. If a shallow gas kick is taken while drilling top hole then the kick should be diverted. Drilling shallow sand too fast can result in large volumes of gas cut mud in the annulus and cause the well to flow, also fast drilling can load up the annulus increasing the mud density leading to lost...

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...

Methylene Blue Capacity

Methylene Blue Test Drilling Fluid

The methylene blue capacity test indicates the concentration of reactive clays present in a drilling fluid. Reactive clays are commercial bentonite and formation solids such as shales. Methylene blue dye is added to a sample of whole mud until all reactive sites have adsorbed the dye. A faint blue turquoise halo will form around the drop of solids when there is an excess of dye. Drilling muds frequently contain other materials that adsorb methylene blue. Treatment with hydrogen peroxide is...

Rotary Drilling General Method and Equipment

Drill String And Bit

5.1 Introduction and Basic Operations The rotary drilling method is comparatively new, having first been practiced by Leschot, a French civil engineer, in 1863. United States patents on rotary equipment were issued as early as 1866 but, as was the case with cable tools, the early application was for water well drilling. It was not until approximately 1900 that two water well drilling contractors, M. C. and C. E. Baker, moved their rotary equipment from South Dakota to Corsicana, Texas where it...

Crown Mounted Compensator

Drilling String Compensator

Wireline Motion Compensation-Logging A motion arrestor for nullifying vessel heave in wireline operations, especially in well logging operations, is available. This compensation device hangs below the hook and uses a working wireline reeved from the top of the riser pipe around the motion arrester working sheave, and to the drill floor. The logging sheave and working sheave are connected to the same yoke, which is suspended from the motion arrester by a pneumatic spring special tensioner . As...

Surface and Subsurface Completion Equipment

Flow Coupling

Well completions involve placing flow control equipment at the surface and indie tubing string. These items may include the following major categories surface and subsurface automatic shutdown systems The equipment must be sized and selected for each reservoir and its flow characteristics. The drilling plan should include a wellhead and geometry to accommodate this production equipment. Production Tree. The production, or Christmas, tree provides the connection between the wellbore and the...

Gel Strength Measurement Procedures

Stir a sample at 600 RPM for about 15 seconds. 2. Turn the RPM knob to the STOP position. 3. Wait the desired rest time normally 10 seconds or 10 minutes . 4. Switch the RPM knob to the GEL position. 5. Record the maximum deflection of the dial before the Gel breaks, as the Gel strength in lb 100 ft2. lb 100 ft2 x 5.077 Gel strength in dynes cm2 . This is the measure of the electro-chemical or attractive forces in the mud under flow dynamic conditions. These forces depend on 1 surface...

Blowout Preventer Operating Procedures

Subsea Drilling Stack

The following covers the use of the blowout preventer BOP stacks and equipment used when drilling from a floating vessel. Figure 3-14 shows typical BOP stack with the major components normally used in a typical BOP stack. Though the size and pressure ratings may vary, all major BOP stacks in use for subsea drilling today contain the major components shown. These major components are 1 hydraulic wellhead connectors 2 ram type BOP's 3 annular type BOP's 4 hydraulic or elec-trohydraulic control...

Mud Gas Separator Poor Boy Degasser

Poor Boy Degasser

The height and diameter of an atmospheric separator are critical dimensions which affect the volume of gas and fluid the separator can efficiently handle. As the mud and gas mixture enters the separator, the operating pressure is atmospheric plus pressure due to friction in the gas vent line. The vertical distance for the inlet to the static fluid level allows time for additional gas break-out and provides an allowance for the fluid to rise somewhat during the operation to overcome friction...

Mud Weight Marsh Funnel Viscosity And pH

Drilling Fluid Meter

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...

Directional Drilling Fundamentals Introduction to Directional Drilling

When preparing to drill a vertical or directional well, all operational components of the process are reviewed, optimized and included in a drilling program. The surface location is scouted to determine the best site that will allow for any natural drift, provide suitable access for drilling rig, service rig, production facilities and can be constructed for a reasonable cost. A casing program is prepared to provide 1 adequate well control, 2 prevent water table contamination, 3 maintain...

Diagram Of A Rig Circulating System

Spinning Chain And Cathead

Fig. 1.19-Example drawworks used in rotary drilling. Fig. 1.19-Example drawworks used in rotary drilling. Friction catheads shown in Fig. 1.20 turn continuously and can be used to assist in lifting or moving equipment on the rig floor. The number of turns of rope on the drum and the tension provided by the operator controls the force of the pull. A second type of cathead generally located between the drawworks housing and the friction cathead can be used to provide the torque needed to screw or...

Leak Off Test Procedure

A Leak-Off Test LOT will be performed On Wild-Cat wells at each casing shoe after setting the surface casing. LOTs are also recommended to be carried out on both appraisal and development wells. Leak Off Test and Formation Integrity Test FIT , also termed the Limit Test, are for formation strength pressure tests made just below the casing seat prior to drilling ahead. Investigate the cement seal around the casing shoe which should be at least as high as the predicted fracture pressure for the...

Entry and Exit Angles

Generally the entry angles should be held between 8 and 16 degrees from horizontal, although entry angles up to 24 degrees have been used on some projects. These boundaries are due chiefly to equipment limitations. The preferred drill path is made up of straight tangent sections before the introduction of any curves. The radius of the curve is determined by the bending characteristic of the product pipeline or in some cases the drill-rod pipe. The curve usually brings the drill-path profile to...

Advantages Disadvantages of Air Drilling Fluids

There are a number of significant advantages for using air as a drilling fluid. Table 5 lists some of these advantages as well as some of the disadvantages. Excellent ROP in dry competent formations. Dust and noise problems on location. Excessive erosion near top of hole where expansion results in high annular velocity. Minimum damage to water-sensitive pay zones. May cause downhole fire when hydrocarbons are encountered. Air Drilling Little or no fluids disposal problems. Hole cleaning success...

Accumulator Drawdown Test

Accumulator Unit Drilling Oil Well

Close bag ''Open valves Open bag ' Close valves fnr --- Preventer valve Valve 6-in. D minimum Riser pipe Fig. 16-68 Typical diverter stack Courtesy PennWell Publishing The lines should be as large as possible with a suggested minimum ID of 6 in. Angles and bends should be minimized in the diveiter lines to avoid unnecessary restrictions. The preventer may be a low-pressure sphcrical preventer or some type of diverter bag used to direct the flow into the lines. Choke Manifold. The choke manifold...

Running The Bop And Riser

Before running the BOP stack check the weather forecast and refer to the 'Rig Operations' manual for the maximum vessel motion heave, roll and pitch for running BOP. Running procedures vary from rig to rig due to the specific design of the stack and to the handling system gantry cranes, fork lifts, trolleys, etc. used for moving the BOP in and out of the moonpool area. There are also a variety of ways to land the BOP stack. For this reason provision of detailed procedures is not possible...

Figure Typical HDD Drill

Directional Drilling Rig

Must be anchored to provide a reaction against which the mechanical system can operate. Anchoring is typically done by driving stakes through openings at the front of the rig, attaching the rig to a buried weight, or simply attaching the rig to a large, heavy piece of equipment on the surface. The drill rig must provide sufficient thrust and the drill pipe sufficient strength to advance the drill string the full length of the proposed bore hole and sufficient pulling force to retract casing...

Drill Off Test Procedure

Select a WOB near maximum allowable . 2. Record the time to drill off a weight increment, ie 5000 lbs. 3. Record length of pipe drilled during step 2. 4. From steps 2 and 3 the drill rate in feet per hours may be found. 5. Repeat steps 2 and 3 at least four times. The last test should be at the same value as the first. This repeat test will determine if the formation has changed or not. 6. Plot seconds to drill off versus bit weight. 7. Plot penetration rate versus...

Stabilizers and Reamers

Oilwell Bha

Stabilizers and rolling cutter reamers are special thick walled drill collar subs that are placed in the BHA to force the drill collars to rotate at or near the center of the borehole. By keeping the drill collars at or near the center of the borehole the drill bit will drill on a nearly straight course projected by the center axis of the rigid BHA. Stabilizers and rolling cutter reamers have blades or rolling cutters that protrude from the sub wall into the annulus to near the borehole...

Retort Water Oil and Solids

Retort Mud

Accurate measurement of water, oil and solids content provides fundamental information for control of mud properties and is essential for evaluating solids control equipment.___ The volume percent of liquid phase water and oil are measured by heating a known volume of whole mud in a retort unit. The liquid is evaporated from the mud, vapor is condensed and measured as oil and fresh water in a graduated glass tube. Suspended solids are calculated by difference of liquid collected subtracted...

Zinc Carbonate Scavenger

There are several methods commonly used or available to determine the presence of H2S in drilling fluids. Gas detectors or monitors are used on drilling rigs to detect unreacted H2S gas at the surface. The Hach test is used to detect H2S in the acid form, or as soluble sulfides in the makeup water, filtrate or mud. The Garrett Gas Train also analyzes the soluble sulfides in the filtrate of the mud. In addition, both tests can also determine the total sulfides, both soluble and insoluble, in a...

Standard API Drill Pipe

Appendix B gives the dimensions and mechanical properties for standard API drill pipe. This is the drill pipe used in most rotary drilling operations shallow and deep . API drill pipe are fabricated by various API certified manufacturers around the world, principally for use in the drilling of deep wells for the recovery of oil and natural gas. Table B-3 gives the drill pipe dimensions outside diameter, inside diameter, and weight per unit length of the pipe body of various drill pipe sizes....

Ellipse Of Uncertainty

Ellipse Uncertain

The concept of an ellipse at any point in a drill hole to quantify the possible locations of the point is illustrated with the following example. Suppose the measured depth is 2500 feet as shown in the sketch and that systematic errors errors which regularly re-occur and are not compensating at any survey station are 1 in azimuth, 0.5 in inclination, and 1 part in 500 for measured depth. Further, suppose the inclination and azimuth are thought to be 30 and 90 , respectively. The expected...

Blowout Prevention Stack

Blowout Prevention

Blowout prevention equipment was developed for use in drilling deep wells for the recovery of oil and natural gas. Later this unique oil and gas industry equipment was adapted for use in drilling deep geothermal wells. Natural deposits of oil and gas exist in porous rock formations deep in the earth's crust. These deposits were created by millions of years of sediment burial and confinement by geologic structures. Over time, increased sedimentary burial created high pressures and temperatures...

Example Maximum Available

Oil Bit Drill Classification

The maximum available weight on bit WOB for a tangential horizontal well is planned with the drill bit and BHA in the horizontal section, which is the important case. Let the horizontal plan which has been solved in a previous example be as shown in the sketch. Let the drillpipe be composed of 8,000 feet of 5 0D by 4.276 ID drillpipe with an average weight of 21.6 ppf and the BHA be 90 feet with average diameters of 7 by 2.5 114 lb ft . Mud weight is 11.0 ppg. The gravity weight of the...

Drilling Fluid System

Typical Fluid System

For HDD construction the primary impact on the environment revolves around the use of drilling fluids. Many regulatory problems result from a misunderstanding of the effects of drilling fluids. Informing the regulatory agencies about the purpose and composition of HDD drilling fluids is important for many successful HDD projects1. For many HDD projects the drilling fluid system comprises a substantial portion of the HDD equipment and cost. The system is composed of both the equipment and the...

Drill Bit Selection Criteria

A common criterion for drill bit selection is 'BALANCED WEAR . Balanced wear is the method of bit selection in which the teeth, bearings, and gauge, wear-out at exactly the same time. It is easy, but does not necessarily give minimum cost. Some of the problems in selecting drill bits with the 'MINIMUM COST' method are 1. bit selection can only be based on drilling experience 2. lowest cost is usually interpreted as lowest cost per foot which is not necessarily true 3. cost comparisons between...

Electric Motors For Shale Shakers

Centrifugal Force Centrifuge

With the exception of specialized motors for centrifuge feed, practically all AC electric motors encountered in drilling-fluid operations are integral-horsepower, across-the-line start, horizontal squirrel-cage motors. Across-the-line motors are the simplest and lowest cost. The motor is connected directly to the input power through a starter switch. Full current and torque are realized at startup. This is acceptable with solids-control and processing equipment however, it is suggested that...

Drilling and Steering

Drill Head Steering Tool

Drilling curved and horizontal bore holes requires specialized drilling equipment. This equipment is contained in a bottom-hole assembly BHA that consists of a drilling tool, a bent subassembly, and a steering tracking tool. Pilot-hole directional control is achieved by using a nonrotating drill string with an asymmetrical leading edge. The asymmetry of the leading edge results in a steering bias. When a change of direction is required, the drill string is rotated so that the direction of the...

Surface flow head surface test tree

The surface flow head is the primary closing and safety assembly located on the surface. The surface flow head is attached to the top of the test string, sufficiently high above rotary table to accommodate rig heave. It should have a pressure rating equal to or greater than the maximum expected surface pressure, and have sufficient tensile strength to pick up the weight of the test string to unseat the packer. The assembly consists of various components and the components selected for each test...

Chronology Of Submersible Rigs

Zapata Scarpion Jack

CHRONOLOGY OF JACKUP RIGS, 1953-1969 In 1955, the first 3-legged jack-up appeared on the scene Figure 1-6 . The rig was the R. G. LeTourneau jack-up, the Scorpion, for Zapata Offshore Company. The Scorpion, an independent leg jack-up, used a rack and pinion elevating system on a truss framed leg. The rig worked very successfully for several years but was lost during a move in the Gulf of Mexico. The Scorpion was closely followed by The Offshore Company Rig No. 54. For Rig No. 54, however, a...

Of Drilling Operations

At present, as the oil industry is coming out of recession, the costs for individual types of rig is varying considerably. The table below illustrates the average cost comparisons between rig types at time of writing These figures are general and should only be used as a guide. Even though jack-up costs have been traditionally cheaper than those of semis, demand for deep water jackups has pushed their day rates above most semis. 2.1 Specific cost breakdown - offshore exploration wells To...

Designing Pilot Tests

Drilling Fluid Tests Lab

Adjustments to mud properties such as changing fluid loss properties treating carbonate bicarbonate contamination adjusting MBT - clay content of the mud changing oil water ratio of oil muds increasing electrical stability of oil muds 4. Study of effects of breakover, converting or displacement of muds, such as displacing water-based mud with oil-based mud or vice versa converting from freshwater mud to saturated salt mud breakover to lime or gyp mud reducing...

Mountain Climbers Freedom Fighters and Craftspeople

Your first step in segmenting the small business market is to look at your customer base behaviorally and divide your customers up into buckets based on how profitable they are to you. Then you need to find the distinguishing characteristics of each bucket, the traits that make each bucket unique. That trait often comes down to what they buy from you, but you may also find that your most profitable buckets have other similarities, including demographics like age, gender, and ethnicity, or...

Specific cost breakdown onshore exploration wells

For comparison with the offshore well discussed in section 2,1, the following represents a shallow 1000 m European land well to be drilled in 1990. The cost breakdown is for a 1000 m well with 7 inch casing set at 500 m and 6 inch hole drilled to TD. It is assumed that there are two days spent coring, the well is then logged and abandoned. Estimated days on well is a total of 20. Site survey, rental, preparation and restoration Breaking down these costs into fixed, daily and unit costs, we find...

Techniques To Control Catastrophic Blowouts

Gas Well Blowout Offshore Libya

Control over a catastrophic blowout can be gained by any technique that blocks the escaping reservoir fluid either in the wellbore or in the formation. The method most frequently used is wellbore blockage, i.e., the recapping of a wild well. Relief well techniques, although more expensive to implement, have popular support because water pollution can be minimized by allowing the flowing wells to burn. Relief wells are sometimes drilled to establish direct connection with the wild-well bore...

Uses of Prehydrated Bentonite

Bentonite is added to water based muds to increase the viscosity and gel strength, suspend solids and increase the carrying capacity of the mud. Bentonite forms a filter cake and, if properly dispersed, is the main agent for reducing water loss. Bentonite will yield in fresh water less than 50 g l salt but not in salty water. Hence if bentonite is to be used in salty water, it must be prehydrated in fresh water. Before adding bentonite to the water or any other chemical , test the water for...

Offshore Oil Rig Layout

Oil Rig Layout

Fig. 16-12 Slot-type jackup rig Courtesy Western Oceanic Inc. Fig. 16-13 Cantilever-type jaekup rig Courtesy Western Oceanic Inc. Fig. 16-13 Cantilever-type jaekup rig Courtesy Western Oceanic Inc. of semisubmersibles is stability. They are more frequently out of the range of motion-creating wave periods than are ship vessels. Therefore, their range of acceptable operating conditions is greater. The special designs used for environment operating efficiency have some disadvantages Semis have...

Preparing For Rig Acceptance On A Cold Stacked

This is a much more difficult and time-consuming process. Cold stacked rigs have generally been moth-balled using inhibitive chemicals. Providing that this has been done professionally then there should be little problem bringing the rig back into operational mode. The factors influencing the ease with which the rig can be brought back into operational mode are cold stacking procedures applied inspection during cold stacking recommissioning procedures applied A copy of the cold stacking...

Wind Wave and Current Forces on Offshore Structures

Force The Wind

The forces produced by wind, wave, and current are the primary design loads on mobile drilling units and other offshore structures. These forces are dynamic and ever-changing rarely can they be expressed as a mathematical function of time. They are statistical in nature and should, if possible, be handled by means of statistical tools. The most commonly used method so far for evaluating wave loads on an offshore structure has been to base the calculations on one or more design waves of...

Well Cost Estimation AFE Preparation

Projected Drilling Time, Time Categories, Time Consideration, Cost Categories, Tangible and Intangible Costs, Location Preparation, Drilling Rig and Tools, Drilling Fluids, Rental Equipment, Cementing, Support Services, Transportation. Supervision and Administration. Tubulars, Wellhead Equipment, Completion Equipment A Case study homework problem 774 F Casing and tubing tables 847

Rules Of Thumb For Bit Selection

Shale has a better drilling response to RPM. Limestone has a better drilling response to bit weight. Bits with roller bearings can be run at a higher RPM than bits with journal bearings. Bits with sealed bearings can give longer life than bits with open bearings, Milled tooth bits with journal bearings can be run at higher weights than milled tooth bits with roller bearings. Diamond product bits can run at higher RPM than three cone bits. Bits with high offset may wear more on gauge. Bits with...