bluuebunny/crossref_metadata_2025 huggingface dataset:
Second Ripley Surfactant Flood Pilot Test
Authors: Reppert T. R. , Bragg J. R. , Wilkinson J. R. , Snow T. M. , Maer N. K. , Gale W. W.
Published: December 2007

A second successful surfactant flood pilot test was conducted by Exxon on the Lewis Ripley lease in a watered-out portion of the Weiler sand, Loudon Field, Illinois. The salinity-tolerant, micellar/polymer process tested in this pilot incorporated several process modifications developed since a previous test was conducted in 1980. These changes included using a 25% smaller microemulsion bank size and addition of formaldehyde to injected fluids to inhibit bacterial degradation of biopolymer. The pilot was performed in a single, 0.71-acre [2873 m2], 5-spot operated to approximate a confined pattern. Extensive data on flood performance were obtained from a comprehensive pilot monitoring program, including use of fluid tracers, observation wells, and post-test cores.

Approximately 68% of the waterflood residual oil present in the test pattern was recovered. This actually exceeded the oil recovery achieved in the first pilot, despite using a smaller microemulsion bank. Improved mobility control and lower surfactant retention contributed to enhancing process performance. Formaldehyde was effectively transported and prevented bacterial degradation of biopolymer. It appears to be an effective biocide for use in subsequent surfactant flooding operations at Loudon. During the pilot, an inexpensive and efficient method was developed to separate produced oil-water-surfactant emulsions. While all test objectives were met, the effect of well spacing on oil recovery and chemical transport was not addressed.
Polymer Retention in Porous Media
Authors: Huh C. , Lange E. A. , Cannella W. J.
Published: December 2007

Retention of a polymer in reservoir rock is examined theoretically and experimentally. In the theoretical part, a pore-level description of mechanical entrapment of a polymer in a model porous medium is developed, which shows that the trapping rate is proportional to the flux of polymer, and decreases almost linearly with the amount of trapped polymer until the maximum retention is reached. The maximum retention increases with increasing polymer concentration, and also with increasing flow velocity. The dynamics of polymer trapping indicates that if a polymer has a good solvency in water, it has less tendency to be trapped; but if a polymer has a high intramolecular permeability, it will have a high tendency for trapping. Based on the pore-level considerations, a phenomenological polymer retention model is proposed that accounts for both the adsorption of polymer molecules on rock surfaces and the mechanical entrapment in pore matrices. An analytical solution for flow of a single-phase polymer solution in a core is obtained to interpret retention data from laboratory corefloods.

In the experimental part, the retention of xanthan biopolymers from semi-dilute solutions flowing in a sandstone core is measured as a function of polymer concentration, flow velocity, and permeability of rock. The proposed retention model is shown to adequately represent two characteristic features of typical polymer effluent profiles from corefloods, that is, the frontal delay and the gradual approach to feed concentration. Treating retention with adsorption alone generally fails to describe these features. The effects of dispersion and the commonly-encountered, high accumulation of polymer near the core face are also examined by analyzing the coreflood effluent data with a finite-difference numerical solution of the above linear flow problem.
Experimental Validation of a New Method for Optimizing Miscible Flooding of Stratified Reservoirs
Authors: Ingsøy P. , Skjaeveland S. M.
Published: December 2007

Miscible displacement experiments were conducted in a stratified model reservoirs that permitted visual observation of the flow processes. Concentrating on favorable mobility ratio displacements, the results are analyzed by a VE theory which includes gravity effects1,2. The results show that the front shape, and hence the recovery, of gravity stable displacements can be predicted by the theory. Further, rates for breakdown of gravity stabilization are predicted in agreement with experimental results. It is shown that channeling of the injection fluid into high permeability layers may be stabilized by viscous cross-flow, even during relatively high injection rates. Observation of unexpectedly large mixing zones are explained as viscous mixing caused by cross flow between layers.
A Method of Alternating Steam and Water Injection for Recovering Heavy Oils
Authors: Sufi A. H.
Published: December 2007

Various techniques have been suggested for injecting steam into heave oil reservoirs that offer limited injectivity into the formation. These include the use of any water-saturated stringers that may be present in the pay or the use of horizontal wells to heat the reservoir from the injector to the producer. An experimental study was conducted using a scaled physical model to study the scenario with a horizontal well. The model was an element of symmetry from a reservoir having no initial fluid mobility. A horizontal well was placed at the base of the model to heat the formation from a vertical injector to a vertical producer.

Results of injecting steam into the region heated by the horizontal well were disappointing due to low mass injection rates. It was possible to inject high mass rates using hot water as the injected fluid. This however, resulted in relatively low oil production rates. To obtain a balance between high mass injection rates and high oil production rates, a process of alternating steam and hot-water injection was developed. This allowed the reservoir to be heated as hot water was injected into the reservoir and oil to be produced by gravity drainage during steam injection. A number of alternating steam and hot water cycles were required before continuous steam injection at the maximum rate was possible. The initial heating time with the horizontal well was varied with minimal effect. Using the alternating process, an oil recovery of 76.4% was achieved.
Field Measurements of Remaining Oil Saturation
Authors: Causin E. , Rochon J. , Marzorati D.
Published: December 2007

Some of the most promising techniques proposed for evaluating the remaining oil saturation (RÛS) of watered-out formations were tested in a few wells of three different fields Chuelles (Prance), Cortemaggiore (Italy) and a field in the Gulf of Guinea (Africa).

The work was carried out with the following main objectives :

– to identify a screening for selecting the best ROS measurement method(s) to be applied under different reservoir and/or well conditions; – to compare for the same well the results obtained applying different methods with various investigation depths; – to emphasize the importance of the in-situ ROS determination in heterogeneous reservoirs.

The techniques selected were:

– conventional carbon-oxygen logging; – pulsed neutron capture tool (log-inject-log); – single well tracer test; – interwell tracer test. The logging methods give results in good agreement in the high-porosity reservoirs conside red and can reveal a heterogeneous distribution of the oil saturation. The single well tracer test may be difficult to interpret when a significant heterogeneity and/or fluid drift occurs. In other cases, this tracer method can be very accurate. The interwell tracer test can give interesting results about flow behaviour in the reservoir, despite difficulties of test analysis. It can also measure an average ROS value at the end of a flooding process.

From this series of on-site experiments, we conclude that:

using more than one method improves the accuracy of in-situ ROS determinations; ROS measurements performed on one well are representative of the surrounding area; in-situ ROS measured at the end of the flooding process may be quite different from the residual oil saturation (Sor) measured in laboratory.
Characterization of Crude Oil Wetting Behavior by Adhesion Tests
Authors: Buckley J. S. , Morrow N. R.
Published: December 2007

Wettability in a rock/oil/brine system determines the distribution of fluids and can have a dramatic effect on oil recovery. A better understanding of the state of wetting in the presence of a crude oil is required for design of displacement experiments and interpretation of results for satisfactory prediction of oil recovery by waterflooding. The adhesion test has been developed to characterize interactions between a crude oil and brines of varying composition.

Adhesion maps show several consistent trends for most of the crude oils examined which are unlike those for refined mineral oils. At low salinity, there is a characteristic pH above which adhesion does not occur. This pH has been shown to correspond reasonably well with the cutoff predicted by calculations based on electrostatic forces and DLVO theory.1 In higher salinity brines, electrostatic forces are less important, and the adhesion test results indicate that other mechanisms must be responsible for determining wetting behavior. In this area of greatest practical interest, the adhesion test provides an empirical measure of the interactions between oil and solid. The effects of temperature, surface preparation, oil composition, and oxidation are reported.
A Model for Small-Scale Permeability Measurement With Applications to Reservoir Characterization
Authors: Jensen J. L.
Published: December 2007

Traditionally, quantitative assessment ot small-scale permeability variations has depended primarily upon core plug measurements. Minipermeameters, however, are increasingly being used to supplement core plug data despite some unresolved issues concerning the minipermeameter measurement. Two of the more important are whether the minipermeameter can provide a truly quantitative assessment of permeability and how the measurements may be applied in reservoir description.

To address these issues, a statistical model of minipermeameter and core plug measurements has been developed. The model uses the Monte Carlo method to emulate both sampling techniques. Three applications of such measurements were examined using the model: Correlations of permeability with wireline porosity log measurements; heterogeneity measurement; and prediction of effective permeability.

In all three cases, we found that, even if the minipermeameter does not give a precise permeability value, the ability to sample frequently can provide more accurate information about formation properties than does core plug data taken at one foot intervals.
Applying Digital Data-Encoding Techniques to Mud Pulse Telemetry
Authors: Monroe S. P.
Published: December 2007

More and more downhole devices are requiring two-way communication with the surface to telemeter data and device status and/or receive telemetered instructions which effect the operation or status of the downhole device. This paper examines the application of digital data-encoding techniques to MWD mud pulse telemetry and shows how they can significantly improve data transmission rates over conventional MWD telemetry methodologies. It further represents a study of how established technologies can be reapplied and open up new opportunities to improve communication systems in our industry. The analysis describes MWD telemetry in particular, but it is also applicable to other active downhole devices, such as adjustable bent subs or variable stabilizers.

Traditional mud pulse telemetry methodologies along with recent innovations which have focussed on encoding data by using a set of unipolar pulses in combinatorial patterns within a fixed time interval or by employing phase shift keying (PSK) to form different data patterns are reviewed. An examination will follow of digital data encoding techniques used in high density mass storage systems which can be applied to mud pulse telemetry and discussion of their advantages and disadvantages. A recommendation, using the nature, benefit, and limitations observed as design factors, will then be made for selecting an optimal encoding scheme.
Expert System for Productive Water Wells: SEPA
Authors: Lazzereschi S. , Tous Bravo C. , Estok F.
Published: December 2007

Water is essential to, and plays an important role in the oil industry. Subsurface water-bearing sand formations for water production are preferred for various reasons. This type of water is produced through water wells.

SEPA has been conceived in order to capture and make available the knowledge and experience of MARAVEN's staff involved in the maintenance and operation of these wells.lt can also be used as a training aid for new professionals dealing with this kind of wells.

SEPA is a menu driven and conversational diagnosis system, assisting the user in identifying and helping him with the solution of problems encountered in the production/operation of water wells. Loss of water flow potential with or without sediments and normal water flow with sediments are the contemplated problem areas. Within each of the problems an analysis is made, in order to ascertain whether the cause is due to any one or a combination of the following: –Properties/conditions of the water aquifer.–Type of well completion,–Well equipment installed.

SEPA has been developed in IBM/PC, using Teknowledge's M.l software and is installed in two different geographical user environments ( Lagunillas and Pariaguan ). The knowledge base consists of 1245 entries (517 rules, 334 facts and 394 meta-facts).
DIANA: An Expert System for Fault Diagnosis in Gas Compression Plants
Authors: Ramirez R. , Haor M. , Backhurst M. , Lugo L.
Published: December 2007

DIANA is an expert system developed for assisting the maintenance and operations departments with the diagnosis and correction of failures of the unmanned mini compression plants of Lagoven S.A. in Lake Maracaibo. It is anticipated that the system will be used in problems associated with sixty-three (63) shut-down alarms, the start-up sequence and the on-line troubleshooting.

There are thirteen miniplants in various parts of Lake Maracaibo which together with other types of gas plants, compress the gas produced with the crude oil. The compressed gas passes to a distribution system where it is used for: Gas liftingFuel (industrial and domestic)Petrochemical and fertilizer manufactureRe-injection to reservoirs for conservation

The use of this expert system will help to reduce the down-time and repetitive start-ups bydiagnosing the cause of the shut-down before restarting the plant. This will reduce the impacton both gas generator and power turbine, as one start-up of these equipments is roughly equivalent to eight hours run-time. The overall reliability and availability of the plants should improve thus increasing crude oil production and reducing operating and maintenance costs.
Computer Laboratory System
Authors: Wienck L. K. , Surjaatmadja J. B. , Strange A. F. , Almond S. W.
Published: December 2007

The collection of data concerning well characteristics, cement properties, and corresponding cement tests has been of primary interest to field operators, laboratory technicians, and service companies. Such data provides the designer a tool which allows him to critically evaluate past jobs in order to design a cement system for a particular well. It is therefore important that the data can be retrieved for this purpose.

Previously, data was stored using a paper filing system. Difficulties encountered with such a system were loss or misplacement of data, and inaccessibility of data at critical times. The determination of correlations between well and slurry characteristics becomes difficult if not impossible.

Computer data filing of well characteristics, slurry design, and test results aids in archiving and retrieving of cement information. One such system is a menu-driven PC software package written to fulfill the needs of field and laboratory personnel. Using this system, analysis required for job designs can be performed without the inconvenience of manual searching in a paper filing system.

This paper discusses the implementation of such a system in an actual laboratory environment. Added features such as automatic reporting and computing, locating needed information, and networking further increase laboratory efficiency, thus promoting faster turnaround time for creating job designs.
The Effect of Hole Inclination on Gas Migration
Authors: Shipley S. E. , Mitchell B. J.
Published: December 2007

A laboratory model was constructed to investigate "worm hole" gas migration through an inclined cement column. The model consisted of 10 foot long PVC tubes. Gas was allowed to migrate through the initially overbalanced cement placed in the 10 foot tubes. The tubes were inclined from the vertical, at angles between zero and 80 degrees. Migrated gas did not flow at a 0° inclination angle.

At 30°, the gas migration flow rate peaked. And at angles greater than 30°, gas migration flow rate decreased.

The laboratory model was altered so hydrostatic pressure at the bottom of each inclined tube could be measured with respect to setting time. On pressure verses setting time plot, pressure plateaus were observed. During these pressure plateaus, pressure changed very little with respect to time.

These plateaus were persistent for all inclination angles. It is theorized that these plateaus are associated with the different cement growth periods.
Verification of Slurry Response Number Evaluation Method for Gas Migration Control
Authors: Harris K. L. , Ravi K. M. , King D. S. , Wilkinson J. G. , Faul R. R.
Published: December 2007

To date, the means of efficiently dealing with annular gas migration by way of cement slurry design has been unstructured in approach. The major tools still relied upon are past experiences and a basic knowledge of gas migration theory. Although an accepted procedure for determining a well's potential to flow is available,1 research has not been heavily conducted relating gas flow potential to a specific cement slurry performance required to achieve a predictable success. Instead, "types" of cements (low fluid loss, thixotropic, etc.) are recommended in relation to the degree of flow potential that may be encountered in a well.

In response to this deficiency, a method was recently developed and published by Sutton and Ravi.2 Labeled the Slurry Response Number, SRN, this engineering tool defines the capability of a specific cementing system to combat gas migration in a specific gas well. It is the purpose of this paper to show - through several case histories - that this derived relationship does exist, and can be used to more efficiently design anti-gas migration slurries.

More specifically, the field cases observed in this study display a relationship between the Gas Flow Potential (GFP) - a mathematical term Indicating the probability of gas flow given a set of cement Job conditions - and the more recently developed SRN. As reported by Sutton and Ravi, the SRN Is a number attached to a specific cementing system (cement, spacer, and drilling fluid), based on fluid loss and static gel strength properties, that directly grades the capability of a cement slurry to prevent gas migration. This unique rating system can be used very effectively for relative comparisons between cement slurries or as confirmed through the case histories presented in this text, can serve as a guideline in choosing a cement slurry design for a specific well with a calculated gas flow potential.
Downhole Adjustable Gauge Stabilizer Improves Drilling Efficiency in Directional Wells
Authors: Eddison A. , Symons J.
Published: December 2007

This paper evaluates the use of a downhole adjustable stabilizer in place of conventional stabilizers through the tangent sections of directional wells. It includes a survey of more than 100 directional wells and illustrates typical applications of the tool.

The strategic placement of undergauge and full gauge nearbit and/or first string stabilizers to control hole inclination is now proving unnecessary. A correctly positioned adjustable stabilizer allows changes to be made to the Bottomhole Assembly (BHA) without pulling out of hole.

Not only can expensive BHA trips be avoided, but correct utilisation of the an adjustable stabilizer will improve the trajectory of the hole section and minimise doglegs to reduce torque and pipe drag.
New Ideas in Offshore Development Drilling
Authors: Patteson R. M. , Cole F. , Gillett B.
Published: December 2007

ARCO Oil and Gas Company is reducing tangible and intangible development drilling costs by using a combination of modified equipment and different techniques. Field tests were performed in the Gulf of Mexico in the High Island 24L area and the West Cameron 248 field.

ARCO's shallow water free standing caissons were typically installed by overdriving successful development wells with a large O.D. caisson. The first test case was a combination 30" × 48" caisson, which functioned as drivepipe and caisson. The drivepipe/caisson combination eliminates the time and cost of overdriving a caisson.

The second field test was a predrill of a template prior to installing a jacket and deck. A template with deviated drivepipe was installed using a small construction jackup boat prior to rig arrival. The drive pipe preinstallation included a starter wellhead that was a combination "quick connection (snap latch)" diverter connection and landing profile for either conductor or surface casing. The casing head (screw on) is landed through the contractor's 21-1/4" diverter onto the landing profile with or without the optional conductor string in place. The diverter and high pressure stacks were directly moved from the finished well to the next well reducing handling time.

The techniques in the field tests described above have reduced dry hole drilling costs significantly. The emphasis is on modification of procedure and existing equipment, rather than development of new technology.
U.S. Petroleum Engineering Manpower Supply & Demand
Authors: Ghalambor A.
Published: December 2007

The purpose of this paper is Co report the results of the supply and demand surveys conducted annually by the SPE manpower committee. 1,2

The 1990 Demand Survey was sent to the companies in the upstream side of the petroleum industry, they included major operators, independent producers, and various service companies. A total of 21 responses were received compared to the 23 in 1989. A group of six respondents had 7 to 42 engineers employed, three with 60-76 engineers, four with 105-339, and five with more than 500 engineers. The remaining responses were not usable. Most of the surveys had been completed prior to the Geo-political and military events of August 2, 1990 in the Persian Gulf.

The following questions are asked in the survey for the years 1985, 1986, 1987, 1988, and 1989: Total Number of Engineers Employed at the year-endTotal number of BS or MS degreed Petroleum Engineers Employed at the year-endTotal Number of On-campus Engineering Grad* uates HiredActual Number of BS or MS degreed Petroleum Engineers HiredTotal Number of Engineering Graduates Hired

The following questions are asked in the survey for the years 1990, 1991, 1992, 1993, and 1994. Total High and Low Number of Engineers to be on the Job at year-end.Total High and Low Number of On-campus Engineering Graduates to be HiredTotal High and Low Number of BS and MS degreed Petroleum Engineering Graduates to be Hired.

The 1989-90 supply survey was sent to 28 petroleum engineering programs in the O.S. Twenty-five of these schools offer degree programs in Petroleum Engineering and three offer options in petroleum engineering within another engineering degree program. A total of 26 schools responded to the surveys, which approximately represent 97% of the U.S. enrollment.

Each school reports the number of graduates during the 1989-90 academic year at the B.S., M.S., and Ph.D. levels. Those graduates who are non U.S. citizens, non U.S. residents, attending graduate schools, or entering the military are reported as not seeking a job. The remainder are considered as a number of those who are seeking a job.

The type of employment is divided into the following nine employer categories: Major ProducersIndependent ProducersGas Transmission CompaniesService and Drilling CompaniesGovernment (Federal and State)ConsultingOther Petroleum Related (Finance, Education)Non-Petroleum RelatedUnknown (Employer Not Reported)

Additionally, the Petroleum Engineering enrollment data from the seme schools were obtained by the SPE Manpower Committee for the 1990-91 academic year. The enrollment data reported were for the fall semester of each academic year.
Wettability Determination: Pore Surface Analysis
Authors: Mitchell A. G. , Hazell L. B. , Webb K. J.
Published: December 2007

The nature of pore morphology and surface chemistry are inherent in determining the recovery performance of reservoir rock through their influence on relative permeability. Assessment of pore morphology can be made directly by using imaging techniques, although recovery prediction based on this assessment is still difficult. The surface chemistry of the pore structure can determine the very important parameter, wettability. Determination of the most representative wetting state of the reservoir is essential to the laboratory core analyst, in order to establish representative relative permeability data. This paper discusses the application of surface science analytical techniques to the characterisation of the pore surfaces of reservoir material.

Both inorganic and organic analyses have been performed on reservoir samples of known core properties. Techniques such as X-ray Photoelectron Spectroscopy (XPS), Secondary Ion Mass Spectrometry (SIMS) and Laser Induced Mass Analysis (LIMA) have been used. Particular emphasis has been paid to the correlations generated between wettability parameters and the organic content on the pore surfaces. The work demonstrates quite clearly that direct analysis analysis of the pore surfaces gives information pertaining to the wetting state. Further, chemical information is obtained which helps identify the functionality of organic species that leads to oil wetting character.

The suggestion is made that the techniques outlined could be used to rapidly determine the wetting state of reservoir material. The surface analysis approach could also lead to a better understanding of how reservoir quality and wetting state can be modified, thus leading to improved predictive capabilities.
Flow Into Oil Wells Through Perforations
Authors: Meyer Henry
Published: December 2007

Introduction

In modern well completion, most wells are completed by perforating the casing. If this completion practice is good, the flow into the well from a given reservoir through these perforations will be essentially equal to the flow into an uncased well. In order to prescribe an efficient completion practice, it is necessary to understand the fluid mechanics of flow through these restrictions. Previous attempts at an analytic solution of the problem have involved so many simplifying assumptions that the results are quite specialized. Solutions by electrical analogy suffer from the inherent nuisance of constructing models and even more basically from the fact that the analogy between flow of an electric current through an electrolyte and fluid flow through a porous rock is not in all cases exact.

This paper presents what is intended to be a more general solution of the problem of the effect of perforation on well production. It is divided into two parts. In the first part different cases are considered in which the rock is completely filled with one fluid, and for simplicity the liquid level in the well itself is taken to be above the top of the producing formation. The second part of this paper is concerned with flow of the denser fluid when the porous rock contains two immiscible fluids and there is consequently an interface between them.

The body of the report is essentially a collection and explanation of mathematical solutions for special cases. The mathematical details are relegated to appendices.

Jet Contraction

Unconfined jet flowing from an orifice will experience a contraction due to its inertial properties. At the minimal cross-section of the jet [vena contracta], the streamlines are parallel and the pressure equal to that in the surrounding fluid. The volume rate of flow in a free jet with contraction will be very nearly equal to that from an orifice which does not produce contraction, e.g., a rounded orifice whose area is equal to the minimal cross-section of the contracted jet. As previously mentioned, jet contraction is largely due to the inertial character of fluid; rectilinear flow of a fluid around a sharp corner without separation would involve infinite acceleration.
Pressure Transient Analysis of Horizontal Wells in a Naturally Fractured Reservoir
Authors: Williams E. T. , Kikani J.
Published: December 2007

This paper presents case histories for a number of horizontal well pressure tests in the Bakken Formation of the Williston Basin. The Bakken formation is a very rich organic source rock with extensive natural fracturing present due to regional tectonics, localized structure, and internal expulsion forces. Numerous operators are currently attempting to exploit this vast resource with the utilization of horizontal wells.

Pressure surveys have been carried out on a number of these horizontal wells. The pressure transient tests were generally designed to obtain information related to original reservoir pressures and the potential skin damage effects. However, complexities introduced by horizontal well dynamics have made it difficult to interpret these welltests using conventional techniques.

A combination of analytical and numerical methods is used to provide a consistent interpretation of the well tests taking into account the possible dual porosity nature of the reservoir. In addition, the orientations of the wells provide some evidence to support arguments about permeability anisotropy in the reservoir. Anisotropic effects are of special interest in horizontal well applications as a critical consideration in the orientation of horizontal wellbores. To date, the orientation of horizontal wells has been relatively random and has been directly influenced by both geographic or land consideration, and structural interpretation.

Numerical studies have been carried out on a state-of-the-art numerical simulator which provides specific capabilities for horizontal completions, local grid refinement, and dual porosity/permeability systems.
Coalbed Methane Production Facilities: A Case History
Authors: Moore D. W.
Published: December 2007

This paper describes the production facilities ARCO has recently installed to develop reserves on approximately fifty sections of land in the La Plata County, Colorado area of the San Juan Basin for producing methane gas from coal beds in the Cretaceous Fruitland formation. The project involves 107 wells and is expected to reach a peak rate of 85 MMCFD (2.4 E+06m3/d). The facilities described include artificial lift,wellhead separation, gathering systems, compression, gas treating, water disposal, field automation and corrosion protection. Operating experience is also discussed. Existing production engineering technology is adequate to economically develop these resources so long as design parameters and equipment limitations are understood.
Fishing With 1.5- and 1.75-in. Coiled Tubing at Western Prudhoe Bay, Alaska
Authors: Mullin M. A. , McCarty S. H. , Plante M. E.
Published: December 2007

Coiled tubing use in the Western Operating Area of the Prudhoe Bay oil field in the Alaska Arctic increased to over 750 operations in 1989. Coiled tubing is routinely used to run inflatable bridge plugs and packers, and electric line logging tools as well as performing a variety of stimulation, remedial cementing and clean-out operations. Development of fishing capability is the logical extension of coiled tubing technology in this field given this high activity level. During the second half of 1989, 21 fishing operations were attempted using coiled tubing with an 81% success rate. Cost savings in excess of $2MM were realized in the initial phase of this project.

Successful fishing operations have been performed with both 1.5 inch and 1.75 inch coiled tubing utilizing hydraulic jars, mud motors, plus an assortment of "off-the-shelf" and field manufactured fishing tools. None of the operations resulted in leaving coiled tubing in the hole or in leaving the well in a worse condition than at the start of the operation. Utilization of mud motors has been particularly successful in diversifying potential application of this technology to adaptation of existing rotary fishing techniques. Included in this paper is a summary of the preliminary durability testing, a general discussion of the methodology involved, as well as three case histories. The case histories consist of fishing coiled tubing with coiled tubing, post fracturing inflatable bridge plug fishing and fishing an inflatable bridge plug buried by large pieces of cement.
General Minifrac Analysis for Heterogeneous Formation Including Spurt Loss
Authors: Soliman M. Y. , Poulsen D. K. , Kuhlman R. D.
Published: December 2007

Conventional minifrac analysis assumes the presence of a homogeneous formation and an ideal formation/fluid system. These conditions usually lead to a leakoff rate that is inversely proportional to (time)1/2. This paper shows that in heterogeneous formations, such as naturally fractured formations, leakoff rate can be better modeled as being inversely proportional to (time) where n is named l·eakof f exponent. It is also theorized that many formation/fluid systems will exhibit a leakoff exponent different from 0.5.

This paper presents methods for determining this l·eakoff exponent. It also considers the effect of spurt loss on minifrac analysis and suggests a method for determining same. In addition, the paper discusses determination of closure pressure and time.
A Statistical Review of API and EPA Sampling and Analysis of Oil and Gas Field Wastes
Authors: Holliday G. H. , Deuel L. E.
Published: December 2007

Resource Conservation and Recovery Act [RCRA] mandates a study of oil and gas field wastes. EPA and API performed independent studies of the same sites. The studies resulted in two independent sets of analytical values for constituents in liquids, solids and produced waters from drilling and producing operations. A statistical analysis of the paired values resulted in concluding no acceptable correlation exists between many of the reported constituent concentrations.
Reservoir Management Training: An Integrated Approach
Authors: Satter A.
Published: December 2007

U. S. petroleum reserves are dwindling, and fewer significant discoveries have been made in recent years. However, technological advances in all areas of petroleum exploration and exploitation, along with rapidly increasing computing power, are providing the tools to better manage reservoirs to maximize economic recovery of hydrocarbons. Sound reservoir management practices are of paramount importance in the petroleum industry. Innovative managers and trained personnel are needed to carry out the functions that the reservoir management process (goal setting, planning, implementing, monitoring, and evaluating) requires. This paper deals with an integrated, multi-disciplinary, high-technology approach to reservoir management training. It will focus on training needs, candidates and their disciplines, course contents, methods, duration, source of instructors, and the benefits to be gained. It is derived from almost two decades of Texaco’s experience in comprehensive reservoir management training.
Analysis of Kansas Hugoton Infill Drilling: Part I-Total Field ResuIts
Authors: McCoy T. F. , Fetkovich M. J. , Needham R. B. , Reese D. E.
Published: December 2007

This paper compares the performance of infill wells drilled in the Kansas Hugoton to the companion original wells - regionally, by operator, and the field as a whole, using official deliverability tests and production history. We present the pitfalls of using official deliverability and wellhead shut-in pressure differences between the infill wells and the companion original wells as indications of additional gas-in-place and suggest more reliable methods of interpreting infill well performance. The results of the first 659 infill wells drilled in the Kansas Hugoton reveal that the infill wells have not found any evidence of additional gas-in-place.
The Economics Of Oil Spills
Authors: Massie W. W.
Published: December 2007

This paper discusses marine oil spills: their types, the public's perception of their risk, dean-up options, and actions both before and after a spill to minimize their consequences. Lessons are derived from a number of actual spills. Actions are grouped in three categories: macro (international), meso (joint industry) and micro (single company). Special sections discuss the role and requirements for computer simulations, and evaluate the probable effectiveness of proposed legislation. The establishment of an equiped and specially trained team of spill clean-up workers who could be deployed worldwide is suggested as one means of alleviating spill consequences. Use of fault tree analysis is proposed as a means of evaluating the (potential) effectiveness of legal steps.
Responsible Approach to the Use of Oil Based Muds
Authors: Potma G. J. , Drinkwater A. R. S.
Published: December 2007

This paper describes the background for a responsible application of oil-based mud in NAM operations, with a clear policy for environmental protection as a first priority. The implications of current and anticipated Dutch legislation are discussed, together with a review of relevant equipment and procedures that can meet all demands. Finally, developments in NAM in the use of alternative muds and improved cuttings cleaning technology are described.
The Jackup Durability Problem
Authors: Massie W. W. , Liu P.
Published: December 2007

This paper summarizes the more salient results of an on-going study of elevated jack-up rig durability carried out by the Workgroup Offshore Technology (WOT) of the Delft University of Technology. Significant discoveries, critical in a design or performance analysis, are presented here. The references include all the reports produced in this study so far.

It is concluded that many common approaches used with jack-ups today have serious shortcomings and that many more or less accepted design approaches fail when applied to elevated jack-ups in deeper water. This can explain the disparity of field data and results found using various analysis approaches on one and the same jack-up rig.

Elevated jack-up platforms demonstrate significant nonlinearities in their overall dynamic structural behavior. The most important of these involve interactions of the legs with: the sea bed via a spudcan, the deck via the deck-leg clamping system, and the sea itself: waves and currents acting on the moving structure.

Inclusion of all these nonlinearities in a design production computer simulations is uneconomical; instead, these can be checked against a benchmark, complete simulation to be developed within this project.
Future Trends in the North Sea : What's Ahead?
Authors: Giannesini J. F. , Badour D.
Published: December 2007

This paper examines the characteristics of as yet undeveloped North Sea discoveries in order to determine the future development trends for the operators in the years to come.

A data bank has been compiled listing the discoveries made so far in the British, Norwegian, Dutch and Danish offshore zones. This data bank lists 447 discoveries, of which only about 40 were in the development phase in early 1990.

The detailed analysis of the discoveries clearly shows that, by the end of this century and the beginning of the next, the North Sea operators will have to focus on increasingly small accumulations, located in medium water depths and generally not too far from existing installations.

After more than 25 years of activity, the North Sea today offers the advantage of many infrastructures capable of enabling production of neighboring accumulations at reduced cost. An examination of current development trends highlights the growing interest of the operators in satellite developments, whether subsea or not. It is now clear that a large share of R and D efforts will have to be focused on the systems capable of improving the economics of this type of development and, in particular, of extending the connection distances.

The challenge is a serious one because, today, there are more than 160 oil accumulations not covered by any precise development plan, and containing at least 5-5 billion barrels of recoverable oil.

The production of these fields will demand innovative technologies. Effective solutions already available include horizontal wells and, in a slightly longer term, multi-phase production. Other technologies must be exploited, such as reusable production installations, entailing a necessary standardization.

Innovation is not limited to technology. At the financial level and from the standpoint of conducting operations, new associative structures are necessary, in order to mobilize the tens of billions of dollars which will have to be invested, and make them profitable. Operators and investors will have to adapt to a new development culture. As 1993 approaches, this represents a vast opportunity for Europe as a whole and for a new generation of ‘entrepreneurs’.
Horizontal Well Performance at Prudhoe Bay
Authors: Broman W. M. , Stagg T. O. , Rosenweig J. J.
Published: December 2007

The first horizontal wells in the Prudhoe Bay Unit were drilled In the central gravity drainage area to increase standoff between the wellbore and the gas cap for improved recovery and increased production rates. Subsequent applications of horizontal wells have included producers in the peripheral area of the field and adjacent waterflood regions, drainholes and gas injectors. Innovative and cost effective horizontal drilling and completion techniques were developed. Horizontal wells have been drilled at angles up to 98 degrees and for lengths exceeding 2100′. There are currently twenty-seven horizontal wells, including two gas injectors, In the Prudhoe Bay Unit with significant opportunity for further development utilizing horizontal well technology.

The performance of the Prudhoe Bay Unit horizontal wells have been evaluated after 1 – 5 years of production to determine the incremental benefits for future justification of the additional costs associated with drilling and completing horizontal wells in comparison to conventional completions.

This paper describes the overall performance of horizontal wells In the Western Operating Area of the Prudhoe Bay Unit Including surveillance and wellwork achievements, drilling and completion technology developed and the reservoir modelling and analytical efforts to date. The current and future strategies of horizontal well applications are also addressed.
Chemical Bridging for Well Control During Stimulation and Workover Operations
Authors: McCabe M. A. , Terracina J. M.
Published: December 2007

Oil field operators around the world are making increased use of polymer gel plugs to control wells and divert treating fluids during stimulation and workover operations. Use of this versatile method has eliminated the need in many cases for mechanical packers, bridge plugs and mechanical diverters. Benefits gained from use of gel plugs are usually economical; however, in many applications, gel plugs are used because mechanical devices may be undesirable.

One method often used to obtain a temporary plug is to apply a water soluble polymer to a fluid which forms a highly viscous gel plug. These plugs can be designed to remain viscous for hours to several weeks. If time constraints change after the plug has been pumped, the plugs can be broken down with acid and removed ahead of schedule.

This paper describes the chemistry of various gel plugs used at different temperatures and conditions in stimulation and workover operations. Several case histories detailing circumstances and conditions where various gel plugs have been applied are presented.
Water Injection Quality in Ekofisk—UV Sterilization and Monitoring Techniques
Authors: Hamouda A. A.
Published: December 2007

Water injection in Ekofisk Field (2/4K) in the Norwegian sector of the North Sea has started late 1987. The waterflood was decided on after the success of a pilot water flood trial initiated in the spring of 1981. Ekofisk reservoir is described as a fine-grained chalky limestone with porosities frequently above 40% and a matrix permeability of only 1 to 2 md. However, a fracture system raises overall permeability to about 100 md.

An important factor in the success of a waterflood project is the quality of the water required for injection into the reservoir. The water quality is greatly affected by several contaminants such as corrosion products/suspended solids, scale and bacteria.

Controling corrosion and minimizing solids generation are two major problems associated with the waterflood. The two problems are related since the solids picked up are corrosion products and/or biomass that cause corrosion. Microbial corrosion may be eleminated/ minimized by frequent treatment with bactericides. The treatment frequency depends on the bactericidal demands and type of bactericide. These, interns are related to the bacterial activities, hence dependent on the monitoring techniques for bacteria counts.

Monitoring of microbial corrosion is always difficult due to the sessile nature of bacteria and the lack of meaningful correlation between bacteria counts and the bacterial activity.

The water injection system on 2/4K is considered to be a unique system since continuous disinfiction of the injected water by UV sterilization technique is used.

Experience gained from the use of the UV sterilization, the bactericidal treatment regime and a comparison between various monitoring techniques of the bacteria are discussed in this pacer.
A Comprehensive Study of Cementation and Fracture Porosity Relationships for Reservoir Characterization Pembina and Garrington Fields, Canada Examples
Authors: Rodriguez Argenis
Published: December 2007

Basic data for conventional clastic reservoir description and characterization is derived from producing intervals, in which porosity, permeability, pressure, and saturation parameters are evaluated. How fair these parameters represent a naturally fractured reservoir for characterization purposes is currently under discussion. It is believed that additional data is required for a proper reservoir description.

In this study, variation of porosity with depth is evaluated in order to determine wheter quartz cementation in fine-grained sandstone, from Pembina and Garrington fields, is likely to occur primarily near the rock's maximum depth of burial, and whether this cementation is likely to have taken place almost entirely prior to the earliest stages of fracture porosity development in the rock and to subsequent filling of those fractures by quartz. Results obtained suggest that authigenic sillca overgrowth is the primary mechanism responsible for cementation of these rocks; this silica overgrowth increases with depth and the bulk of cementation occurs prior to whatever fracturing has tuken place.

The significance of these findings to characterization of naturally fractured reservoirs and to all applications involving fluidflow in the subsurface lies in the realization that those rocks which undergo the greatest degree of cementation at depth are likely to be most prone to fracturing and most able to support a network of open fractures during the cause of uplift and erosional unloading or during any lateral release of pressure that might occur as an accompaniment to gravity tectonics.

This realization can direct petroleum explorationists to search for rock units that could form fractured reservoirs in a basin.