Bit Size

Roller cone bits are available in virtually any desirable size range from 33 s-26-inch bits. In most cases, any type of design, cutting structure, and jet system is available. PDC and diamond hits are generally not available in an off-the-shelf fashion in sizes greater than 15 in. Diamond bits are generally prepared custom tailored. It is unfortunate that PDC bits are not currently available in very large diameters since roller cone bits can create excessive torque in large-diameter holes. Deep...

Displacement Process

Pumping the cement into the annulus is as important to the successful cementing program as the slurry design. An improper displacement process can be the primary cause of bad cement jobs. The variables include placement rates, type and amount of prellushes or spacers, and the actual type of displacement process. Flow Regimes. The displacement rate affects the flow regime in the annulus. (See Chapter 18 for additional details on hydraulics.) High flow rates convert the flow regime from laminar...

Example

Using the hole geometries in Fig. 6-1, determine the flow rate required to achieve an annular velocity of 75 ft min. In addition, determine the surface horsepower required if the pump pressure is limited to 2.500 psi. Use 5-in, drillpipe for a and c and 4' 2-in. pipe for b. 1. From Fig. 6 1, the annular geometries in the largest hole sections are 2. Use Eq. 6.1 to determine the required pump rate for a Likewise, for b. Q 604 gal min for c, Q I,992 gal min 3. Determine the surface horsepower...

Field Testing Procedures

A discussion of all testing procedures for drilling fluids is impractical for this text. Table summarizes the basic field testing procedures for water-based and oil-based muds. This table does not cover all tests nor relate any recommendations. Testing procedures and equipment may vary from one mud company to another. The American Petroleum Institute (API) provides standards for most mud testing procedures. Document API RP 13B is available from the institute and can usually be obtained from...

Friction Pressure Determination

Pumping a drilling fluid requires overcoming frictional drag forces from fluid layers and solids particles. The pump pressure (PP) can be described as the summation of the frictional forces in the circulation system PDS drillstring friction pressure, psi The pressure drop in the bit results from fluid acceleration and not solely friction forces. As a result, it will be discussed in a separate section. Equations to determine friction pressures vary according to the flow regimes, such as laminar...

General Types of Additives

Marsh Funnel Images

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...

Magrange II

The Magnetic Range Detector (Magrange II) can determine direction as well as distance to the relief well. The equipment used in the Magrange II system consists of a downhole instrument, a winch and seven-conductor cable, a surface electronic unit, a programmable calculator, and a plotter. The downhole instrument contains magnetic field sensors arranged in a non interfering orthogonal configuration and in a gradiometric measurement configuration. The sensors, along with their associated...

Overview of the Planning Process

It requires that some aspects of the plan be developed before designing other items. For example, the mud density plan must be developed before the casing program since mud weights have an impact on pipe requirements. Fig. t-2 illustrates a commonly used flow path for a well plan. Bit programming can be done at any time in the plan after the historical data have been analyzed. The bit program is usually based on the drilling parameters from offset wells....

P

1,500 (8.5- - T) 225 (8.5 - 7) 8.0 psi + 160 psi 168 psi 8. The total pressure surge and equivalent mud weight is pressure x 19.23 EMW -- --- + mud weight 9. Therefore, the fracture gradient of 17.0 lb gal would he exceeded (17.1 lb gal) at a pipe velocity of 93 ft min. 10. In reality, the flow regime in the annulus was turbulent opposite the liner. The assumption of laminar flow in this example was done for simplicity and illustration. Open-ended pipe increases the complexity of the...

Pipe Body Manufacturing

API's Specification 5A states that casing, liners, and tubing conforming to this standard must be seamless or electric welded. Seamless pipe is a wrought steel tubular product made without a welded seam. It is manufactured by hot-working steel and, if necessary, by subsequently cold-finishing the hot-worked tubular product to produce the desired shape. The process may involve a plug mill or mandrel mil rolling, A typical seamless process is shown in Fig. 11-1. Electric-welded fERW) pipe has one...

Problems

14.1 Suppose a well is completed in a 12,350-psi zone at 6,850 ft. The shutin tubing pressure (SITP) is 8,772 psi. What packer fluid density is required to balance bottom-hole pressure Construct a burst-resultant plot for the production casing, assuming that a near-surface tubing leak allows pressure to act on the (calculated packer fluid weight. Use a 9.0-lb gal backup fluid. Reconstruct the plot with a 9.0-lb gal packer fluid. What is the maximum pressure difference between the two plots at...

Purposes

The hydraulics system serves many purposes in the well. Since it is centered around the mud system, the purposes of mud and hydraulics are often common to each other (refer to Chapter 8). The hydraulics system has many effects on the well. Therefore, the reasons for giving attention to hydraulics are abundant. The more common reasons are as follows control subsurface pressures provide a buoyant effect to the drill string and casing minimize hole erosion due to the mud's washing action during...

References

Applied Petroleum Reservoir Engineering. Englewood Cliffs, NJ Prentice-Hall Inc., 1959. ETA Offshore Seminars Inc. Technology of Offshore Drilling, Completion, and Production. Tulsa PennWell Books, 1976. Gatlin, C. Petroleum Engineering Drilling and Well Completions. Englcwood Cliffs, NJ Prentice-Hall Inc., 1960. Gray Tool Co. Oilfield Equipment Catalog. Houston, 1983. Hensley, Dennis. Personal communication. Houston, 1984. Simmons, Evan. Personal communication....

Solution

Determine the maximum allowable surge pressure so the 16.6-lb gal mud does not exceed the 16.9-lb gal equivalent value 0.052 (16.9 - K> .6)( 10.000 ft) 156 psi 2. The 156-psi surge pressure is the maximum amount that can be generated by the friction pressure opposite the pipe and liner, or 3. Substituting the pressure equations for Pr and P, . T (38)(6,400)< V,J (I5)(6,400) 1 I 1,500 (8.5 - 4.5 ) 225 (8.5 - 4.5) 156 psi s 3.118 Vp. + 3.922 Vlc + 266 psi 4. Since the sum of the velocity...

T

Fig. 8-22 The mud hydrostatic pressure usually exceeds the pore pressure and is less than the fracture gradient (values shown are for illustrative purposes) wetting of the formation by capillary invasion. Note that detergents are used primarily on surface holes and have less effect on deep, high-temperature holes. Corrosion Control. If the drillstring and casing have teen adequately maintained, corrosion while drilling can usually be held to a minimum with proper treatments of the mud system....

Table

N pipe may have joints that exceed a 22 Rockwell hardness. Since this 22 hardness is an often-used upper range, certain joints of N-80 are not suitable for sour service, L-80 pipe, normally more expensive than N-80, is tested to ensure all joints have a hardness of 22 or less. The supplier must certify that these testing procedures have been performed. Many non-API grades of pipe are available and widely used in the drilling industry. The non-APi,T label...

Table Common Sources of Corrosion and Treatment

Increase mud density maintain pH at 10 or above use a cationic corrosive inhibitor Increase mud density maintain pH at 10 or above use an ITS or sulfide scavenger in conjunction with pH control Microbiocides maintain pH at 10.5 or above Change mud system to a lignite surfactant or oil mud Reduce yield point and gel strengths correct mechanical equipment maintain pH at 10 or above use a cationic inhibitor turn mud guns and hopper off when not in use add scavenger.

With T Configuration

Fig. 7-4 Milled tooth bit nomenclature The shank of the bit connects the body to the bit sub or lowermost drill collar. The thread connections arc API regular threads, a semirounded thread. Connection sizes for various diameter bits are shown in Table 7-1. The top of the shank is used for identification. It contains such information as 1) bit diameter in inches, 2) assembly number. 3) type, 4) manufacturer's trademark, and 5) serial number (see Fig. 7-4). The shank seal and shoulder provide the...

Introduction to Drilling Fluids Chemistry

High-weight mud systems usually contain more solids than low-weight systems. Extra solids in a high-weight mud will originate from the gels, chemicals, weight material, and drill solids from the formation. Good solids control equipment and proper additions of water and chemicals to a high-mud-weight system will eliminate many solids buildup problems. Additions of weight material, chemicals, and formation solids will necessitate adding extra water. Water dilution in...

Table Common Weighting Materials

Average Maximum Mud Specific Weight, , Item Chemical Name Gravity, lb gal * Exclusive of salts, drilled solids, and various less-common materials. * Exclusive of salts, drilled solids, and various less-common materials. different products have been successfully used to provide the necessary hydrostatic pressure in drilling fluids. Table 8-5 illustrates common density control materials. Workovers and some drilling operations have used soluble salts to provide a necessary hydrostatic pressure....

Specialty Mud Additives

With the increasing number of highly deviated holes being drilled, it has become common practice to maintain some type of spotting fluid at the wellsite to aid in pipe sticking problems. Regardless of the type of spotting fluid, immediate remedial procedures must be taken once the pipe has become stuck. Products that have come into the market and proven to be effective usually have some of the following characteristics reduce the differential sticking force erode the filter...

Casing and Tubing Concepts

Casing and tubing play a vital role in drilling operations. The design of the tubulars requires a knowledge of the operating conditions to be imposed on the pipe as well as a working understanding of various concepts related to pipe properties. The drilling engineer must be aware of these concepts before beginning the actual design operations. These concepts includc items such as manufacturing processes, physical properties, and testing procedures. Over the years, the API has developed a number...

Table Formula Factors and Dt Hange for Transition Collapse

Grades indicated without letter designation are not API grades but are grades in use or grades being considered for use and arc shown for information purposes, Cotirtesy American Petroleum Institute Grades indicated without letter designation are not API grades but are grades in use or grades being considered for use and arc shown for information purposes, Cotirtesy American Petroleum Institute Table 11-8 D t Range for Elastic Collapse Table 11-8 D t Range for Elastic Collapse Grades indicated...

Problems And Solutions On Netwas Group

Well Control Problems and Solutions, Tulsa PennWell Publishing Co., 1978. Applied Geological Services, Users Guide, Lafayette, Louisiania Adams and Rountree Technology, Inc. Personal conversation with Dr. Tom Burnett, Lafayette, Louisiana Adams and Rountree Technology, Inc., 1983. Various publications, Louisiana Stale Department of Natural Resources. Fertl, Walter F. Abnormal Formation Pressures, Elsevier Press. Formation pressure can be the major factor affecting drilling...

F V

4) Production screen _Gravel (sized sand) Controlling Well Pressure. Two major opposing arguments exist for packer fluid density selection in high-pressure wells * Should the density be sufficient to overcome wellbore pressures in the event of a tubing leak, i.e., can the fluid kill the well * Should a low-density fluid be used if a leak occurs at the top of the tubing Both arguments have merit and should receive consideration. Many operators desire a packer fluid density sufficient to balance...

Table Typical Mixtures for Gunk Squeezes

Ratios of mud-to-DOB and mud-to-DOBC that yield pumpable M-DOBs and DOBCs having 5-psi shear strengths. Prepared by adding 40(1 tb of bentonite to I bbl of diesei oil **Prepared by adding 200 lb of bentonite and 200 lb of cement to I bbl of diesei oil M-DOBC, mud-diesel oil-bentonite-cement Prepared by adding 40(1 tb of bentonite to I bbl of diesei oil **Prepared by adding 200 lb of bentonite and 200 lb of cement to I bbl of diesei oil M-DOBC, mud-diesel oil-bentonite-cement treated ben to ni...

Log Headers

Drilling records similar to the previously described information are not available on all offset wells. In these cases, a log header can yield useful drilling data. Easily attainable data from the log headers. Fig. 2-15, include the following mud weight and viscosity at each logging depth inferred casing sizes and actual setting depths If enough logging runs were made, a useful depth vs days plot can be constructed. Fig. 2-16 is the depth vs days plot for Fig. 2-15. n some cases, drilling and...

Hydraulics

Since the hydraulics system plays an active role during the drilling operations, its proper design and maintenance can accelerate the drilling effort and lower the overall well cost. Likewise, an improperly designed hydraulics system can slow drill rate, fail to clean the hole of cuttings, and cause kicks. In most cases, common sense and commercially available computer programs are the only elements required to design the system. The hydraulics system is the mud system in the wellbore when it...

Dib

V fluid velocity, ft sec Q How rate, gal min d pipe diameter, in. The critical velocity (Vj lor laminar and turbulence determination is computed from Eq. 18.22 _ 1.08 PV + 1.08 V(PV) + 12.34d2 YP p Vc critical velocity, ft sec PV plastic velocity, cp YP yield point, lb 100 ft2 p mud weight, lb gal Friction pressures for laminar flow can be calculated as follows pe I A . + < r> < ,1 (18,23) L section length, ft Turbulent flow is calculated according to Eq. 18.24 In the annulus, the same...

How to Plan a Mud Program

Planning a mud program is an essential step in the development of a workable overall weil plan. Key steps, listed below, are followed on each well. Obtain pore pressures and casing program Look for geological hazards beginning with the deepest hole section After checking geometry, ECDs. and hydraulics, set optimum viscosities Establish maximum fluid loss by interval Select mud types by interval, trying to match one interval to the next Set other critical properties (allowable sand content, pH,...

Size Selection Problems

Many interrelated size selection problems must be considered before the final hole geometry is established. These problems primarily relate to casing size and open-hole considerations, and they arc interrelated with casing design. A working knowledge of casing design problems (Chapter 12) will influence pipe size selection. Casing Design. The large flow string in Fig. 6-lc resulted in the use of a l3-y -in. intermediate string and a 20-in. surface casing. However, these strings may be difficult...

Scout Tickets

Seoul tickets have been available as a commercial service for many years. The tickets were originally prepared by oil company representatives who scouted operations of other oil companies. Current scout tickets contain a brief summary of the well (see Fig. 2-13). The data usually include the following well name, location, and operator casing geometries and cement volumes tops of various geological zones The source of the data for scout tickets is the state or federal report forms filed by oil...

C

(Rounding the solution may cause slight variations with published data) The minimum collapse pressure for the plastic to elastic transition zone (P,) is calculated from Eq. 11.8 Eq. 1.8 for P, is applicable for D t values from (D t)p , Eq. 11.7, for plastic collapse pressure to the intersection (D t),,,, Eq. 1 i .9, for elastic collapse. Values for (D t),c are calculated from Eq. 11.9 The factors and applicable D t range for the transition collapse pressure formula are shown in Table 11-7. The...

Production History

Production records in the offset area can provide clucs to problems that may be encountered in the prospect well. Oil and gas production can reduce the formation pressure, which can create differential pipe sticking in the prospect well. Production records provide pressure data from the llowing zones. Unfortunately, pressures in the over- and underlying formations will not change appreciably. This obscures detection with drilling parameters. (Chapter 5 gives suggestions on the amount of...

Contents

Well Planning Objective, Classification of Well Types, Formation Pressures, Planning Costs, Overview of the Planning Process Offset Well Selection, Data Sources, Bit Records, 1ADC Reports, Scout Tickets, Mud Logging Records, Log Headers, Production History, Seismic Studies Pressure Prediction Methods, Origin of Abnormal Pressures, Seismic Analysis, Log Analysis Theoretical Determination, Field Determination of Fracture Gradients 5. Casing Setting Depth Selection 116 Types of Casing and Tubing,...

Completion Factors Affecting the Well Plan and Drilling

It is difficult to discuss out of context the completion factors that affect well planning and drilling. Some have been discussed in this chapter and in other sections of this book. Although incomplete, Table 14-2 provides an overview of some considerations. Table 14-2 Overview of Completion Factors Affecting Planning and Drilling Item Possible Effects on Planning through casing Shot density Gravel packing Larger casing and hole diameters to accommodate the strings different cement plans to...

Mud Records

Drilling mud records describe the physical and chemical characteristics of the mud system. The reports are usually prepared daily. In addition to the mud data, hole and drilling conditions can be inferred. Many drilling personnel believe that the mud record is the most important and useful planning data. Mud engineers usually prepare a daily mud check report form. Copies are distributed to the operator and drilling contractor. The form. Fig. 2 10, contains current drilling data such as the...

Calculation Methods

The drilling industry currently uses computers to make most planning and survey analysis calculations. Although the calculations are not extremely difficult to make manually, the computer eases the difficulty and minimizes Ihe possibility of errors. Survey Techniques. The magnetic compass is widely used in making directional well surveys. Magnetic survey instruments are available as 1 singleshot instruments that take only one reading on a single photographic disc film during one run into a well...

Bit Records

An excellent source of offset drilling information is the bit record. It contains data relative to the actual drilling operation, A typical record for a relatively shallow well is shown in Fig. 2-5. The heading of the bit record provides information such as the following drillstring characteristics tlT CONDITION CODE - AP - REPAIRED fiR-RERUS tlT CONDITION CODE - AP - REPAIRED fiR-RERUS Fig. 2-5 Bit record for a shallow well In addition, the bit heading provides dates for spudding, drilling out...

Buoyancy

The drilling fluid provides a beneficial effect relative to drillstring weight or hook load. When pipe is lowered into the well, the mud system will support, or buoy, some of the pipe weight. This effect is termed buoyancy, or buoyant forces. The buoyed weight of the drillstring will be less than the in-air weight of the pipe. Buoyant forces are a function of the volume and weight of the displaced fluid. Heavier muds have greater buoyant forces than low-density muds. The buoyed pipe weight can...

Minimum Acceptable Input Horsepower

16.1 A 2,000-hp rig is operating at an elevation of 2.800 ft in a 95 F environment. Determine the available horsepower at the crankshaft. 16.2 Assume that a 3,000-hp rig is working at 85UF. Compute and plot the available horsepower at the following altitudes sea level ,000 ft 2.000, ft 3,000 ft 4,000 ft 5,000 ft 6.0 X ft. 16.3 Rework Problem 16.2 and assume the minimum and maximum temperatures during any 24-hr period are 57 F and 103 F, respectively. 16.4 Refer to Example 16.2. Make the...

Packer Fluids

A packcr fluid is placed between the tubing and production casing above the packcr. Among its many purposes are the following assist in controlling well pressure minimize differential pressure across the packer Packcr fluid selection is usually the responsibility of the drilling engineer. t is not an uncommon practice for the completions fluid to be used as the packer fluid. The selection criteria for the two fluids are not completely dissimilar. The major considerations for a completions fluid...

Field Determination of Fracture Gradients

It is common practice to pressure-test each new casing seat in field applications to determine the exact minimum fracture gradient. The primary reason for this practice is due to the inability of any theoretical procedure to account for all possible formation characteristics. For example, several authors have noted wells that exhibited lower-lhan-expected fracture gradients due to abnormally low bulk densities in the rock. The most common procedure used for the field determination of fracture...

Design A Production Casing For The Flowing Circumstances

Casing Burst Pressure Table

Design the production casing for the following circumstances Fig. 12-24 Collapse design for production casing 1. The bottom-hole pressure of 7,600 psi is plotted in Fig. 12-25. 2. Since a 9.0-lb gal packer fluid is used, its hydrostatic pressure cancels the 0 2,000 4,000 6,000 8.000 10,000 12,000 Fig, 12-25 Burst design for Example 12.6 effect of the burst backup fluid. Therefore, the resultant is equal to a HHP of 7,600 psi. 3. A design factor of 1.0 converts the resultant to the design line....

Special MODU Drilling Considerations

Mobile offshore drilling units MODU have many special drilling systems and considerations. A partial list of these follows motion compensation systems All of these considerations do not apply uniformly to jackups and floating vessels, and all will not be discussed in this section since they have been presented elsewhere in this text or in other published texts. Vessel Preloading. Foundation preloading has been widely used as a method of proof testing for various types of foundations and has...

L i sin

Avert A MD cos -J 10.6 t A MD - cos I. - cos I, sin A, - sin A.JJ An rth - I, - I, A-, - A, -- l0-7 A MD cos 1. - cos I cos A. - cos A2 AeaSt - 1, I, A, - A, - Avert A MD sin L - sin I, I0.9 Dogleg Severity. Large angle changes occurring over a short course length can place high bending stresses on the pipe. In addition, these doglegs can cause keyseating problems. Most operators place a limit on the amount of angle change allowable over a 100-ft segment. Generally, the limit is 4 -6 per 100...

Stabilization

Drilling straight or directional holes requires proper positioning of stabilizers in the BHA. Although it seems contradictory that drilling straight and directional holes would require the same principles, the underlying concept is to control the direction of the bit. Stabilizers are used to achieve this goal. The most common assembly arrangements arc pendulum and packed hole. The pendulum arrangement, Fig. 15-6, uses the weight of the drill collars acting on pivotal stabilizers to direct the...

Formation Pressures

The formation, or pore, pressure encountered by the well significantly affects the well plan. The pressures may be normal, abnormal high , or subnormal low . Chapter 3 gives details on pore pressure and detection. Normal pressure wells generally do not create planning problems. The mud weights are in the range of 8.5-9,5 lb gal. Kicks and blowout prevention problems should be minimized but not eliminated altogether. Casing requirements can be stringent even in normal pressure wells deeper than...

J

Fig. 12-18 Collapse evaluation for the tentative pipe design in Example 12.4 Intermediate casing design when used with a drilling liner is different than the design for a stand-alone intermediate string. Drilling conditions involved with both strings must be considered. In addition, if the liner will be used as a production string and not a tie-back to the surface, the intermediate casing also must be evaluated for production conditions. Since the intermediate casing and the liner will be...

Preface

My goal for this book was to prepare a document that could serve as a guide for most drilling and well planning applications. I believe it contains a good blend of theory and commonly accepted practices. In addition, most concepts have been presented both narratively and with example problems so the drilling engineer using this book can make good, logical decisions when special situations arise. Drilling topics must be presented in some logical format. 1 chose to discuss each item in this book...

Table Oil Mud Osmotic Pressures

Dissolved Salt Concentration, ppm Osmotic Pressure, psi 52,000 100,000 182,000 250,000 307,000 357,000 400,000 500 1,000 3,000 5,800 9,400 13,900 16,100 24,400 55,000 105,000 149,000 189,000 226,000 Calculated for oil mud opposite a freshwater shale the semipermeable membrane across which osmotic pressure occurs is created by emulsifiers and the oil film around each water droplet. Formation instability can be controlled by properly regulating the salinity in the water phase of an oil mud....

The Adams And Rountree Dwpln Program

A directional well is going to be drilled to 10,000 ftTVD under the following conditions. Evaluate the plan for 2 and 47100 ft buildup rates by computing the final drift angles. The Adams and Rountree DWPLN program is used to compute the following results 0 ft east 2,500 ft north 2,800 ft cast 10,000 ft TVD 11,000 ft TVD - 3,000 ft TVD Graphical Presentation. Most directional well plans arc presented in graphical as well as tabular form Figs. 10-6 and 10-7 . The vertical section presentation...

Mud Clinging Constant

A well is experiencing lost circulation problems at the bottom of the casing string. A liner will be run into the well. If the liner is lowered at a maximum rate of 93 ft min, will the surge pressures exceed the fracture gradient Use the Bingham model and assume laminar annular How. In addition, assume the peak pipe velocity is the same as the average value. casing depth casing ID open hole depth open hole OD liner size liner length drillpipe 7 in. flush joint 3,600 ft - 15 lb 100 ft- YP...

Table Cement Components and Characteristics

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...

Solution To Problems In Netwas Group

4.1 Determine fracture gradients for the following conditions. Use the methods of 1 Hubbert and Willis, 2 Matthews and Kelly, and 3 Eaton. Assume Louisiana conditions for the Matthews and Kelly calculations. Solution 3,000 ft Hubbert and Willis 12.2-14.0 lb gal Matthews and Kelly 13.8 lb gal Eaton 13.9 lb gal 4.2 Prepare a graph of fracture gradients vs depth for the methods used in Problem 4.1. Assume normal formation pressures. 4.3 Calculate the fracture gradient for the following set of...

Intermediate Casing and Liner

Drilling Liner

Fig. 12-19 Burst load tine for intermediate string and drilling liner line are shown in Fig. 12-20. Since the load line requires special attention, the resultant also demands special consideration. Tension. Although burst and collapse Tor the intermediate-liner combination are evaluated simultaneously, the tension loads are calculated for separate strings. This procedure is necessitated since each string is run and cemented in different density lluids. The tension toads are used to evaluate...

Types of Drilling Fluids

Fig. 8-5 A water-based mud has water as the continuous phase it may but not necessarily contain oil as the discontinuous phase Clear, fresh water is one of the oldest muds used in the industry, it is generally used with no special additives except perhaps a corrosion inhibitor. The fresh water may hydrate formation clays and convert itself into a native mud. In fact, the term mud is believed to have been first used when fresh water and surface soils were mixed to develop a viscous fluid that...

Acknowledgments

Many people and companies must be acknowledged for their assistance in the preparation of this books Undoubtably, I will fail to mention all of them. To them I sincerely apologize for the oversight. Above all else, I must acknowledge the ladies in my life who tolerated my moodiness. Crystal Adams gave to this effort in ways that I probably will never know or understand. My daughters, Donna and Holly, were deprived of a daddy on many occasions when I felt obligated to write, proofread, or...

Mud Logging Records

Mud Logging Unit

A mud log is a foot-by-foot record of the drilling, mud, and formation parameters. Mud logging units are often used on high pressure or troublesome wells. Many engineers consider the mud log to be the best source of penetration PARISH ACADIA FIELD CROWLEY WORTH SER 156172 amp 159825 OPR Amarillo O. Co fmly Dixie Petro of La Inc RESULT PLOWING DUAL GAS WELL LOCK 9-9S-IE 747' FSL amp 953' FEL of sec 13500' test-Nod 1 RH Elcv 20' RKB-CHF amp 27' Grd. SPUD 2-9-78 COMP 6-2-78 PBTD 13303' TD 14008'...

Neal J Adams

Copyright 1985 by PennWell Publishing Company 1421 South Sheridan Road R O, Box 1260 Tulsa, Oklahoma 74101 Library of Congress cataloging in publication data I. Oil well drilling. 2. Gas well drilling. I. Title. TN871.2.A33 1985 622',338 84-1110 ISBN 0-87814-265-7 All rights reserved. No part of this book may be reproduced, stored in a retrieval system, or transcribed in any form or by any means, electronic or mechanical, including photocopying and recording, without the prior written...

Data Sources

Sources of data should be available for virtually every well drilled in the U.S. Drilling costs prohibit the rank wildcatting that occurred years ago. Al though wildcats are currently being drilled, seismic data, as a minimum, should be available for pore pressure estimation. Common types of data used by the drilling engineer are as follows databases or service company files Each type of record contains valuable data that may not be available with other records. For example, log headers and...

Calculation Of Pressure Loss In Surface Equipment Kelly Swivel

Washpipe Swivel

Refer to Examples 18.3 and 18.4 and compute the friction pressures for the system in Example 8.4. Use the Power Law model and a flow rate of 125 gal min. If Va Vc, compute the pressure drop for laminar and turbulent flow and choose the larger value. 1. Referring to Examples 18,1 and 18.2, the data to be used are 6. Since 158.6 psi gt 93,4 psi, assume the pressure loss is the greater value, 7. Some groups within the industry bypass Step 3 altogether and compute the pressure drops from Eqs. 18.29...

Flow Regimes

While drilling fluids are flowing in a well, the manner in which the fluid behaves may vary. This behavior is often termed the flow regime. The most common regimes are laminar, turbulent, and transitional. Unfortunately, it is impossible to clearly define each type in the weil. As an example, mud flow may be predominantly laminar, although the flow near the pipe walls during pipe rotation may be turbulent. Laminar Flow. The most common annular flow regime is laminar. It exists from very low...

Matching the Area Average

An easy, beneficial approach to optimizing drilling is to select drilling parameters such as bit type, weight, and rotary speed to ensure that drilling rates and cost per foot will equal the area average. Unfortunately, easily accessible lield data arc often not used. The effort requires less than I hour in most cases and can easily save 10-30 in actual rotating costs. Fig. 7-33 Bit selection based on minimum cost analysis from offset wells A amp B The procedure for this technique is simple 1....

Offset Well Selection

Contour Map Normal Fault

The drilling engineer is usually not responsible for selecting well sites. However, he must work with the geologist for the following reasons 1. Develop an understanding of the expected drilling geology 2. Define fault block structures to help select offset wells that should be similar in nature to the prospect well 3. identify geological anomalies as they may be encountered in drilling the prospect well A close working relationship between drilling and geology groups can be the difference...

Lubinski Maximum Permissable Doglegs

How to Design Drill Strings for Deep Wells. World Oil, February I, 1968. Coins, W.C. Better Understanding Prevents Tubular Buckling Problems. World Oil, January-February, 1980. Hansford, J.E., and A. Lubinski. Cumulative Fatigue Damage of Drill Pipe in Dog-Legs. Presented at the AIME-SPE meeting, Denver, Colorado, 965. Hansford, J.E., and A. Lubinski. The Effects of Drilling Vessel Pitch or Roll on Kelly and Drill Pipe Fatigue. Tram,, AIME, volume 231, 1964. Lubinski, A. A Study of...

Cementing

Cementing is an integral, necessary aspect of drilling oi and gas wells. Cement is used to secure casing strings and to isolate zones for production purposes as well as to solve various hole problems. A properly planned cement program is essential to a successfully drilled well. Cement planning consists of several features, including the following assessment of hole conditions such as temperature, size, etc. evaluation of mud properties equipment selection, such as central zers, scratcbcrs, and...

Special Cementing Problems

Oil Drilling Problems

Cement slurries often must be designed to control special problems. Although it is unlikely that a solution exists for each situation, proper planning will help achieve an effective cement job. Service companies usually offer advice and expertise to overcome most difficult problems. Salt Sections. Formations containing significant salt sections will wash out if conventional water-based mud and cement slurries are used. Drilling muds are usually modified so that the water phase is salt saturated...

Tubing Design

Tubing design is an important facet of the well plan. The tubing is the flow string through which the produced oil and gas move from the reservoir to the surface handling facilities. In addition to the produced fluids, the tubing may be required to control pressures and fluids during stimulation or squeeze conditions. Poor tubing designs may result in tubing failure, which necessitates expensive remedial operations. The typical production system is shown in Fig. 13-1. It contains the tubing, a...

Log Analysis

Resistivity Log With Depth Picture

Log analysis is a common procedure for pore pressure estimation in both offset wells and the actual well drilling. New MWD measurement-while-drilling tools implement log analysis techniques in a real-time drilling mode. The analysis techniques use the effect of the abnormally high porosities on rock properties such as electrical conductivity, sonic travel time, and bulk density, Both the resistivity or reciprocated conductivity log and the sonic log presented here are based on one of these...

Types of Completions

Formation Damage Wellbore

Perhaps the most common types of completions are perforated systems. Gravel packing is common in formations with sand control problems. Perforated Systems. A perforated system Fig. 14-26 typically consists of a packer-tubing seal with holes perforated in the production casing. The perforations should extend beyond the damaged area near the wellbore to be effective. A tubing or casing gun lowered on electric wireline or a tubing-conveyed gun is used to perforate the well. Fig. 14 26...

Casing Setting Depth Selection

The first design task in preparing the well plan is selecting the depths to which the casing will he run and cemented. The drilling engineer must consider geological conditions such as formation pressures and fracture gradients, hole problems, internal company policies, and, in many cases, a variety of government regulations. The results of the program will allow the well to be drilled safely without the necessity of building a steel monument of casing strings. Unfortunately, many well plans...

A ALoas

Well logging is ail important operation in oil and gas production. In addition to identifying oil and gas zones, logging can be used effectively for drilling progress evaluation. A typical log analyst is a specialist who can evaluate well logs for porosity, fluid content, saturation levels, and permeability estimates. Although these types of calculations are essential to the operation of the well, other important parameters may be needed by the drilling engineer to successfully drill the well....

Cont

8,8 Calculate the required circulation rate to air-drill a 7 -in. hole with 4-in. drillpipe at 65 ft hr and 4,800 ft 75 ft hr 85 ft hr. Plot the results. 8.9 An air rig is operating in eastern New Mexico at 5,400 ft, A 6-in. bit is being used with 3V2-m. drillpipe. Compute and plot the required air circulation rates for drill rates from 10-100 ft hr. Use 10-ft hr increments, 8.10 Refer to Example 8.4. Assume that the compressors can output only 1,100 cu ft min, What is the maximum allowable...

Drilling With Foam

Circulation System Solutions Drilling

Compute the volume of water required to drop the density of 200 bbl of 11.5-tb gal CaCl, brine to 10.5 lb gal. 1 From Table B4 CaCl2I - 36.6 CaCl,F 26.7 sp gr 1.3806 H,0 CaClz 42 1.3806 36.6 - 26.7 26.7 - 21.5 gai bbl 3 21.5 gal bbl x 200 bbl 4,300 gal Solids Systems solids tolerance . The solids concentration in the mud may be used to describe the system. A Clearwater mud has virtually no detectable solids. A low-solids system has some solids, although efforts are usually made to minimize...

Rotating Systems

The two common methods of turning the bit are I the rig's rotary table system and 2 downhole motors. The rig's rotary system does not place any restrictions on bit selection. Therefore, bit choice depends on the previously defined parameters, such as formation hardness and mud types. PDC bits in deep holes may be preferable when a rotary table is used. Deep wells often produce a significant amount of rotary torque due to bit and wall friction. Torque requirements are increased with high bit...

Eaton Frac Gradient Curves

Variable Overburden Stress Eaton

Casing was set on a Texas Gulf Coast well at 7,200 ft. It was estimated that formation pressure was equivalent to 11,0-lb gal mud. What is the fracture gradient immediately below the casing seat'.'1 Use Ihe Matthews and Kelly procedure. 1. P 11.0 lb gal 0.052 7,200 ft 3. Depth equivalent, D 0.535 D, a where 0.535 psi ft is the rock matrix stress 16.7 lb gal equivalent mud weight A graphical solution to the Matthews and Kelly technique is presented in Fig. 4-3. Note that the curved lines on the...

Table Common Brine Systems

Clay Hydration

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...

Purposes of Directional Drilling

Directional Drilling Applications

Controlled directional drilling is the process of deviating a wellbore along a predetermined course to a target whose location is given as lateral distance from the vertical. This definition is the basis for all controlled directional drilling, whether to maintain the wellbore as nearly vertical as possible or as a planned deviation from the vertical. Vertical drilling, although considered fundamental in most areas, can be very difficult to achieve in some regions due to steeply dipping...

Rig Site Preparation

Drilling Rig Spud Can

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...

Intermediate Casing

Casing String Design

Designs for intermediate pipe are different in principle than surface casing designs. Although the designs are computed in a similar manner, the philosophy for selecting burst and collapse design lines is altered. The primary purpose for the differences is to ensure a worst-case approach. Burst. The maximum burst loading occurs when a kick is taken and the annul us contains both gas and mud. The mud to be considered is the heaviest mud used below the intermediate casing. The casing must be able...

Hydrostatic Pressure

The hydrostatic pressure of the drilling fluid is an essential feature in maintaining control of a well and preventing blowouts. It is defined, in a practical sense, as the static pressure of a column of fluid. Although the fluid is generally mud, it can include air, natural gas, foam, mist, or aerated muds. Only liquid-based systems such as mud will be considered in this text. The hydrostatic pressure of a mud column is a function of the mud weight and the true vertical depth of the well. It...

Pressure Prediction Methods

Fluid Pressure

Several methods of pressure prediction are available to the engineer. These methods can be grouped logically as follows 1. areal analysis from seismic data drilling parameter evaluation production or test data The real-time analysis involves monitoring drilling and logging parameters while the prospect well is drilled. Subnormal pressures present few direct well control problems. However, subnormal pressures do cause many drilling and well planning problems. For clarity, the term abnormal...

Table Screen Cloth Sizes

Spray Discharge Rope Discharge

Too coarse for good solids removal Too coarse for good solids removal The shape of opening refers to square or oblong mesh. Square mesh screens have the same number of horizontal and vertical wires per inch, whereas oblong rnesh screens have a. different number of horizontal and vertical wires per inch Fig. 16-47 . The size of opening is the distance between wires in the screen cloth and is usually measured in fractions of an inch or microns. Screens of the same mesh may have different-sized...

Measurement While Drilling MWD

Mud Logging Jobs

The most recent technical innovations in drilling logging available to the on-site engineer have been MWD logs. The MWD tool is designed to provide a real-time, or instantaneous, recording and transmission to the surface of down-hole data. One advantage of the MWD tool over mud logging is that the data Fig. 17-14 Example of a mud log Courtesy The Analysts HC'.F im IT To i2'e _ S li lt ' 5 are available virtually at the time of the recording and are not delayed by the time required to pump the...

Dogleg Severity Analysis

Drill Pipe Dogleg Severity

The most common type of drillpipe failure is fatigue wear. It generally occurs in doglegs where the pipe goes through cyclic bending stresses. These stresses occur because the outer wall of the pipe in a dogleg is stretched and creates a greater tension load see Fig. 15-20 . As the pipe rotates a half cycle, the stresses change to the other side of the pipe. For example, the stress may change from 50,000 psi to -20,000 psi and again to 50,000 psi in the course of one cycle or rotation of the...

Noise Logging

Noise Logging

Noise logging is a technique for measuring and analyzing acoustical noise generated downhole by turbulent flows of liquids or gases. Noise amplitude and frequency data are recorded vs depth to produce a log from which a downhole flow can be located and traccd from source to sink. The log will also describe the flow as single- or two-phase and will provide information for estimating the flow rate. To date, noise logging has been used successfully to locate cross-flow channeling behind casing, to...

Drill Collar Selection

The drill collars are the first section of the drillstring to be designed. The collars' length and size affect the type of drillpipe that must be used. Drill-collar selection is usually based on 1 buckling considerations in the lower sections of the drillstring when weight is set on the bit or 2 using a sufficient amount of drill collars to avoid running the drillpipe in compression. The design approaches that satisfy these design criteria are the buoyancy factor method and the pressure-area...

Stress Evaluation

Grade selection for the tubing string is dependent on the determination of the stresses. The calculation procedures for the stresses must be completed in the following order 3. stresses resulting from tubing length changes This approach will be followed in this section. Lubinski's work on tubing design used a sign convention that is not completely consistent with some industry approaches. To avoid confusion, a listing of the sign conventions is shown in Table 13-3. This convention, as used by...

Surge Pressures

Swabbing And Surging Pictures

Fig, 18-12 Annular fluid flow resulting from pipe movement wellbore pressure below formation pressure. Surge pressures increase the total weIIbore pressure and can cause formation fracturing and lost circulation. Computing swab and surge pressures is difficult because of the manner in which the fluid flows as pipe is moved in the well. As shown in Fig. 18-12, pipe moving down the annulus causes the mud adjacent to the pipe to be dragged downward. Since the annulus is a fixed volume, however,...

Theoretical Determination

Normal Fracture Gradient

A number of theoretical and fie I d-d eve loped equations have been used to approximate formation fracture gradients. Many of these are suitable for immediate application in a given area, while some require a hindsight approach based on density or other logging measurements taken after the well has been drilled, A common base for most fracture gradient determination principles is the assumption that the geological area in question is a tectonically relaxed basin containing plastic-like shales...

Drilling Fluids Selection

A complete and comprehensive mud plan must be included in the well planning process. History has proven that an incomplete mud plan will cost the operator many hours of rig time and may mean the difference between a productive or a nonproductive well. The use of a drilling fluid to remove cuttings from the borehole was first conceived by Fauvelle, a French engineer, in 1845. Drilling fluids describes a broad range of fluids, both liquids and gases, used in drilling operations to achieve...

Info

The fast-line velocity can be computed as the product of pipe speed and number of lines strung over the block. 5. The efficiency of the mechanical system for the chains and shafts between the draw works and the engines was calculated in Example 16.2 as 0.834 Wire rope must be monitored for fatigue wear resulting from raising and lowering the drillstring or casing. The usual practice is to evaluate the number of ton-miles of work performed by the wire rope. A ton-mile is defined as the amount of...

Casing Physical Properties

Casing Table

The physical properties of oil-fieId tubular goods include grade, pressure resistance, drift diameter, and weight. These properties relate to the pipe's ability to meet the demands of the imposed drilling conditions. The limitations of the properties must be considered before final pipe selection. Grade, The pipe grade is a designation that defines the pipe's yield strength and certain special characteristics. The grade usually consists of a letter and a 2- or 3-digit number such as N-80. In...

Production Casing

Casing Burst Pressure

Features of the maximum load concept when applied to production casing differ slightly from the standard approaches for other types of casing. The differences relate to burst and collapse design factors and to burst load lluids. However, an attempt is made to continue implementing the worst-case philosophy in the designs. Burst, Production casing may be exposed to bottom-hole pressures BHP if a tubing leak develops. The worst case occurs when a small leak at the bottom of the tubing allows gas...

Casing Cementing Attachment Sdn

Wellhead Section Diagram

A well was drilled to 10,000 ft in Jim Hogg County, Texas. A 10.2-Ib gal mud was used. The 5-in. production casing was set at 10,000 ft and cemented with a 3,000-ft, 16.4-lb gal slurry After the cement was displaced into the annulus, the float valve in the guide shoe would not seal to prevent U-tubing the cement. Compute the amount of pressure that had to be held at the top of the casing ID . Draw a schematic of the well with mud and cement. 1. The hydrostatic pressure in the annulus is...

Directional Considerations

The drill bit indirectly affects the directional control problem in a well. The contributing factors include cutting structure on the cone The effect of the bottom-hole assembly BHA on directional control will be discussed in Chapter 15. Rotary drilling operations have an inherent tendency to a right-hand walk. This tendency is increased with the offset of the cones from the bit center. True rolling bits without cone offset decrease the right-hand walking characteristic. Remember, however, that...

Table Summary of Various Pertinent API Publications Relating to Casing and Tubing

Spec 5A Specification for Casing, Tubing, and Drill Pipe Spec 5AC Specification for Restricted Yield Strength Casing and Tub Spec 5AX Specification for High-Strength Casing, Tubing, and Drill Std 5B Specification for Threading, Gaging, and Thread Inspection of Casing, Tubing, and Line Pipe Threads Spec 5L Specification for Line Pipe RP 5C1 Recommended Practice for Care and Use of Casing and Bui 5A2 Bulletin on Thread Compounds Bui 5C2 Bulletin on Performance Properties of Casing and Tubing Bui...

Burst Collapse and Tension Evaluation

Previous sections defined stress as the controlling criteria for tubing design. Pipe selected for stress considerations will be overdesigncd in burst, collapse, and tension. Example 13.2 will illustrate this feature with respect to Example 13.1. Show that burst, collapse, and tension values are overdesigned when nsing stress as the controlling criteria. Use Example 13.1. The maximum properties for J-55, 2.875-in., 6.4-lb ft tubing is as follows Burst 7,260 psi Collapse 7,680 psi Tension 99,660...

Measurements While Drilling

Dogleg Severity Formula

Fig. 17-15 MWD log Courtesy The Analysts Fig. 17-15 MWD log Courtesy The Analysts Fig. 17-16 Schlumberger-Analysts's MWD collar Courtesy The Analysts Fig. 17-16 Schlumberger-Analysts's MWD collar Courtesy The Analysts current flow. The too uses ultra-long-spacing normal devices to obtain deep-investigation readings that are influenced by the anomaly. A standard resistivity log such as the 1SF is used to construct a layered model of the formation that can be used to compute the ULSEL readings to...