bluuebunny/crossref_metadata_2025 huggingface dataset:
East Flour Bluff (Deep) Cycling
Authors: Smith Louis E. , Page George O. , Snyder Louis J.
Published: December 2007

The East Flour Bluff (Deep) Field is composed of a series of abnormal pressure gas reservoirs. A production test of the J-55 zone indicated a condensate yield of more than 100 BPM. Laboratory analysis showed that the dew point pressure was near the 7800 psi reservoir pressure and indicated severe retrograde behavior. Initial production from the zone, which reduced the reservoir pressure to 6800 psi, confirmed the analysis as condensate recovery dropped to 80 BFM. An additional zone was tested and found to have initial condensate yield of 45 BPM. This paper describes how cycling operations were evaluated. Reservoir performance calculations were made for natural depletion and for several possible cycling cases using a compositional reservoir simulator. In these calculations the B-W-R equation of state was used to predict phase behavior. Economic analyses of these cases combined with anticipated deliverability requirements for depletion of area reserves under the existing gas sales contract resulted in selection of the optimum cycling plan. Of interest is the flexibility designed into the compressor installation which is capable of high pressure injection as well as low pressure sales compression without requiring recylindering.

Introduction

The East Flour Bluff (Deep) Field is composed of 13 abnormal pressure gas reservoirs. Production is from Marine Frio sandstones which Production is from Marine Frio sandstones which occur from 9,000 to 11,000 feet subsea. The field is located in the Laguna Madre waterway near Corpus Christi, Texas, as shown in Fig. 1. Gas from this field is committed for sale along with gas from the Flour Bluff, East Flour Bluff, and Pita Island Fields. All leases in the East Flour Bluff (Deep) Field are included in a single royalty unit. In mid-1968, the East Flour Bluff (Deep) J-55 reservoir was tested and found to have an original yield of 102 barrels of condensate per million standard cubic feet of gas produced. Laboratory analysis of a recombined gas sample showed a dew point close to the original reservoir pressure of 7800 psi and indicated severe retrograde behavior. Subsequent production from this reservoir indicated a dew production from this reservoir indicated a dew point of about 7500 psi; condensate yield has point of about 7500 psi; condensate yield has dropped to 80 BPM at a reservoir pressure of 6800 psi. The other major reservoir, the J-77, was tested and found to contain a 45 BPM gas condensate. From these results, it was apparent that gas cycling of these reservoirs should be evaluated in an attempt to maximize condensate recovery.
The Evidence for and Implications of a Fractal Distribution of Petroleum Reserves
Authors: Brett J. F. , Feldkamp L. D.
Published: December 2007

This paper presents preliminary empirical and physical evidence that oil and gas field sizes are fractally distributed. Further, the paper shows that this evidence predicts a fractal dimension greater than 1.0, which implies that larger quantities of hydrocarbons exist in smaller fields than in larger fields. If this hypothesis is true more hydrocarbons remain undiscovered in smaller fields than have been discovered to date, even in mature areas. If the hypothesis is false, the outlook for mature areas in not nearly so optimistic.

The paper also presents a list of "key questions" that should be answered before one could be certain of a fractal distribution of reserves, and it gives a reliable estimate of the distribution's dimension.
Estimating Oil Reserve Variability by Combining Geologic and Engineering Parameters
Authors: Holtz M. H.
Published: December 2007

Uncertainty in oil reserve analysis results from both sources of error in an analysis and the affects of changing production technology. This uncertainty can be constrained by analyzing reserves within the context of a geologic play. The geologic plays are based on categorization of geologic heterogeneity, which corresponds to engineering parameters.

Monte Carlo simulation can be used to combine the effects of both error in reserve analysis and the affects of changing production technology. When this approach is used within a geologic play framework, the resulting reserve probability distributions can accommodate geologic uncertainty and quantify reserve variability potential (RVP). Calculating the RVP of a individual reservoir is a three step process. First the OOIP/acre values for a given play are fit to a general probability distribution function. Second, play probability distribution functions are fit for reservoir recovery efficiencies at various stages of reservoir development Finally, the delerministically calculated average OOIP/acre for individual reservoirs is applied with the play volumetric and recovery probability distributions, to generate RVP distributions. The 50th percentile reserve value and the 10-90 percentile range is the RPV, and this describes the reserve uncertainly.

This method allows more accurate reserve estimates and bridges the gap between advocates of deterministic versus probabilistic reserve estimation. Geologic assurance is built into the RVP, and engineers are thus better able to assess risk in reserve calculations. Applying the concept of RVP also eliminates the need to categorize reserves as proved, probable, and possible by modeling reserves as a continuum.
A Consistent Probabilistic Approach to Reserves Estimates
Authors: Capen E. C.
Published: December 2007

This paper breaks no new ground in it's call for using practical probabilistic methods for defining reserves. In fact the problem has always begged for a probabilistic solution. The bigger surprise is that an industry which prides itself on its use of science, technology, and frontier risk assessment methodologies finds itself in the 1990's with a reserves definition more reminiscent of the 1890's. The petroleum industry uncovers uncertainty at virtually every stage. Its definitions need to reflect that fact. I hope this paper provides a provocation or two for future debate on this important topic.

When presenting some of these ideas during a panel discussion at the SPE 1991 Annual Technical Meeting, I half jokingly remarked that had the Society been charged with describing the probability of a fair coin, it could not have agreed on a method of quantification: The Society suggests the following guidelines. Heads: A likely event or an event that certainly may occur. Tails: An entirely possible event or a probable event. Having to attach actual numbers to heads or tails would prove confusing to the membership and will add nothing of value.
Effective Environmental Management
Authors: Frederick J. D.
Published: December 2007

The emergence of the new environmentalism and the resultant wave of regulation forces industry to rethink how it deals with related environmental issues.

How does business account for environmental programs to ensure that society is apprised early enough to avoid catastrophic and costly over-regulation? How does business streamline to reduce environmentally related costs while maintaining the high quality of its product or service?

Information that is publicly released concerning environmental issues must be properly managed to guard against misuse.

Consultants can be a cost-effective tool when properly managed and when utilized as a supplement to in-house staff.

Industry must look upon agency staff as partners in achieving a common societal goal, rather than as adversaries seeking to curtail business.
Optimum Timing for Property Divestment
Authors: Rosiere D. W.
Published: December 2007

An economic analysis technique has been developed to aid in determining optimum divestment time for oil and gas properties. This technique can be a useful planning tool in defining the operation and divestment portfolio of a maturing property base, and can be programmed within a computer spreadsheet using data extracted from only one economic forecast of continued operations.

The technique identifies the optimum time to divest by comparing at each remaining year of economic life, "the net gain that would be realized from sale" to "the net present value (NPV) of continuing operations for one more year, plus the net discounted gain from sale at the end of that year." In other words, the analysis addresses at the beginning of each remaining year, "Is it moire profitable to sell now, or operate for another year and then sell?"

Optimum divestment time can be determined graphically or from tabulated comparison values. Cumulative differences in comparison values for each year can show expected loss from divesting at times other than optimum. If property divestment is imminent, the comparison can be used to determine a minimum sales price that yields maximized economic gain compared to continued operations.
Division of Technology Ownership Between a Service Company and Customer
Authors: Daunis J. R. , Scott F. L.
Published: December 2007

This paper discusses the increased emphasis on division and allocation of ownership, costs and risks associated with technology rights and Intellectual Property (i.e. intangible assets such as patents, trademarks, copyrights, computer programs or software, trade secrets and other technical know how and show how) between a Service Company supplier of oil and gas products and services, such as Halliburton Company, and a Customer, such as Atlantic Richfield Company. There is increasing industry wide interest in Strategic Alliances between Service Companies and Customers. Atlantic Richfield Company and Halliburton Company have recently entered into such a Strategic Alliance. One of many aspects of such an Alliance includes an allocation of the ownership of Intellectual Property Rights related to or resulting from the working relationship between the Service Company and the Customer.
Fracture Characterization From Measured and Simulated Bottom hole Pressure
Authors: Fragachan F. E. , Mack M. G. , Nolte K. G. , Teggin D. E.
Published: December 2007

This paper presents analyses of fracturing pressures measured, through a dead-string completion, in ten wells located in northern Mexico. Measured pressures are simulated with a novel pseudo-three-dimensional (P3D) model, matching the observed field data. Closure pressure is derived from a combination of a "step-rate" test, performed at the beginning of the treatment, and analysis of the pressure decline observed at the end of the treatment (closure on the proppant provides an upper bound to the closure pressure).

One well is discussed where bottomhole pressures were observed to be higher than the overburden, and indicated a fracture also propagating in the horizontal plane ("T" fracture). Two other wells showed a wellbore screenout as soon as proppant hit the perforated interval. Finally, a well where a tip-screenout was observed is considered.

Conclusions and recommendations are provided regarding the analyses of fracturing pressures and their importance for understanding and improving the fracturing process.
Numerical Simulation Study of Water Shut-Off Treatment Using Polymers
Authors: Hwan R-N. R.
Published: December 2007

Polymers are frequently used to treat high water-cut producing wells in an effort to reduce water production. The application of polymer solution was reported to be successful in some cases but disappointing in others. This study applies numerical simulation to investigate the effectiveness of the polymer treatment for reducing water production from oil wells with water coning and from waterflood producers.

The results of the study show that near-wellbore, non-gel type polymer treatment in lowering water production can only be effective for a period of time. The water production will gradually rise to and exceed the pre-treatment level. An effective treatment requires deep polymer penetration in the formation to reduce water coning and the water production from waterflood producers. Water coning heightens at high production rates, low perforation intervals, high oil-water viscosity ratios, etc. The polymer treatment is not very effective for the wells with severe water coning problems.
Fracturing Fluid Leakoff and Damage Mechanisms in Coalbed Methane Reservoirs
Authors: Conway M. W. , Penny G. S. , Schraufnagel R. A.
Published: December 2007

Fracturing fluid leakoff in coalbed methane reservoirs can be highly damaging to the cleat permeability of coal. During the fracturing treatment, the cleats sub-parallel to the fracture are thought to open and accept fluid. Laboratory and field evidence suggests that severe damage can result deep within the formation. This work investigates mechanisms of fluid leakoff, damage and control in large scale cleated coal samples and in coal core samples from the San Juan and Black Warrior Basins. The leakoff properties, regained permeability and retained conductivity of the proppant pack have been studied with various cleat orientations and fluid loss additives, including 100 mesh sand. The damage of various fracturing fluids has been further measured vs penetration depth in fresh coal cores from the Black Warrior Basin in a multiport core flow apparatus.

Three damage mechanisms have been identified including 1) leakoff of whole gel during spurt or uncontrolled leakoff, 2) leakoff of water only during filter cake control prior to breaking and 3) leakoff of broken polymer while breaking. The application of 100 mesh sand can control leakoff to cleats: however, the cleats and pack only cleanup if appropriate breakers are applied. Leakoff of water only with filter cake control is the least damaging mechanism to cleat permeability. Finally, the leakoff of broken guar is as damaging as whole guar due to polymer adsorption onto coal surfaces; experimentally modified guars that show minimum adsorption are less damaging.
Quantifying Layered Reservoir Properties With a Novel Permeability Test
Authors: Jochen J. E. , Hopkins C. W. , Frantz J. H.
Published: December 2007

This paper presents a new test procedure designed to measure individual layer reservoir properties (permeability, skin factor, and reservoir pressure) in a single wellbore and in a reasonable amount of time for low permeability gas wells. The method involves (1) isolating a small interval with packers, either in an open- or cased-hole, (2) injecting nitrogen into the interval at a rate such that the bottomhole pressure builds up to a pre-determined value (below fracturing pressure), and (3) shutting in the well, preferably downhole, and monitoring the pressure falloff. The pressure falloff data is then analyzed to determine reservoir properties. Essentially, this method can be described as a nitrogen slug test and can be applied to any formation where single-phase gas is produced.

We have found that average reservoir properties determined with conventional analyses of a single pressure buildup test conducted over a large interval can lead to optimistic predictions of the future performance of a well producing from a layered reservoir system. Therefore, being able to quantify individual layer properties can lead to better reservoir characterization, modified completions, and improved performance projections. Existing techniques, such as multiple pressure buildup tests, are inadequate for measuring reservoir permeability in several intervals in a single wellbore because, often in low productivity gas wells, either a pre-stimulation rate is not attained or the time required to reach the correct semilog straight line for a conventional well test analysis is too long. Knowledge of layered reservoir properties impacts completion decisions (where to perforate), fracture design considerations, and post-fracture analyses.
Openhole DST of a Horizontal Well: A Case Study
Authors: Finley D. B. , Wendler C. E.
Published: December 2007

The last several years have seen an increase in the popularity of horizontal wells1. There are a number of applications for horizontal wells that are an enhancement to the traditional vertical well. By increasing the wellbore's contact area with the reservoir, a horizontal well increases the drainage efficiency of a marginal reservoir by: more efficiently exploiting naturally fractured formationsreducing the likelihood of water coning and/or fingeringimproving EOR via horizontal injection wellsintersecting vertical or near vertical formations

To determine if a horizontal well will indeed provide the intended enhancement to productivity (or injectivity), an evaluation of the formation parameters and characteristics is recommended.

Drill stem testing of vertical wells has long been a popular means of formation evaluation. However, the testing and subsequent formation evaluation of a horizontal well presents additional challenges. The successful operation of the downhole tools as well as the analysis of the collected data are not as straightforward as for a vertical well.

This paper presents a case study of the successful testing and subsequent analyses of four open hole DSTs of a horizontal well. These DSTs were conducted during the well's drilling phase at ever increasing degrees of deviation; from ±45 degrees for the first test to ±90 degrees for the fourth test. This paper presents and discusses the: downhole tools used and their relative positions in the holeplanning and preparation for the testsanalysis of the collected data for formation parameters and characteristicsaspects of the horizontal hole that affected the analysis.
Scale Dependence of Mechanical Properties: Application to the Oil and Gas Industry
Authors: Schatz J. F. , Schatz John F. , Olszewski A. J. , Schraufnagel R. A.
Published: December 2007

A method and underlying mathematical model are introduced for determining the size scaling and frequency sensitivity of mechanical properties. The method allows laboratory triaxial and ultrasonic data, as well as log data such as the dipole sonic log, or a subset of these, to be used for determining static moduli on a larger scale. Applications are in hydraulic fracture design, in-situ stress estimation from logs, and wellbore/formation deformation studies. The model is based on soft discontinuities and inhomogeneities as the primary causes of scale effects in geologic media. Because of its basis in physical mechanisms, the model has the potential of being more widely applicable than if it were purely empirical. A computer program is developed to allow easy data reduction and application. Validation is performed with lab and field data at five different depths and rock types from a coalbed methane well.
When Can a Fracture Be Initiated Through a Circular Wellbore in an Oil Sand Reservoir?
Authors: Wang Yarlong , Dusseault M. B. , Chhina Harbir
Published: December 2007

Oil sands and other poorly consolidated sandstones (PCS) behave differently under different loading procedures, and retain memory of their load histories in the three-dimensional array of contacts and forces. These factors complicate predictions of the response of PCS to external loadings. Prediction of hydraulic fracture initiation pressure in a PCS is difficult, as fracture initiation depends on in situ stress state, material constitutive behavior, and ultimately may be controlled by stress path and history. In this paper, load paths corresponding to certain field activities and laboratory tests during pumping and injection are analyzed to evaluate cases that arise when hydraulic fracture initiation is attempted in a PCS reservoir. Fracture initiation pressures following different loading paths are presented by applying elastic and elastoplastic models. Hydraulic fracturing tests conducted in oil sands in the Cold Lake region in Alberta are used as examples. The bottomhole pressure records are used to compare with our analytical results.

The conclusion is that, for the same in situ stress, wellbore hydraulic fracturing pressure records in a PCS may respond totally different when different stress paths have been followed. This load history of a wellbore environment depends on drilling and pressurization history. Conventional elastic equations for predicting fracture initiation pressures are not appropriate; one must in general interpret wellbore pressure records for hydraulic fracture in PCS using elastoplastic models, incorporating material properties and loading history.
UNAVAILABLE - Decline-Curve Analysis With Type Curves - Analysis of Gas Well Production Data
Authors: Palacio J.C. , Blasingame T.A.
Published: December 2007

This paper is not available.

It was an oral presentation at the SPE Rocky Mountain Regional/Low Permeability Reservoirs Symposium, held in Denver, Colorado, 12-14 April, 1993. The authors did not provide the manuscript or copyright permission for addition to the proceedings.
Analytical Upscaling of Small-Scale Permeability Using a Full Tensor
Authors: Aasum Yngve , Kasap Ekrem , Kelkar Mohan
Published: December 2007

Computational costs limit large scale reservoir simulations to coarse grid systems. Determination of an effective permeability for a simulation grid block requires a proper scale-up of small scale permeability heterogeneities within that grid block. Conventional scale-up techniques are limited to a diagonal tensor representation of effective permeability. Therefore, such techniques cannot handle general permeability anisotropy (full tensor) exemplified by cross-bedded permeability structures that may be present on a smaller scale. An analytical method is developed to calculate an effective permeability tensor for a grid block by accounting for small scale heterogeneities within the grid block. The method honors both the location and the orientation of the small scale heterogeneities. Effective permeability tensors calculated using the analytical method and a numerical method show excellent agreement. Miscible displacement simulations show that the effective permeability tensor method outperforms conventional scale-up techniques in predicting flood front locations in cases of general permeability anisotropy.
Economic and Environmentally Beneficial Reuse of Drilling Waste
Authors: Longwell H. J. , Grieve D. V. , Raque A. K.
Published: December 2007

Mobile Bay drilling operations are conducted under strict "zero discharge" of drilling and completion fluid wastes. This regulatory constraint challenges drilling operators to develop waste management systems for the collection, treatment, and onshore disposal or reuse of these wastes.

This paper presents a generally applicable, multi-step process used in the development of a successful drilling waste management plan, and proposes the reuse of treated drilling wastes as municipal landfill daily or intermediate cover material.
Road Mixing Sand Produced From Steamdrive Operations
Authors: Cornwell J. R.
Published: December 2007

Thermally enhanced oil recovery (EOR) operations in the southern San Joaquin Valley (SJV) of California increase oil recovery, but also cause excessive sand production. Sand and heavy hydrocarbon materials removed from tanks and other production facilities are typically non-hazardous by California waste characterization criteria. The tank bottom hydrocarbons exhibit cohesive properties that support the beneficial reuse of these materials as binders in road paving materials. Tank bottoms mixed with local aggregate yields a product that has minimal environmental impact.

Road mix variability can be high due to the nature of the materials used, but does not severely impact the overall quality of the final product. Process and issues that directly or indirectly impact road mix variability include: free liquid removal, aggregate mining, produced sand characteristics, oil/binder viscosity and mixing operations. Despite the variability of road mix materials and processes, test results show that heavy oil road mix products meet most of the minimum standards for commercial cold mix paving products.

Potential environmental concerns with oilfield road mix are offset when net air and waste management benefits of this process are considered. Air emissions are a potential concern and are related to the level of volatile organic constituents (VOC) in the oil. Offsetting this concern are:

– Low VOC content in most SJV heavy crude. – Particulate reduction from paving onsite roads.

In addition, offsite disposal of tank bottoms yields higher emissions from transport and disposal and fills up valuable landfill space with non-hazardous materials.
An Operational Perspective on the Handling and Disposal of NORM in the Gulf of Mexico
Authors: Shannon B. E.
Published: December 2007

The Gulf of Mexico (GOM) Offshore Continental Shelf (OCS) Regional Office of the Minerals Management Service (MMS) published a Letter to Lessees and Operators (LTD dated November 20, 1990, concerning the reporting, disposal, and transportation of produced well solids containing naturally occurring radioactive materials (NORM). On December 11,1991, the MMS published another LTL which provided clarification to the November 20, 1990, LTL. These interim guidelines are designed to provide operators with disposal options while also providing the MMS with data on the offshore oil and gas industry's handling of NORM-contaminated produced well solids. This paper will review the interim guidelines and current operational practices.

The Environmental Protection Agency (EPA) must publish Best Available Technology Economically Achievable (BAT) Guidelines and New Source Performance Standards (NSPS) by January 15,1993, for the offshore subcategory of the oil and gas extraction point source category. In the development of these effluent limitation guidelines, EPA has conducted a field study to determine if the discharge of NORM-contaminated produced water had any bioaccumulation or biomagnification potential in shallow waters of the GOM. An American Petroleum Institute (API) study designed to assess risk factors of fish consumption near production platforms, will also be discussed.
Fugitive Emissions From an Offshore Oil and Gas Production Platform
Authors: Jelinek K. A. , Rooney T. C. , Webb M. G.
Published: December 2007

A study was commissioned to obtain fugitive emissions data from a production facility that contains oil and gas production equipment and is located in the Outer Continental Shelf Gulf of Mexico region. A total of 10,212 components were inventoried and screened for leaks. Less than 1 % or 84 screening values were above 500 ppmv, and 54 of these leaking components were further analyzed using the bagging method. The samples were analyzed for hydrocarbons C1 through C6+ and three samples were tested for ВЕТХ components. A site specific correlation equation for the platform was developed. The results were compared to mass emissions calculated by published emission factors (US EPA AP-42)1. The study confirmed that the platform does not qualify as a major source under Title III of the CAAA. Overprediction of the emissions calculated by the AP-42 factor method was also confirmed.
Development of Sampling and Analytical Methods for Measuring BTEX and VOC From Glycol Dehydration Units
Authors: Rueter C. O. , Ogle L. D. , Reif D. L. , Evans J. M.
Published: December 2007

Emissions of benzene, toluene, ethyl benzene, and the xylene isomers (BTEX) and volatile organic compounds (VOC) from the reboiler still vent of glycol dehydration units have become a major concern for the natural gas industry as a result of increasing regulatory pressure. The Clean Air Act Amendments (CAAA) of 1990 have provided an impetus for air toxics regulations, and several states are regulating or considering regulation of these units.

A key issue in developing approaches for handling these emissions has been accurate measurement of the emissions. The primary method used to date has been rich/lean glycol sampling at atmospheric pressure, which is favored for its simplicity. However, there are several potential errors associated with this approach, including the flashing and loss of BTEX and VOC during sampling. Direct (stack) measurement of these emissions has not been widely used because of the stream temperature and water content.

To address these difficulties, the Gas Research Institute (GRI) is sponsoring a program to develop and refine sampling and analytical methods. Input to the program is provided by an Industry Working Group that contains representatives from several industry organizations. After an initial field experiment was performed to screen potential methods, surviving methods were refined in the laboratory using a synthetic still vent overhead stream. The refined methods are being evaluated in two additional field experiments, and the final, recommended methods will be validated in a series of experiments in mid-1993.
Particulate Emission Testing Methodologies as Applied to Natural-Gas-Fired Turbines
Authors: Wilson M. J. , Frederick J. D.
Published: December 2007

As the allowable emission limits for New Source Review have been reduced due to the requirements of the installation of Best Available Control Technology, source testing methodologies have not kept pace with the control technology. An example of the emission limits being kept below quantification by practical source test methodologies is that of particulate testing of natural gas fired cogeneration turbines. Normal testing procedure utilizing EPA Method 5 results in spurious particulate emission rates which should not be considered in determining compliance with permitted limits.

In an attempt to establish a reliable emissions factor which accurately characterizes the particulate emissions from General Electric LM5000 gas turbines, a study of EPA Method 5 and the results of twenty-five particulate tests was conducted. Various test time periods were utilized. A lower limit of applicability to EPA Method 5 is supported by actual field data.
Issues in the Modeling of the Atmospheric Dispersion of Hydrogen Sulfide Emissions
Authors: Kaiser G. D.
Published: December 2007

The purpose of this paper is to discuss some of the issues involved in the modeling of the accidental release of hydrogen sulfide (H2S) during oil and gas extraction activities. The focus is on wellhead blowouts or pipeline ruptures that lead to large releases of sour gas.

First, the types of possible source terms are reviewed, including characteristics such as rate of release, H2S content and duration of release. In particular, it is shown that most sour gas streams are less dense than is air. Second, the availability and suitability of atmospheric dispersion models is discussed. One of the most important issues is that of lift-off; that is, whether a buoyant plume that is initially on the ground will in fact lift off. For plumes that are marginally buoyant (e.g after dilution during an initial jet phase), lift-off is unlikely.

Another important issue is the choice of an appropriate airborne concentration as a Level of Concern (LOC). Quantitities such as the Emergency Response Planing Guideline (ERPG) and the LC01 (the concentration that would prove fatal to one percent of those exposed to it) are discussed. Some examples of predicted distances to these LOCs are given for severe accidents in unfavorable weather conditions.

The paper also briefly discusses the following: a) seepage of H2S from buried pipelines; b) burning plumes and releases from flare stacks; c) the reasons why "pooling" of sour gas in hollows is unlikely; d) the behavior of sour gas dispersion in complex terrain.
Hydrocarbon Emission Estimates and Controls for Natural Gas Glycol Dehydration Units
Authors: Grizzle P. L.
Published: December 2007

The evaluation and reduction of hydrocarbon emissions from glycol dehydration units has required a concerted effort in the areas of methods development, emission measurements and field testing, and control technology evaluation and application. Of five emission estimate methods evaluated, excellent estimates of benzene, toluene, ethylbenzene, and toluene (BTEX) and good estimates of total volatile organic compounds (VOC) can be achieved with rich/lean glycol mass balance. Rich/Lean glycol BTEX emission estimates are independent of atmospheric and pressurized sample collection, whereas, higher estimates of VOC are obtained from pressurized samples. Confirmation of the rich/lean glycol method has been made from total capture stack condensation on small glycol units (< 15 MMSCFD) and from partial-stack condensation on large units. BTEX emission data obtained from total capture condensation and rich/lean mass balance are in excellent agreement. The agreement in total VOC emissions from the two methods is dependent on the inlet gas composition. From total capture stack condensation field tests, a combination of condensation and use of the non-condensible gases as fuel to the reboiler has been determined to be the most cost effective method to reduce emissions. Prototype units have been developed and are presently in operation in Louisiana and Oklahoma.
Estimating Hydrocarbon Emissions from Triethylene Glycol Dehydration of Natural Gas
Authors: Thompson P. A. , Berry C. A. , Espenscheid A. P. , Cunningham J. A. , Evans J. M.
Published: December 2007

Increasingly stringent environmental regulations have caused emissions of air toxics from natural gas dehydration units to be a concern for the natural gas industry. Of particular interest are emissions of benzene, toluene, ethylbenzene, and xylenes, collectively known as BTEX. Radian Corporation and the Gas Research Institute have developed a software program called GRI-DEHY© to provide gas producers with an easy-to-use tool for estimating emissions of BTEX and other VOCs from triethylene glycol dehydration units. This program uses fundamental chemical engineering thermodynamics along with available experimental data to make its emissions estimates. GRI-DEHY provides a rapid, inexpensive method for determining which dehydration units are in compliance with applicable regulatory emission levels, which units may require minor control approaches, and which units may require retrofit controls. Pre-release testing has shown that GRI-DEHY provides good emissions estimates, especially for the BTEX compounds.
The Importance of Environmental Site Assessments of Oil and Gas Properties Prior to Property Purchase or Sale: Examples of Environmental Hazards
Authors: McNeill A. D. , Reed T. M. , Hunnicutt J. C.
Published: December 2007

The ever-expanding magnitude of environmental laws and regulations is increasing the due diligence required before buying or selling an oil and gas property. The environmental hazards on an oil and gas property can pose future financial and environmental liabilities for both the purchaser and the seller which can be disastrous. By performing an environmental site assessment prior to oil and gas property transfer, the purchaser and the seller can limit their financial and environmental risks.

An Environmental Site Assessment is typically divided into three distinct phases: Phase I, qualitative investigation; Phase II, quantitative evaluation; Phase III, hazard management. The qualitative investigation, or Phase I, is a thorough records review and on-site inspection to determine whether any suspected environmental hazards exist on a site or in its vicinity. If any suspected hazards are discovered, Phase II is initiated, which involves further investigation of the site and representative sampling to quantify the extent of the hazards. Phase III is the implementation of remedial options. The qualitative (Phase I) and quantitative (Phase II) information is used to build a workable plan for controlling or eliminating environmental hazards found on a property.

This paper documents examples of environmental hazards identified from three years of environmental site assessments. The assessments were on oil and gas properties comprising over 2000 well sites and 500 facilities, operated by both major and independent oil companies.
Purchase/Sale of Property: The Black Hole of Corporate Liability Ways to Minimize Risk
Authors: Curtis B. W. , Kirchof C. E.
Published: December 2007

Environmental implications regarding the purchase and sale of property have become one of the big unknowns in corporate liability. This paper and presentation will focus on practical ways to identify such risks and liabilities and subsequently minimize them in the sales agreement. Specifically, it will explain the various kinds of detailed auditing procedures that must be done prior to the transfer of facilities or property. Such auditing not only includes the historical and document searches, but also and more importantly, the actual physical auditing and in most cases sampling that must occur. In addition, the paper and presentation will outline the ways parties can protect themselves with language in the purchase/sale agreements and how to obtain the best results through certain negotiating techniques.
Environmental Due Diligence in Oil and Gas Acquisitions
Authors: Clark B. F.
Published: December 2007

Rising costs attendant to increasing environmental awareness and regulation have captured the attention and exploration budgets of many independent oil and gas exploration companies. Many of these smaller companies are riding the horns of a dangerous dilemma. On the one hand, they cannot afford to maintain a permanent staff of environmental engineers and auditors necessary to investigate potential liability arising under federal and state "Superfund" laws. On the other hand, they cannot afford the risk of ignoring potential liability when buying leases and producing properties.

In order to minimize exposure for Superfund and manage environmental liability risks, many companies are conducting environmental site assessments prior to acquiring oil and gas exploration prospects. In order to keep down the costs of such investigations, smaller independents that lack environmental expertise on staff can enlist their landmen to conduct the preliminary aspects of the investigation called a "Phase I." Most of what is involved in a Phase I consists of the type of duties traditionally handled in our industry by petroleum landmen. In the oil and gas industry, landmen specializing in environmental audits arethe logical alternative to the more costly environmental engineering consulting firm.
An Approach to Resolve Uncertainty in Quantitative Risk Assessment
Authors: Gordon R. D. , Cayias J. L.
Published: December 2007

A general method to determine uncertainty in risk assessment using Monte Carlo simulation with Latin Hypercube Sampling is presented. This method is compared with a traditional approach to show that its uncertainty is several orders of magnitude less. Part of the approach is to remove health conservative assumptions and replace them with realistic data. If a measure of health conservatism is needed for risk management, it may be added as a safety factor.
Mitigation Measures for Threatened and Endangered Species
Authors: Boss T. R. , Hackney P. D.
Published: December 2007

Any project construction or operation that may potentially impact a threatened or endangered (T&E) plant or animal species or plant community will require notification to the appropriate federal or state agency. Mitigation measures may be required by the agencies to avoid or reduce impacts to these T&E species.
Environmental Practices Training for Oilfield Operations Personnel: Course Content and Measurement
Authors: Griffin J. M. , Marinello S. A. , Cox J. R.
Published: December 2007

This paper includes both a review for course content for Environmental Practices Training, and a measurement criterion for evaluating a company's environmental practices. The format for the course applies to a short-course, industry-directed, classroom presentation. Outlines used by the author(s) in addressing these issues for a major oil company as well as video-based instruction will be included. As management must knowingly or unknowingly approve the content of these courses, it appears prudent that appropriate decision makers within the industry determine what constitutes environmental practices training in a sufficiently precise manner. Coupled with this determination is a need for verifiable, repeatable, and defensible measurement tool. The authors propose the Waste Index for meeting this need for a measurement tool. A defense for a measurement tool is made, the criterion described and is then illustrated by a case history example employing actual field data.
A Business Approach to Environmental Communications
Authors: Allyn J. B.
Published: December 2007

The objective of this article is to provide a business framework for decision-making regarding the design and implementation of environmental communications programs in the production and exploration areas of the petroleum industry.

An assessment is first discussed which analyzes the impact of external factors on a company's decision making, evaluates the risk to a company's business of communicating or not communicating, and assigns quantitative and qualitative costs and benefits to environmental communications.

Although difficult to quantify in term of dollars, the business advantages in environmental communications activities can be assessed qualitatively by examining successful and unsuccessful case studies such as those discussed in the article.
Release Reporting for the Oil and Gas Exploration and Production Industry as Required by the CWA, CERLA, and SARA Title III
Authors: Toellner J. J.
Published: December 2007

Environmental regulations on reporting of hazardous chemical releases have proven to be very complex and confusing. An effort by the American Petroleum Institute (API) and the author has been undertaken to provide the oil and gas industry concise and straightforward guidance on which releases are reportable to which government agencies. This paper addresses the various federal reporting requirements addressed in the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA); the Emergency Planning and Community Right-to-Know Act (EPCRA), commonly referred to as SARA Title III; and the Clean Water Act (CWA).

This paper covers the reporting of what most in industry consider emergency or incidental releases. These are releases which are typically unplanned and not covered by a permit issued by a government agency. The paper does not address state and local requirements which, in many cases, may be more stringent.

A series of flowcharts (Figures #1 – #7) have been developed to provide guidance on release reporting. The flowcharts are designed to help the user make accurate reporting decisions in an efficient manner.
Emergency Planning for H2S Releases: Utilizing Shelter in Place and Interagency Drills
Authors: Wheeler W. H. , Byrd W. R.
Published: December 2007

This paper highlights the implementation of Shelter in Place techniques and associated emergency procedures involving state and local emergency planning personnel as well as local residents. Several unique emergency planning enhancements recently made by an Operator in a populated sour gas/oil production area will be presented, including:

a shelter and evacuation drill involving Operator, emergency response personnel and residents, an automatic phone notification system with multi-call capability and call verification, a flexible siren/public address system designed for local acoustic conditions, and community education programs including distribution of a local historical calendar with emergency information.
Microcosm Studies of Factors That Influence Bioremediation of Crude Oils in Soil
Authors: McMillen S. J. , Kerr J. M. , Gray N. R.
Published: December 2007

Bioremediation treatments were evaluated on the microcosm scale for their effectiveness in removing petroleum hydrocarbons from soil. Three compositionally distinct crude oils were applied to native soils from their respective oil production areas. The crude oils varied in API gravity (21 to 31 at 60°F) and in hydrocarbon class distribution. A total of 8 treatment regimes that included the variables of moisture content, fertilizer application, tilling, and pH control were examined for their effectiveness in enhancing biodegradation rates over no action and sterile controls. The microcosms were monitored for 52 weeks.

The extent of biodegradation was determined by the total extractable hydrocarbon (TEH) concentrations, hydrocarbon class distributions, gas chromatography, C17/pristane and C18/phytane ratios, and hopane concentrations in the initial and final oils. The estimated half-lives of the crude oils were determined to be greater than two years under all but one treatment regime. A very rigorous treatment of monitoring and controlling soil pH, nutrient concentrations, and moisture content on a weekly basis reduced the half-life of a crude oil to 8 weeks. Half-lives were measured by TEH loss and confirmed by hydrocarbon class distribution changes and gas chromatography "fingerprints." Hopane concentrations were used to more accurately predict crude oil half-life.
An Exposure/Risk-Based Corrective Action Approach for Petroleum-Contaminated Sites
Authors: Stanley C. C. , Johnson P. C.
Published: December 2007

A practical and easy to use exposure/risk-based methodology for guiding corrective action activities at petroleum contaminated sites has been developed. In this approach, site characterization, assessment of potential beneficial uses, exposure/risk characterization, site prioritization, and selection of corrective action alternatives are integrated into a series of worksheets. These worksheets guide the user through the necessary steps to derive site-specific target clean-up levels and the corresponding appropriate corrective action. The risk characterization activities discussed here focus on exposure to groundwater, which is expected to be the pathway of greatest concern at the majority of petroleum contaminated sites. However, it is not difficult to see how this worksheet based approach can be extended to other pathways. The worksheets comprise a final document that is a valuable tool for regulators, contractors, and responsible parties to consistently prioritize sites and develop corrective action plans. This approach is currently being reviewed by several state agencies. In addition, the approach has been presented to the United States Environmental Protection Agency (EPA), and the American Society for Testing in Materials (ASTM).
Sweetening of Sour Crude Using Gas Stripping Process
Authors: Clanton G.W. , Gipson R.E.
Published: December 2007

A reduction of the hydrogen sulfide content of crude oil can be accomplished by stripping with gas in a contact tower at low pressures. In addition, stabilization of the oil or condensate is accomplished simultaneously with less shrinkage and tank losses as compared with multi-stage separation.

Several simplified processes can be utilized to accomplish the desired results and are discussed in the paper. A computer program is available which will simplify the tray-by-tray equilibrium calculations for design purposes. The process can be adapted to purposes. The process can be adapted to both small and large installations and sulfur recovery from the sour overhead vapor may be added to the larger installations in order to accomplish a shorter payout. Also some form of hydrocarbon recovery from the stripping and flash gas would be desirable in areas where gas liquids have any value.

Design and installation of a unit was made which reduces the sulfur content from 500 ppm to less than 30 ppm using sweet natural gas for stripping and at the same time reduces the vapor pressure to less than 15 psia @ 100 degrees F to prevent vaporization losses during transportation in warm ocean waters. The processes shown herein afford a method whereby the H2S content of sour crude oil or condensate can be reduced at the production site. This helps to produce production site. This helps to produce a more valuable product and prevent pollution problems before they occur pollution problems before they occur in the more populated refinery area.

Introduction

Sweetening of sour crudes has recently become more important with the advent of new pollution control regulations and increased refinery treating costs. The stripping process utilizes Henry's law which states that the amount of a slightly soluble gas that dissolves in a liquid at a given temperature is very nearly proportional to the amount of the particular gas in the surrounding atmosphere.