bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimal Strategy of Disposing of Mercury-Contaminated Waste
Authors: Rangponsumrit Manisa , Athichanagorn Suwat , Chaianansutcharit Thotsaphon 
Published: December 2007

Abstract
Mercury contaminated waste is one of the byproducts from hydrocarbon production in many gas fields in the Gulf of Thailand. One method to dispose the toxic waste is to inject mercury contaminated waste into confined depleted reservoirs through a depleted well. The advantages of this approach are high disposal capacity and permanent waste elimination. In the selected field of this study, the most suitable structure which is confined and in the last stage of production, was chosen. Since the selected reservoirs are not completely depleted, gas should first be produced. Thus, there is a need to optimize both the production and waste disposal strategy. In this study, a 3D reservoir simulator is used to determine strategy, which maximizes gas production and mercury contaminated waste disposal.
The reservoir simulation model for the reservoirs in the chosen compartment was constructed from seismic, well log, and special core analysis data. Initial reservoir conditions and fluid properties were entered into the model, and history matching on production performance and reservoir pressure was performed to fine tune the reservoir model. Then, reservoir simulation was performed to optimize hydrocarbon production by varying perforation plan and production gas rate. Finally, mercury contaminated slurry injection was optimized by performing sensitivity simulation on slurry density, injection rate, and slurry viscosity. The effect of these parameters on injection capability was also investigated. The optimal injection criterion is minimum injection time under a condition that the injection pressure is not high enough to create any fracture in the reservoirs.
Multistage Approach on Pore Pressure Prediction—A Case Study in South China Sea
Authors: Xie Yuhong , Cao Shunhua , Liu Chang , Yan Gongrui , Yi Ping , Cai Jun , Xu Liqiang 
Published: December 2007

Abstract
A multistage approach on pore pressure prediction was successfully used for a drilling program in the South China Sea. The objectives were to optimize the casing-shoe position by predicting the overpressure profile in the formation and to select the optimal mud weight by forecasting the formation pressure variation.
Before spudding the well, data from a surface seismic survey and log data from a nearby well were collected to build a pore pressure uncertainty model. This initial model had a pore pressure profile with relatively large uncertainties. While drilling, the model was updated in stages with additional measurements, such as those derived from vertical seismic profiles (VSPs), dipole sonic logs, gamma ray (GR) logs, etc. These additional data significantly reduced the uncertainty of pore pressure estimation.
At each intermediate total depth (TD), wireline logs and VSPs were acquired. Pore pressure profile above the current TD was estimated using the wireline logs and VSP velocity. Pore pressure profile below the current TD was estimated using the look-ahead VSP inversion result. Above the current TD, a cross-check validation was made by comparing the pore pressure profiles estimated from wireline logs and VSP data. The predicted pore pressure model was calibrated with the actual mud weight and a well integrity test at 3505 m.
At the well-planning stage, the maximum pore pressure was estimated to be 1.55 g/cm3. At intermediate drilling stages, the pore pressure was consistently estimated to be between 1.9 and 2.1 g/cm3 below a depth of 4100 m. This prediction was later confirmed by the formation test pressure value of 1.98 g/cm3 at 4226 m.
All pore pressure prediction results were delivered within six hours after each intermediate data acquisition. The pore pressure prediction results were successfully used for the critical decision of setting the casing shoe and selecting the mud weight.
Triaxial Induction Logging: Theory, Modeling, Inversion, and Interpretation
Authors: Wang Hanming , Barber Tom , Chen Kouchiang , Davydycheva Sofia , Frey Mark , Homan Dean , Minerbo Gerald , Morriss Chris , Rosthal Richard , Smits Jan , Tumbiolo Giovanni 
Published: December 2007

Abstract
Thinly laminated sand-shale formations represent a difficult challenge for petrophysical evaluation. The conductive shale laminations have a profound effect on the traditional induction log, causing it to read the shale laminations significantly lower than the high-resistivity sand layers. This misreading leads to pessimistic computations of water saturation and estimations of reserve. The newly developed triaxial induction logging tool provides much more information than the conventional induction logging measurement. It is not only sensitive to the effective horizontal resistivity, which is dominated by the conductive shale layers, but it is also sensitive to the effective vertical resistivity, which is determined by the conductive shale and the resistive sand, at any dip angle.
A key challenge of developing the triaxial induction array is the large borehole effect on coplanar couplings when the tool is eccentered in the transverse direction in water-base mud boreholes. To reduce the borehole effect to a manageable level, a new design with multiple electrodes has been implemented. Tank experiments and numerical modeling results show the borehole effect is reduced dramatically by using this design.
A parametric inversion algorithm to simultaneously determine the horizontal resistivity, vertical resistivity, formation dip, and azimuthal angle and bed boundary position from the triaxial induction logging data will be presented. The inversion problem is solved by employing a weighted, constrained, and regularized Gauss-Newton minimization scheme. To archive the practical application of the inversion algorithm, a fast Jacobian matrix computation is implemented to improve the efficiency. Furthermore, a multiplicative regularization technique is used to automatically determine the regularization coefficient. Synthetic examples will be presented to indicate the robustness of the algorithm.
A quantitative interpretation method of water saturation in laminated shale-sand formation will be presented. Shale anisotropy is taken into account for building the interpretation model. Two field examples demonstrate the laminated shale-sand analysis improves the estimate of hydrocarbons in place.
Efficient Field-Scale Simulation of Black Oil in a Naturally Fractured Reservoir via Discrete Fracture Networks and Homogenized Media
Authors: Li Liyong , Lee Seong H. 
Published: December 2007

Abstract
This paper describes a hybrid finite volume method, designed to simulate multi-phase flow in a field-scale naturally fractured reservoir. Lee et al. (WRR 37:443-455, 2001) developed a hierarchical approach in which the permeability contribution from short fractures is derived in an analytical expression and that from medium fractures is numerically solved using a boundary element method. The long fractures are modeled explicitly as major fluid conduits. Reservoirs with well-developed naturally fractures include many complex fracture networks that cannot be easily modeled by simple long fracture formulation and/or homogenized single continuity model. We thus propose a numerically efficient hybrid method in which small and medium fractures are modeled by effective permeability and large fractures are modeled by discrete fracture networks. A simple, systematic way is devised to calculate transport parameters between fracture networks and discretized, homogenized media. An efficient numerical algorithm is also devised to solve the dual system of fracture network and finite volume grid. Black oil formulation is implemented in the simulator to demonstrate practical applications of this hybrid finite volume method.
Old and Modern Well Log Data and Its Reliability Through a Novel Certification Process
Authors: Camacho V. R. , Lobato-Barradas G. , Campos S. Berumen , Daal A. , Martell B. , Adams D. , Cruz E. , Hernandez V. 
Published: December 2007

Abstract
The main objective of this paper is to present a certification process to achieve the reliability of well log data for any user, independently where or when the log was ran. For example, the analogical log data (old data) is digitally recaptured and processed through quality control criteria's, edited and spliced curve by curve, where all technical steps are documented in the corresponding digital file in order to provide the user the details of how the technical process was used and made. Finally, a digital signature certifies all files. At that moment anyone can use the certified products for interpretations, correlations or petrophysical evaluations.
As it is the case in most oil producing companies, two log data generation are present in Mexico: analogical and digital. Analogical process was initiated in 1904, when the first well was drilled, and the digital process began in 1979 through the "Cyber System Unit" used by Schlumberger. Those two generations, analogical and digital log data, demand new technologies and process to equalize the quality of old and modern data in order to use and manage this information in applications and databases.
The certification process includes on line log inventory using the log and services codification published by The American Petroleum Institute (API), log quality control routine for "Digital Log Interchange Standard" (DLIS), "Log Information Standard" (LIS) and "Log ASII Standard" (LAS), including: originals, edited and spliced logs. The authenticity and reliability of each file is warranted by a digital signature, it specifies who made the process and who accepted the final product.
The certification process was designed to equalize the quality of analogical and digital log generations, to establish the log reliability for any user and, finally to improve the data management. All these factors impact positively log data base preparation for project execution.
Optimize Drilling and Reduce Casing Strings Using Remote Real-Time Well Hydraulic Monitoring
Authors: Tollefsen E. , Goobie R. B. , Noeth S. , Sayers C. , Boer L. den , Hooyman P. , Akinniranye G. , Cooke J. , Thomas R. , Carter E. 
Published: December 2007

Abstract
Remote real-time pore pressure monitoring using a combination of Logging-While-Drilling (LWD) services coupled with a predrill pore-pressure model provides significant insight into wellbore stability and allows for optimizing casing points. This paper presents the results of a job in the Gulf of Mexico (GoM) that allowed an operator to drill confidently in a very tight hydraulic envelope and eliminate a string of casing.
The real-time use of data from the LWD formation pressure and sonic tools provides confidence in geopressure predictions. These LWD measurements allow the predrill velocity-to-pore-pressure transforms established during predrill modeling to be updated while drilling using the velocities from the sonic tool and pressures from the LWD formation pressure tool. This calibrated transform is then applied to revise the predrill pore-pressure model while drilling, thus reducing the uncertainty in the pore-pressure prediction ahead of the bit. In this case, the predrill model used velocities extracted from a 3D mechanical earth model of the northern GoM based on velocities derived from checkshots and sonic logs. These velocity data are kriged to give a 3D velocity model with uncertainty estimates.
Using state of the art Logging-While-Drilling (LWD) technologies, a new methodology was initiated to optimize drilling performance on a Vermillion 338 well. Continuously updated LWD annular pressure measurements effectively gauge wellbore pressures and help the driller rapidly intervene in pressure and/or geomechanical wellbore stability issues. A complete understanding of the hydraulic forces on a borehole can increase the rate of penetration, provide greater safety, minimize casing strings, reduce or eliminate kicks and formation fracturing, and allow faster and less expensive completions.
The technique described in this paper allows for incorporating real-time measurements into a pre-drill model, thus reducing the uncertainty ahead of the bit and allowing the operator to extend both the 9-5/8-in. intermediate casing and 7-in. liner to TD. As a result, a critical casing string was pushed 1,287 ft deeper than planned and a pre-planned 5-in. liner eliminated. The reduction in casing expense, as well as slim-hole drilling and completion costs resulted in a savings to the operator of approximately $1.7 million.
Feasibility Study of In-Situ Combustion in Naturally Fractured Heavy Oil Reservoirs
Authors: Tabasinejad F. , Karrat R. , Vossoughi S. 
Published: December 2007

Abstract
In-situ combustion is a thermal recovery method used for enhanced heavy oil recovery. In this process air is injected to the reservoir in order to achieve ignition and to maintain the combustion front while pushing the heated oil toward producing wells.
This study deals with the feasibility of in-situ combustion process in fractured heavy oil reservoirs. A one dimensional, three-phase in-situ combustion simulator with six components, two cracking and three oxidation reactions is used in this study.
Primarily, a conventional simulation model based on experimental data available in the literature was constructed and sensitivity study tests were performed. In the second part of this project, the conventional model was modified to a fractured model and various parameters and mechanisms such as oil recovery factor, average temperature of the system, cumulative oil and water production, diffusion, and wet combustion process were investigated.
Results indicate the importance of grid block size, injection rates, kinetic models, and equilibrium ratios of heavy and light oil components on simulation process. Simulation results indicate that the optimum water/oil ratio leads to an increase in the amount of oil recovery and a reduction in the amount of air to be injected.
The study presented here with its promising outcome is a pre-requisite to justify laboratory experimental investigation of the in-situ combustion process in naturally fractured reservoirs.
Drilling Waste Management: Improvements to the Dewatering Process through Chemical Optimisation—Results of a Pilot Test
Authors: Mohammadi M. Kalhor , Almassi F. , Sampaio J. H. B. , Tahmasbi K. 
Published: December 2007

Abstract
Environmental legislation in Western Australia requires controls over the discharge of drilling wastes to preserve the natural environment. Nowadays, drilling operators use standard practices and treatments to reduce the drilling waste, which includes drilling fluids and wastewater.
Dewatering of the drilling fluids waste is one waste management practice that can help operators remain in compliance with environmental legislation. However, there are still some issues concerning the chemical cost and successfulness of the dewatering process. There is a clear incentive to reduce costs through optimum chemical selection, which, in turn, can lead to reduce equipment costs.
The primary objective of the research work reported here is to optimise the chemical consumption in the dewatering process. This has been achieved through a series of pilot tests carried out in the laboratory, and this paper describes the laboratory procedures employed to reach an optimum outcome. The procedures include the selection of the proper coagulants and flocculants by the common jar test method, and, in addition, the determination of the optimum chemical concentration by comparing the effectiveness of the dewatering process after centrifuge testing.
Design Criteria for Improved Performance of Fractured Wells
Authors: Poe B. D. 
Published: December 2007

Abstract
This paper presents the results of an investigation concerning the development of more accurate predictive and interpretive models of the boundary-dominated flow performance of vertically fractured wells located in closed rectangularly bounded reservoirs. In particular, improvements in the characterization of the dimensionless productivity index of vertically fractured wells in closed rectangularly bounded reservoirs during boundary-dominated flow have been made using a mathematically rigorous model for pseudosteady state flow. This model has been used to develop predictive and analysis graphical design charts of the dimensionless productivity index for improved fracture stimulation design and evaluation.
Other issues investigated in this work were the development of a general relationship for evaluating the pseudosteady state shape factor of a vertically fractured well in a closed rectangularly bounded reservoir, along with a review of appropriate applications of the apparent wellbore radius concept to vertically fractured wells in finite reservoirs. Example applications of the dimensionless productivity index and pseudosteady state shape factor solutions developed in this work are provided for fracture stimulation design.
Inflow Profiles Obtained With Pulsed Neutron Logs in Subcritical-Velocity Wells
Authors: Poe B. D. , Butsch R. J. 
Published: December 2007

Abstract
This paper addresses some recent developments in a production logging technique that uses Pulsed Neutron log measurements to evaluate the formation inflow into a wellbore, in which one or more of the completed intervals may be located in the annulus between the casing and tubing strings above the end of the tubing. Of particular importance in this work is the capability of determining the formation inflow profile in the well in cases where the well outflow velocity is less than that required to continuously transport and unload liquids from the well. Sub-critical velocities are commonly encountered in low productivity gas wells that produce liquids, whether they are produced directly from the formation and/or condensed well fluids, water and hydrocarbons.
This paper presents a sub-critical velocity analysis that has been implemented in a Pulsed Neutron production logging technique in order to have the capability to reliably evaluate the formation inflow into wells in which the velocities are so low that no other production logging methodology is possible. Coupled with the numerical modeling of the Pulsed Neutron production log evaluation, test pit measurements of the annular flow water velocities with the Pulsed Neutron logging technique have been reliably and accurately measured to as low as 3 ft/min (0.05 ft/s).
Characterization of Reservoir Properties Using Production Logs
Authors: Poe B. D. , Atwood W. K. , Kohring J. , Brook K. 
Published: December 2007

Abstract
This paper presents the results of an investigation involving the development of a reliable and accurate methodology for establishing the stabilized deliverability performance of multi-layer commingled reservoir systems using multi-rate production log measurements. Both linear and non-linear systems are considered in this work, providing a basis for the analysis of reservoirs that exhibit Darcy and non-Darcy flow, respectively.
An extension of the conventional Selective Inflow Performance analysis is presented in this paper to obtain estimates of the formation and well completion properties such as effective permeability, radial flow steady state damage/stimulation skin effect, and non-Darcy flow coefficient. In the specific case where the deliverability performance of a vertically fractured well is considered, estimates of the effective fracture half-length and average fracture conductivity may be derived from the analysis. In cases where the multi-rate deliverability measurements are obtained under boundary dominated flow conditions, conventional deliverability analysis techniques may also be employed to derive estimates of the reservoir drainage area in addition to the well and reservoir parameters that can be obtained in a transient flow analysis. Applications of the analyses reported in this paper demonstrate the use of the analyses for evaluation of the inflow performance of commingled multi-layer reservoirs using multi-rate production log measurements.
Determining Parameters of Matrix-Fracture Interface Fluid Transfer from Laboratory Tests
Authors: Civan F. , Rasmussen M. L. 
Published: December 2007

Abstract
Methodology is presented and proven for determination of the best estimate parameter values affecting the matrix-to-fracture interface fluid transfer in naturally fractured reservoirs. Improved matrix-fracture-transfer models are applied based on presumed matrix block shapes. Fracture surface hindered interface fluid transfer is considered between the matrix blocks and surrounding natural fractures. Analytical solutions developed for special boundary conditions are applied for the typical laboratory tests for rectangular and cylindrical shape rock samples. The workable equations and straight-line data plotting schemes are developed for effective analysis and interpretation of laboratory data obtained from various shape oil-saturated reservoir rock samples immersed into brine. This allows the rapid determination of the characteristic parameters of the matrix-fracture transfer models for various shape matrix blocks, which are essential for prediction of petroleum recovery from naturally fractured reservoirs by computer simulation. The methodology is verified using various experimental data concerning water imbibition into oil-bearing rock, and the values of the characteristic parameters, such as the diffusion coefficient, and skin coefficient and thickness, are determined.
Future Exploitation Strategy Using Integrated Subsurface-to-Surface Methodology: Field Case Study—Litoral De Tabasco Asset
Authors: Rosales A. , Barrera J. , Gonzalez L. E. , Martinez I. 
Published: December 2007

Abstract
In reservoir development studies or exploitation studies for a hydrocarbon producing field, it's necessary to go through different stages, from visualization to planning all involved activities. In visualization we must consider basic factors that will contribute to an optimal exploitation plan. Thus we need tools capable of integrating the whole system, from subsurface production all the way to the surface. Different subsurface productivity techniques, production methods, secondary recovery projects, facilities required, among others are the fundamental base for an adequate reservoir exploitation planning, considering all limitations within the system as well as related costs.
In this study, it's considered the analysis done for Field Exploitation for Litoral de Tabasco Asset (AILT), which comprises 14 hydrocarbon fields and all related production facilities of Region Marina Sur Oeste (RMSO). Different analysis techniques were applied such as: material balance (MB), nodal analysis (NA), simulation of multiphase gathering systems, statistics, integrating all this disciplines in a network to evaluate production scenarios for 15 years, considering production forecasts, pressure drops along the system and Asset production facilities limitations and needs. The integrated model will allow determining the optimal option according to the evaluated scenarios and facilities needs along the productive life of all analyzed fields.