bluuebunny/crossref_metadata_2025 huggingface dataset:
Completion Systems for Large Diameter Casing
Authors: Weirich J. B. , Lorenz M. , Leggett D.
Published: December 2007

Completion operations, for oil and gas wells, arc usually performed in casing sizes not exceeding 13-3/8" (34.0 cm) with the majority of completions being performed in 9-5/8" (24.5 cm) and smaller. As such, the availability of completion equipment, for large diameter casings, becomes extremely limited or nonexistent. Occasionally, conditions may exist which require the completion to be designed in a casing size larger than 13-3/8" (34.0 cm). In order to complete in these casing sizes, special equipment must be designed.

This paper discusses the design criteria, development, and subsequent use of perforating and gravel pack equipment generated for use in 20" (50.8 cm) casing. The theoretical approach to the evolution of this equipment is applicable to the development of additional systems.
Oilfield Liquid Measurement for Sarawak Shell Bhd and Petronas Carigali in Baram Delta Area
Authors: Pushparatnam E. , Teo C. K.
Published: December 2007

This paper describes the measurement of crude oil volume in an oil/water mixture that discharges from an oilfield. Measurement is carried out using a turbine meter, a densitometer and a flowcomputer. The system is capable of determining the volume of crude oil in a flowing stream of a crude oil/water mixture within 2% of the total liquid volume.
Production and Reserves Monitoring (PARM) System
Authors: Rennie R. G. , Senduk R. , Tabalujan H.
Published: December 2007

Huffco Indonesia has developed and installed a computerized database system called PARM System - "Production and Reserves Monitoring System". This integrated database handles data that includes reservoir, geological, production, operations and mechanical well data. While the PARM System data are acquired and controlled from many technical and operations disciplines within the company it is always input as close to the original source as possible.

The PARM System, as an integrated production and reserves data source for Huffco Indonesia, has applications across a wide range of engineering and operations disciplines. Daily production and operations reports, monthly production allocation and product distribution reports, daily drilling reports and summary reports and many other necessary routine reports are generated by the PARM System. Benefits of analysis of large volumes of data, which were previously very cumbersome to attempt, are now being realized by engineering groups. Ad-hoc data retrievals provide consistent current and historical data for production and reservoir engineering applications.

An integrated computerized database system such as the PARM System, provides a cost and time efficient engineering and operations tool. It pro ides unparalleled accessibility to any data likely to affect or resulting from the oil and gas production of a well, zone or field. Accuracy of original data is improved due to multi-user review and built-in integrity checks. Development of a system, such as the PARM System, should be done on a prototype basis under direct engineering management.

Application of computer technology to the petroleum industry is manifested in the PARM System by virtue of capturing and handling of the basic oil and gas operations and engineering data. This paper describes the design and implementation concepts of the PARM System as well as engineering and operations applications ranging from simple reports and data retrievals to interfacing with reservoir simulation software.
Analyzing Dual Porosity Systems by Rectangular Hyperbolic Method
Authors: Mead H. N.
Published: December 2007

The purpose of this paper is threefold:(1) to present a method of buildup analysis (RHM) that can determine the percentage of reservoir column open to the wellbore which is contributing reservoir fluid, (2) to determine the average permeability of the permeable portion of the reservoir open to the wellbore and (3) to determine the possible existence of a dual porosity system and the characteristics of the fracture or vugular system that might produce reservoir fluid into the wellbore. Since RHM is a relatively new concept, two appendices are attached to explain the general aspects of the RHM procedure. The writer presented a paper related to this one at the 1987 SPE Regional California Meeting in April, 1987, (see reference 4).
A Critical Evaluation of the Deviation Time Method to Calculate Discontinuity Radias From Well Tests in Composite Reservoirs
Authors: Ambastha A. K. , Ramey H. J.
Published: December 2007

Reservoirs with a fluid bank, or a buming front, reservoirs with a reduced or an increased permeability region around the wellbore, and geothermal reservoirs are often modeled as composite reservoirs. Reservoirs with a fluid bank include reservoirs undergoing waterflood, chemical flood, polymer flood, C02 flood, and steam injection. Eight well tests reported in the literature exhibiting composite reservoir behavior have been analyzed using the deviation time method. The dimensionless deviation times obtained from pressure and pressure derivative responses for a well in a composite reservoir have been used for analyzing the well tests. Analysis shows the estimate of discontinuity radius to be sensitive to both the real and the dimensionless deviation times used. The estimated discontinuity radius from the deviation time method may represent a lower bound for discontinuity radius, if the swept region is not cylindrical Also, obtaining an accurate deviation time for small mobility contrasts may be difficult.

Limitations on the deviation time method due to wellbore storage effects have been quantified indicating a need to minimize wellbore storage in composite reservoir well tests. The effects of a transition region on the dimensionless deviation time have been studied using an analytical solution for a three-region reservoir.
The Oilfield Microbiology Assistance System (OMAS)
Authors: Horacek G. L.
Published: December 2007

An artificial intelligence knowledge base (expert system) has been developed to assist oilfield personnel in analyzing for bacterial involvement in water-related field problems. The expert system also advises on the probability that bacterial contamination is involved in corrosion and can make biocide recommendations for several common bacteria-mediated field problems. The new expert system, Oilfield Microbiology Assistance System (OMAS), is a floppy-disc-based computer program that runs on most IBM and IBM - compatible personal computers. On-line help is included with the program diskette. The expert system was developed using INSIGHT 2+ software and is distributed to company personnel in a "read-only" format. The expert system covers situations encountered in the oilfield environment but can be tailored for other specific applications.
Experience Gained in the Monitoring of the Das Island LNG Installation in Sour Gas Service
Authors: Pattinson J.
Published: December 2007

The Das Island Gas Liquefaction plant accepts a range of feed gases. The different streams are listed in Table 1. As can be seen from this table, many of the gas streams are sour, containing significantly more H2S than the 0.05 psia given by NACE standard MR-01-75 in its definition of sour service. These incoming gases are also damp and so corrosion and consequent hydrogen damage will occur unless remedial action is taken. Aqueous corrosion has two components; an oxidising or anodic reaction such as Fe→Fe2++2e

and a reducing or cathodic reaction, which, in the case of damp H2S, is 2H++2e→2H→H2

The second stage of this latter reaction is poisoned by the presence of sulphide ions and the hydrogen atoms, instead of combining to produce hydrogen molecules, are taken up into nearby steel. Thus atomic hydrogen dissolves in the steel structure and can cause a decrease in the metal's toughness. However, if the steel contains inclusions then these hydrogen atoms combine at the inclusion/metal interfaces and the resulting pressure of hydrogen gas leads to delamination and cracking – known as hydrogen induced cracking (HIC).

The first step of liquefaction is the compression of the various gas streams in four stages until a single stream of gas is produced at 780 psi which goes on to be scrubbed of H2S and CO2. The gas liquefaction plant is split into two identical trains with the first stage compression being common to both. The schematic of the compression process is shown in Figure 1. The design process conditions are given in Table 2.
Preliminary Investigation Into the Utilization of Gas Containing 21% H2S in Oilfield Gas Turbines
Authors: Rabbo M. F. Abd
Published: December 2007

Oil fields electrical power generation is commonly dependent on separated sweet gas for fuel in typical turbine/generators set up. As discoveries and subsequent development of sour oil and gas fields are becoming common place, either the produced sour gas is sweetened or diesel is used for fue-lling the gas turbine/generators. However, due to the high cost of diesel fuel, most operating companies opt for sweetening the gas for fuelling gas turbines. Sour gas of hydrogen sulphide (H2S) content above 2% was always discarded as fuel for fear of hot corrosion (sulphodation) of the hot section of the gas turbine would lead to catastrophic failure. This paper is set out to investigate possible modifications to a typical oil field gas turbine in order to economically allow for burning sour gas without the onset of hot corrosion. The study looked at a typical example of an oil field gas turbine generator currently being operated by diesel fuel and discussed the necessary modifications to operate the turbine on sour gas containing upto 21% H2S by volume. The economies of diesel, sour and sweetened gas operations were highlighted.
A New Technique for Deriving the Resistivity Parameters of Archie's Equation From Combination of Logs and Core Measurements
Authors: Aldoleimi A. M. , Berta D.
Published: December 2007

A new approach in determining the parameters of the Archie's equation a, m and n is presented in this paper. It is based on the use of water saturation from the core or from an EPT type measurement and the resistivity of the formation where this water saturation is known.

The proposed method is an extension to a 3D space of the usual regression technique used in a plane, as in the laboratory determination of m and n. Both a spatial visualization and a regression may be used to obtain the Archie parameters.

This method may be applied in different situations: –in a reservoir at any water saturation in a well drilled with a waterbase mud where both MSFL and EPT type logs have been run.–in a reservoir at irreducible water saturation and in a well drilled with a tagged oil base mud of known water loss where the resistivity of the formation is measured by an induction tool and the water saturation is known from either the core or an EPT type tool.–in a reservoir at residual oil saturation (after a waterflood), in a well drilled with a waterbase mud where the resistivity of the formation is measured by a long spacing resistivity tool and the water saturation is known from either an EPT type log or a core.

Examples are given of the use of this technique in a carbonate field of the Middle East from two different reservoirs: The high heterogeneity of the first reservoir makes it necessary to sort the data per lithofacies and therefore reduces the number of data points, whereas in the second, more homogeneous results are fairly straight forward and provide an answer close to the accepted triplet (1,2,2) for (a, m, n).
Basic Reservoir Engineering and History-Match Study on the Fractured Raman Reservoir, Turkey
Authors: Sener I. , Bakiler C. S.
Published: December 2007

Raman oil field, located in southeastern Turkey, has been recently analyzed and studied in detail for the final objective of determining the future recovery potential under various production alternatives. The original oil-in-place in Raman is estimated to be 611.4 MMSTB of 15 to 19 API oil.

Production formation in Raman is the fractured Mardin limestone which receives pressure support from an underlying strong bottom aquifer. The reservoir-aquifer interaction takes place through an extensive network of mostly vertical fractures. In addition to being fractured, the producing Mardin formation is also heavily faulted.

The primary recovery mechanism and the recovery efficiency in Raman strongly rely on the presence of vertical fractures that are also responsible for bringing the steady-state aquifer support. With the flow direction being mainly vertical, rapid coning caused by strong influx leaves most of the oil bypassed between the wells.

This paper covers a review of reservoir geology, basic reservoir engineering to characterize the production mechanism, the fractured nature of the reservoir, the interaction with the aquifer; and finally, the history match and subsequent predictions with a suitable fractured reservoir simulator.
Case Histories of Electrical Submersible Pump Operations and Unique Scaling Tendency in Pumping Wells of Kuwait Oil Fields
Authors: Chawla M. L. , Ghoniem S. A.
Published: December 2007

Most of the crude production in Kuwait is from the naturally flowing wells. Eight wells of field ‘A’ were put on artificial lift in the year 1981 and Electrical submersible pump (ESP) was selected as the primary mode of lift. Between 1985 to 1988 fourteen wells of an other field ‘B’ were completed with ESPs. At the present production level, approximately 6% of Kuwait's production is contributed by the ESPs.

While the pump performance in field ‘A’ has been satisfactory, with reasonable run life of downhole equipment, on the other hand several premature failures of downhole equipment in field ‘B’ were experienced. ESP teardown inspection at the manufacturer's works indicated severe scale deposition in the pump internals resulting in blocked fluid passage and locked pump shaft. Scale deposition problem in pumps of field ‘B’ is unique where only traces of water are produced from most wells. This paper addresses the possible mechanism of scale deposition, remedial measures tried and future course of action to inhibit scale. Pump design data, operational experience and downhole equipment failure frequency for the two fields are included.
In-Place Determination of Reservoir Relative Permeability Using Well Test Analysis
Authors: Al-Khalifa A. A. , Home R. N. , Aziz K.
Published: December 2007

This paper describes a new method to estimate two- and three-phase relative permeabilities in-situ, using pressure transient analysis. The technique requires a short drawdown test, consisting of a number of steps of increasing flow rate. The resulting relative permeabilities reflect the properties of the whole drainage area, rather than those of a small laboratory core. The proposed technique is a major improvement over current historical performance methods. These existing methods need data over long periods, yet only cover a range of saturation up to present conditions - all future projections require extrapolation. By contrast, the new method estimates relative permeabilities at sandface saturations, which cover a range of future reservoir conditions. The well test can be repeated at a later stage of depletion to forecast still further into the future.

The proposed technique applies the solutions of multiphase diffusivity equation in terms of the pseudopressure function, m(p). These solutions have already been reported for constant rate tests in solution gas-drive reservoirs. This paper extends the pseudopressure solutions to three-phase systems. Two- and three-phase solutions are then superposed to obtain multiple-rate solutions, the basis for two-and three-phase relative permeability equations. A saturation equation developed originally by Bϕe et al. for solution gas-drive reservoirs, is also extended here to three-phase reservoirs. These pressure-saturation equations can be used to estimate sandface saturations during the test.

Using a commercial black-oil simulator, example well tests were simulated over a 40% range in gas saturation. Both two- and three-phase results show close agreement with input relative permeability curves. In cases where relative permeability is not homogeneous within the drainage area, the resulting estimates of relative permeability curves were very representative of in-situ heterogeneities.

The proposed technique offers a means to estimate two- and three-phase relative permeabilities at in-situ reservoir conditions, accounting for heterogeneities, wettability and fluid composition. It also seems to be the most appropriate way to obtain estimates for subsequent reservoir engineering analysis.
Structural Interpretation From VSP's in India
Authors: Mohan V. C. , Edwards J. E. , Saran R.
Published: December 2007

Vertical Seismic Profiles (VSPs) are an important source of near-well structural information. This paper describes the VSP acquisition techniques and processing procedures used in two examples in southern India to locate and define faults and to measure dip. The interpretation of the structural features from the VSP's deconvolved up-going wavefield is also discussed, and the results are then compared with modeled reflector responses for the structural features. The offset of the fault from the well and the dip of the reflectors beneath the well can be estimated from the VSP data.
The Role of the Doctor of Engineering Degree in Graduate Education
Authors: Bosch Wouter , Carlile Robert E.
Published: December 2007

American Institute of Mining, Metallurgical and Petroleum Engineers, Inc.

This paper was prepared for the 42nd Annual Fall Meeting of the Society of Petroleum Engineers of AIME, to be held in Houston, Tex., Oct. 1–4, 1967. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor of the appropriate journal provided agreement to give proper credit is made.

Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines.

At a recent panel discussion held at Carnegie Institute of Technology the following remarks were made.

Faculty members of today's universities must not be afraid of innovation and should enjoy the privilege of trying new approaches to education and of being wrong in these attempts to improve old priorities. Universities must give effective education …or be doomed to failure.

From these two remarks one can gain a remarkable insight into transitions which have been creeping into the academic and industrial realms of education.

The first observation is that of the modernization of universities and their often archaic attitudes toward long established and heretofore untouchable areas of education. The Doctor of Philosophy degree is one such entrenched conformity that has stood for decades as the ultimate in scholastic achievement.

Let's face the current situation for what it is. In today's technological implosion, the modern institute of technology no longer conforms to the classical definition. It is no longer solely a cloistered society devoted to the development of mechanical skills and arts, but is today an institution that develops specialized and highly narrowed areas of competency, these fields of specialization being directly proportional to the competency and specialized interests of the active faculty of that institution and/or to the breadth of inquisitiveness of the candidate.

Following the Morrill Land Grant College Bill of July, 1862, the next five decades saw the establishment of some 150 land grant engineering institutions. In all but four of these institutions, engineering was decreed as a part of a unified, four-year curriculum directed not toward professional education but, rather toward professionally oriented general education.
Wireline Actuated PDC Underreamer Increases Drilling Efficiency in the Gulf of Mexico
Authors: Easton A. , Graham T. E.
Published: December 2007

A method has been developed for simultaneously drilling and underreaming from casing point to casing point with only one round trip. The successful development of the method from the planning stage through field testing is presented and the method is evaluated using field results.

The method involves the use of a hydraulically activated PDC underreamer and a wireline retrievable spear. After casing is set, the underreamer is run in the hole with the wireline spear in place keeping the underreamer closed. Cement, float equipment, and a few feet of rat hole are drilled before the spear is retrieved and simultaneous drilling and underreaming begins.

Using this method, Mobil Oil Company was able to substantially reduce the cost of drilling and underreaming a section from casing point to casing point at Green Canyon Block 18 in the Gulf of Mexico.
The Refinement of a Drillstring Simulator: Its Validation and Applications
Authors: Child A. J. , Ward A. L.
Published: December 2007

This paper describes aspects of the development and validation of a drillstring mechanics computer model. It illustrates a number of specific applications and shows how the use of such a model can be of benefit to the economics of drilling a well both in direct (eg. optimisation of well profile / drillstring configurations) and indirect (eg. post failure analysis understanding) ways.
Selecting Distinguished Scholars
Authors: Menzie D.E.
Published: December 2007

American Institute of Mining, Metallurgical and Petroleum Engineers, Inc.

This paper was prepared for the 42nd Annual Fall Meeting of the Society of Petroleum Engineers of AIME, to be held in Houston, Tex., Oct. 1–4, 1967. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor of the appropriate journal provided agreement to give proper credit is made.

Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines.

Introduction

In August, 1967, an analysis was made of information pertaining to present and past participants of the Petroleum and Geological Engineering "Honors Scholars" Program at the University of Oklahoma. This study was conducted for the purpose of discovering ways to determine the scholastic success of a prospective honor scholar and to enable more accurate selection future participants.

Included in this study is a listing of information concerning each student's ACT (American College Test) standard scores and grade point average. Letters and questionnaires were sent to each student, and through the students' cooperation, much of the data was collected.

This paper describes the background of the Honors-Distinguished Scholars Program at OU, discusses the findings about the students in the study, gives an analysis of the information, and offers suggestions for further improving the selection of honor scholars.

It should be noted that this is an initial report. As the program continues more inclusive information may be gathered about the scholars' university program, industry achievement, and the quality of their success.

BACKGROUND OF THE HONORS PROGRAM

In 1963, believing that outstanding high school students should be given the opportunity of participating in and gaining from a highly enriched educational experience, members of the faculty in the Oklahoma University School of Petroleum and Geological Engineering began thinking of ways to unite further the student in Petroleum Engineering and the petroleum industry in which the student expected someday to work.

Noting that the school already had a scholarship program established with many participating petroleum companies, the Petroleum Engineering faculty devised a program which would permit stronger involvement of both the student and the company. The "Honors Scholars" Program was thus initiated in the Fall of 1964.

Requirements for Admittance to the Program

The requirements for admittance to the honors program are high in order to insure outstanding performance of the participants.
Triaxial Collapse Design Considerations for Well Tubulars
Authors: Peterson J. L.
Published: December 2007

Determination of the differential collapse pressure rating of pipe without evaluating the effect of the internal pressure is always non conservative. The errors are highest (5 to 10 percent or greater) for thick wall pipe (API yield collapse mode) at high axial load and high internal pressure. The errors are negligible for thin wall tubulars or other applications where the axial load or internal pressure is low. The derivation of the triaxial analysis for thick wall pipe is provided. In addition, the equation is expressed on a single figure allowing the user to quickly determine the impact of ignoring the internal pressure for an application using thick wall tubulars. Adjustments are also provided for other than thick wall pipe to facilitate quick evaluation.
Operations at a Deep Relief Well: The TXO Marshall
Authors: Grace R. D. , Kuckes A. F. , Branton J.
Published: December 2007

Technology in directional surveying and borehole proximity surveying is advancing rapidly and is to the point that relief wells are now a realistic, economical and reliable alternative in well control operations. This paper chronicles relief well operations at the TXO Marshall located in Leon County, Texas. Operations at the Marshall successfully resulted in the second deepest wellbore intercept in the history of the industry. Magnetic multishot, magnetic single shot, Gyroscopic, and MWD data are compared, and the results are presented. Reliabilty and repeatibility of directional surveys are discussed in depth. Borehole proximity technology and advances in that technology is addressed.
Participation: The Solution to the AIME Student Chapter Problem
Authors: Crafton James W. , Brill James P.
Published: December 2007

American Institute of Mining, Metallurgical and Petroleum Engineers, Inc.

This paper was prepared for the 42nd Annual Fall Meeting of the Society of Petroleum Engineers of AIME, to be held in Houston, Tex., Oct. 1–4, 1967. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor of the appropriate journal provided agreement to give proper credit is made.

Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines.

For many years AIME student chapters have struggled with periodic ups and downs. An analysis of problems which confront these chapters is presented in the hopes that the discussion will help chapters recognize and solve their problems. Possible solutions and guidelines for more effective chapter operation are thoroughly discussed. The importance and responsibilities of the student members, officers, and faculty advisor are reviewed.

The factor which characterizes a dynamic AIME student chapter is the PARTICIPATION which the chapter receives from its members and the degree to which the chapter PARTICIPATES in SPE and AIME activities.

Introduction

In the history of The Society of Petroleum Engineers we have never taken a more active interest in the activities of students than now. Yet we are just beginning to realize the potential of the AIME student chapters. When we try to be so vitally interested in the student, we cannot neglect this most intimate and continuous contact with him.

It often seems that bad things get worse and good things remain the same. Perhaps this happens with the AIME student chapters as well. In a poor, weak, nearly defunct chapter, the lack of incentive curtails any interest or desire to attempt improvement. Perhaps if the operation of a strong, active chapter is investigated, it will be possible to provide others with an awareness of, an interest in, and possible solutions to the problems facing AIME student chapters. Therefore, let us take a look at some of the characteristics and ideas inherent in a dynamic chapter and glance briefly at some of the problems that cause a chapter to weaken and to remain weak.

THE PROBLEM or "Through the Looking Glass Darkly"

In an active, dynamic chapter, the members want to attend meetings. They feel privileged when they are asked to work on chapter projects. It is relatively easy to generate enthusiasm in the organization. The student chapter almost creates its own progress, yet this does not make the successful chapter immune to decline.
Educational Opportunity in Depressed Economic Times
Authors: Gadomski C. R. , Eubanks W. A.
Published: December 2007

The difficult economic conditions of the oil industry in the 1980's provided Schlumberger with an opportunity to enhance the technical and professional expertise of our personnel. This paper describes two major programs initiated during these economically depressed times -the Advanced Degree Program and the Summer Petroleum Engineering Seminar. Both proved to be successful to Schlumberger and the individuals involved. The Advanced Degree Program was an educational leave of absence granted for one year to selected field personnel. The Summer Petroleum Engineering Seminar, administered in conjunction with the University of Texas at Austin, was a 12-week program of intense instruction for field engineers in applicable topics of petroleum engineering. Included in this paper will be the philosophy of establishing the programs, costs incurred, and the benefits gained.
Measuring Offshore Subsidence with Seabed Pressure Gauges
Authors: Mes M. J.
Published: December 2007

Phillips Petroleum Company Norway successfully completed the development, installation and application of pressure gauges to measure platform subsidence as a function of time.

Four pressure gauge systems were installed in the greater Ekofisk area in 1987. On each of the 2/4-E Tor, 2/7-C Edda and 2/4-F Albuskjell platforms one system was installed, serving as platform bench mark references. One system was installed on the 2/4-H Hotel platform, for which the subsidence must be measured as a function of time. The measurement system as it was installed, is described.

The interpretation of the Tor and Albuskjell data is demonstrated with actual data. How this interpretation is used to derive subsidence information is discussed.

The apparent uncertainty from prototype data indicates that the progression of subsidence can be measured with a relative uncertainty of the order of ± 1 cm.
Overpressure Calibrated Design of Hydraulic Fracture Stimulations
Authors: Shlyapobersky J. , Wong G. K. , Walhaug W. W.
Published: December 2007

This paper presents a new concept, model, and procedure to design hydraulic fracturing treatments. The purpose of the paper is to develop an approach in designing hydraulic fracture stimulations that would be more consistent with field observations and would better match the field net fracture propagation pressure.

The concept and procedure consist of using the net fracture pressure measured shortly after shut-in (overpressure) to determine the apparent fracture toughness (Γ or K1c) of the formation. This field calibrated K1c or overpressure is then used as an input to an approximate hydraulic fracture simulator, called ENERFRAC, to design the hydraulic fracture stimulation volume and proppant injection schedule.

The field overpressure needed to determine the K1c can be accurately measured using a minifrac test. The overpressure is defined as the difference between the corrected instantaneous shut-in pressure and the minimum in-situ stress. Frequently, the field calibrated K1c could be one to two orders of magnitude larger than those measured in the laboratory using small samples. This high value of K1c is attributed to the field and scale dependent process zone at the fracture tip.

The field calibrated K1c could dominate the fracture growth and needs to be included in the hydraulic fracture model to predict realistic fracture dimensions. This paper provides an approximate model, called ENERFRAC, that incorporates the effect of K1c in addition to the other interacting processes of viscous fluid flow, elastic rock deformation, and fluid loss in the conventional models of contained and uncontained fractures.

This paper outlines the procedure for the overpressure calibrated design and provides three field examples to illustrate the design procedure and to show the effect of designing with and without overpressures. Examples of treatments that are more aggressive (with smaller pad and larger amount of proppant) or more conservative (with larger pad) than those generated by the Khristianovic/Geertsma/deKlerk model (KGD) are presented. Thus, the proposed overpressure calibrated design not only provides a stimulation that is more consistent with field observations but may also reduce the risk of premature sand-out.
The Effect of Flow From Perforations on Two-Phase Flow: Implications for Production Logging
Authors: Zhu Ding , Hill A. D.
Published: December 2007

The phenomenon of a dense phase (water) entering through perforations into a stream of a less dense phase (gas or oil) has been examined in a model wellbore. When water entered a gas stream, some of the water fell through the gas stream to occupy a portion of the wellbore below the perforations for all conditions tested and anomalous pressure behavior was observed in the region of the perforations. In the oil-water tests, all of the water was swept upwards by the oil only at the highest oil flow rate (5000 b/d) and lowest water flow rate (50 b/d) with the pipe vertical. The deleterious effect of dense phase fallback on production log interpretation is demonstrated.
Production System Optimization: Model Applications, Capabilities, and Pitfalls
Authors: Iyoho A. W. , Lea J. F.
Published: December 2007

This paper discusses the state of the art in total production-system analysis useful for economical design of well inflow parameters, sizing of tubulars and accessories, and determining well flow constraints. In addition, capabilities and pitfalls are cited in model applications.

To bridge the gap between model developers and users, the structure of a typical computer program is discussed. Field cases are then used to emphasize good geological and engineering practices as opposed to total reliance on model results. Applications of optimization programs to naturally flowing wells, wells on pump, gas-lift wells, and fractured wells are presented, with emphasis on greater technical cooperation. The beam-pump and injection-well examples presented in the paper should be particularly interesting since these areas have seen limited total-system analysis.

Major conclusions are that the total system approach can provide important analytical answers to production problems. However, model application must be combined with sound technical and economic judgement, and a willingness to cooperate with geologists and engineers from all disciplines, to realize its full potential.
Successful Water Control Examples in Gulf of Mexico Gravel Packed Gas Completions
Authors: Carroll J. F. , Bullen B.
Published: December 2007

Numerous methods of water control have been attempted in gravel-pack completions. Many of these methods utilize predesigned hardware to plug off anticipated sources of future water production. The problems associated with these methods include predictions of reservoir performance and the extra expense and installation of the completion hardware necessary to achieve future predicted water production. Other methods of water control use chemical injection treatments. These treatments are usually expensive and hard to control.

Laboratory tests were made to evaluate a new method of controlling fluid migration in an internal gravel-pack completion. Production data which confirm the success of this method in the Gulf of Mexico are presented.
Casinghead Gas Processing at the Belridge Field
Authors: Jan R. J. , Reed T. G.
Published: December 2007

Thermal enhanced recovery has been practiced at the oil fields near Bakersfield since late 1950s. Typically, 600 to 700 psig steam, at about 70 to 80 % quality is injected into the formation to heat the oil and to drive the oil to the producing wells.

The injection of steam results in the formation of various gases in the formation which are produced as casing head gas. Because of it's low heating value, it is also called waste gas. Typically, the gas is saturated with steam, has a composition of about 80 % CO2, with up to 5 % H2S and a heating value of between 200 to 500 BTU per cubic foot.

Environmental regulation in California dictates that the casing head gas cannot be vented to the atmosphere but must be gathered and disposed of. Normally entrained oil and condensate are removed before final burning in an inc inerator.

A process has been developed and implemented at Mobil's Belridge field whereby up to 5 MMSCFD of waste gas is gathered, treated, and blended with fuel gas which is burned in the steam generators. The blending of gases has become an integral part of the operation and quality control of a steam generator through a Programmable Logic Controller.

The system has been in service for two years. Savings in operating cost alone has more than paid for the initial capital investment. Further, the simplified system design has lowered the wellhead casing pressure and resulted in an increase in the oil production.
Effects of Wellbore Pressure on Perforator Penetration Depth
Authors: Behrmann L. A. , Halleck P. M.
Published: December 2007

Industry has generally assumed that perforator penetration depth is independent of wellbore pressure. However, recent test data clearly show that modern perforator penetration performance is significantly affected by wellbore pressure. Two series of tests were performed using unstressed and stressed Berea sandstone. The unstressed tests used modified API Section II Berea test targets with wellbore pressure equal to pore pressure. Three different perforators at a 0.75-in. gun-to-casing clearance were tested. The penetration reduction from ambient to 15,000 psi wellbore/pore pressure was charge dependent and ranged from 22% to 28%.

Tests with nonequal wellbore and pore pressures in unstressed Berea targets showed penetration reduction to be independent of pore pressure.

Test of a single perforator in stressed Berea at an effective stress of 2000 psi also showed penetration reduction with wellbore pressure. This penetration reduction suggests that for the perforator tested, wellbore pressure may be a more dominant effect than in situ stress for deep wells.
Exploitation of Deeply Buried Coalbed Methane Using Different Hydraulic Fracturing Techniques in the Piceance Basin, Colorado and San Juan Basin New Mexico
Authors: Jeu S. J. , Logan T. L. , McBane R. A.
Published: December 2007

This paper reports on observations of hydraulic fracturing in coal seams gained in research activities, conducted by Resource Enterprises, Inc. and sponsored by the Gas Research Institute in their Western Cretaceous Coal Seam Project. The fracture treatments span a period from 1986 through 1988 and involve activities in the Piceance and San Juan Basins. Findings resulting from this work are that hydraulic fracture designs must reflect the lithology of the bounding strata as this affects fracture height growth and fracture geometry. Where coal seams are adjacent to sandstone, diagnostics show that hydraulic fracture growth occurs in both the sandstone and the coal and fracturing pressures are less than 1.1 psi/ft. It was also demonstrated that a linear fracture fluid could be used effectively to place proppant in the coal zone if the sandstone overlies the coal. Much higher treating pressures were encountered in fracture treatments where coals were bound by shale. Diagnostics showed the fracture to be contained primarily to the coals and the high treating pressures may have resulted in part from a complex fracture geometry. Several possible reasons for this behavior are listed. High strength casing was found to be useful in accommodating the higher treating pressures and it allowed a larger treatment to be pumped where many jobs have had to be terminated prematurely when the burst strength of the tubulars was reached. Higher injection rates and the use of solid fluid loss material are recommended to create sufficient width in the complex geometry and thereby increase the likelihood of a successful treatment. Caution is advised in the use of conventional interpretations of Nolte-Smith (log net pressure vs. lot time) plots because of the abnormally high treating pressures associated with coal and the potentially-complex fracture geometry that have been observed in mineback experiments are well beyond the scope of the simple Nolte-Smith technique.
Ekofisk Formation Pilot Waterflood
Authors: Sylte J. E. , Hallenbeck L. D. , Thomas L. K.
Published: December 2007

This paper describes the design, operation and evaluation of a pilot waterflood project initiated in the Lower Ekofisk Formation of the Ekofisk Field located in the Norwegian sector of the North Sea. Previously, a pilot waterflood project in the Tor Formation led to approval in 1983 of full scale water injection in the Tor Formation.

The Ekofisk and Tor Formations are both low matrix permeability chalks characterized by intense natural fracturing. This natural fracturing has enhanced overall permeability and made commercial production possible from these volumetric solution gas drive reservoirs. The Ekofisk Formation was initially given lower waterflood priority based on spontaneous imbibition laboratory experiments. However, the large values of initial oil in place, in combination with the recognition that mechanisms other than imbibition may play a role in waterflood performance necessitated a pilot be performed. Additionally, the pilot was designed to evaluate rock stability and injectivity in this fractured chalk reservoir.

The pilot project consisted of one injector and three producers in an unconfined four spot pattern. As of May 1988, a total of 10 million barrels of water had been injected over a 22 month period. Results have been favorable and have been utilized to justify expansion of the waterflood to the Lower Ekofisk Formation.

Factors which were taken into consideration during the analysis include lack of both vertical and horizontal confinement, significant initial gas saturation, influence of gas injection, regional permeability variations, anisotropy and layering effects. Three dimensional simulation results are included which tie all the parameters together and form the basis for extrapolating results to full field.
Productivity of a Horizontal Well
Authors: Babu D. K. , Odeh A. S.
Published: December 2007

Two appendices describe the mathematical and algebraic details that led to the formulas provided in the text of this paper. Appendix A presents the general solution, and briefly describes the techniques for deriving simple, closed form expressions for single, double, and triple sums of infinite series. Appendix B describes these procedures in a little more detail, and also indicates certain methods for averaging the variable wellbore pressures in the general anisotropic cases.

Uniform Flux Boundary Condition

For well problems similar to the one treated in this paper, a uniform flux, or a uniform pressure is commonly imposed as a boundary condition at the well surface. Recognizing that neither is entirely correct, the question that has been debated is whether one is preferable to the other, or whether both give satisfactorily accurate solutions. Muskat(7) shoved that the uniform flux boundary condition gives values accurate to 0.5 percent. We also investigated the implication of the uniform flux assumption. We used our exact solution (Equations A1–A3) and computed the wellbore pressure, pwf at various locations y along the well length L. We did this for isotropic and anisotropic systems where the wells were located at the center, or away from the center. For the anisotropic runs the value of kz was equal to, or twice as large as, that of ky, and was ten times that of kz. Also L/b-0.5. We found that the maximum variation in pwf values was 7 psi for the worst case. This was the anisotropic case with kx=2ky, kx=10kz, and the well was located away from the center. For the other cases, the variation was less than 3 psi. Since one expects pwf to be of the order of several hundred, if not thousand pounds, we concluded that the uniform flux assumption resulted in approximately uniform pressure. Therefore, we expect a uniform pressure boundary condition to result in approximately uniform flux. Thus we concluded that these two boundary conditions lead to approximately the same solution.

Treatment of Anisotropy

As described in some detail in Appendix B, permeability anisotropy introduces angular dependence of wellbore pressures in the vertical (x=z) plane. This angular dependence can be removed by an averaging procedure, and the averaged pressure is identical to that of an equivalent isotropic reservoir with scaled dimensions. It is also indicated in Appendix B that this average pressure is the actual pressure measured at an angle θ given by: θ=are tan (kz/kx)1/4 from the x-axis. In much of the subsequent work in this paper, computations and derivations will be performed assuming homogeneity and isotropy. However, the final results will be expressed in terms of the permeabilities (kx, ky, kz) for the general anisotropic reservoir. Furthermore, it will be assumed that the pressures are computed at an angular position of θ=[are tan(kz/kx)1/4] on the well perimeter in the general anisotropic cases.
Coiled-Tubing-Conveyed Logging Systems
Authors: MacEwen H.
Published: December 2007

Traditional logging techniques for highly deviated and horizontal wells are increasingly becoming a matter of concern to operators. One of the major difficulties has been the special equipment, time and associated cost required to place the logging string on bottom and log or perforate a zone of interest.

Coiled-tubing-conveyed wireline logging and perforating tool strings are now proving to be a quick, cost-effective, accurate method of logging these wells with difficult deviation profiles.

The paper outlines the development and current capabilities of the system, including the computer modelling which takes place before each job to design the operating limits necessary to avoid buckling the coiled tubing downhole. Results of the first field applications using the system are presented; specialist applications, including PLT surveys of wells using gas as a lift medium while logging, are discussed.