bluuebunny/crossref_metadata_2025 huggingface dataset:
The Effect of Long-term Shut-in Periods on Fracture Conductivity
Authors: Bilden D. M. , Fletcher P. A. , Montgomery C. T. , Guillory R. J. , Allen T. P.
Published: December 2007

Polymer residue is known to be a major cause of propped fracture conductivity damage. Many factors that can contribute to the significance of this damage are polymer type, initial and final polymer concentrations, breaker types and concentrations, formation mineralogy, bottom hole static temperature, shut-in time and fluid cleanup rates.

Most fracturing treatments are designed with good fluid stability for a specific period of time that corresponds to the job pump time. It is then desired to break the fluid as quickly and completely as possible to facilitate rapid cleanup of the well and minimize conductivity damage. A common belief has been that if the treatment is shut-in in the reservoir too long, fracture conductivity damage may increase. This belief has led to operational completion practices that are costly and unnecessary.

A laboratory study was conducted to study the effects of long-term shut-in periods of up to seven days. The results indicated that additional conductivity damage would not occur under the conditions tested. These observations resulted in changes in completion procedures that improved rig time efficiency for the completion of remotely located offshore wells.
Hydraulic Wellbore Erosion While Drilling
Authors: Chemerinski Bill , Robinson Leon
Published: December 2007

This study shows that nozzle velocity and not annular velocity causes hole enlargement in competent formations. Five similar wells were selected where pump rates and nozzle sizes could be controlled to evaluate the effect of nozzle shear rate and annular velocity. After the wells were drilled, caliper logs evaluated hole erosion. These comparative studies revealed that annular velocity did not cause erosion. Holes in which the nozzle velocity was low and annular velocities high eroded less than holes with high nozzle velocities and low annular velocities.

Two wells were drilled in competent formations with an oil-base drilling fluid and three were drilled with a water-base drilling fluid. Below surface casing, all wells used IADC code 427, 517 and 537 drill bits. The data indicates that even with oil-base drilling fluid, high nozzle shear-rates eroded the wellbore more than holes drilled with lower nozzle shear rates. High annular velocities did not erode the hole.

Adequate bottomhole scavenging was maintained even with lower nozzle velocities. Drilling rates did not decrease because of inadequate bottomhole cleaning.

This paper describes the drilling conditions, and the caliper logs, and discusses sequences of events that could explain the observations. Some preliminary guidelines are presented so that drillers can prevent erosion of the wellbore from high shear rates at the bit nozzles.
Manipulation of Coupled Osmotic Flows for Stabilisation of Shales Exposed to Water-Based Drilling Fluids
Authors: van Oort E. , Hale A. H. , Mody F. K.
Published: December 2007

Coupled osmotic flows have been studied as a means of stabilising shales exposed to water-based muds. The prime factor that governs the magnitude of chemical osmotic flow, i.e. the shale-fluid membrane efficiency, was investigated in detail. Its dependence on shale parameters, fluid parameters and external conditions was quantified. Membrane efficiency was found to increase with an increase in (hydrated) solute-to-pore-size ratio, with an increase in the shale’s high-surface area clay content and with a decrease shale permeability when increasing effective confining stress. Moreover, new drilling fluid chemistries for improving the efficiencies of low- and non-selective shale-fluid systems were identified. Induced osmotic flow with optimised shale-fluid membrane efficiencies in water-based environments is presented as a new strategy for improving wellbore stability in shales.
Innovative Through-Tubing Workover Process Utilizing a Cement Packer
Authors: Hathcock Larry , Gardner Craig , Herbert Paul , Hoss Richard , King Lee , Norman David
Published: December 2007

Over the years, cement packers have been used to provide zonal isolation above the production packer without pulling the completion. Experience has shown that the risks associated with placement of the packers is fairly high and leaks are difficult to repair. A number of ways to place cement packers have been developed over the years and a new method has been recently field trial tested in the Gulf of Mexico in the SMI 288 field. This paper introduces a novel approach developed to install a completion, in a through-tubing process, to recover otherwise uneconomical, behind pipe reserves that are above existing production packer installations. The entire process takes advantage of significantly improved mature technologies. The application of this process can increase recoverable reserves and avoid expensive workover costs when the reserve estimates are questionable. This paper will discuss the methodology used and the results of a case history included to illustrate the implementation of the process. It involved creating a window in the tubing across the new zone and placement of a cement packer above the window. The window was created so as to lower the completion drawdown and lower the risk of completing in wells requiring sand control.
Portland Cement - Blast Furnace Slag Blends in Oilwell Cementing Applications
Authors: Mueller Dan T. , DiLullo Gino , Hibbeler Jeff , Kelly Patrick
Published: December 2007

Recent investigations of blast furnace slag cementing technologies have been expanded to include Portland cement/blast furnace slag blends. Mixtures of Portland cement and blast furnace slag, while having a iong history of use in the construction industry, have not been used extensively in oilwell cementing applications. Test results indicate that blending blast furnace slag with Portland cement produces a high quality well cementing material. Presented are the design guidelines and laboratory test data relative to mixtures of blast furnace slag and Portland cements. Case histories delineating the use of blast furnace slag - Portland cement blends in field applications are also included.
The Determination of Dynamic Proppant Concentration Field in Slot Flow in the FFCF
Authors: Beason Ronnie , Fagan John
Published: December 2007

This paper presents a methodology for the determination of dynamic proppant concentration mapping in slot flow in the Fracturing Fluid Characterization Facility (FFCF). The technique presented here is used in the FFCF for the purpose of monitoring and mapping proppant concentration as a function of time for clear slot flow and flow in the High Pressure Simulator (HPS) at the FFCF. The methodology allows the FFCF user, for the first time to determine the instantaneous spacial proppant concentration during slot flow of slurries.

The technique uses a method of measuring spacial light attenuation through the slot flow and a mapping of the light intensity using a calibrated standard to proppant concentration. The method makes use of video technology and the real time digitizing, quantifying, and mapping of the real time video. The paper will present the overall software and hardware scheme used to accomplish this visualization task, snapshots of the real time videos produced by the technique, and how the technique is used in the FFCF. The technique, for the first time, allows the researcher of proppant flow to study the dynamics of proppant flow in fracturing fluids as well as allows the quantification of the flow for the purpose of fluid dynamics modeling. The technique is currently available to researchers in the FFCF in the low pressure slot and will be available in production in the High Pressure Simulator in late 1995.
A New Microbial Plugging Process and Its Impact on Fracture Remediation
Authors: Zhong Lirong , Islam M. R.
Published: December 2007

Microbial mineral precipitation occurs constantly over the geological time. This process induces natural cementation or plugging in sediments or rock formations. Petroleum microbiologists employed the process as a reservoir selective plugging method to enhance the production of hydrocarbon resources.

Mineral precipitation is induced as a result of microbial activities. Bacteria can deposit minerals directly from the medium through their metabolic activities. They can also precipitate minerals indirectly from the medium by changing regional geological environmental conditions. Mineral precipitations and the dead bacteria bodies can persist as a part of the environment and result in plugging or cementing in pores in that environment. The process is optimized with bacteria Bacillus Pasteurii to precipitate CaCO3 so that the bacteriogenic cementation occurs in hours rather than in years. It is suggested that the process be used to plug fractures in water-producing zones to prevent excessive water production during oil recovery. The same technique can be used to consolidate sands in an unconsolidated fractures.

A series of experiments was conducted to investigate the possibility of using microbial plugging process to remediate fractures and to test factors affecting that process. The effects of pH, temperature and medium on mineral precipitation and bacteria growth are studied in detail. Also, the effect of fracture width and fracture fillings is studied. It is found that the microbial mineral plugging technique is effective in plugging fractures.
Application of Sequence Stratigraphic Modeling to Integrated Reservoir Management at Aneth Unit, Greater Aneth Field, Utah
Authors: Amateis L. J.
Published: December 2007

Infill drilling, workovers, and extremely low decline rates proved existing geological models were inadequate to explain reservoir performance. A three dimensional geological model was built using all available geological and reservoir data. The model combined with reservoir engineering analysis has been used to identify workover locations, horizontal well locations, and is being used in an ongoing study for CO2 flooding the reservoir.
Continuous Improvement In Well Design Optimises Development
Authors: Harrison P. F. , Mitchell A. W.
Published: December 2007

The Sherwood sandstone oil reservoir in the Wytch Farm field straddles the coastline of Southern England. The onshore reserves were developed from multiple well sites using limited step-out wells. After four years production, development of the offshore reserves began. Extended reach drilling was applied to drill wells with step-outs of up to 7km with 2.2km reservoir sections.

This paper describes how the extended reach well reservoir trajectories were designed to optimise oil production rate, maximise reserve recovery and limit water-cut development. The offshore development which uses 1990's technology is contrasted with the onshore development from the previous decade.
Surface Potential and Permeability of Rock Cores Under Asphaltenic Oil Flow Conditions
Authors: Alkafeef S. F. , Gochin R. J. , Smith A. L.
Published: December 2007

The surface properties, wetting behaviour and permeability of rock samples are central to understanding recovery behaviour in oil reservoirs. This paper will present a method new to petroleum engineering to show how area/length ratios for porous systems can be obtained by combining streaming potential and streaming current measurements on rock cores. This has allows streaming current measurements (independent of surface conductivity errors) to be made on rock samples using hydrocarbon solvents with increasing concentrations of asphaltene. Negative surface potentials for the rock became steadily more positive as asphaltene coated the pore surfaces, with permeability reduction agreeing well with petrographic analysis.
Steady-State Relative Permeability Measurements Corrected for Capillary Effects
Authors: Virnovsky G.A. , Skjaeveland S.M. , Surdal J. , Ingsoy P.
Published: December 2007

A new method is presented which enables to interpret steady-state flow experiments eliminating errors caused by the capillary end-effect. This is achieved by retaining the capillary term in the equations that are used to interpret the flow data.

The standard experimental procedure has to be extended to include variations in both total flowrate and the ratio of phase flowrates. Consistent values of saturation and relative permeability of each phase are then calculated at the inlet end.

Necessary modifications in laboratory procedures and influence of hysteresis are discussed and the theoretical development is exemplified by numerical simulation of coreflood experiments.

Introduction

During a steady-state procedure for measurement of relative permeability curves, the total flowrate of oil and water is usually kept constant while their ratio is changed at the inlet end of the core. After a change, it is necessary to wait until equilibrium in the core is re-established, i.e., when both the pressure drop and the effluent flowrate ratio do not change with time. The individual flowrates and the pressure drop is then used to calculate the individual phase relative permeability values by Darcy's law, relating them to the average saturation in the core, determined by material balance.

The main inaccuracies of this method stem from the basic assumption that the capillary pressure can be neglected. Actually, because of capillary effects, the saturation distribution along the core is non-uniform, and the pressure drop is different in each phase. The capillary effects are difficult to avoid even if the total flowrate is high and for some rocks high flowrate cannot be reached for reasons like limited equipment capacity or stress that may cause rock damage.

In this paper a new steady-state technique is described that includes capillary effects.

The proposed experimental setup is not very much different from that of the conventional steady-state method. For a fixed fractional flow at the inlet, a number of steady-state experiments is required with varying total flowrate to include the capillary effect in the analysis of the data. The capillary pressure curve has to be measured separately.

Theory

The following standard equations describe one-dimensional, two-phase flow of immiscible, incompressible fluids in a porous medium,

(1)

From Eqs. (1) it follows that the expression for the velocity of the first phase is

(2)

Conservation of mass gives

(3)

Let us consider steady-state flow only. Then the saturation in the core is solely a function of the x-coordinate.

P. 85
Application of Seismic-Guided Reservoir Property Mapping to the Dulang West Field, Offshore Peninsular Malaysia
Authors: Corbett Chip , Solomon G. J. , Sonrexa Kartikay , Ujang Salehudin , Ariffin Tajjul
Published: December 2007

A process is demonstrated for building a deterministic reservoir model, using 3D acoustic impedance inversion and seismic-guided log property distribution. The extraction of fluid and pore volumes at proposed drilling locations assists the qualification of reservoir development scenarios. Fluid flow simulation assists the field development.
Accurate Well Condition Estimates Under Multiphase Flow Conditions
Authors: Roadifer R. D. , Yeh N. S. , Jones J. R.
Published: December 2007

This work considers the analysis of pressure transient data obtained from wells produced under multiphase flow conditions. Both fully-penetrating and restricted=entry wells are considered. In particular, we examine methods for the calculation of the damage skin factor (and the pseudoskin factor caused by partial penetration) in reservoirs with multiple flowing phases. A new semi-theoretical method which accounts for the nonlinearities naturally arising from multiphase flow effects in the reservoir and at the well is presented for calculating these skin factors.

Numerical results for an extensive array of two-phase (oil-water, gas-water and oil-gas; including gas condensates) and three-phase (oil-gas-water) reservoir systems are presented and include the analysis of pressure transient data obtained from both fully-penetrating wells and restricted-entry wells. Our new semi-theoretical skin factor method is shown to provide extremely accurate estimates for both the damage skin factor and pseudoskin factor due to partial-penetration, even when the saturation and pressure dependent fluid properties vary substantially over the course of the well test.

Pressure analysis alone is considered in this work; i.e., we do not consider pseudopressure analysis, either single phase or multiphase. As such, the analysis methods presented are much simpler to use than corresponding pseudopressure analysis techniques and for the multiphase cases do not require a priori knowledge of relative permeabilities. This should result in a more general acceptance and usability by the petroleum engineering community.
Description of Heterogeneous Reservoir Using Tracer and Pressure Data Simultaneously
Authors: Deng Xianfa , Home Roland
Published: December 2007

The nonlinear least square regression method is an indirect method to obtain reservoir properties from observed data. It has been applied widely in well test analysis, especially for interpreting transient pressure data. Based on the difference between observed and calculated pressure data, the estimates of the parameters are adjusted until the calculated response is sufficiently close to that of observations. This method works for limited observations and is most successful if the objective function is convex or has few local minima. However, as the number of observations increases, as in the case of data from multiple wells, the calculation in the indirect method becomes inefficient. Another disadvantage is that the optimization may converge to a local minimum and hence the estimated result will depend on the initial guess of the parameters. This paper presents an approach to interpret pressure data and tracer data from multiple wells simultaneously to characterize the areal permeability distribution in heterogeneous reservoirs. Since tracer data are more sensitive to heterogeneity than pressure data, integration of two kinds of data should give more information about the reservoir. A correlation between permeability and dispersivity was investigated, and used to reformulate the convection-dispersion equation and diffusion equation to a system of first-order equations in permeability. The system of equations was then solved to yield the permeability distribution for appropriate boundary conditions. Advantages and disadvantages of this new scheme are discussed. Though the work focused on isotropic heterogeneous reservoirs, there is no technical difficulty to extend it to anisotropic reservoirs provided that the dispersivity-permeability correlation is renewed. Moreover, this method can conveniently incorporate geological data as constraints.
Use of Inverse Modeling for Conditioning Geostatistical Models to Vertical Tracer Profiles
Authors: Maroongroge Vichai , Saad Naji , Pope Gary A. , Sepehrnoori Kamy
Published: December 2007

A new tracer test for estimating reservoir heterogeneity called vertical tracer profiling (VTP) is presented. This interwell tracer test is performed by injecting and/or collecting tracer samples at different locations along the wellbore. The problem in analyzing this and conventional interwell tracer data is finding the solution to an inverse problem, that is, the inference of the reservoir heterogeneity from the tracer production data. In this paper two inverse modeling techniques are presented and compared in terms of speed and quality of results. The first technique uses a tracer simulator as a forward model in a simulated annealing geostatistical algorithm for conditioning the generated model to tracer history. The second technique uses a least square history matching technique applied to the tracer history coupled with a geostatistical modeling method to solve the inverse problem. These techniques were used to investigate the effectiveness of vertical tracer profiling for determining reservoir zonation compared to traditional sampling of the tracer data. Both 2D and 3D models were used to test the efficiency of the inverse modeling algorithms, the use of tracer data for estimating horizontal correlation, and the advantages of the vertical tracer profiling. The 2D permeability field used in this study was measured on a sample of Antolini sandstone and the 3D permeability field was generated using a Gaussian simulation technique for a fining upwards geologic sequence. The geostatistically generated 2D models were tested by comparing model simulation results with experimental waterflood. The 3D models were also compared using waterflooding simulations.
Analysis Of Diversification In Certain Natural Gas Companies
Authors: Jessup F.M.
Published: December 2007

Ten major interstate natural gas pipe-line companies have been studied for the effect of diversification on net income. This comparison indicates that diversification has generally paid off for those so indulging. Diversification by acquisition would seem to be as successful as diversification by internal expansion; however, the greatest success was achieved by those companies who had good earnings in the beginning and were able to hold the line on costs as the new revenues increased.

This study proves the success of using public utility leverage to add unregulated public utility leverage to add unregulated industrial profits to the regulated profits of natural gas pipeline companies. By use of diversification, the industry can substantially improve its probabilities of maintaining its position in the economy while facing the crisis problems of gas supply, high cost of money and public confidence.

Introduction

Forecasting is the art of analyzing what is known about the past in terms of its meaning for the future. It is necessary to analyze the forces underlying current trends in order to be able to recognize the signals of change and make plans to capitalize on any variability in terms of profit, however, is the forecast of opportunity for it and this is the motivator of proposed activities.

In the natural gas industry, there have been two very depressive features that predict difficult times ahead. The features are the lack of understanding on the part of regulatory bodies and the growing supply crisis, also directly attributable to regulatory problems.

With the declining profit margin on natural gas, some companies have diversified to try to maintain their position in the economy. This diversification, it must be remembered that a profit can be determined only on the basis of a calculation showing the difference added to profit by undertaking the action decided upon, as against the probable result if that action had not been probable result if that action had not been taken.
Capillary Pressure Curves for Low Permeability Chalk Obtained by NMR Imaging of Core Saturation Profiles
Authors: Nørgaard Jens Vintner , Olsen Dan , Springer Niels , Reffstrup Jan
Published: December 2007

A new technique for obtaining water-oil capillary pressure curves, based on NMR imaging of the saturation distribution in flooded cores is presented.

In this technique, a steady state fluid saturation profile is developed by flooding the core at a constant flow rate. At the steady state situation where the saturation distribution no longer changes, the local pressure difference between the wetting and non-wetting phases represents the capillary pressure.

The saturation profile is measured using an NMR technique and for a drainage case, the pressure in the non-wetting phase is calculated numerically. The paper presents the NMR technique and the procedure for calculating the pressure distribution in the sample.

Inhomogeneous samples produce irregular saturation profiles, which may be interpreted in terms of variation in permeability, porosity, and capillary pressure.

Capillary pressure curves for North Sea chalk obtained by the new technique show good agreement with capillary pressure curves obtained by traditional techniques.
Do Electronic Pressure Gauges have 20/20 Vision?
Authors: Hailstone J. , Ovens J.
Published: December 2007

Modern well test analysis relies crucially on the ability of high precision, electronic gauges to accurately record changes in wellbore pressure and temperature in a pressure transient test. However, the gauges themselves may possess certain characteristics which cause a less than ideal response and hence result in the recorded pressure response being systematically different from the actual pressure in the wellbore. This may have an impact on the test interpretation. For instance, long term drift may be interpreted as artificial barriers, possibly leading to an erroneous geological interpretation of the data.

A gauge transfer function, which mathematically relates the input and output pressures and temperatures to each other, allows the non ideal behaviour of the gauge to be modelled. Inclusion of the transfer function in existing computer tools used to analyse Pressure Transient tests will improve the resulting analysis. Based on laboratory test data obtained from a European Joint Industry Project** (EJIP), gauge transfer functions have been determined for two high quality electronic gauges. Details of the transfer functions, analysis of the test results and illustrations of their application in improving a well test analysis are presented.
Conditional Simulation of Subseismic Faults
Authors: Godderij R. R. G. G. , Chessa A. G. , Bruining J. , Kreft E.
Published: December 2007

Extensive fault patterns occur in almost any reservoir. The importance of seismic faults is generally recognized. Subseismic faults, even if they are non-sealing, can also be important. For instance they can confine the flow to channels due to gravity effects.

Here we describe a simulation method, based on a marked point process, to construct realizations of subseismic fault maps that honor fault data obtained from well to well correlation.

We use an adapted version of the ellipsoidal model of Barnett et al.1 to characterize a single fault. The statistical fault properties which are necessary for the simulation are based on a field data-set.
A Hydraulic (Flow) Unit Based Model for the Determination of Petrophysical Properties from NMR Relaxation Measurements
Authors: Ohen Henry A. , Ajufo Austin , Curby Federica Manni
Published: December 2007

This paper presents preliminary results of a Hydraulic (flow) Units based research program aimed at defining more effective guidelines for the use of nuclear magnetic resonance tools (NMRT) for petrophysical evaluation. Successful application of the Hydraulic Units concept for predicting petrophysical properties from wireline logs has been demonstrated previously. In this paper, we show obvious but crucial relationships between the Hydraulic Units concept and nuclear magnetic resonance (NMR) relaxation data. The linkage between these two technologies is possible because the hydraulic unit zonation indicators referred to as flow zone indicators (FZI) and NMR relaxation data are related to the surface phenomenon which controls the microscopic attributes of the rock. It is shown that although NMR relaxation measurements respond to pore body size rather than pore throat size, an effective NMR based permeability model, which includes pore size to pore throat size ratios, can be developed. The phenomenological model presented herein consists of mathematical relationships between FZI and NMR relaxation data, specific surface area, tortuosity and relaxivity (ρ). Laboratory (NMR) relaxation time measurements on CORESPEC-1000 together with core analysis data of permeability, porosity, centrifuge capillary pressure and thin section petrography have been used to validate the model.

The results show that the observed variability in the relaxivity constant (ρ) is due to the existence of different hydraulic units in the reservoir rock. We also demonstrate that relaxation time cut-off (T1c) used for determining producible fluid from relaxation time distributions may vary slightly as a function of rock types.

Hydraulic units based predictive algorithms for the estimation of relaxivity (ρ) and T1c, using pore throat size distributions (mercury injection data), and centrifuge capillary pressure data are validated. A more effective permeability estimation algorithm is also presented.
Comparison of Nuclear Magnetic Resonance Techniques in the Delaware
Authors: Logan Dale , Morriss Chris , Williams Rick
Published: December 2007

The Delaware formation is a very fine grained sandstone, often 4000 feet thick, located in West Texas and SE New Mexico. Resistivity based log interpretation in the Delaware has proven to be ineffective in most circumstances. Deep invasion and high irreducible water volumes lead to water saturation calculations that rarely reflect future production. Recent work in this formation demonstrates that Nuclear Magnetic Resonance (NMR) is an effective evaluation tool.

Lab NMR measurements on core plugs accurately predict pore size distributions that have been used to estimate permeability and irreducible water volume (Bvirr). Lab NMR also demonstrates that water saturated rock has a distinctly different NMR response to partially oil saturated rock. This leads to an estimate of residual oil saturation from NMR.

This success is then duplicated using downhole measurements made by the Nuclear Magnetic Tool (NMT) and the Combinable Magnetic Resonance Tool (CMR). Downhole NMR estimates of porosity, pore size, permeability and residual oil saturation on five wells are then validated by comparison to mudlogs, sidewall cores and production results.
Technical Considerations in Converting Jack-Up Drilling Rigs to Mobile Offshore Production Units
Authors: Duhon R. D. , Kreider G. J. , Barnes J. E.
Published: December 2007

There is a growing need for converting jack-up drilling rigs to Mobile Offshore Production Units for early production, long-term testing and as a low cost reusable alternative to platforms for short life marginal fields. Installing process equipment on drilling rigs offers a unique set of challenges. These include new loads imposed upon the rig, storage of hydrocarbon liquids, gas venting and flaring, location of and installation of equipment, safety considerations and installation of pipeline risers. The specific technical challenge of converting jack-up rigs for Mobile Offshore Production Units (MOPU) is discussed with example solutions from two projects, one installed in Venezuela and one off the West Coast of Africa.
Workover Rig Operation on a Mature North Sea Platform - A Partnership for Success
Authors: Adams D. M. , Fletcher C. , Guyan G. , van Gils J. , Schenk C.
Published: December 2007

An economic appraisal and engineering analysis identified both the profitability and technical feasibility of installing a dedicated workover rig, in addition to the existing drilling rig, on a mature North Sea platform.

The paper discusses the formation of an alliance between a drilling contractor and a well services contractor to provide the expertise necessary to plan and execute workover operations. The paper expands on the following integral concepts included in the contract: Integration of planning and operations, utilizing the combined resources and experience of both the well services contractor and the drilling contractor.Flexible manning levels, thus allowing up and down manning as required for various activities associated with workover operations.Multi-skilling of the workover rig crews to minimise the required manpower with training under the guidance of the alliance.Co-operation of subcontractors with the concept of multi-skilling.The responsibilities and indemnities provisions in the subcontracts to reflect as closely as possible the responsibilities and indemnities provisions in the contract with the operator and main contractor..

The resulting operating contract exemplifies the optimization of resources available from a partnering agreement between contractors and operators, and illustrates the utility of clearly allocating the risk between the parties. Success of the concepts

integrated in the contract, particularly with respect to the value of partnering agreements between contractors and operators, may result in similar future agreements for managing the operator’s assets.
Automation in Cyclical Rate Primary Reservoir Significantly Reduces Beam Pump Failures
Authors: Findlay C. P. , Herring R. B. , Pike J. S.
Published: December 2007

Conoco, Inc. operates the Dagger Draw field in Eddy County, New Mexico (see Figure 1). The field produces 2500 BOPD/8500 BWPD/11000 MCFPD from 35 wells on beam pump. The typical well utilizes an API 87 high strength rod design with either a 912 or 1280 conventional pumping unit running 8–9 SPM with a 168" stroke length. The 7, 900-ft reservoir is under primary development.

A 20-month study is documented during which automated Pump-Off Controllers (POCs) were installed to reduce the high rod failure in the field. Data collected for six months prior to installation indicated that 35 wells averaged 9.8 rod failures per month. In the 14 months following POC installation, rod failures have been reduced 76% to an average of 2.4 per month. Automated surveillance of the POCs using a central computer has resulted in increased efficiency. Manpower requirements have been reduced by one employee in the field.

A previously unknown seven to eight day variable production cycle was observed field wide. This discovery helps to explain the failure of Conoco’s previous attempts to control the fluid pound or gas pound with time clocks.
Identifying Inhibitors of Hydrate Formation Rate with Viscometric Experiments
Authors: Kalbus James S. , Christiansen Richard L. , Sloan E. Dendy
Published: December 2007

Inhibiting the rate of hydrate formation with low concentration additives is an economically and environmentally attractive alternative to prevention of hydrates with large doses of methanol. Here, a method for screening possible rate inhibitors is described. In the method, a viscometer is used to follow the development of hydrate formation for water-THF solutions and for water-gas solutions at conditions favoring hydrate formation. The method was applied to about 30 different chemicals, plus binary combinations of many of these chemicals. The best chemical additives included BASF F-127, Mirawet ASC, Surfynol-465, sodium dodecyl sulfate(SDS), Mirataine CBS with polyvinylpyrτolidone(PVP), and SDS with PVP.
Underbalanced Completions
Authors: Walker Tim , Hopmann Mark
Published: December 2007

The majority of wells today are drilled and completed conventionally. That is, they are drilled with kill-weight fluids which may or may not be detrimental to the formation. Wells that are drilled underbalanced, with less-than kill-weight fluid, foam or air, are often exposed to damaging fluids during completion operations. Technology new to the industry or currently being developed will help eliminate these problems and allow for a true underbalanced operation. This technology includes two-stage drilling, downhole lubricators, downhole swab valves, and isolation equipment used in fracturing operations. This paper addresses these issues and the importance that they play in a successful underbalanced completion.
Educating for Leadership, Management and Teamwork
Authors: Graves R. M. , Turley J. A. , Macon B. A.
Published: December 2007

Beyond the mandatory aspects of technical competence, one of the most practical skills that Petroleum Engineering educators can teach students is how to work well with others. Because teamwork assignments in the classroom foster not only good communication skills but also advanced thinking skills, these assignments can provide students with the appropriate foundation for working in a corporate setting. Success in the workplace depends largely upon how well an employee gets along with others. In the oil and gas industry, the technically competent petroleum engineer who can coordinate and manage the efforts of other engineers performing traditional functions in the organization has the potential to rise to the top of the corporate ladder. Helping petroleum engineering students to become good managers and good communicators can be accomplished by teaching teamwork skills.

However, students must see the relevance of teamwork and communication assignments to their profession; otherwise, they become resentful and fail to perform will. Experience has shown us that students learn more effectively when classroom activities are directly related to their interests and have significance for the students' future work. The synthesis of academic and industry perspectives can assure that classroom teamwork experiences are relevant and timely from the point of view of the faculty, students, and industry employers. This paper presents such a synthesis and provides additional information to help define the role of the petroleum engineer in today’s multi-discipline, cross-functional corporate environment. The paper also presents the most recent feedback from both industry representatives and academicians regarding the feasibility of including teamwork and leadership instruction in the undergraduate petroleum engineering curriculum.

This feedback from industry and academia illustrates the need for continued cooperation and better communication between these two groups. Though the goals of both are similar (e.g., enhancing success and fostering excellence in the field), the means to reach those goals are often very different, and any number of representatives of the two groups would bring widely different perspectives into the discussion. To aid in understanding these similarities and differences in perspectives, this paper focuses on examining the issue from both sides.
1995 U.S. Petroleum Engineering Workforce Supply and Demand
Authors: Reece Cynthia A. , Meyer Joann M. , Takla L. A.
Published: December 2007

Results of the 1995 SPE Petroleum Engineering Workforce supply and demand surveys are outlined. Total engineering employment in the upstream sector is expected to decline slightly through 1997, while petroleum engineering employment will grow slightly in 1996 and 1997. The number of engineers hired, including petroleum, will decrease in 1995 but rebound in 1996 to 1994 levels. The number of petroleum engineering graduates seeking U.S. employment is forecast to decline slightly over the next two academic years. These graduates, however, should find improved employment outlooks in 1996 and 1997.
Use of a Database to Integrate Petroleum Resource and Reserve Estimates from Exploration to Production
Authors: Pollen S. , Andersen T. , Manner M. , Rustad L. J.
Published: December 2007

As a major Norwegian oil company Norsk Hydro is involved as operator or partner in a large number of commercial petroleum fields and exploration licenses.

The requirements for reporting reserve estimates have led to the development of a corporate database. This has improved the quality of the estimates and increased the flexibility in using approved data for different purposes.
Field Evaluation of Disc-Stack Centrifuges for Separating Oil/Water Emulsions on Offshore Platforms
Authors: Khatib Z. I. , Faucher M. S. , Sellman E. L.
Published: December 2007

Separate handling of fluids following a remediation/workover job or treating of slop oil emulsions has become a good practice to reduce upsets in oil and water treating facilities and to avoid production shut-in. This paper demonstrates that the use of high-speed disc-stack centrifuges can be a cost-effective process for handling these fluids, treating difficult emulsions, and generating little or no waste. The physical operation of these centrifuges as dehydrators (purifiers) and/or as deoilers (clarifiers) and their performance in various field applications are presented.
Tubing Flowrate Controller: Maximize Gas Well Production From Start to Finish
Authors: Elmer William G.
Published: December 2007

Many gas wells have liquid loading problems caused by oversized tubing, resulting in premature abandonment. This paper suggests that small tubing can be used in most any packeriess sweet gas well, regardless of anticipated flowrate, without restricting production capacity. A method of flowrate control is recommended that insures that tubing flow stays at rates necessary to maintain mist flow, allowing all liquids to be produced up the tubing string. Excess volumes are produced up the casing/tubing annulus, where pressure drop due to friction is usually negligible. Maintaining mist flow up the tubing is accomplished by regulating the amount of gas allowed to exit through the annulus. This single loop process is controlled using cost effective, simple, reliable, oilfield equipment.
Environmental Effects Of Discharge And Reinjection Of Produced Water.
Authors: Furuholt Edgar
Published: December 2007

There has been much focus on possible acute toxicity of produced water and which natural components and chemicals contributes most to the toxicity. This paper describes a method for risk analyses of discharges to sea based on exposure dose instead of the more common method using concentration. Results are presented from such analyses for the produced water from 4 Norwegian oil/gas fields. A comparison of environmental effects of discharge and reinjection of produced water is also presented based on available methods for assessment of environmental impacts.
Beneficial Reuse of Oilfield Waste Outside of the Oil and Gas Industry
Authors: Marinello S. A. , Herbert B. F. , Lillo H. , Curtice S. , Stark C. L , Redweick R. , Mohrbacher J. D. , Rubin M.
Published: December 2007

If a beneficial reuse of an oilfield waste can be found, that specific byproduct is no longer a waste, but a product. With such downstream use, the environmental liabilities of the former waste are, except for any packaging or transportation requirements, potentially eliminated

There is a problem, however, with the lack of an active infrastructure to implement the process. Some states have limited programs, but participation is a problem. It is apparent that a "Waste Clearinghouse" addressing oilfield waste in conjunction with major industrial waste and feed strems in needed, but implementation remains in the future. An active network of participating suppliers and users would be the goal of such action. In order to establish the network, it might be necessary to lobby for modified legislation to provide economic motivation, perhaps through modified taxation, and to affect liability issues. The benefits for industry would be a reduction in waste disposal and associated liabilities and "virgin" feedstock requirements.

From the operators viewpoint, this scenario would require a compilation of the different waste/byproduct streams and their characteristics and a prioritizing of those wastes by characteristics that might affect their reuse potential. These might include: (1) the greatest likelihood of finding a market; (2) the highest potential waste volume reduction; (3) the highest cost of disposal and (4) the greatest associated hazards.1

For the industry as a whole, an inventorying of these byproducts and characteristics would be tied to the identification of consumers/outlets for specific byproducts. This might be accomplished through the funding of consultants/contractors specializing in clearinghouse activities and/or research into potential applications and uses.

The industry needs to change it's view of waste/byproduct streams in order to be more aware of potential downstream uses. Existing examples of reuse can be used as models for further efforts.
Environmental Management Strategies For An Enhanced Oil Recovery Project, Trinidad
Authors: Dyal Shyam , Nijhawan Arun , Ramnath Kelvin
Published: December 2007

The Government of the Republic of Trinidad and Tobago has embarked on a major energy sector project to recover proven reserves of crude oil contained in onshore and offshore producing fields, using secondary recovery techniques. Onshore reserves of crude oil are produced using steam flooding techniques while offshore reserves are recovered through water injection techniques. These projects are being undertaken by Petrotrin and Trinmar Limited respectively.

An Environmental Impact Assessment (E1A) conducted prior to the start of the projects served to identify key environmental sensitivities associated with each project. Environmental Management Strategies were developed by both Companies to mitigate against the potential impacts of each project and are in various stages of implementation. These include: The establishment of Environmental Units, the conduct of employees training programmes, the implementation of preventative maintenance programmes, the introduction of new oily wastewater treatment facilities, application of environmentally acceptable solid waste disposal methods, regular monitoring of effluent quality, ensuring compliance with interim Company Standards and the development of oil spill contingency plans.

In addition, Petrotrin has begun a groundwater quality monitoring programme, a rationalization programme for storage facilities and adopted and implemented various components of ARPEL's environmental guidelines. Additional strategies implemented by TRINMAR Limited include risk analysis for submarine pipelines, a gas emission control programme and the conduct of annual Environmental Audits.

Environmental Management Act, 1995 which provides for the establishment and operation of an Environmental Management Authority, has just been enacted. However the enforcement of environmental legislation has been hampered by the lack of coherent effluent standards and regulatory agencies. The onus for managing the environmental impacts of the projects undertaken therefore lie within the respective Companies. The extent to which this is done is largely due to their management's commitment to achieving acceptable levels of environmental performance. The Environmental Management Strategies adopted by both Companies ensure that activities associated with the projects comply with their respective corporate missions and environmental policy statements.
Management of Change Reviews Improve Facility Safety and Optimize Operations
Authors: Ritchie Carolyn J.
Published: December 2007

Most offshore facilities are subject to periodic modifications and changes to improve operations. These improvements can take many forms, such as increased efficiency, safety and environmental enhancements, or equipment upgrades due to technical innovations. Proposed changes to an offshore facility should be reviewed prior to implementation so that facility safety and environmental protection are not compromised. Often, in the course of the management of change review, ways to optimize operations are discovered. Three case studies are discussed in this paper. These include modifications to existing equipment, structural support, safety, control and relief systems.