bluuebunny/crossref_metadata_2025_split huggingface dataset:
Drilling Fluids for Short Radius Horizontal Wells
Authors: Ezzat A. M. , Esmail O. J. , AI-Ammari S. M. 
Published: December 2007

Abstract
Several old wells have been successfully sidetracked and short radius horizontal holes were placed at the top of the Arab-D reservoir. The main objectives of this type of recompletion are to reduce water coning and improve the oil recovery at the water flood front. Several attempts were made to sidetrack the first well. The downhole motor failed to build the hole angle at the required buildup rate while penetrating the anhydrite formation between the base of Arab-C and the Arab-D. Hole enlargement across the anhydrite section was found to be the reason for the tool failure.
Laboratory studies were carried out on anhydrite core samples taken from the base of the Arab-C section. Examination of the core samples by XRD provided detailed mineralogical composition of the rock. To determine the dissolution and erosion effect of different fluids, core plugs were hot rolled in stainless steel cages placed in steel aging cells filled with the drilling fuild samples. NaCl brine-based fluids dissolved up to 3 wt% of the rock sample and eroded additional 7 wt%. CaCl2 brine system treated with Ca(OH)2 and CaSO4.2H2O showed no dissolution and very little erosion. Oil-based invert emulsion mud with CaCl2 brine as the internal phase showed absolutely no effect on the rock samples.
A non-damaging oil-based mud formulation was developed and successfully used to sidetrack and drill several short radius wells. This paper presents the laboratory data along with the drilling and completion fluids formulations being used. Problems that were encountered during the drilling of the first well are also discussed.
Biodegradation of Synthetic Muds : Oxidative Pretreatments
Authors: Rabion A. , Perié F. , Bassères A. , Guillerme M. , Zurdo C. 
Published: December 2007

Abstract
This report describes a simple pretreatment to enhance olefin-based pseudo-oil-based mud biodegradation under bottom of the sea conditions. The suggested treatment involves the oxidation of cuttings with diluted nitric acid prior to liquid-solid separation, sea-water neutralization of the mud, and biodegradation. Saturated hydrocarbons such as polyalphaolefins contained in cuttings were not degraded under the proposed reaction conditions. Comparison of oxidized and untreated olefms-impregnated cuttings clearly demonstrates that oxidized cuttings biodegrade more rapidly than untreated ones. Furthermore, we demonstrate that oxidized cuttings allowed for an enhanced evolvement of carbon dioxide as compared to unsoiled sediments. In addition it was shown that olefins have an inhibitory effect upon the sediment mineralization -and that overal CO2 evolvement is significantly lower with untreated cuttings soiled sediments as compared to the unsoiled sediments.
An Evaluation of the Radiation Health Physics Data Collected at a Commercial NORM Oilfield Waste Disposal Facility With Application to Field Production Facilities
Authors: Lyon F. L. , Hebert M. B. , Marinello S. A. 
Published: December 2007

Abstract
Regulations pertaining to naturally occurring radioactive materials (NORM) in oilfield wastes have now been promulgated in many of the major oil & gas producing states (AR, AL, LA, MS, NM, TX, etc ). This paper will evaluate the radiation exposure of workers and members of the general public to these wastes by looking at the radiation health physics data compiled at the largest NORM oilfield waste disposal facility in the country. This facility, owned by Newpark Environmental Services, has been in operation since October, 1994 In this paper, we will assume that the facility (operating under a typical worker protection plan) represents a worst case scenario for exposure to radiation when compared to oil & gas production facilities containing diffuse NORM.
Monitoring methods used to determine both external and internal exposure will be described for both occupational doses (not to exceed 5000, millirem (mrem) per year) and doses to individual members of the public (not to exceed 100 mrem per year). Occupational monitoring included measurements of external dose using individual thermoluminescent dosimeters (TLDs), breathing zone air samples (BZA) to determine the potential intake to workers in conjunction with derived air concentration (DAC) limits, and urine bioassay samples to determine actual individual intakes in conjunction with annual limits of intake (ALI). Public monitoring included continuous external gamma monitoring using environmental TLDs at multiple locations around the facility, downwind boundary effluent air monitoring and passive radon monitoring. From these measurements, a total effective dose equivalent (TEDE) can be calculated and compared to the limits for occupational and public exposure.
Though the data were analyzed over time in the paper, they can be summarized, since the opening of the facility through September 30, 1996 (24 months), as follows: The average annual TEDE for occupational dose is &lt;5 mrem/year.The same calculation for public exposure is &lt;25 mrem/year. The public dose is higher because 100% occupancy must be assumed, whereas workers exposure is based on actual time on the job.
Through the end of 1996 (27 months), 129,999 barrels of NORM oilfield wastes were received with an average specific activity of 131 picoCuries per gram (pCi/g) for 226Ra and 708 pCi/g total activity (the range was 3-5,865 pCi/g 226Ra and 15-28,509 pCi/g total activity).
Enhanced Ettringite Formation: A Treatment Option for the Remediation of Boron- and Selenium-Containing Wastes
Authors: Hassett D. J. 
Published: December 2007

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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: