bluuebunny/crossref_metadata_2025 huggingface dataset:
Rapid Characterization of PAH's in Oils and Soils by Total Scanning Fluorescence
Authors: Gray N. R. , McMillen S. J. , Requejo A. G. , Kerr J. M. , Denoux Guy , McDonald T. J.
Published: December 2007

Total Scanning Fluorescence (TSF) is a rapid and inexpensive technique that can be used for the analysis of polynuclear aromatic hydrocarbons (PAH's). The basis for the use of fluorescence is that, in general, emission/excitation wavelength maxima increase with increasing number of aromatic rings. The output of the TSF analysis is a fluorescence "fingerprint" consisting of a 3-D emission/excitation intensity contour diagram. This "fingerprint" can provide information about the content and relative composition of PAH's in samples.

To date, this technique has been applied primarily to the analysis of sediment samples collected as part of offshore geochemical exploration programs. In this study, TSF has been evaluated for the rapid screening of oils and soil extracts containing biodegraded crude oil. Analysis of ten crude oils from the southern and western regions of the U.S. shows that their fluorescence characteristics vary widely. These differences can be directly related to varying PAH composition. TSF "fingerprints" of oil subjected to bioremediation for 52 weeks show systematic differences from those of the unaltered oils. These differences suggest that TSF can be used to measure the abundance and composition of PAH's in samples and to detect loss of PAH's in samples that have undergone biodegradation.
The Effect of pH on Microbial Degradation of Oil-Based Drilling Mud in a Slurry-Phase Bioreactor
Authors: Crews Bonny , Malachosky Edward , Hinman L. D.
Published: December 2007

A slurry phase bioreactor was used to degrade the hydrocarbon component of oil-based drilling mud residues to an acceptable level for land disposal. The initial oil and grease concentration in the residue was approximately 26% by weight. Laboratory treatability studies had indicated a potential for biological degradation of the material. Initial target levels of nutrients were set at 200 ppm P as phosphoric acid, and 500 ppm N as ammonium nitrate. Daily samples were taken from the bioreactor to monitor pH and microbiological activity (as oxygen uptake rate, OUR). Samples were analyzed weekly for oil and grease content, cations and anions, and phosphate, ammonia, and nitrate levels.

Despite adequate nutrient additions, sufficient aeration, and a pH within physiological range, the OUR rarely indicated bacterial activity sufficient to degrade the oily waste. The full-scale bioreactor behavior was contrary to that of bench-scale reactors used in the treatability studies. Several parameters which were investigated as potential causes of the variations in activity included aeration (as dissolved oxygen, DO), mixing, pH, and nitrogen-phosphorous ratio (N:P). The calcareous calcium chloride-based drilling waste was found to reduce the bioavailable phosphate, and resulted in low levels of soluble phosphate and a subsequent high N:P.

The pH of the system was lowered to 6.0-6.3 by phosphoric acid addition to increase phosphate availability. This resulted in a dramatic increase in the OUR (from ≤ 0.1 mg O2 L−1min−1 to 0.5 mg O2 L−1 min−1) and a subsequent downward trend of the total oil and grease in the slurry prior to the dismantling of the bioreactor and land disposal of the waste.
Synthetic-Based Mud Systems Offer Environmental Benefits Over Traditional Mud Systems
Authors: Candler J. E. , Rushing J. H. , Leuterman A. J. J.
Published: December 2007

This paper addresses critical issues concerning the regulation of synthetic-based fluids in Outer Continental Shelf waters. Synthetic-based muds were not envisioned when discharge criteria were formulated a decade ago. It is critical that the U.S. Environmental Protection Agency investigate this new category, since the original permit language and discharge criteria may inhibit the utilization of this new technology and prevent the realization of volume reduction that can be achieved using synthetic-based muds.

To date, the EPA has not addressed the use of inhibitive mud systems as a control technology for reducing the quantity of pollutants. Drilling through shale formations is an integral part of drilling wells in the Gulf of Mexico. Solving problems associated with these formations can benefit the EPA, industry, and the environment.

The use of synthetic-based muds offers greater waste reducing capabilities than water-based muds. They also permit drilling in areas which now require oil-based mud to combat troublesome shales. Compared to hauling oil-based mud, synthetic-based muds offer significant non-water quality advantages in the areas of air pollution, worker safety, reduction of potential spills, and reduction in landfill usage.
Construction and Operation of a Biological Treatment Cell for the Treatment of Hydrocarbon-Contaminated Soil in Alaska
Authors: Ratliff M. D.
Published: December 2007

The paper is a case study of a successful biological remediation cell (biocell) that was constructed and is being used in Kenai, Alaska. The cell was constructed to remediate petroleum hydrocarbon-contaminated soil. Biological remediation is a promising technology that can prove both environmentally friendly and cost effective in the treatment of petroleum hydrocarbon-contaminated soil. A biocell can be easy to construct and operate. The biocell utilized an enclosed treatment area and a sprinkler system to saturate the contaminated soil. The excess water was drained to a sump where it was pumped to holding tanks and profiled. Any nutrients or adjustments necessary to promote rapid biological growth and degradation were noted and performed. The project has proven to be successful and beneficial to the overall remediation project which was undertaken.
Resolving the Toxic Discharge Problems of the Sussex Field, Wyoming
Authors: Brus K. R.
Published: December 2007

In many locations in the Rocky Mountains, water associated with oil production is very fresh (less than 5000 mg/1 Total Dissolved Solids (TDS)). Many operators in Wyoming discharge excess produced water to the surface, where it is depended upon by local livestock and wildlife. Much of Wyoming is semi-arid high plains, where the evaporation rate is 4 to 5 times the yearly precipitation total, so water is a precious commodity. When the EPA issued the Clean Water Act and the National Pollutant Discharge Elimination System (NPDES) in the 1970's, regulations were imposed affecting the quality of produced water discharges, restricting the TDS, specific chemical constituent concentrations and the dissolved oil and grease concentration. Operators must comply to the restrictions or face fines and eventual cancellation of the permit.

In 1988, the State of Wyoming issued a toxicity reduction regulation that required compliance by year's end 1992, to comply with national EPA requirements. Produced water that is discharged to streams has to fulfill whole-effluent Acute Toxicity testing protocol, in which immature fathead minnows and water fleas are exposed to the discharge fluid. If the water fails this testing, the toxicity has to be removed or reduced or the discharge discontinued. Many locations cannot economically tolerate the expense of some of the options for compliance, which could include sub-surface disposal. Furthermore, if all the water is injected, many streams will be dry most of the year, and the livestock and wildlife would suffer.

This presentation will recount the procedure that Conoco used to resolve the toxicity problem at the Sussex Field discharge. The process included 1) selection of toxicity reduction over sub-surface discharge, including economic considerations, 2) an attempt to identify the toxic components of the discharge, 3) selection of a toxicity remediation process, 4) design of a workable treatment facility and 5) installation and operation, at comparatively low capital expense, of a workable system.
An Evaluation of Produced Water Management Options in the Natural Gas Production Industry
Authors: Lawrence A. W. , Miller J. A. , Miller D. L. , Linz D. G.
Published: December 2007

Potential environmental impacts of natural gas production have become the focus of increased regulatory activity in recent years. Because produced water accounts for greater than 80 percent by volume of the residual materials generated in the production of natural gas, cost-effective and environmentally acceptable disposal of these waters is critical to the continued economic production of natural gas. This Gas Research Institute (GRI) sponsored study is evaluating the technical and economic feasibility of a spectrum of produced water treatment and disposal options using an engineering economic management model developed by the study team.

This paper describes the model which was developed in a PC-based, linked spreadsheet format to allow the user to interactively evaluate alternative scenarios for treatment and disposal of a specific produced water with a stated volumetric production rate and water quality. The model contains twelve treatment process modules ranging from gravity settling to thermo-mechanical evaporation. Final disposal modules include: surface discharge; reinjection via Class II Injection Well; evaporation; and reuse. Modules for water transportation from well head to treatment site are included. Each process module contains a performance-cost relationship to facilitate computation of capital and operating cost for a given produced water management scenario.

The model is used to compute unit costs for produced water treatment and disposal according to a number of possible management scenarios ranging from discharge to surface waters to reinjection via Class II Injection Well. These computed costs are then compared to published costs for several existing produced water disposal operations. Modifications of the model to specifically address the management of produced water from offshore gas production activities are described.

The model developed in this study may be useful to natural gas producers both as an initial screening tool for evaluating produced water management options in the development of a new gas field and also in the consideration of the economically feasible responses to increased regulatory requirements. In addition, the model is being used by GRI to assist in delineating productive areas for research on produced water treatment which have the potential for reducing the future cost of disposal.
On-Site Monitoring of Drilling Fluids Toxicity
Authors: Hoskin S. J. , Strohl A. W.
Published: December 2007

On-site monitoring of drilling fluids toxicity can play an important role in decisions concerning offshore drilling fluids discharges and engineering.

Two on-site methods of monitoring the toxicity of offshore drilling fluids discharges are (1) mathematical models that predict mysid LC50 values based on mud additive concentrations and (2) the Microtox® toxicity analyzer. This study introduces a new Microtox technique which allows contact of the test organism with the entire solid phase of the drilling fluid.

Laboratory and field drilling fluids are evaluated using this new technique. Results are correlated with mysid toxicity tests and traditional Microtox tests and compared with a mathematical model. The result is a valuable system for on-site compliance monitoring of drilling fluids toxicity.
Advances in Water Clarifier Chemistry for Treatment of Produced Water on Gulf of Mexico and North Sea Offshore Production Facilities
Authors: Durham D. K.
Published: December 2007

Since 1987 EPA regulations applying to produced water discharge in the Gulf of Mexico have become increasingly stringent and have made it increasingly difficult for many platforms to remain in compliance with respect to oil content in the overboard produced water. In the North Sea a similar situation exists with respect to oil content specifications on discharged produced water set by regulatory agencies in the various North Sea sectors.

Because of this situation an intensive product development program was initiated to develop new water clarifiers that would allow the existing offshore water treating systems in the Gulf of Mexico and North Sea to treat the overboard water to meet the new stricter specifications pertaining to the overboard discharge of produced water.

This paper discusses the development of these new dithiocarbamate (DTC) based water clarifiers which effectively reduce insoluble hydrocarbon in offshore water treating systems where other conventional and first generation dithiocarbamate water clarifiers have been found to be ineffective, create unmanageable side effects, or are less cost effective.

Product selection and application techniques for these new dithiocarbamate water clarifiers and conventional water clarifiers are also discussed along with observations concerning the advantages and disadvantages of various types of offshore water treatment systems and equipment.
Environmental Considerations in Production Chemical Usage
Authors: Caudle D. D. , Bansal K. M.
Published: December 2007

Oilfield chemicals are primarily used to make crude saleable, to minimize process problems, and to treat produced water to meet regulatory guidelines for disposal into the sea (offshore) or injection underground (onshore). Where these chemicals end up depends on such factors as the nature of the chemicals, injection location, solubility, and distribution coefficient of the chemicals in the oil and water phases. Chemicals that end up in the water phase will get into the environment only if the water is discharged to the environment.

This paper examines a number of issues which impact the amount of chemical used and the limits on the minimization of its use. These issues include: attitudes towards chemical usage, process limitations, and physical/chemical behavior of the chemicals, and interactions with other chemicals in the system.

Wastes from the production treating chemicals are also discussed in this paper. A total system approach is proposed to minimize the chemical usage in production operations.
"Dry" Drilling Location—An Ultimate Source Reduction Challenge: Theory, Design, and Economics
Authors: Wojtanowicz A. K.
Published: December 2007

The term "dry" wellsite denotes a drilling operation without the use of an earthen reserve mud pit in land drilling, or without the overboard dumping of bulk drilling fluid in offshore drilling. As the two field practices have been increasingly scrutinized in environmentally sensitive areas, and the hauling off of bulk waste drilling mud is either too expensive or impossible to do, the minimum-volume control (source reduction) becomes an important part of drilling technology. This paper presents mechanistic and economic models of the controlled-volume drilling process and their theoretical use to design a "dry" location.

The mechanistic model quantifies all phenomena and operations related to drilling fluid as they affect the volume of waste mud and cuttings discharged from a wellsite. The model simulates the treatment of drilling process discontinuities (non-drilling operations) when rapid volumetric changes occur. Also presented is the steady-state model of "drilling ahead" operations with active mechanisms for drilling mud dilution, separation of cuttings, dewatering, and recycling.

The economic model involves a breakeven analysis of all components of the mud management process (i.e. mud making, maintenance, processing, and disposal) together with temporary storage requirements. A computer program simulating drilling and mud management processes relates drilling technology, field practices, local geology, and regulatory constraints to the volumes of active, stored, and waste mud and the costs of mud making, maintenance, and disposal. Investigated in the computer simulation study are volumetric effects of various parameters such as drilling conditions, dewatering unit performance, and solids control efficiency. The study shows that drilling can be designed and conducted in such a way that the wellsite discharge will be minimal.

Also presented is an example design of a dry drilling location where the cost of source separation technology (dewatering) is fully offset by the savings in disposal and mud costs. The study demonstrates that dry drilling locations are technically feasible and economically sound when designed using principles of volumetric control of the drilling mud. Also discussed is a mathematical model and design methodology for well-planning considerations.
Post-Fracture Production Performance and Waterflood Management at Prudhoe Bay
Authors: Schuldt D. M. , Suttles D. J. , Martins J. P. , Breit V. S.
Published: December 2007

An aggressive hydraulic fracturing campaign, involving over 360 wells, has been conducted at Prudhoe Bay, primarily within the waterflood region of the field. High declines in gross fluid production rates (oil plus water) were observed in the first few months after the fracture stimulations were performed. Work was initiated to determine the cause of these declines and to identify any actions which would mitigate them.

A combination of diagnostic well work, field data analysis and reservoir studies to investigate the decline mechanisms are presented. The paper highlights the use of numerical simulation for investigating the reservoir mechanisms of decline, and the benefits associated with alternative waterflood management schemes.
Estimation of the Pseudoskin Factor Caused by a Restricted-Entry Well Under Multiphase Flow Conditions
Authors: Roadifer R. D. , Reynolds A. C.
Published: December 2007

This work considers the analysis of pressure transient data obtained from a restricted-entry well under multiphase flow conditions. In particular, we examine the pseudoskin factor caused by partial penetration in a reservoir with multiple flowing phases.

Only the total skin factor, which is a linear combination of the mechanical skin factor due to damage or stimulation and the pseudoskin factor due to partial penetration, can be obtained directly from semilog analysis of pseudoradial flow pressure data. In order to obtain the true mechanical skin factor, an independent estimate of the pseudoskin factor due to to restricted entry is required.

The pseudoskin factor correlations of Yeh and Reynolds1 and Ding and Reynolds2 for a restricted-entry well completed in a multilayer reservoir are extended to obtain a new correlation for computation of the pseudoskin factor caused by a restricted-entry well in a reservoir with multiple flowing phases. An extensive set of two-phase (oil-water, gas-water, oil-gas) and three-phase (oil-gas-water) examples are presented and indicate this correlation yields accurate estimates of the pseudoskin factor.

Because this correlation is dependent upon the analysis of pressure transient data obtained under multiphase flow conditions, conditions under which such analysis can be performed and procedures for that analysis are discussed. A new semi-theoretical procedure for analyzing solution-gas systems in which free gas is produced at the sandface is presented. Numerical results for all of the multiphase systems considered in this study indicate that the common practice of approximating a gas cap or aquifer as a constant pressure boundary cannot be justified.
Improved Modeling of Oil/Water Flow in Naturally Fractured Reservoirs Using Effective Fracture Relative Permeabilities
Authors: Babadagli Tayfun , Ershaghi Iraj
Published: December 2007

Pseudo relative permeability curves have been used to model heterogeneous (layered) reservoirs in the past. Although the two-phase flow and the nature of heterogeneity are different from the layered systems, the same concept can be applied to the modeling of naturally fractured reservoirs. The proposed relative permeabilities are shown to be not only a function of saturation values but are also dependent on flow velocity, permeability and capillary pressure levels of the matrix.

The EFRP’s (Effective Fracture Relative Permeability) were generated for different rates and matrix properties in oil water systems. Using the EFRP curves, a dual porosity system can be reduced to a fracture network model. This provides a significant reduction and modification in modeling of dual porosity systems.

This type of modeling approach will reduce the time spent for matrix and transfer flow calculations and more emphasis can be devoted to represent the irregularity of the fracture pattern.
Modeling Thermal and Pressure Drops for Multiphase Flow in Thermal Horizontal Wells
Authors: Le Gallo Y. L. , Latil M. J.
Published: December 2007

Use of horizontal wells can improve the performance of thermal recovery by steam drive. In most common cases, flow in horizontal wells is turbulent due to high flow rates and thermal effects. The well behavior is then modified during hot water or steam injection and hot oil production. Therefore, accurate wellbore pressure and temperature drop computations are fundamental in the simulation of thermal recovery processes with horizontal wells.

To compute pressure and temperature profiles in horizontal wells, we use multiphase flow models for steam injection and oil production to account, for energy and momentum exchanges with the reservoir.

For steam injection, a two-phase flow model based on Beggs & Brill approach was implemented for pressure drop computations in horizontal wells. This steady state model uses empirical correlations and simplified physics to describe steam, gas and water flow in the well. It is valid over a wide range of temperature, pressure and steam quality conditions. For oil production, a blackoil model based on multiphase flow in pipes was used to compute the pressure profile in horizontal wells. This steady state model is valid for single and multiphase flow over a wide range of experimental conditions. Temperature profile computations in injection and production wells use the same thermal model based on steady stale energy balance for the wells which includes fluid friction energy losses and heat exchange with the reservoir. Pressure and temperature models were integrated to a. 3-D three-phase fully implicit, blackoil and compositional thermal reservoir simulator.

Temperature and pressure drops modify horizontal well performances when applied to a full-field scale steam flooding process. Oil production flowrates and pressure, steam injection flowrates and breakthrough time at production well are altered. A numerical sensitivity analysis presents the influence of the key parameters for horizontal wells.
Analytical Technique for Resolving Frontal Instability in Reservoir Simulation
Authors: Elemo R. O. , Lawal A. S.
Published: December 2007

Frontal instability occurs in every phase of reservoir simulation (water flooding, steam flooding, chemical and carbon dioxide flooding) and in multiphase fluid flow. Whenever saturation front changes with time and spatial distribution, S(x, t), the key issue is usually the resolution of the changes of fractional flow curve with saturation (df/dS). That also implies evaluation of the derivative of relative permeability curves with saturation. An analytical technique is developed to evaluate the required derivatives and the results are used to estimate the recovery of gas displacing oil with changes in mobility ratio. The proposed technique can be accurately used to develop an algorithm for fractional flow curves. The technique is very attractive as a diagnostic tool for inquiring into the necessity for extensive reservoir simulation studies and should enjoy popularity with field engineers.
Bending and Fatigue Characteristics of Pipe Connections for Offshore Pipelines
Authors: Azar Jamal J. , Vincent Price , Ketcham Bruce V.
Published: December 2007

An experimental program has been performed to determine the suitability of various pipe connections for use in offshore pipelines and, more particularly, in lines placed by the controlled catenary method. The types of connections chosen were the welded, the full runout buttress, a special hydril and the 8-round API connections. Test data showed, both in the static and cyclic tests, that the welded connection is superior to the threaded connections; however, considering the severity of the tests, it can also be concluded that the full runout buttress thread is satisfactory for subsea pipeline service.

Introduction

A series of static and cyclic bending tests on four types of pipe connections were conducted to determine their suitability for use in offshore pipelines and, more particularly, in lines placed by the controlled particularly, in lines placed by the controlled catenary method. The pipe specimens chosen for the tests were eight 5/8-in., 0.593-in. wall, 50.87-lb/ft, Grade-B, seamless, schedule 100 line pipe. This particular pipe was selected since standard casing collars could be obtained and this was the size and grade of pipe used in some of the Cook Inlet pipelines. The types of threaded connections chosen were the full runout buttress, a special hydril, and the 8-round API. The standard for comparison purpose was the welded-type connection made according to the same standards as used in the Cook Inlet pipelines. pipelines. In the authors' opinions, the test results as presented in this paper are of significance in the design and selection of pipe connection configuration for use in pipe connection configuration for use in offshore drilling.

TEST DESCRIPTION AND OBJECTIVES

The static bending test was conducted to simulate the bending which might occur in laying pipe by the controlled catenary system should some degree of the tension control on the lines be lost in the laying operation. A test apparatus [Fig. 11 was chosen in which evenly distributed load could be applied to the pipe rather than the conventional system where pipe rather than the conventional system where the specimen supported at each end is bent by point loading at the midpoint. Uniform loading point loading at the midpoint. Uniform loading along the length of the specimen is more representative of the bending to which the pipe, normally, would be exposed in the laying operation.

Uniform loading was achieved by applying the same amount of bending moment to each end of the 20-ft section of pipe with the connection in the middle.
Infill Drilling in Gravity-Dominated WAG Floods, Prudhoe Bay Field, Alaska
Authors: Wilcox T. C. , Polzin M. W. , Kuo S. S. , Saidikowski R. M. , Humphrey K. J.
Published: December 2007

Introduction

This extended abstract describes the use of infill drilling to improve solvent sweep efficiency and EOR recovery in a gravity dominated WAG flood.

Much of the incremental oil recovery in the Prudhoe Bay Miscible Gas Project (PBMGP) is displaced from a relatively small volume of swept reservoir surrounding each WAG injector. Solvent override occurs due to high vertical permeability and the large density difference between solvent and reservoir fluids. Solvent rises to the top of the reservoir or underneath shales, forming cone-shaped swept intervals around WAG injectors (Figure 1).

Vertical sweep by solvent in gravity dominated WAG floods can be improved by increasing the viscous-to-gravity ratio1,2. A higher viscous-to-gravity ratio (HVGR) expands the solvent swept areas around the injection wells before gravity segregation occurs. However, little can be done in the PBMGP to reduce gravity forces, and water and solvent injection rates are currently near the maximum attainable.

Reduced well spacing remains the only viable method to increase viscous-to-gravity ratio. Most of the benefit from reduced well spacing is due to displacing oil from new WAG cones around the new injectors.
A Boundary-Element Algorithm for Modeling 3D Horizontal Well Problems Using 2D Grids
Authors: Koh L. S. , Tiab Djebbar
Published: December 2007

Three-dimensional fluid flow through porous media problems have assumed increased significance and complexity in recent years due to a growing interest in horizontal well applications. Various predictive tools based on analytical and numerical methods have emerged to address such problems. They have various drawbacks. A versatile boundary-element algorithm was developed in this work to provide a viable alternative.

The algorithm is capable of solving transient and steady-state problems in isotropic or anisotropic reservoirs and handling finite reservoirs and finite-radius well(s) of arbitrary geometry. It also allows the prescription of arbitrary combinations of the two common types of boundary conditions (Dirichlet and Neumann). It, can thus be used to solve a wide variety of three-dimensional horizontal well problems in relatively complex situations.

A major advantage is gained due to the need to discretize only the domain boundary and not the domain itself, thus effectively reducing the dimensionality of the problem by one and eliminating grid orientation effects and numerical dispersion. The reduction in problem dimensions allows three-dimensional problems to be modeled using two-dimensional grids.

This paper provides a summary description of the main features of the algorithm. The application of the algorithm is demonstrated using two examples involving horizontal wells.
Using Authoring Languages To Create Interactive Learning Environments
Authors: Walsh J. W. , Powell R. B.
Published: December 2007

Providing technical training is necessary to all companies. Whether the training is for new employees or new material for established employees, the most effective training tools are those that provide "hands-on" experience and immediate feed back. Microcomputers have provided a platform for training programs which allow simulations of physical or mathematical problems. With video and sound capabilities these programs can include realistic pictures and entertaining segments. Programs can be designed primarily to be used by one person or by several people, each working on different aspects of a problem. These teaching tools can also be straight forward going directly through logical steps or be structured to provide decision branches to allow users to investigate how different paths solve a problem. The software can be designed to evaluate solutions by the "correctness" of the result obtained and resources (time and cost) to achieve the given result.

Authoring languages offer programmers an environment for developing a structure of paths for a learning program. Interactive screens are then defined and conditions set to take users along each path. Using an authoring language, programs can be quickly written.

This paper outlines how an authoring language can be used to develop teaching tools. An example is presented showing how a training need goes from suggestion to finished product. The example used is a training program for PLANIMETER, a software program for computing reserves from isopach maps. This program is designed for geologists, petroleum engineers, and technicians. The paper outlines how the learning goals are organized into a program structure. Screens can then be created by a variety of methods: scanning images, creating graphs, and displaying text. The example utilizes Quest, an authoring language from Allen Communications in Salt Lake City, Utah. Once screens aredefined the user response and interface are added. The example will outline the general procedure for developing a learning tool using an authoring language.
Automated Decline-Curve Analysis Using Robust (LAV) Nonlinear Parameter Estimation Under MS-Windows™ 3.X
Authors: Chen Jianping , Prouty J. L.
Published: December 2007

The type curves developed by Fetkovich1 are widely used tools for decline curve analysis. Fetkovich combined the analytical constant pressure infinite (early transient period for finite systems) solutions with the "empirical" exponential, hyperbolic, and harmonic decline curve equations developed by Arps2. There are software applications that have computerized this analysis technique; however, attempts to automate the matching process have been hindered by two problems: (1) a way to identify the transition from one flow period to the next, and (2) a way to minimize the adverse impact of oudiers, data considered to be bad observations. This paper presents methods to handle these issues.

Recognizing the point of transition between flow regimes is sometimes difficult, even when the matching process is done manually. If, however, the curves are regenerated using the proper derivatives of the production, the software can locate the transition simply by looking for a minimum. The process of estimating reservoir parameters is simplified as well.

To handle outliers, this paper proposes a robust algorithm consisting of a nonlinear parameter estimation using Least Absolute Value (LAV) as the criterion for minimization. One advantage of this approach is that it provides a smooth transition between full acceptance and total rejection of a given observation. Oudiers are systematically assigned less weight in the objection function. This method also avoids the computation of a second derivation of the model function. Most importandy, tests have shown that when outliers are introduced into the observations, the LAV algorithm still produces accurate parameter estimates.

The above techniques have been implemented in software that operates in the MS-Windows™ environment With its graphical user interface (GUI), this environment allows for clear visual displays of the matching process and the results. Moreover, it provides the user with many more options than the traditional, non-graphical operating systems. Because programming under MS-Windows is still relatively new to the industry, this paper also discusses some aspects of Windows programming, especially as it relates to petroleum applications.
Intelligent Approach of Rod Pumping Problems
Authors: Alegre Lideniro , Da Rocha A. F. , Morooka C. K.
Published: December 2007

Identification problem (diagnosis) in rod-puinpimg involves both pattern recognition and symbolic reasoning, since dynamometer card provides important information but not all data required for decision making. A surface dynamometer card (SDC) is a record of the load vs. position of the polished rod in rod pumping units. Because of the rod stretch, the SDC cannot generally provide all information needed to understand how the pump is operating downhole. For this purpose, the engineer uses also information about the characteristics of the well, the type of oil being pumped, etc., besides taking into consideration the SDC shape, maximum and minimum load values, etc. A new type of neuron is used to built neural nets having powerful numeric and symbolic processing capabilities, besides permiling knowledge to be encoded not only on the wiring of the net. but also on the selection of the types of neurons and synapsis composing the net. This new type of neural nets was used to develop SICAD, a hierarchical neural system whose purpose is the intelligent control of rod-pumping. SICAD is composed by two famillies of neural nets specialized, respectively, in pattern recognition (PRN) and expert reasoning (ERN). Different modes of interactions between ERN and PRN define different pumping control strategies. The present paper analyses the roles played by PRN, ERN and their interactions. It also discusses the basic conditions under which SICAD may support different end products for an intelligent management of rod-pumping oil
The Development and Implementation of a Drilling Database: A Case Study
Authors: McCammon K. C. , MacKinlay W. M. , Yoder D. L.
Published: December 2007

Conoco has been using a drilling database to track costs and optimize operations for the past 5 years. This paper discusses the evolution of the database, field and office implementation, system usage and features, and the current impressions and future plans for the system. It also provides recommended guidelines based on Conoco's experience.

Drilling cost reduction has become increasingly important in today's economy. Key factors in reducing drilling costs are optimizing operations, benchmarking, and utilizing manpower to its fullest potential. Before decisions affecting performance are made, information needs to be gathered and analyzed in an efficient manner. A database combined with engineering analysis programs can provide the tools necessary to quickly perform the advanced analysis that is vital to compete in the current economic environment.

To accomplish these objectives, Conoco has been using a drilling database system worldwide for several years. Work on the database system was initiated in 1988 as a joint development effort between Conoco and DRD Corporation. The system has developed into a database system that captures a broad scope of drilling information and generates a wide range of reports and graphics to assist in the optimization of drilling operations.
Downsizing the Safe System to the Client/Server Model
Authors: Crump J. J. , Hobi J. A. , Montgomery E. W. , O’Gorman T. P.
Published: December 2007

Shell has successfully downsized a database that records and reports health and safety events for employees, moving it to a microcomputer-based client / server environment. It was enhanced to handle any kind of HS&E event involving employees, contractors, and other people. This paper highlights evaluation of alternative platforms, system development, and initial operations.
Optimal Scheduling for Cyclic Steam Injection Projects
Authors: Curry Guy L. , Chang Gordon Y.K. , Harper Ronald G.
Published: December 2007

In this article, a well steam injection scheduling model which maximizes the profit per day for oil production leases is discussed. The model can be used to produce operating resteaming schedules and to evaluate the profitability for any number of steam profitability for any number of steam generators. There are no limitations on the size of the problem which can be handled by this approach exclusive of computer storage capability and run time.

The model consists of nonlinear regressing nonlinear optimization and a scheduling algorithm. Weekly well production data from a production reporting system is utilized to production reporting system is utilized to extend the system to a reporting, operating control and planning system that not only provides management with production history provides management with production history but analysis tools for better decisions as well.

Introduction

Within the past few years, there has been considerable interest shown in the application of thermal recovery processes. Cyclic steam injection has been the most frequent and successful process applied to thermal recovery programs. This process consists of injecting programs. This process consists of injecting varying quantities of steam into a well for varying periods of time. The object of the process is to increase the production rate of process is to increase the production rate of a well for a given time period, or to extend the total production life of the well. Either or both of these two activities can have a sizable impact upon the profitability of the lease.

In addition to the problem of determining the quantity and duration of steam injection, the engineer is concerned with calculating the optimal cycle schedule and number of steam generators required for a lease. This article discusses a method for optimizing the profit from cyclic steaming operations. The objective of the method is to develop a practical model which solves the scheduling problem with little effort, on the part of the engineer involved. The model combines an optimization procedure, a scheduling procedure and a curve-fitting program into a computerized system which produces program into a computerized system which produces the desired schedule without manual intervention. The model will curve fit and plot the well production response curves,, find the optimal production response curves,, find the optimal recycle times and produce a schedule for steaming all wells over a given planning horizon. The model can also be used to evaluate the optimal number of steamers for a given set of wells taking into consideration steamer utilization factors.
Regulations for the Control of NORM
Authors: Gray P. R.
Published: December 2007

Responding to the public's concern over radioactive contamination, the perceived need to protect the health of employees, the public, and the environment, and the need to control the spread of contaminated materials into commerce and unrestricted areas, have led regulatory agencies, both state and federal, to develop regulations for the control of NORM.

As a result, regulations for the control of NORM are being developed at an increasing pace by the petroleum producing states. At the present time, Louisiana, Mississippi, and Arkansas are the only states with NORM regulations in effect, but several others, including Texas, Alabama, Kentucky, New Mexico, and Oklahoma could have their regulations in effect during 1993. It is expected that the majority of the petroleum producing states will have regulations within two to three years.

The federal government is also considering regulations for the control of NORM, and it is probable that the Environmental Protection Agency will develop federal regulations for NORM control. Some of the Canadian provinces, e.g., British Columbia, Alberta, and Saskatchewan, will also have NORM regulations shortly.

There is still some controversy over acceptable exemption levels for radium. More data, particularly accurate measurements of radon emanation rates and better risk assessments for NORM exposures, are needed. The impact of the regulations on the petroleum industry will be very costly and will require some changes in operating procedures.
In-Place Purchases Of Gas Reserves
Authors: Jacobs John C.
Published: December 2007

1962 Economic and Valution Symposium, Dallas, March 15–16, 1962

Introduction

In this paper the term "in-place purchase" of natural gas shall mean the purchase of a developed natural gas productive property by a pipeline company for cash plus a series of installment payments. As such, in-place purchases are but one facet of the larger problem of obtaining a gas supply for interstate pipeline systems. This one facet represents a small but important part of obtaining gas supply, and a generally misunderstood part. This paper is designed to show what in-place purchases are, what in-place purchases are not, and the position of in-place purchases in the larger scheme which is our natural gas industry. This description will be oriented from the general point of view of the problem of obtaining gas supply for an interstate pipeline system, and the effect of the various solutions of this problem upon the parties involved. The paper emphasizes the practical experience gained from participating in the day-to-day gas buying market, as opposed to theories.*

First, what is the gas supply responsibility? Fig. 1 shows the reason for our interstate pipeline system. Gas reserves are concentrated in the Texas-Louisiana area, whereas markets are concentrated in the Northeastern, North Central and Pacific Coast States. The interstate gas pipeline industry has developed, in the large part during the last two decades, to provide a means of moving gas from the areas of concentrated reserves to the areas of concentrated markets as shown in Fig. 2. As shown in Fig. 3, which covers all gas marketed in the United States-intrastate as well as interstate-the gas industry is a sizeable industry; one with a rapid rate of growth; and one in which considerable future growth is expected. Note also that this is an industry of large numbers. For example, the 13 trillion cu ft of gas marketed in 1961 at an approximate average cost of 14 cents/Mcf in the field represents a dollar outlay of $1,820,000,-000. The reserves representing this annual sale, if a 20-year supply and the same unit cost is assumed, would represent a dollar value of $36,400,000,000. Consequently in discussing gas supply, we are at one place-in addition to the federal government-where it cannot be said that $1 billion is an impressively large number.

In this era of growth the obtaining of new gas supply is almost entirely for pipeline expansions. Not only are large quantities of gas required, as shown in Fig. 3, but the problem is complicated by competition, Federal Power Commission control of field prices, Natural Gas Act standards regarding the expansion of pipeline systems, and the large number of parties which must be satisfied in any practical solution to a gas supply problem.

P. 79^
Investigation of Dynamic Mud Cake Formation: The Concept of Minimum Overbalance Pressure
Authors: Jiao Di , Sharma M. M.
Published: December 2007

Dynamic filtration experiments were conducted on cores with water based muds at different mud flow rates. It was observed that the thickness of the mud cake was a sensitive function of the mud rheology, the mud shear rate and the permeability of the rock. A model was developed to relate the process of cake buildup under dynamic conditions to the mud and rock properties. Excellent agreement between the model and the experiments was obtained. As predicted by the model (and observed experimentally) no cake was formed on rocks with low permeabilities when the overbalance pressure was reduced below some critical value.

It has been generally accepted that no filter cakes form on rocks with very high permeability (lost circulation). It is shown in this paper that there is also a lower bound on the permeability below which no cake will form and that a minimum overbalance pressure must be maintained in the mud column to ensure mud cake formation. We also present equations that allow laboratory dynamic filtration results to be used directly to predict the critical permeability and the minimum overbalance pressure required for cake formation in the field.
Risk Analysis and Monte Carlo Simulation Applied to the Generation of Drilling AFE Estimates
Authors: Peterson S. K. , Murtha I. A. , Schneider F. F.
Published: December 2007

The purpose of this paper is to present a methodology for developing an AFE-generating model, using a specific offshore field development case study to illustrate the technique. The model utilizes risk analysis and incorporates Monte Carlo simulation in conjunction with statistical analysis of historical drilling data to generate more accurate, risked, AFE estimates. In addition to the general methodology, we present an example of an AFE estimate using the presented techniques with an interpretation and statistical analysis of three years of drilling data for the North Sea.
Drilling of Horizontal Wells in Western Siberia
Authors: Jelsma H. H. , Comeaux B. C. , Meyerov B.
Published: December 2007

The pursuit of oil and gas in the former Soviet Union poses both technical and political challenges to Western companies. This paper discusses how some of the difficulties were overcome while drilling horizontal wells in Western Siberia. It describes various combinations of Russian and Western technology which have been used to provide the most cost effective methods. It also provides a general understanding of political and environmental issues involved in drilling in Siberia which are largely unknown to the West.