bluuebunny/crossref_metadata_2025 huggingface dataset:
Enhanced Ettringite Formation: A Treatment Option for the Remediation of Boron- and Selenium-Containing Wastes
Authors: Hassett D. J.
Published: December 2007

The enhanced ettringite formation process (EEFP), a technology developed at the Energy & Environmental Research Center, is a process for the treatment of waste streams containing difficult-to-remove and potentially toxic trace elements such as boron and selenium. This easily implemented technology, based on the mineral ettringite, a calcium aluminosulfate hydroxide hydrate (Ca6Al2[SO4]3[OH]l2.26H2O), has possible applications for a suite of potentially hazardous trace elements, including but not limited to arsenic, boron, chromium, molybdenum, selenium, and vanadium. The EEFP has been optimized to reduce boron and selenium concentrations (including selenate and selenite) up to two orders of magnitude using a simple process that incorporates the problematic trace elements from a large volume of contaminated water into a relatively small mass of ettringite. The EEFP has been used successfully in laboratory experiments to treat boron- and selenium-containing wastes from industrial process streams. Key in this treatment option is that it is not sensitive to the selenium redox state as is the case with some other treatment options such as iron precipitation. Additionally, the process may reduce sulfate concentrations and sometimes aluminum and calcium concentrations as well. The treated water can often meet drinking water standards. This process is an important addition to currently available waste treatment options, many of which are either not economical or effective for these key elements of concern. The EEFP has been developed sufficiently for use in a field demonstration leading ultimately to a marketable commercial technology for the treatment of some of the most difficult-to-treat aqueous waste streams. This technology has been patented.
An Alternative Approach to Risk Analysis Recognizing the Limitations of Conventional Probabilistic Methods
Authors: Forth Ron
Published: December 2007

When decisions are made without perfect knowledge of the results that may ensue, an unavoidable exposure to risk occurs. Petroleum industry business decisions often carry substantial economic consequences, thus it is critical to understand the risk involved. Exploration provides a suitable context for examining risk analysis issues. A common means of handling risk is to quantify it numerically in the form of probabilities. Conventional probabilistic risk analysis is appealing in that a complex situation can be reduced to a mathematical problem subject to computation. However, a critical examination of the extension of probabilistic techniques to typical business situations raises concerns. Logical inconsistencies are encountered when the theory of probability is applied in practice due to the limited number of opportunities normally available to evaluate the outcome of decisions. Specific concerns with probability based techniques are discussed as grounding for an alternative approach that seeks to avoid their limitations. A different paradigm is suggested to comprehend and manage risk, including a rationale for decision making without recourse to numerical probabilities. Risk is expressed in terms of a reasonable range of possible outcomes and described by linguistic statements. The decision process encourages quality technical analysis to reduce uncertainty, contingency planning, and mitigation measures that may allow acceptance of the risk that remains.
Canada's Heavy Oil Industry: A Technological Revolution
Authors: Towson D. E.
Published: December 2007

Over the past decade, Canada's heavy oil industry has experienced a remarkable resurgence, much of which has been technologically driven. High cash flows and the forecasts of ever increasing oil prices resulted in a high level of activity in heavy oil and oil sands development in Canada in the early 80's. Much of this activity was temporarily shelved with the oil price crash in the middle of the decade. A large resource base combined with limited prospects for new light oil discoveries were the driving forces for renewed development. However, level oil prices necessitated reduced development and operating costs. This has been achieved through a concerted application of technology.

Horizontal wells, progressive cavity pumps, foamy oil/sand production, cyclic steam stimulation and steam assisted gravity drainage (SAGD) in a number of forms have all played a part. Of these, the advent of low cost, precision drilled, horizontal wells has had the greatest impact. Improved primary production, particularly in areas with bottom water, enhanced cyclic steam stimulation, steam assisted gravity drainage and horizontal well steam drive are some of the new or enhanced recovery processes made possible with horizontal wells.

Field activity in Canada has now reached an unprecedented level with new commercial and experimental projects being initiated on a regular basis. This paper describes a number of the technological advances made possible by horizontal wells and illustrates them with descriptions of field projects.
The Guerra Experiment - A Field Test of Tertiary Detergent Flooding
Authors: Ely Richard
Published: December 2007

A tertiary recovery process that showed promise in the laboratory is being field promise in the laboratory is being field tested in a watered-out portion of the Guerra Field in Starr County, Texas. The process consists of the injection of a slug of complex surfactant followed by brine. The sand within the two-acre inverted five-spot test pattern is unconsolidated Jackson sand lying between 2270 and 2290 feet subsea and having a porosity of .33 and average horizontal permeability of 2.5 darcies. Viscosity of the 36 degrees API oil is 1.6 centipoise at the reservoir temperature of 122 degrees F. Although the original oil saturation had been 1900 STB/AF, the residual oil saturation was 1000 STB/AF at a reservoir pressure of 300 psi at the time the test began. Salinity of both the connate and injected water is 20,000 ppm.

About 1.0 pore volume of water has been injected, counting the slug of water which contained detergent. Only traces of oil and detergent have been produced, but there is evidence that an oil bank has been formed. Unintentional flooding of an adjacent sand with a portion of the detergent solution may account for late arrival of the oil bank at the producing wells.

Laboratory tests showed that a slug of surfactant solution followed by about 1.5 pore volumes of brine successfully removed 100%. of the residual Guerra crude oil from Guerra sandpacks. The laboratory experiments included microscopic observations of the oil displacement mechanisms and investigation of the effects of sandpack size, slug volume and concentration, temperature, and flood rate on the displacement history.

Introduction

There have been numerous reports of the ability of non-ionic detergents to displace oil from porous media. Dabbous and Taber traced the reports of detergent flooding from 1927. In spite of encouraging results of laboratory tests, there have been no reports of field tests of large slugs of concentrated detergents.

Much of the hesitancy to field-test the detergent process has been caused by fears that detergents would be excessively adsorbed by porous media.
Stochastic Modeling Technique as Applied to History Matching of Eocene-Misoa Reservoir, Lake Maracaibo, Venezuela
Authors: Jimenez Z. , Azpiritxaga I. , Lozada T.
Published: December 2007

The Eocene Lower Misoa reservoir in Lake Maracaibo, Venezuela is divided into five sedimentological units. The upper three units are characterized by distributory channels, mouth bars and crevasse plain, whereas the lower units were deposited in coastal plain bars and tidal channels. The resulting sedimentary bodies have five lithofacies with quantified petrophysical properties. The paper describes stochastic modeling of the Lower Misoa reservoir in which nine realizations of reservoir heterogeneities were generated. The geometry and the quality of each sedimentary unit were defined for every realization. A finely gridded, quantitative flow unit model was developed into a 125x60x280 grid, the dimensions of each block being 180 m square and .3048 m in height. The realizations were scaled up to conform to the size of the coarse full field model with variable vertical dimensions, 29x42x(5,10,11,12) that was to be used for dynamic flow simulation. A number of history match runs was made with this model with various stochastic representations and the model results were compared with the field performance.

Discussion and Results

Reservoir heterogeneities present the biggest uncertainties in the history matching phase of any simulation. The usual deterministic approach employs a trial and error process of varying the rock properties (, K) among others to match the historical pressure-production performance. In contrast, stochastic modeling technique attempts to match the historical performance by bracketing a range of probable scenarios of reservoir heterogeneities thereby reducing the risk of numerous and inappropriate manipulations of the rock data.

In this study, nine realizations of reservoir heterogeneities were generated (Table 1) to bracket a range of possible scenarios. An interface between the stochastic software and the reservoir simulation model was developed to represent the stochastic realizations into the fluid flow model. In the first stage of the simulation, a comparison between the volume of the in place oil obtained from these realizations was made. As Fig. I shows there is little variation in the results. The minimum value obtained was 370 MMSTB (Re-1) and the maximum was 465 MMSTB (Re-6), it ought to be noted that all the OOIP values are less than the oil in place number (490 MMSTB) obtained through a deterministic approach. Three out of nine realizations produced excellent match with the pressure-production history (Figs. 2, 3) without the need of any data manipulation. The match obtained from the deterministic model is included for comparison.

Conclusions

The judicious use of stochastic modeling approach for reservoir characterization should save significant time and labor from the traditional method of history matching process. An estimated 50 % of the history match time was saved by using the stochastic technique in the current study when compared with using the deterministic study.
The Optimal Application of Multi-Lateral / Multi-Branch Completions
Authors: Sugiyama Hironori , Tochikawa Tetsuro , Peden J. M. , Nicoll G.
Published: December 2007

Drilling several branches into a reservoir from a main wellbore (multi-lateral/multi-branch wells) offers potential benefits in terms of improving drainage, productivity and well economics. This technique has become increasingly popular since the 1990's to the extent that multi-lateral/multi-branch well technology has now become one of the most important innovations within the oil industry.

In the paper, the authors review and summarize multi-lateral/multi-branch wells as a development option for oil and gas fields. The process of screening multi-lateral/multi-branch wells applications is discussed, identifying not only the potential benefits ofeconomics and efficient access to reserves, but also the risk associated with both the reservoir application and mechanical systems. Emphasis is placed on providing guidelines for each stage of this evaluation and design processes for these wells, incorporating a multi-disciplinary understanding of the reservoir geology, reservoir dynamics, completion design and operational management of the well. The importance of contingency planning in the process is highlighted, as a means of risk management.
Determining the Value of Reservoir Data by Using Nonlinear Production Optimization Techniques
Authors: Palke Miles R. , Horne Roland N.
Published: December 2007

This paper describes a new method of analyzing the cost of uncertainty in reservoir data. The method is based on the use of nonlinear optimization techniques. Nonlinear optimization techniques are mathematical or heuristic methods of determining the set of decision variable values that maximizes an objective function value. Given the appropriate model, optimization techniques can be used to determine the best set of production engineering parameters for an oil or gas field. The optimization technique considered is the Genetic Algorithm (GA). However, the optimized engineering parameters depend largely upon the input reservoir rock and fluid properties. If the reservoir property values differ from the expected values, the engineering parameters selected as optimal by numerical optimization will probably be suboptimal.

This leads to a new technique for assessing the cost of uncertainty in reservoir data. The cost of uncertainty in a reservoir parameter depends upon the discrepancy between the optimal net present value (NPV) for the actual parameter value and the NPV realized when optimization is performed for the expected value of the parameter. For a parameter, such as porosity or permeability, a probability distribution is determined. From this distribution, five representative values are chosen to discretize the distribution. The engineering parameters are optimized for the expected property value (the third representative value). The NPVs based on these engineering parameter values and the other four reservoir parameter values are determined. Then the optimal NPVs are determined for the four remaining reservoir parameter values. Combining the probability of each representative parameter value and the discrepancy between optimal and suboptimal NPVs for that parameter value yields the cost of uncertainty for that reservoir parameter.

When the cost of uncertainty has been established for each reservoir parameter, the engineer will be able to decide which parameter should be further tested, and to what extent. This allows careful weighing of the cost of testing procedures, including seismic, logging, and transient testing, against the cost of uncertainty in the reservoir parameter values.
Study on HDCDF and its Application in Troublesome Ultra-Deep Well YK-1
Authors: Piao Changhao , Qin Licao , Shen Danqing , Li Yingmin
Published: December 2007

HDCDF (High Density Cationic Drilling Fluid)system is developed to deal with downhole problems caused by abnormal formation pressure, high pressure brines and salt-gypsum-contained formation etc. in the foothill belt drilling. HDCDF system uses the high molecular weight cationic polymer as an encapsulating and flocculating agent, the organic quaternary compound as a shale inhibitor, the cationic polymer and amphoteric polymer as fluid loss reducers, the low molecular weight amphoteric polymer as a deflocculant and barite or hematite as a weighting agent. Results of lab studies and applications in foothill belt ultra-deep well drilling show that HDCDF system, whose density is higher than 2.20g/cm3 in lab and up to 2.44g/cm3 in the YK-1 well drilling, has a lot of advantages, such as excellent inhibition, preferable rheology, low fluid loss, high temperature stability, minimal formation damage and so on. HDCDF system is fit for geology, drilling and other engineering requirements in troublesome ultra-deep well YK−1 drilling.
Use of Neural Networks to Predict the Permeability and Porosity of Zone "C" of the Cantagallo Field in Colombia
Authors: Soto B. R. , Ardila J.F. , Femeynes H. , Bejarano A.
Published: December 2007

Permeability and porosity have a significant impact upon field operations and reservoir management. Combined measurement of these properties from cores and well tests can provide the best results, but the cost may be prohibitive for routine use. The common correlation used to predict permeability is obtained from the graph of the logarithm of core permeability versus core porosity. However, sometimes the correlation coefficients are not good, often less than 0.6. This correlation assumes that the permeability is only a function of porosity. Investigations have shown that permeability is not only a function of porosity, but also of true resistivity, irreducible water saturation, hydrocarbon density and rock type. Determination, prediction, or estimation of permeability using those variables without actual core measurements has been a fundamental problem for petroleum engineers and geoscientists. Neural networks have shown great potential for generating accurate analyses and results that otherwise seem not to be useful or relevant in the analysis of large amount of data.

In this work, a neural network model has been developed using core data and well log analysis to predict permeability and porosity of zone "C" of the Cantagallo field in Colombia. The algorithm used in this case was back propagation. The input variables were gamma ray, true resistivity, spontaneous potential, and neutron porosity from logs. Core permeability and porosity data were obtained from the Yarigui-l3 and Yarigui-l2 wells. These data were necessary for training and testing the neural network. The correlation coefficients obtained from conventional statistical analysis for permeability and porosity for this field were 0.598 and 0.396, respectively. The correlation coefficients for the permeability and porosity of the neural network models were 0.996 and 0.979, respectively. New oil zones were selected to be perforated in wells Yarigui-69 and Yarigui-l7 because of the attractive permeability obtained from the neural network analysis. The production was increased in each well by at least 120 bopd.

Introduction

The importance of permeability is reflected by the number of approaches that have been developed for its evaluation. They can be categorized into three major techniques:laboratory testing of core samples,well test analysis, andwell log analysis.

An early correlation of permeability with porosity and intergranular area was proposed by Kozeny in 1927 and then modified by Carman. Their equation is as follows:

(1)

Berg derived a correlation of permeability with porosity and grain diameter on the basis of a systematic packing of spherical particles:
Permeability Damage by Deposition of Colloidal Particles
Authors: Nabzar L. , Chauveteau G.
Published: December 2007

The formation damage due to retention of colloidal particles suspended in injection waters has been recently analyzed as consisting of four more or less overlapping steps: 1) deposition onto pore surface, 2) pore bridging, with accumulation upstream from bridged pores 3) internal cake building near non-percolation threshold and, 4) external cake formation. A new formation damage model accounting for these different steps has been recently proposed. The results reported in this paper show the consistency between model predictions and experimental results in the convective diffusion regime in the absence of pore bridging. The experiments have been carried out by injecting both negatively and positively charged well-characterized hydrophilic latex microspheres inside model granular packs made of negatively charged sharp-edged silicon carbide grains of narrow size distribution. To prevent any pore bridging, dilute suspensions of latexes having a size much smaller than that of pore throats were injected at low Peclet number.

In the absence of any energy barrier between particles and pore walls, i.e. with positively charged latexes or with negatively charged ones at high ionic strength, the model predictions assuming that the potential of pore surface is homogeneous are in very good agreement with experimental results. Colloidal particles are progressively deposited onto pore surface as a monolayer which reduces pore size and thus permeability. Maximum surface coverage is found to be that predicted by random sequential adsorption theory and the corresponding hydrodynamic thickness is equal to nearly 0.8 times the particle diameter. With negatively charged latexes at low and medium ionic strength, the results reveals that the pore surface of our model porous medium is definitely heterogeneous in term of surface potential. Since the surfaces of natural porous media are obviously heterogeneous, this heterogeneity must be taken into account in the model to predict both deposition kinetics and subsequent permeability reduction.
Modified Acidification Procedures for Deep Gas Sandstone Reservoirs Offshore Netherlands
Authors: Rodot F.
Published: December 2007

ELF Petroland gas wells were acidized traditionally with HC1-HF (Mud-acid)

The standard acidification procedures have been modified as follows: HF has been removed from the treatments and HCl alone is used, and in reduced quantities.The acid is followed with an overflush designed to push the acid into the sandstone far enough so all the acid can spend on the carbonates of formation. The results show a dramatic decrease of clean up time needed, and thus of the gas quantity flared.

Those simple modifications in procedures led to substantial savings, good production performance, and ecological improvements.
Determination of the Filtration Coefficient and the Transition Time for Water Injection Wells
Authors: Wennberg K. E. , Sharma M. M.
Published: December 2007

Injectivity decline due to particles in the injection water takes place to some degree in most injection wells. To understand and predict this decline requires knowledge of the rate of particle deposition for the water/formation system considered. The rate constant for particle deposition is commonly referred to as the filtration coefficient. The filtration coefficient is a dynamic quantity and changes with the number of previously deposited particles. Many investigators have carried out extensive theoretical and experimental work aimed at determining the filtration coefficient under varying conditions. This paper presents a review of past work and its application to injection wells. Tables presenting experimental values for the filtration coefficient as well as theoretical and empirical correlations are reproduced and evaluated. Finally, a new method of determining the development of the filtration coefficient with time, utilizing a concept of critical porosity, is outlined. In particular, this method includes a correlation for the transition time, i.e. the time when an external filter cake starts building on the wellbore.
Service Quality in the Argentine Electrical Market
Authors: Díaz L. Ruiz , Rovira J. M. , Colombo D.
Published: December 2007

The following is an analysis of the policies of the National Authority of Regulations (ENRE) and the effect on the quality of electric service in different sectors (Generators, transportation, distributors, suppliers and services within the electric branch, as well as the clients), and the consequences on the distributing companies.

The initial conditions of the networks of the distribution company (Edenor S.A.) are described, at the time of its privatization, the exact actions of quality improvement and the results.

The implementation of the Quality Control System is described at an individual client level, showing the earliest information obtained.

The report is based on the analysis of the current legal documentation, field information, and its processing in the computer systems that have been developed.
Processing of EFM Information as a Management Tool in the Processes of Assignment and Control in the Gas Industry
Authors: Roffo Edgardo , Seghesso Gabriela
Published: December 2007

The following work describes the processing and flow of the information arising from EFM devices and collected by SCADA system to be used in the different stages of the gas transportation operation.

Different type of information collected from EFM devices (instant values, hourly and daily LOGS, Event and Alanti records) is shown, as well as the processing of such information, produced by the Measurement System in order to generate audited information.

The information previously mentioned is used in the processes of Assignment and Control, through the SPAC application (Nomination, Scheduling, Allocation and Control processing System) allowing, among other tilings, to perform an accurate follow up of the received and delivered volume, as well as performing projections of such volumes at the closure of the working day.

This allows any of the parties involved to forecast and make corrective actions during the day in order to guarantee the accomplishment of the transportation schedule.

Furthermore, it is highly important to sliare consistent information between the Gas Transportation Company and its Customers who have remote access to such information by means of SPAC system.
Energy Economie Information System. Latin American Energy Organization (OLADE)
Authors: Torres Stella Mans
Published: December 2007

The main purpose of this report is to make a brief description of the SIEE (Energy-Economic Information System) from OLADE, with special emphasis on natural gas and the electric power sector.

Two different information areas are enhanced: The historical and the prospective ones. It is intended to present the different indicators which can be built for the various modules which integrate those two areas, and also have an outlook at the system's potentials to carry out studies easing decision making processes.
Air Quality and Platform Removal from the Santa Barbara Channel: A Case Study
Authors: Sheehan Philip E.
Published: December 2007

Over a period of 35 weeks in 1996, four oil and gas production platforms located in California state waters were dismantled and removed. This paper describes the phases of the project, documents the permit process, defines the emission sources and quantifies the air emissions.
Reflections on a Downhole Steam Generator Program
Authors: Donaldson A. B.
Published: December 2007

Downhole steam generator development activities are discussed beginning with the Department of Energy program carried out at Sandia National Laboratories, Albuquerque, New Mexico. This was followed by a venture which was funded by a Fortune 500 company with the objective of commercializing the development work from Sandia. The activities at both facilities are discussed, with emphasis on field operations. Field projects included experience in a variety of heavy oil fields in Texas, New Mexico and California. The purpose of this "reflection" is to provide a historical record of these activities and to make projections which may be helpful in considering future extractive methods for heavy oil.
The Cost of Quitting a Stripper Well
Authors: Merklein H.A.
Published: December 2007

Some three out of four producing oil wells in this country are classified as stripper wells. Taken together, these stripper wells produced at a rate of approximately 1.3 million produced at a rate of approximately 1.3 million BOPD in 1970. This corresponds to about 14 percent of the total U. S. oil production. percent of the total U. S. oil production. Clearly, the decision to farm out or to abandon a stripper well assumes a status of national significance. Is that decision, as it is presently rendered, always optimal? The authors presently rendered, always optimal? The authors think not, and by presenting their case they focus attention on an area in the oil industry that has been neglected in the past. Hopefully, the paper will engender a discussion within the industry.

It is agreed that wells are often abandoned or farmed out too early, simply because they get choked to death by valid (in an accounting sense) but unrealistic (in an economic sense) and excessive cost allocations. There are two kinds of these, and both deserve review.

1. Variable costs, by definition, vary with output. More specifically, they become zero when a well is abandoned. Examples of such costs are well maintenance and repair, lifting costs, etc. But other "variable" costs are not eliminated by shutting down a well. An example would be the lease operator's wage allocation to a well, if as a result of abandoning that well, he does not pick up another one. If that is the case, his wages are simply transferred to the remaining wells. Certain concrete proposals on how to handle this problem are offered. problem are offered.

2. Fixed costs, by definition, do not vary with output rates, at least not in the short run. In the long run, they are eliminated by closing down operations and appropriate divestitures. But, as in the preceding variable-cost case, oil wells are charged with fixed costs that are not eliminated by abandoning them. For example, overhead charges currently allocated on a per-well basis are not reduced as a result of shutting down a well. They are reallocated to the remaining wells. Yet, overhead charges are typically treated as fixed costs in the oil industry. The authors propose a new system, the "variable-fixed cost" propose a new system, the "variable-fixed cost" allocation system. If instituted, it will have a major impact upon oil (and gas) production.

At the present time of rising production costs and intensified exploration activities on a worldwide scale, this paper draws attention away from what be in store, in the future and abroad, toward what is in store, now and at home. It may reverse or, at least, retard the current trend of declining average lives of oil wells that have come down to 24 years in 1970 from 30 years a decade earlier. If so, the paper will have contributed to a substantial paper will have contributed to a substantial increase in recoverable U. S. oil reserves.
The Role of Independent Oil and Gas Companies in California's Changing Marketplace
Authors: Marquez T.
Published: December 2007

As the major oil companies divest properties in California, the role of independent oil companies grows in importance. California is one of only two states in the country where the major oil companies dominate drilling and production. It is important for the major oil companies to have a strong, vibrant independent presence. A healthy independent oil and gas presence in California assures the majors of the following in their divestment programs: Financially capable companies to assume plugging, abandonment and environmental liabilities; Responsible acquisition companies to assure that the major's reputations remain intact; and a competitive market place.

Independents have traditionally been risk takers in other producing areas, often leading exploration and development efforts and new technologies. A greater number of independents also assure more innovation in California's oil and gas operations. This paper documents the efforts of California independents over the past decade as they have successfully filled the void left by the major oil companies divestment of California properties. Further, it is demonstrated that the health of the oil and gas industry in California has improved by the emergence of these innovative and progressive California independent oil and gas companies.
Permeability Damage from Drilling Fluid Additives
Authors: Barna Bruce A. , Patton John T.
Published: December 2007

This detailed evaluation of various drilling mud particulate additives indicates that the composition of fluid loss and rheology agents has a decided influence on the permeability damage characteristics of the permeability damage characteristics of the resulting drilling fluids. Research was conducted at Michigan Technological U. in an effort to quantify the loss in wellbore permeability attributable to the particulate permeability attributable to the particulate additives in various drilling fluid formulations.

Preliminary tests were performed on Berea sandstone followed by experiments with cores from the Huntington Beach field, Calif. This is an area where significant permeability damage during drilling has been reported.

Water-base laboratory muds were formulated with 1 lb/bbl of clarified Kelzan XC polymer and 6 lb/bbl of the type and size of particle to be tested. Particulate materials investigated include drill solids, calcium carbonate, bentonite and starch. The latter three were fractionated into three size ranges from -200 to -400 mesh plus an "as received" sample of each.

Permeabilities to brine, before and after plugging with drilling fluid, were used to plugging with drilling fluid, were used to evaluate permeability damage. Plugging of the cores was arbitrarily defined as the point at which the pressure drop across the drilling fluid filter cake exceeded 100 psi. The plugged core was backflushed with brine at a pressure less than 50 psi before assessing the degree of permeability damage. permeability damage. Significant differences in the amounts of permeability regain were noted for the different permeability regain were noted for the different types of particles but not for the particle sizes. The greatest damage was noted for the gelatinous starch particles. Calcium carbonate and bentonite additives, however, were found actually to improve the performance of the base fluid. This aspect may be explained by the formation of a protective filter cake that limits the invasion of gelatinous, colloidal particles. This cake is effectively removed when the flow of fluids is reversed to simulate the clean-up, which occurs when a new well is placed in production. production. The results of this study should have valuable applications in the design of drilling fluids used in partially depleted reservoirs. They may also be used in designing nondamaging well-killing and workover fluids.
Drilling the Deep Well in the Rocky Mountains
Authors: Maser A.J. , Dallas D.E. , Myers R.G.
Published: December 2007

This paper was prepared for the Rocky Mountain Regional Meeting of the Society of Petroleum Engineers of AIME, to be held in Denver, Colo., April 10–12, 1972. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor of the appropriate journal provided agreement to give proper credit is made. provided agreement to give proper credit is made. Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines.

There are many problems associated with deep well drilling. This paper will attempt to isolate these problems more common to the Rocky Mountain area:

The care of the drilling string and corrosion problems encountered and methods of damage prevention as employed by Mountain Fuel Supply Company.

A discussion of chemicals used in conjunction with the drilling mud system to control corrosion damage to casing and drill string.

The inspection methods and means of detecting the presence of corrosives.

A presentation showing how the Rocky Mountains are affected due to the mountainous terrain in which our drilling operations occur.

A discussion of pressure control methods and equipment used to allow us to drill with an underbalanced mud system.

The training methods and programs to assure proper procedures from drilling crews in case of blowout or high pressure formation kicks. pressure formation kicks. Results and values of training program observed during actual situation on the job.
Improved Primary And Remedial Cementing With Thixotropic Cement Systems
Authors: Spangle L.B. , Calvert D.G.
Published: December 2007

Specially designed thixotropic cement systems often aid in cement placement and obtain adequate fill-up in areas or situations where more conventional slurries are unsuccessful. These slurries are thin when mixed initially but develop a high gel strength almost immediately after placement. The purpose of the high gel strength is to make the cement column support its own weight and thus relieve hydrostatic pressure at the bottom of the column.

Originally developed to prevent fall-back of the cement column in areas of low fracture gradients, the thixotropic systems have proved capable of solving many difficult cementing problems. They have application in shutting off problems. They have application in shutting off lost circulation during drilling patching holes in casing, and reducing gas-cutting of the cement column during cementing operations.

The thixotropic, or Regulated Fill-Up Cement, slurries have been used successfully on many wells to date. Since their use permits casing to be set through the pay sections without excessive loss of slurry to the formation, more selective and efficient stimulation treatments can be used. Thus, production increases from stimulation treatments have been two to three folds greater than in wells where conventional slurries were used.

This paper describes the thixotropic slurries and compares their physical properties with conventional slurries. Information related to the hydraulics of cementing with thixotropic and conventional slurries is included.

Introduction

There are areas where the formation fracture gradients are of such low magnitudes that obtaining good cement jobs is difficult. These formations are normally highly-fractured zones, shale zones, granite washes, glacial deposits, etc. When using conventional cement systems, the combination of the hydrostatic pressure and frictional pressure is of such magnitude that these zones will break down and receive most of the cement slurry. Even in cases where a substantial quantity of cement is not lost to the formation during placement, the cement column will recede or fall back after the well is shut in. This leaves long sections of the pipe with no cement to support it.

The usual approach to the fill-up problem under such conditions is a reduction of cement slurry density. This approach has several disadvantages due to the limits of cement weight variance.
Low Pressure Carbon Dioxide Lowers Heavy Oil Viscosity in IOR Applications
Authors: Cady Gilbert , Foster Dan
Published: December 2007

This paper discusses the reduction of heavy oil viscosity by carbon dioxide injection for improved oil recovery (IOR). Carbon dioxide injection is recognized as a viable injection gas for reservoir stimulation in light oil (30° API or higher) reservoirs. Carbon dioxide is also applicable in heavy oil (10 to 25° API) reservoirs since it lowers oil viscosity, swells the oil, provides component extraction, and is soluble in both oil and water. Carbon dioxide sources include natural reservoirs, extraction of carbon dioxide from industrial processes, generation by oxygen combustion in reservoirs, and thermo-converter generation at the surface. The surface-combustor provides Carbon Dioxide in areas which lack sufficient supplies and require the transportation of Carbon Dioxide by pipeline or high pressure trucks. Research and development of this versatile surface and downhole combustors continue today at several U.S. Universities.

IOR benefits.

The benefits of using Carbon Dioxide include crude oil and water swelling, component extraction, oil viscosity reduction, and reservoir pressuring.

An article by Simon and Graue(1) in 1965 indicates that carbon dioxide solution in crude oil lowers the viscosity to approximately 0.02 to 0.12 of the oil's original viscosity at 120°F. They studied 5 oils which were below 20°API and had viscosities from 58.6 to 1300 cp at 120°F. The result of their study indicates viscosity reductions from 0.025 to 0.115 at a pressure of 1000 psia.

A 1986 topical report by Chung (2) reported on the viscosity reduction in 7 heavy oils which ranged from 10°API to 21.6°API. The oil viscosities ranged from 49 to 1484 cp at various temperatures (75 to 200°F). Chung observed viscosity reductions from 0.03 to 0.15 of the original oil viscosity.
Multi-Stage Fracture Stimulations are Making Better Wells Along the Cedar Creek Anticline
Authors: Green T. W. , Besler M. R. , Zander D. M.
Published: December 2007

In 1996, Williston Basin Interstate Pipeline Company (WBI), a wholly owned subsidiary of MDU Resources Group, Inc., implemented a pilot program to improve production from the Eagle Gas Sands in Southeastern Montana. The program included running Formation Micro-Scanner™ Logs (FMS) logs to identify natural fractures and permeable pay intervals and using three-dimensional fracture modeling to determine the optimum fracture treatment size. By applying technologies and multi-stage fracture treatments, WBI has more than tripled gas production rates. While the optimal completion program has yet to be determined, especially in the deeper (1700+ft) horizons, all wells drilled and completed in 1996 are producing gas. This 100 percent success ratio is a significant improvement over previous years when less than 60% of the wells responded to stimulation. A savings of $420,000 was realized in 1996 by eliminating the need to restimulate 50% of the wells. First year incremental NPV increased by 20% or $11,600 per well for the 24-well program in 1996. This equates to an incremental 10-year NPV of over $335,000 per well and over $8.8 million for the drilling program.
Radioactive Pollution at the Oil Fields of the Apsheron Peninsula, Caspian Sea, Azerbaijan
Authors: Djahanguiri F. , Reimer G. M. , Holub R. , Aliev C. S. , Zolotovitskaya T.
Published: December 2007

Naturally Occurring Radioactive Materials (NORM) in the oil fields of the Apsheron* Peninsula (AP), Azerbaijan is widespread. NORM is a major source of environmental contamination of soils, surface and ground waters in Azerbaijan and the Caspian Sea. Geological formations at AP are composed of clays, sandstone, and limestone with radioactivity background within 6 μR/hr. At the tectonically disturbed zones of AP, radioactivity increases to 15-20 μR/hr. At some oil fields in South-Western area of AP and around iodine plants the level of radioactivity varies from 600 to 5,000 μR/hr. The origin of NORM in oil fields of AP is related to drilling, production, and processing operations. Other sources of contamination are oil well equipment where separation of contaminated water from oil and its subsequent reinjection into the oil field.

There are no environmental regulations in Azerbaijan related to NORM. The state committee for Nature Protection is responsible for environmental protection of Azerbaijan but it is hoped that this paper will bring attention to the environmental community that pollution at AP and around the Caspian Sea is close to national disaster. In some oil fields, soil contamination is so extensive and elevated that it needs to be disposed of as low-level radioactive waste.

The Azerbaijan government must have international assistance to clean-up its own environment. Azerbaijan needs financial support of international organizations and multinational oil companies, and involvement of industrialized nations for collecting field data and its interpretation for improving the environment at the Caspian Sea and its surroundings. Furthermore, experience gained from study of NORM in this region would be useful for researchers throughout the world. There is a very limited information about NORM and its health effects in literature.
Coiled Tubing Operations From a Floating Vessel
Authors: Engel S.P. , Monroe C.
Published: December 2007

For many years, coiled tubing has been successfully operated from floating facilities. With recent advances relating to the understanding of plastic fatigue of coil, there are evolving concerns associated with the fatigue of a continually moving reel.

This paper quantifies reel motion with respect to the relative position of the reel, heave amplitude and period and the effect of running rates. A fatigue computer model is used to assess the operating limits and time to failure in a hypothetical case and a heave animation simulator is used to optimise rig-up configurations. Real and potential operating solutions are offered and a definition of maximum operating heave is addressed.
Coiled Tubing Deployed ESPs Utilizing Internally Installed Power Cable - A Project Update
Authors: Cooper R. , Head P.
Published: December 2007

Whilst previous papers1,2 have considered the background to, and details of, the development of a coiled tubing deployed ESP system, this paper considers field experience from the system to date. The system has been used to deploy ESPs in two locations; the first onshore, United Kingdom and the second offshore in the Middle East3. The second case is of particular interest as the four well minimum facility development was completed using a coiled tubing unit on a derrick-less platform. Several intervention operations have since been performed, also using a coiled tubing unit. Since the industry has been reluctant to use ESPs in remote locations such as subsea wells or minimum facility developments, due to questions of completion reliability, this represents an ideal test scenario; the system was originally conceived to enable rigless ESP completions. Whilst the system has been generally acclaimed as successful, various technique aspects of the system are discussed with particular emphasis on design improvements that will enhance future performance.
Large Coiled Tubing Fatigue Life
Authors: Avakov Vladimir A. , Martin John
Published: December 2007

As a result of full-scale and accelerated fatigue tests, a new data on coiled tubing (CT) fatigue life is now available. For a full-scale field test, operators set up an operational coiled tubing unit and induce stress/strain conditions identical to field conditions by moving pressurized CT from the reel to the well and back to the reel. Accelerated tests are performed with a laboratory bending machine that applies stress/strain cycles to the pressurized specimen. These cycles are similar to actual stress/strain cycles applied to CT over the reel or over the tubing guide. In this case, the specimen is 6 to 7 ft long. It is fixed at one end and simulates a cantilever with an alternating load at the other end.

Fatigue tests are performed on 1.25 to 3.50-in. OD CT sizes having the following minimum yield strengths: 70,000 psi (70k tubing)80,000 psi (80k tubing)100,000 psi (100k tubing)

An existing CT fatigue life model is refined to account for the tested CT sizes and materials. Main features of the model are described.
Full-Scale, Low-Cycle Fatigue Tests with 2-in. Coiled Tubing and an Automatic Coiled Tubing Inspection and Monitoring System
Authors: Koper Mark G.M. , Tan Sefer , Rosen Patrik
Published: December 2007

Coiled tubing (CT) is increasingly becoming a viable and preferred alternative to joined pipe in a wide range of oil and gas well operations. Consequently, along with being suitable for use in more applications, CT must maintain its integrity under increased operational conditions of pressure, load, and depth. These operational conditions require extensive safety measures during all phases of a Ct project.

This paper presents the objectives, physical setup, procedures, and successful results of full-scale, low-cycle fatigue tests. Researchers tested two different grades of 2-in. CT to refine the CT fatigue-life prediction model and string management system. In addition, a powerful, automatic CT inspection and monitoring system with multiaxial outer diameter and wall-thickness measuring capabilities was tested and validated.

During the tests, the following models and systems have improved and validated:–tubing fatigue models–string management systems–real-time CT inspection and monitoring systems

In CT operations, these models and systems have to be continually improved and validated to better establish the safety margin and prolong the optimal working life of CT strings. This paper demonstrates how these models and systems can be successfully improved and validated.