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...
Problems Gzk
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
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...
References Ovx
Adams, Neal. Well Control Problems and Solutions, Tulsa PennWell Publishing Company, 1980. Baroid Division, NL Petroleum Services, Manual of Drilling Fluids Technology, Section 2, Houston, 1979. Bingham, M.G. A New Approach to Interpreting Rock Drill ability. Oil amp Gas Journal, 2 November 1964-5 April 1965. Boatman, W.A. Shale Densities Key to Safer, Faster Drilling. World Oil, August 1967. Fertl, W.H. Abnormal Formation Pressures Implications to Exploration, Drilling, and Production of Oil...
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
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...
Hole Geometry Selection
Bit and casing size selection can mean the difference between a well that must be abandoned before completion and a well that is an economic and engineering success. Improper size selection can result in holes so small that the well must be abandoned due to drilling or completion problems. The drilling engineer and well planner is responsible for designing the hole geometry to avoid these problems. However, a successful well is not necessarily an economic success. For example, a well design...
Problems Boy
5.1 Rework Example 5.1 with the following set of design factors. A small-diameter hole with a high-viscosity mud requires the use of 0.4 lb gal factors for swab and surge. The type of mud being used necessitates a maximum limit of 2,200 psi differentia pressure for the normal pressure 2one. Use a 0.2-lb gal safety margin, 5.2 Determine the intermediate casing setting depth for the following set of conditions. Use the Eaton fracture gradient chart in Chapter 4 to determine the formation fracture...
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...
Example Vef
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
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...
Example Acq
In the illustration in Fig. 4-9, what is the effective fracture gradient at the casing seat 1. Convert the water depth to an equivalent section of formation 1,000 ft X 0.465 psi ft 465 psi Fig. 4-7 Graphical determination of fracture gradients using the Eaton approach Courtesy of Adams and Rountree Technology, Inc. 0.45 0.50 055 0.60 0.65 0.70 0.75 0.80 Fracture gradient, ps fl subsea 0.45 0.50 055 0.60 0.65 0.70 0.75 0.80 Fracture gradient, ps fl subsea Fig. 4-8 Offshore fracture gradients as...
Example Cgl
A drilling engineer wants to compare the viability of preplanning a hydraulics program for a well. He knows the expected and actual parameters used on the well. Determine if preplanning the hydraulics program provides a realistic estimate that is sufficiently accurate for field use. The mud parameters used in the actual well were the only values different than the expected conditions. Hole geometry Interval, ft 0-3,500 3.500-10,000 10,000-13,000 maximum pump pressure maximum flow rate pump...
References Oyy
Casner, J.A. 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...
Problems Pxd
13.1 Suppose that high-density cement is pumped down a production tubing string during a squeeze cement job. Can the tubing buckle Why 13.2 Discuss the operating conditions that cause an anchored assembly to increase tubing stress, 13.3 Suppose steam will be injected through tubing in a thermal recovery project. What effect will it have on the tubing If the average temperature change is I50 F, what is the expected length change 13.4 Discuss the significance of the helical spiral in a buckled...
Example Nwp
Use Fig. 5-2a to determine the proper setting depth for intermediate pipe. Assume a 0.3-lb gal factor for swab and surge and a 0.2-lb gal safety factor. Use an arbitrary maximum limit of 2,200 psi differential pressure for normal 1. Evaluate the maximum pressures equivalent mud weights at the total depth of the well. Amount, lb gal Purpose Type of Pressure 15.6 Formation pressure Actual mud weight 0.3 Trip margin Actual mud weight 0.3 Surge pressure Equivalent mud weight 0.2 Safety factor...
Special Cementing 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...
J 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
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...
References Jjr
Angel, R.R. Volume Requirements for Air-Gas Drilling. Houston Gulf Publishing Company, 1980. API Specification for Oil-Well Drilling-Fluid Materials, API Specification 13A, 7th edition. API Division of Production. Dallas, May 1979. Bordclon, Bruce. Personal conversation, Lake Charles, Louisiana. Chesser, B.G., and G.F. Nelson. Applications of Weighted Acid-Soluble Workover Fluids. Journal of Petroleum Technology, January 1975, pp. 35-39. Densimix Inc. Technical articles. Houston, 1982. Dresser...
Types of Completions
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...
Example Kqc
A bit record for the Two Star 3 well was analyzed as the control well for a prospect to be drilled. The record showed that a kick was taken at 10,900 ft. Comments on the bit record were interpreted to indicate that the well was not killed with proper techniques. What is the actual formation pressure, in lb gal, at 10,900 ft Depth 10,900 ft TVD Casing 10,300 ft Mud weight Prior to setting casing at 10,300 ft After setting casing at 10,300 ft Prior to the kick After the kick 9.8 lb gal 12.0 lb...
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...
Example Iiw
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...
References Rgu
Applied Drilling Services Volume I User's Guide. Lafayette, LA Adams and Rountree Technology Inc., 1981. Casing. Tubing, and Drill Pipe. API Specification 5A, 1981 Casing, Tubing, Drill Pipe, and Line Pipe Properties. API Bulletin 5C3.I980 with Supplement 2, 1983. Holmquist and Nadai. Collapse of Deep Well Casing. API Drilling and Production Practices, 1939. Mudge. Kris. Council Petroleum Services Inc., personal discussions. N.L. Atias Bradford tubular brochures. Casing string design and...
c 1
Fig. 18-17 Particle drag coefficient When 10 lt Nr lt OO, the drag coefficient becomes Eq, 18.66 is recommended for most field applications. As can be easily seen, Moore's approach may require several iterations. The apparent viscosity in fiqs. 18.64, 18.66, and 18.68 as proposed by Moore is computed as follows Noic that the consistency index in Eq. 18.19a is used only in the Moore correlation, 2. The annular velocity, V, is computed as
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...
Example Ukw
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
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
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
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
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...
Example
Plot the following resistivity data on semilog paper. Where does the entrance into abnormal pressures occur Use the Hottman and Johnson method to compute formation pressures at each 1,000-ft interval below the entrance into pressures. 1. Plot the data as shown in Fig. 3-17. 2. The estimated entrance into abnormal pressure occurs at 9,700 ft. 3. Extrapolate the normal trend established between 8,000 and 9,700 ft. 4. The observed and extrapolated resistivities at the bottom are 0.30 and 1.60...
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
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
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
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
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 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...
DrillCollar 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
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
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...