bluuebunny/crossref_metadata_2025 huggingface dataset:
Geologic Analysis of Gas Hydrate Deposits
Authors: Malone R. D. , Mroz T. H. , Dominic K. L.
Published: December 2007

Research efforts undertaken by the Morgantown Energy Technology Center, Department of Energy, have focused on the geologic assessment of gas hydrate deposits existing in two different settings (onshore and offshore). Preliminary assessments have been completed for the North Slope of Alaska and the offshore east coast of the United States. Specific sites studied in the onshore setting were the Point Barrow, Kuparuk River, Prudhoe Bay, Cape Simpson, Cape Thompson, and Umiat areas of Alaska. The specific site for the offshore setting was the Blake-Bahama Outer Ridge area of the western Atlantic. This study demonstrates the use of geophysical, geological, and geochemical techniques and data to locate and evaluate the potential gas hydrate resource of these two settings.
Natural Gas Stimulation in Tight, Clay-Bearing Sandstone Using Foamed CO2 as Hydraulic Fracturing Media
Authors: Slatter T. D. , Rucker J. R. , Crisp E. L.
Published: December 2007

Low permeability, clay rich, gas bearing sandstone reservoirs which are susceptible to formation damage caused by conventional fracturing fluids can be successfully fractured using a foamed CO2 fluid. Production has been greatly improved as evidenced by an average 6.5 folds of increase for 12 wells with 5 wells in excess of 14 folds.
Production Potential of a Coalbed Gas Reservoir
Authors: Al-Saadoon F. T. , Byrer C. W.
Published: December 2007

The primary objectives of this research effort were to evaluate in-place gas, reserves, and production potential of coalbed gas using a vertical boreholes pattern. The DOE-U.S. Steel project in the Warrior Basin is selected as a specific site analysis because of the abundance of data, including 712 years of production history, available on the project.

Three models were developed for the implementation of the preceding objectives. The first model is based on the production decline curve method; the second model is based on the extension of the volumetric method; and the third model is based on the extension of the material balance method.

During the 89-month period, it has been reported that the cumulative gas production from the 23-well patter is 2.354 billion scf. That is, about 88.4 percent of the original gas in place has been produced in 89 months.
A Complete Three-Dimensional Simulator for Analysis and Design of Hydraulic Fracturing
Authors: Lam K. Y. , Cleary M. P. , Barr D. T.
Published: December 2007

The formulation, development, implementation and application of a complete three-dimensional hydraulic fracturing simulator, 3DHFRAC, is described. The simulator consists of two principal components: the first represents the solid deformation, crack opening and propagation, using a surface integral scheme, hybridised with finite-elements as needed, and a condition of critical stress-intensity-factor or energy-release-rate to track the motion of the fracture perimeter; the second captures the fluid flow along the open fracture, and into the reservoir. The simulator has been tested extensively by comparison to analytical results, other simpler models cad laboratory experiments: the latter are most vindictive because they have provided a comprehensive self-consistent data-set showing repeatibility and verifying the basic concept of the model, namely a characteristic time deriving from pressures, material moduli and fluid viscosity. Thus uniquely vindicated, the 3DHFRAC model may be applied to study a variety of field conditions: fracture containment by stress-contrast between reservoir and adjacent strata; the role of earth-stress and hydrostatic head gradients in controlling vertical growth of the fractures; fracture propagation after shut-in and its effect on deductions about fluid leak-off coefficients from minifrac tests; and the evolution of interfaces between different fluids, including the transportation of proppant, in typical complex job schedules. An even more exciting application of the model is proposed, namely that of fracture diagnostics in real-time during the job, or at least as a post-mortem determination of fracture geometry: this employs a concept called "surge analysis", namely the matching of measured transient pressure response to the calculations of pressures caused by changes in flow or rheology. Such a capability would finally bring the effort of modelling to full fruition.
Thixotropy Without Viscosity: A New Approach to Rheology Control of Oil Muds
Authors: Grantham C. K. , McLaurine H. C.
Published: December 2007

A new oil mud additive which imparts thixotropic properties to oil base muds has been developed and field tested. This new product is used in combination with an organophilic clay and imparts gel strength to oil base fluids without the corresponding increase in plastic viscosity. The use of this new amide resin is especially useful in developing thixotropy in oil emulsions drilling fluids using low viscosity mineral oils.

The data presented demonstrates that a new additive has been developed which beneficiates organophilic clays without adding to the viscosity of the fluid. This additive causes organophilic clays to yield at ambient temperatures and low shear to produce fluids with minimum rheology changes over a wide range of temperatures. The use of this additive makes possible thixotropic fluids with reduced yield points and improved gel strengths without a corresponding increase in plastic viscosity. These properties make possible the formulation of fluids with inverted flow properties having low plastic viscosities and desirable gel strengths. Using this new additive, oil continuous fluids can be formulated with water contents ranging from 0 to 30 % with minimal changes in rheology. It is further suggested that the application of the amide resin chemistry creates the opportunity for novel waterless drilling, coring and packer fluids.
Directional Drilling With PDC Bits in the Gulf of Thailand
Authors: Perry C. J.
Published: December 2007

Polycrystalline Diamond Compact (PDC) bits have shown individual directional characteristics in the deviated drilling of the 8-1/2" (216 mm) hole section in Unocal's Gulf of Thailand operations.

The effective and successful use of those directional tendencies and the parameters that can affect them are described and illustrated with detailed examples in this paper.

Five typical 8-1/2" PDC bits (Fig 1) make up a data base of over 200 "Rotary Bit" runs in low-toxic oil base mud through soft and medium soft formations. Bits used in correction runs on Positive Displacement Motors (PDM) and turbines with or without the offset stabilizer are discussed.
Study of Severe Slugging in Real Offshore Pipeline Riser-Pipe System
Authors: Farghaly M. A.
Published: December 2007

Severe slugging has been experienced in most of Upper Zakum pipeline riser-pipe system. It is characterised by generation of slugs ranging in length from one to several riser-pipe heights; occurs at low gas and liquid flow rates in undulated, nearly horizontal, pipeline.

The significance of this study arises from the fact that it is an extensive field application and is not a small scale simulation as the case in most published works. This study has covered wide range of pipe diameters, pipe lengths, and flow rates.

By the merit of data acquiring telesystem, after the grace of God, considerable volume of data were collected so accurately that each variable was monitored every 10 seconds. These data were extracted from computer terminal at company main office in Abu Dhabi.

Screened data were applied to predict severe slugging map. The same data were compared with a hydrodynamic computer model developed to predict the slug behavior.

Methods to alleviate or to eliminate severe slugging are discussed. Riser-pipe choking has been found to be an effective solution.
The Economics of Late-Life Field Production in the North Sea
Authors: Griffith J. O. H. , Cox T. F.
Published: December 2007

The major North Sea oilfields, discovered during the 1970's, will be well into their decline within the next ten years. During this period operators will be faced with a number of decisions concerning workover, infill drilling, artificial lift, EOR and, ultimately, abandonment.

This paper places a number of factors against an economic background and highlights problems that may be encountered in justification of various actions proposed to recover additional reserves. The work also addresses the problems of field abandonment.

Results show that, in the U.K. sector, the form of the PRT allowances, together with the scale of abandonment cost to both government and operator, will encourage the delay of abandonment for as long as possible. This, together with the awareness that net income over the final years will be dedicated solely to abandonment, must strongly colour companies approach to the last years of production.
Experiences with Exploration and Appraisal Well Tests Offshore Norway
Authors: Lansink Herbert
Published: December 2007

Norske Shell's testing experience over the last few years centres on 12 wells tested in 340 m (1120 ft) water depth in the Troll field, drilled during 1980 – 1984, and on 6 wells tested in 240 m (790 ft) water depth in the Draugen field, drilled during 1984 – 1986. This paper outlines developments in gravel packing techniques, equipment and procedures, the use of tubing conveyed perforating guns, the selection and application of tools included in the production test string to provide downhole shut-in and a circulation path, and finally, summarises the experience gained with downhole pressure gauges.
Rationality in Completion Design and Equipment Selection in the North Sea
Authors: Peden J. M. , Leadbetter A.
Published: December 2007

The design of completions which are effective and reliable is of increasing significance to the viability of both existing and new fields. With greater emphasis being placed on the input of advanced engineering techniques to oilfield developments, the improvement of the completion design process is an important area for investigation. This paper presents results, based on information supplied by North Sea operators, of an attempt to rationalize how design decisions are reached and what factors influence the selection or specification of completion equipment and completion procedures. The paper discusses the process of constructing design logic flow charts with the completion knowledge acquired in the study.
Computer Monitoring of Surface Parameters While Tripping
Authors: Peltier B.
Published: December 2007

The digital acquisition and processing of surface data while tripping brings a new type of information for the monitoring of rig activities and well condition. The measurement of the hook load and the travelling block altitude can be used to generate a log versus bit position which helps in decision making at the well-site. The high resolution obtained on the drill-string position makes new interpretations possible. Several field examples are presented.
Operational Experiences With Automated Mud Mixing Systems
Authors: Førde R. , O’Hara T.
Published: December 2007

The main objectives in introducing automated chemical handling system were:

To provide more effective product mixing. To minimize chemical losses through inefficient sack cutting operations or broken sacks during transport and storage. To improve the working environment.

The three rigs that Norsk Hydro equipped with automated mud mixing reduced chemical losses to almost zero. This is because the sack cutting operation was totally mechanised. In addition, the arriving sacks were inspected before being processed. Broken sacks or obviously old material was returned to the supplier.

The mixing operation offshore has been computerised and this ensures that accurate and even dosing of additives occurs.

The working environment has been vastly improved both onshore and offshore. The sack-opening operation and mixing process are totally enclosed. Even the empty sacks are automatically compressed into plastic " sausage skins" that allow no exposure to the atmosphere.

Manhandling of sacks is eliminated. The only exception is mixing of lost-circulation or stuck-pipe pills. Due to the relatively smaller quantities of chemical used, these are mixed manually.
Ball-Type Storm Valve System Improves Safety and Saves Rig Time
Authors: Caskey K. D. , Breaux M. J.
Published: December 2007

Safety and economy of offshore operations have been improved by application of a ball-type storm valve system (SVS) that can be installed without left hand rotation, thus eliminating the danger of unscrewing drill pipe joints. The new valve system is latched by setting an overshot down over a stinger and applying weight; releasing is accomplished by right hand rotation and lifting. A retrievable test, treat, and squeeze packer is installed below the valve.

Design of the ball-type SVS offers these advantages :

Ease of operation. When the system is set down, the ball valve automatically closes to shut the well in. Latching onto the system is accomplished without opening the ball. Since the ball valve is not opened by latching on for removal, it can be closed by setting back down in the event high pressure is detected below the SVS. Wireline equipment can be run through the SVS. High volumes of drilling fluid may be circulated through the SVS to condition the mud system prior to removing the SVS from the hole.

Present paper discusses design of the valve, with operational schematics illustrating its operation. Field results are presented describing use of the SVS in stress situations and for some maintenance functions, and resumption of operations. Rig time savings are discussed.
Training Rig Hands in the People's Republic of China
Authors: Turner L. A. , O’Brien W. E.
Published: December 2007

For an oilfield service company to survive in the important markets of the developing countries, it must replace expatriate personnel with qualified local nationals. This is necessary to cut costs and meet the nationalization and technology transfer requirements of host nations. An effective training program is essential to meet these requirements while at the same time maintaining international standards of service quality and safety.

This paper explores the lessons learned by one such training effort — the China Nanhai-Oxy-Sedco Drilling Corporation (CNOSDC) Training Center, located in the Shekou Industrial Zone in mainland China just north of Hong Kong. It discusses some of the problems encountered by our program, and analyses a set of factors which we have found to be significant in making our recruitment and training of Chinese workers more effective. We believe these factors can be used by other service companies and operators to better select their Chinese personnel and expedite their training.

We examine the results of three years of training of seventy-two Chinese employees considering the impact of home province, age, language abilities, educational background and previous work experience upon each man's success or failure. We go on to address questions beneficial to all oil companies and service contractors working in China and other developing nations:

Chinese from some geographic areas or provinces tend to fail while those from other areas do quite well. Why is this the case? How can you identify these areas in your company's recruitment efforts? Some technical schools produce students with a markedly higher chance of failure in our training program, while other schools have produced trainees who do consistently well. Why? College graduates have a high rate of success and a high rate of promotion, but also one of the highest rates of failure. Why is there such a high rate of failure among trainees with college degrees? What kind of Chinese colleges produce trainees most likely to succeed in the oilfield? Motivation, or the lack of it, is decisive in training success and failure. How can key motivational factors be identified and utilized? Are these motivational factors different in China than in the West ?
An Analysis of the Performance of PDC Hybrid Drill Bits
Authors: Williams J. L. , Thompson A. I.
Published: December 2007

This paper details the results of a project to extend the range of PDC bit applications to harder non-uniform formations. These formations had previously proved difficult to drill with PDC.

The resulting design concept is outlined and the targeted formations, field operating parameters and performances are illustrated with emphasis on North Sea bit runs.

The success of the project is shown in the economic analysis.

The result is a new range of bits which have exceeded their design specifications and significantly increased drilling efficiency.
Relationship between Cement Bond Log Output and Borehole Geometrical Parameters
Authors: Jutten J. J. , Parcevaux P.
Published: December 2007

This paper describes and quantifies the importance of some geometrical parameters on the main output of the cement bond log, i.e. the attenuation of a sonic wave propagating along a casing to cement interface. These geometrical parameters are the cement thickness, the casing stand-off, the percentage of cemented area and the shape of the noncemented channels. Also the nature of the fluid in the noncemented channel has been investigated.

These experiments were performed with a laboratory cement bond tool of variable spacing between 0.5 and 3.0 feet, coupled to an oscilloscope and a data acquisition unit.

It is observed that cement sheath thickness is an important parameter that can significantly affect the output of the tool up to a thickness of more than 2 inches. As a first approximation, the percentage of cemented area is confirmed to be in linear relationship with the attenuation rate. Casing stand-off can also change the log output by a factor of up to 30%. Conversely the shape of the channel is found to have no significant influence on the result provided the percentage of cemented area is the same. The nature, from gas to liquids, density and gel strength of the fluid in non cemented channels have surprisingly been found to be negligible factors.

Some of the conclusions are illustrated through the interpretation of several field logs of cased hole or of open hole sections where both the cement and the caliper logs were available.
Recommendation for Standardization of Log Format, Correction Charts, and Definitions of Measurement-While-Drilling-Tools
Authors: Power M. T. , Huchital J. , Ramsey M. , Weeks K. , Rubin B.
Published: December 2007

The IADC-RIM Downhole Telemetry Subcommittee is composed of members representing eight major oil companies, nine service companies, and one drilling contractor. The group has been meeting since January, 1985, in an attempt to bring a degree of standardization to the Measurement While Drilling industry in the areas of log format, correction charts, definitions of pertinent terms, and to present interim standards for specifying MWD – Communication – Channel – Performance as affected by variables such as depth, temperature, mud properties, noise, etc. The final objective is to provide information to the end users (drilling engineers, geologists, petrophysicists, etc.) that will enhance an objective understanding of MWD performance for evaluation and comparison of the products offered by the various MWD companies. The Subcommittee is presently divided into four groups: 1) Log Presentation Standards, 2) Drilling Parameter Influences on MWD Tools, 3) Standardized Tool Reliability Statistics, and 4) Specifications of Telemetry Systems. This paper is presented in four segments that reflect the findings and/or the recommendation of the four work groups, respectively.
Selection of Bits and Mud Types to Drill 12,500 ft Underthrust Herrera Wells in Trinidad
Authors: Jokhoo K.
Published: December 2007

Five different formations are penetrated and three casing strings run and cemented before encountering the hydrocarbon bearing Underthrust Herrera sands. Success depends on drilling 6500 feet (1981 m) of water sensitive and abnormally pressured fractured shales from 4000 to 10,500 feet (1219m-3200m).

Clay mineralogy analyses were obtained on the shale samples and the physical and chemical properties of the active clays determined. Pore pressure profiles of the different formations were approximated from electric logs, "d" exponents and shale densities.

Five different mud systems have been used and in conclusion an inhibitive water base system has been found to be most cost effective. However, an overbalance of 2 to 3 ppg is necessary to keep the long shales sections open while drilling. Bit types were selected based on rock hardness, degree of compaction and mode of deposition. Steel tooth bits were best suited down to 8000 feet and journal bearing tungsten carbide inserts for the deeper formations.

Drilling times and costs have been reduced by ten to fifteen percent. However, there is scope for operational improvement.
Natural Gas Drilling Methods and Practice: San Juan Basin, New Mexico
Authors: Cummings S. G.
Published: December 2007

The majority of published literature on air/gas drilling methods is concentrated on empirical relationships which yield little information on field performance, successes, and failures. This paper, however, concentrates on the field application and results of drilling with natural gas in the San Juan Basin of northwestern New Mexico where natural gas has routinely been used as a circulating media for thirty years.

This paper encompasses gas drilling programs, equipment, volumetric requirements, bit performance, special drilling considerations, safety, and economic evaluation of gas drilling versus mud drilling in a lost circulation area of the San Juan Basin. Results indicate that natural gas is a safe, efficient method for development drilling operations in the San Juan Basin, especially in areas of lost circulation.
Polymerization in Supercritical CO2 To Improve CO2/Oil Mobility Ratios
Authors: Terry R. E. , Zaid A. , Angelos C. , Whitman D. L.
Published: December 2007

The efficiency of carbon dioxide flooding is hindered by mobility problems resulting from the unfavorable mobility ratio, λCO2/λoil. Several approaches were tested in the past to improve CO2 flooding efficiency (1–6). One approach attempted direct thickening of CO2 by dissolving a commercially available polymer in the CO2. In this paper a novel idea to increase the CO2 viscosity is presented. The increasing of CO2 viscosity is attempted by insitu polymerization of monomers miscible with CO2. The polymerization is done while the monomer (solute) is in the CO2 supercritical phase (solvent). CO? viscosity changes are evaluated by direct measurement using a high pressure Ruska rolling ball viscometer.

Several runs have been made and polymerization has been successfully achieved – in the presence of CO2 supercritical phase – as evidenced by NMR and infrared spectrophotometry. Both gas and liquid phase monomers, measured at standard conditions, were tried and both were polymerized. Polymerization initiators that were used consist of commercially available peroxides with a weak O-O bond. Polymerization was carried out at approximately 160°F and 1800 psi. The values of temperature and pressure are typical for oil reservoirs in which CO2 is applied as a miscible fluid. Further evaluation of viscosity changes are done by flowing the mixture of CO2 and polymer in a high pressure sandpack.
Continuous Steam Quality Measurement in a Steam Distribution System Quality Measurement
Authors: Strome R. K. , McStravick D. M.
Published: December 2007

In an effort to provide accurate, reliable data on steam distribution, 67 continuous steam injection wells on Santa Fe Energy Company's steam flood project in the Kern River Field were equipped with steam quality meters using vibrating densitometer principles combined with flowmeters and microprocessors for continuous monitoring of temperature, quality, mass flow rate and energy content.

Although equipment limitations were encountered, techniques for validating steam quality measurements and flow rates by overall system mass balance were developed.

Instrumentation of the type employed in the project combined with the centralized processing of the data from each individual injection well is a new tool for optimizing steam distribution and injection documentation for reservoir modeling.
Evaluation of Gas Flows in Cement
Authors: Rang C. L.
Published: December 2007

Cementing of casing in California can be characterized as having two major concerns, cement "fallback" and gas contamination. The cement fallback problem is widely known. Gas flows into the cements have been recognized for some time, but only recently have they been measurable. Improvements in cement bond logging tools and interpretation techniques have enabled engineers to correctly identify several distinct regimes behind casing. Among them are cement, gas, fluid, or gas-cut cements. Identification and measurement help the drilling and production engineer to design slurries that overcome the cementing concerns.
Fracture Identification in Openhole From a Cement Evaluation Tool
Authors: Westermark R. V. , Scholes P.
Published: December 2007

This paper addresses the use of the cement evaluation tool for open hole fracture identification and orientation by the analysis of acoustic caliper data in granodiorite.

The high acoustic reflectivity of the granodiorite is similar to casing; therefore, the tool's acoustic caliper data required no special processing to determine wellbore diameters. The presence of highly irregular borehole diameter information was interpreted to be the effect of fracturing. By merging the caliper information with directional survey data, a fracture orientation log was prepared.
Waterflood-Induced Fractures: A Simulation Study Of Their Propagation And Effects On Waterflood Sweep Efficiency
Authors: Dikken B.J. , Niko H.
Published: December 2007

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 is usually granted upon request provided proper credit is made.

Fracturing occurs quite often in water injection wells, with sometimes unforeseen consequences on waterflood sweep efficiency. One of the causes of fracturing is often the cooling of hot formations by cold injection water. A special version of a thermal reservoir simulator for prototype applications has thus been constructed that is capable of dealing with propagating waterflood-induced hydraulic fractures. With this simulator, fracture propagation and the effect of growing fractures on the sweep efficiency are studied. Infinite fracture conductivity is assumed. The limitation to very high leak-off fractures justifies disregarding the changes in fracture volume. Fracture growth is calculated using the concept of a critical stress intensity factor. Both poro- and thermo-elastic changes in the horizontal stresses are calculated umerically and their influence on the fracture initiation/propagation is continuously taken into account. In addition, a model of fracture wall impairment because of filter-cake build-up due to poor quality injection water is included.

Results are presented for both thermal and isothermal situations. It is observed in isothermal cases that the voidage replacement ratio (volume balance during injection) determines to a great extent the length to which the fracture eventually may grow. In isothermal situations with balancing pattern injection and production a stationary fracture is observed in the steady-state flow regime. The observed dependence of the stationary fracture half-length on parameters such as the initial horizontal stress and the critical stress intensity factor is in agreement with analytical expressions for single-phase flow situations. As an illustration of thermal fracturing, results pertaining to high-rate water injection in a sandstone reservoir with properties similar to North Sea conditions are discussed. To demonstrate the importance of injection/production balance more clearly, well spacings in the simulations presented were purposely taken to be smaller than in practice. Sweep efficiencies are presented for two voidage replacement ratios with the fracture growing towards a producer; in the worst situation a reduction of the efficiency by about 20% is observed.
Method for Determining the Feasibility of Dynamic Kill of Shallow Gas Flows
Authors: Koederitz W. L. , Beck F. E. , Langlinais J. P. , Bourgoyne A. T.
Published: December 2007

Gas flows from shallow sands present difficult well control challenges when encountered. Contingency plans for handling shallow gas flows generally are based on a dynamic kill procedure. In a dynamic kill, the bottom-hole pressure is increased without the use of a surface choke. With this method, high circulating rates are used to increase annular frictional pressure losses. In this paper, a systematic procedure is presented for estimating the loads present on the well and diverter system during a dynamic kill operation. This is useful both in well design and in planning well control operations. The procedure is based on a steady-state systems analysis calculation applied to a diverted well and includes consideration of the effects of critical (sonic) exit pressure and pressure changes due to elevation, friction, and acceleration.

Example analyses are discussed for well conditions typical of (1) a bottom-supported marine rig or a land rig, and (2) a deep-water floating drilling unit. The floating unit example is presented both with and without the use of a marine riser. The example analyses illustrate the importance of using diverters larger than 6-in. diameter and supports the practice of drilling pilot holes to the depth of the next casing string. The examples also illustrate that a dynamic kill will be significantly more difficult if the length of conductor casing is insufficient to prevent broaching from the conductor casing shoe to the seafloor.
Improved Hydraulics for Rock Bits With Extended Slant Nozzles
Authors: Cholet H. J. , Abdullah H. F. , Chia W-K.
Published: December 2007

A new concept of hydraulic design for rock bits has been developed and tested. The bit was equipped with two nozzle tubes extended downward. Each nozzle was outfitted with two fluid exits to direct the jets 60 degrees from the bit center line onto the hole bottom. In addition, a center nozzle was added to the bit to clean the dome and to increase the cone cleaning effects. In order to obtain the crossflow effect, the third nozzle was blanked off such that a high velocity and consequently a forced circulation over the hole bottom was obtained. The influx of kinetic energy strips off cuttings among the teeth and allows a very rapid removal of cuttings with reduced recycling.

The first part of the paper will describe the experimental studies. The efficiency of stripping the cuttings from the well bore bottom was measured in a cell with ball tracers injected into the flowing fluid. By means of ultra-high speed photography, the path of the tracers and hence the fluid movement was recorded. Furthermore, the bottom hole fluid flow pattern was simulated by a hydrodynamic computer code to quantify the cleaning effects as compared with conventional extended nozzle bits.

The remainder of the paper describes the results of field tests. The average drilling rate and footage increased about 20% with the use of the slant nozzle bits over that normally achieved with extended nozzle bits. The cost savings averaged about 15%, The nozzle is particularly effective in: –Soft formations,–Sticky shale formations,–Relatively high drilling rate formations.
Layer Pulse Testing Using a Wireline Formation Tester
Authors: Saeedi J. , Standen E.
Published: December 2007

A Layer Pulse Test1 was designed, implemented and analyzed in a pinnacle reef in Alberta. Two Repeat Formation Tester (RFT)* surveys were performed in the observation well at a pre-designed interval. The second RFT survey was performed after the pulsed well was put back on production. The design was based on an older, history-matched model of the reef.

A geological and stratigraphic interpretation was performed to update the geological and the numerical model. Subsequently, a three-dimensional, three-phase, single equation numerical simulator2 was used to model the inter-well area and a history match was obtained to the pressure shift in the two RFT surveys.

The vertical pressure profiles from the RFT surveys identified barriers to vertical flow while the geological interpretation and the history match to the pressure shift provided a quantitative distribution of horizontal and vertical permeabilities in the inter-well area.
New Developments in the Analysis of Cores from Naturally Fractured Reservoirs
Authors: Bergosh J. L. , Lord G. D.
Published: December 2007

New techniques have been developed to more accurately quantify porosity and permeability in naturally fractured core. Computerized tomographic scanning and fluorescent epoxy impregnation techniques have lead to improved measurement of fracture porosity. Directional permeability measurements at overburden stress better define permeability anisotropy and permeability reduction from ambient to reservoir conditions.
Working Smarter With Computers
Authors: Dodd D. L.
Published: December 2007

Over the past few years, a wide variety of computer hardware and software has become available, ranging from personal computers to new mainframes, minicomputers, and engineering workstations. Continuing advances will result in even more computing power becoming available. The impact of this evolution will be major. In order to take full advantage of this hardware and software, the use of mainframes, workstations, and personal (or micro) computers must be well planned and integrated into the workplace.

Interactive systems and more "user friendly" software will be increasingly available. It will remain the engineer's responsibility to understand the limits of applicability of these systems and software and, for that purpose, good documentation and support for programs and systems is essential.

A key to effective computer usage is adequate training. Software and hardware vendors, employers, universities and the SPE must all participate in this effort. However, the individual is ultimately responsible for his or her personal development.
Status of Research and Development in the Oil Industry
Authors: Taylor B. G.
Published: December 2007

R & D subjects in petroleum industry are numerous and diverse. We look at formations with Scanning Electron Microscopes and satellites. In order to trace hydrocarbons, we measure almost every physical and mechanical property of the rock; from its radioactivity and electrical resistivity, to magnetic properties. We measure fluid pressure to an accuracy of 0.01 psi. We can do well testing based on moon tides. We draw three-dimensional picture of underground strata based on seismic data. We launch and install offshore platforms which cost millions of dollars, weigh thousands of tons. We drill holes miles deep into very hot formations, and produce from them. We can transport fluid hundreds of miles on sea floors, thousands of miles on giant tankers across oceans, and then refine it to a final product usable by the public. And yet, we cannot answer some very basic questions: Where in a reservoir should we drill, how to anticipate the mechanical condition of the formation we will drill into, what are the relative permeabilities of the formation to its fluids, how to determine when we have a good cement bond, how to determine the size and direction of hydraulic fractures, how to prevent water coning, how to prevent damage caused by formation fluid itself, etc. While we have made giant strides in modeling and processing data through computers, we often do not have the very basic properties needed to fully take advantage of them.

There are many technical disciplines involved in oil and gas exploration and production. We employ almost all engineering disciplines, as well as draw on achievements of other industries. In such an environment, it is difficult to identify why R & D is vital to the petroleum industry.

Any strategy of R & D has to recognize an important element; people. Although people are the most valuable asset of every part of an organization, R & D accomplishments and value is substantially dependent upon the qualifications of those performing the work. Most R & D functions require people with high level of education and specialized training, disciplined in a methodical and logical approach to problems. Yet breakthroughs are often results of unorthodox thinking, the creative ingredient of a human brain which goes beyond what is normal and expected.
Perceptions the Key to Oil Prices
Authors: Powers L. W. , Stevenson W. M.
Published: December 2007

Future crude oil supply and demand was explored in the late summer of 1986 under various pricing scenarios. Key findings include the importance of price perceptions on behavior, the significance of Middle East producers, the correlation between oil price and working rigs and the prediction that oil prices are not likely to fall below $18 to $20/Bbl with real growth in crude prices of about 4 percent a year, from 1990 until the year 2000, assuming a stable Middle East.
Equipment Selection Procedure for Subsea Trees
Authors: Otten J. D. , Brammer N.
Published: December 2007

Subsea trees have typically been field-specific with different designs required for each project. Current industry trends to improve efficiency and cost effectiveness, however, indicate that increased standardization and versatility are required. This paper presents a new procedure to categorize proven equipment and simplify selection of tree components. Using the flowchart principle, the decision process is indicated for each major equipment decision or option, considering the range of equipment available in light of product features, technical specifications, rated capacities, operational histories, and costs.
Fracturing Treatment Design Improved by Conductivity Measurements Under In-Situ Conditions
Authors: Parker M. A. , McDaniel B. W.
Published: December 2007

Gelled fluids are often used in hydraulic fracturing treatments. During these treatments a filter cake of gel solids is usually deposited on the walls of the fracture as the result of fluid leak-off into the formation porosity. The presence of this filter cake may have an adverse effect on the conductivity of the proppant bed used to prop open the hydraulic fracture. Laboratory testing methods that simulate these in situ fracture conditions have been developed. Multiple proppant concentrations and fluid systems have been used in this testing. The resultant data are incorporated into the design of a fracturing treatment to minimize the effect of the gel filter cake. This allows more effective stimulation of oil and gas wells and more realistic predictions of post-frac production improvements. The data presented in this work emphasizes the importance of achieving high concentrations of proppant to minimize the effects of gel filter cakes.
Flow Response of Propped Fracture to Repeated Production Cycles
Authors: Kim C. M. , Willingham J. R.
Published: December 2007

Once a reservoir is hydraulically fractured, the fracture may experience several repeated production/shut-in cycles. Evidence of reduced rate of recovery as wells are placed back on production, has been noted in gas wells that have been exposed to this type of cycling. As the cycling process is repeated, the propped fracture undergoes the ups and downs of closure stress, resulting in a gradual reduction in fracture conductivity.

To observe the phenomenon, a propped fracture using formation rock, was subjected to cyclic loading in the laboratory. Change in fracture conductivity with time and the number of cycles was measured. Interaction between proppant and formation rock was examined. One sand size and two synthetic proppant sizes were evaluated. Two formation rock types of different hardnesses were used in simulating the fracture.

At the same closure stress level, fracture conductivity continuously decreased as the loading cycle is repeated. The amount of reduction in conductivity depended upon the rock hardness and proppant size. For the same hardness rock, the magnitude of closure stress dictated the suitable proppant size to minimize the cyclic effect. Thus, the combination of information obtained through this study is a tool to select a proppant to minimize the cyclic effect.

Suggestions and optimum design criteria to circumvent or minimize the repeated shut-in effect are presented along with the test results.
New High-Performance Field-Installed Sucker Rod Guides
Authors: Murtha T. P. , Pirtle J. , Beaulieu W. B. , Waldrop J. R. , Wood H. V.
Published: December 2007

A field installed sucker rod guide with high resistance to movement from axial loads during well operation has been a target of the petroleum industry for a number of years. Research by J. M. Huber and Phillips 66 Company has led to the development of a new field installed guide which will not only handle the high axial loads but can be used in severe well environments. laboratory and field tests have shown the axial loading resistance of a RytonR PPS composite guide to be ten times greater than nylon guides at temperatures up to 400°F. In addition, these composite guides have excellent chemical resistance, impact strength and wear resistance. laboratory data is correlated with that found in actual dσwnhole service. These results have been translated to successful applications in production wells. General material properties and techniques for guide installation are also presented.
Reserve Predictions From Production Testing in Geopressured Gas Reservoirs
Authors: Ireland M. M. , Robinson J. B.
Published: December 2007

Pressure transient analysis, material balance, and numerical reservoir simulation were evaluated for analyzing production tests in geopressured gas reservoirs. Data requirements, problems obtaining it, and practical limitations are presented for each method. After analyzing two Gulf Coast example cases, guidelines are given to improve the accuracy of volumetric and reserve predictions.
The Application of the Method of Characteristics to the Flow of Miscible Gases in a Reservoir
Authors: Modine A. D. , Bashbush J. L. , Kothari K.
Published: December 2007

A reservoir simulator has been developed to solve gas-water reservoir problems where the gas may be treated as a two component miscible mixture. It is specifically designed to study gas-storage problems where an inert gas such as nitrogen, may be used as a displacing fluid during cycling operations. The model includes both the convective transport of components within the gas phase plus the diffusion or dispersion of components. The solution to the multicomponent gas problem is accomplished using the method of characteristics, so that numerical dispersion is eliminated or minimized.

A description of the model is included along with several example problems. The example problems include comparisons of calculated results with analytical solutions and experimental laboratory data in one and two dimensional models. The experimental data were measured on both liquid-liquid and gas-gas miscible systems.
Formation Damage Due to Synthetic Oil Mud Filtrates at Elevated Temperatures and Pressures
Authors: McKinney L. K. , Azar J. J.
Published: December 2007

An experimental apparatus and a statistically-based test matrix have been designed for use in an on-going test program to determine the extent of formation damage which may be caused by oil-base 'drilling fluids on sandstone cores at elevated temperatures and pressures. Tests with a mineral oil-base synthetic filtrate on Berea sandstone cores have shown that of the three independent variables tested (temperature, flowrate and confining pressure), temperature has the most significant effect on the degree of reduction of relative mobility over the range tested.1 The synthetic filtrate, containing the maximum amount of surfactants expected in a comparable 12 ppg mud, caused severe damage (97-100%) in all cases. The mineral oil, also used as a test fluid to show the minimum damage effect corresponding to the same mud, resulted in little change in relative mobility.
Viscoelastic Gravel-Pack Carrier Fluid
Authors: Nehmer W. L.
Published: December 2007

The ability of a fluid to flow adequately into the formation during gravel-pack treatments is critical to achieving a good pack. Recent studies have indicated "fish-eyes" and/or "microgels" present in many polymer gelled carrier fluids will plug pore throats, leading to impaired leakoff and causing formation damage. Intensive manipulation of the polymer gelled fluid using shear and filter devices will help remove the particles, but it adds to the cost of the treatment in terms of equipment and manpower. Excessive shear will degrade the polymer leading to poor gravel suspension, while too little shear will cause filtration problems.

A gelled carrier fluid using a viscoelastic surfactant system has been found to leak off very efficiently to the formation, and cause no formation damage, without the use of shear/filter devices. Viscoelastic surfactant-base gelled fluids develop viscosity because of the association of surfactant molecules into large rod-shaped aggregates. There is no hydration of polymer involved, so fish-eyes and microgels will not be formed in the viscoelastic fluid. A surfactant-base system having a yield point allows the gravel carrying properties to be much better than fluids gelled with conventional polymer systems (hydroxyethylcellulose [HEC]). For example, a gravel carrier fluid gelled with 80 lb HEC/1,000 gal has a viscosity of about 400 cp at 170 sec-1; a viscoelastic surfactant-base system having only one-half the viscosity still flows into cores about four times more efficiently than the HEC-base fluid. The rheology, leakoff, formation damage and mixing properties of a viscoelastic, surfactant-base, gravel-pack carrier fluid are discussed.
An Analysis of Bit Bearing Failures With Field and Laboratory Data
Authors: Lesage M. L. G. , Falconer I. G. , Wand P. A. , McCann D. P.
Published: December 2007

This paper discusses how to detect the onset of bit bearing failure before the failure results in a lost cone. It does not attempt to understand the physics of wear.

A history of failures was collected for both journal and roller bearing bits from wells where both surface and down-hole mechanical parameters were recorded. The data were then correlated with formation logs to differentiate lithology changes from bit effects.

A separate experimental program was conducted on full size bits to observe how a failing bearing affects a cone's speed, torque and temperature. A journal bearing bit was worn from new to failure under atmospheric conditions and data were acquired at regular intervals of wear. Comparisons are made between journal and roller bearing bits.

This work showed that journal bearings do not necessarily fail in a catastrophic manner as generally believed, but may degrade over several hours. The results suggest a likely technique for separating the onset of bearing failures from lithology effects. A field example is thoroughly examined.
Effects of Nozzle Configuration on Roller Cone Bit Performance
Authors: White D. B. , Curry D. A. , Gavignet A. G.
Published: December 2007

Laboratory experiments have been conducted to study the effects of nozzle size, extension and configuration on the flow patterns, pressures and shear stresses beneath a roller cone bit. The results are used to interpret laboratory drilling data, and to identify conditions when the use of extended nozzles, two nozzles or a centre jet will improve penetration rate.