bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enhanced Calibration Treatment Analysis for Optimizing Fracture Performance: Validation and Field Examples
Authors: Gulrajani S.N. , Vasudevan S. , Ganguly U. 
Published: December 2007

Abstract
Current pressure evaluation techniques that assess fracture behavior from calibration treatments are limited to predicting reservoir parameters that govern fracture growth. In addition, significant variability during the evaluation process can result in subjectivity and hence reduce the effectiveness of such tests. The recently proposed "after-closure" analysis attempts to overcome these limitations by assessing the reservoir- dominated pressure response, following mechanical closure of a hydraulic fracture. After closure linear flow provides an independent assessment of the fracture length induced during the calibration treatment. This prediction constrains the fracture length predicted, either by the conventional pressure decline analysis or a numerical fracture simulator, and hence provides an accuracy check for the pressure evaluation. In addition, the dependency of the pressure response during the linear flow regime on the closure time permits an additional independent assessment for fracture closure pressure. Consequently, the linear flow diagnostic reduces uncertainty in determining the fracture closure pressure that is commonly encountered during the evaluation process. Finally, the reservoir pressure and transmissibility are estimated from the radial flow behavior in a manner similar to conventional well testing. The proposed evaluation methodology combines this after-closure analysis with conventional calibration treatment analysis to predict a cross-validated ensemble of all parameters that govern proppant placement and post stimulation hydrocarbon production. This evaluation methodology thus provides all information required for an optimized design of fracture treatments.
The methodology of this analysis, as well as comprehensive field examples illustrating its application and validity, are presented in this paper.
P. 375
Development and Trends in Hydraulic Fracture Stimulation of German Rotliegend Gas Wells
Authors: Berghofer K. 
Published: December 2007

Abstract
Over the past 15 years there have been significant changes in the design and operational aspects of fracture treatments of German Rotliegend gas wells.
The paper presents a review of pump volumes, pump strategies and post-frac production behavior, from the hydraulic fracture treatments of tight Dethlingen sandstone formations in the Sohlingen field in the eighties to the stimulation of high capacity wells in 1997.
The consistent use of bottom hole pressure gauges with surface readout in mini fracs, and the application of real time 3D fracture stimulation software resulted in the continual reduction of pump volumes in main fracs and the related time and cost requirements.
In frac treatments of Rotliegend gas wells there is a clear trend toward smaller proppant volumes, while the post-frac production rates are going up. The production rates of frac-treated wells were max. 10,000 Sm3 in the early eighties, but have meanwhile gone up to 45,000 Sm3.
Post-fracture analysis showed that, with decreasing reservoir pressure, the risk of uncontrolled fracture growth and proppant convection due to underhydrostatic closure pressures increases. Therefore, it appears desirable to stimulate Rotliegend gas wells before reservoir pressure declines to below the critical level.
The future development of fracture stimulation technology is seen to bring an ongoing decrease of proppant volumes pumped in one stage, and the application of multistage fracturing using coiled tubing to place proppant.
P. 569
Application of Novel Upscaling Approaches to the Magnus and Andrew Reservoirs
Authors: King M.J. , MacDonald D.G. , Todd S.P. , Leung H. 
Published: December 2007

Abstract
Cases studies from three North Sea turbidite reservoirs will be presented, which together demonstrate our current understanding of permeability and relative permeability upscaling. The three formations, the Magnus, Magnus Sand Member (MSM), the Magnus, Lower Kimmeridge Clay Formation (LKCF), and the Andrew reservoir each provide distinct challenges for reservoir modelling, either because of reservoir complexity, the fluids in place, or the phase of field life. To meet these challenges, several novel upscaling approaches have been developed. Their use will be explored and current best practice delineated. This best practice differs significantly from previous definitions of "effective permeability" by placing more emphasis on extracting multiple properties from the fine scale geologic models. Distinct upscaling calculations are required to assess
the quality of sands, the quality of barriers, and the tortuosity of flow around these barriers.
Similarly, when constructing upscaled relative permeabilities, the "effective" curves are distinguished from the "pseudo" curves. The former describe the physical displacement of fluids, while the latter include the additional numerical dispersion corrections required when implementing the relative permeability functions within a coarsely gridded full field simulator.
P. 133
Novel Lubricants for Water-Based Drilling Fluids
Authors: Growcock F. B. , Frederick T. P. , Reece A. R. , Green G. W. , Ruffin M. D. 
Published: December 2007

Abstract
As drilling in directional and extended-reach wells continues to gain popularity, high torque and drag become increasingly important issues. This is particularly true for water-based muds (WBM), which generally give rise to high coefficients of friction (COF) between the drillstring and the wellbore and, therefore, high torque and drag. In addition, water-based muds can also increase wear rates in the wellbore. For contact between steel and rock, oil-based muds (OBM) and synthetic-based muds (SBM) generally produce COF that are lower than those produced by WBM. However, use of OBM and SBM is severely limited by environmental concerns and high costs. It would be advantageous to identify environmentally friendly WBM that are as lubricious as OBM and SBM.
This paper discusses a recent project the aim of which was to find suitable lubricants for WBM that would reduce the COF between drillstring steel and sandstone without having adverse effects on the formation or the environment. Laboratory COF measurements are shown to correlate with simulated field results. Trends in lubricant performance appear to be relatively independent of the type of mud system, although absolute performance decreases with increasing solids content and the presence of other surface-active components. A simple mechanistic lubricity model is described that emphasizes the role played by lubricant-induced wettability changes.
A New Chemical Approach to Mitigate Sulfide Production in Oilfield Water Injection Systems
Authors: Johnson M. D. , Harless M. L. , Dickinson A. L. , Burger E. D. 
Published: December 2007

Abstract
Uncontrolled growth and activity of sulfate-reducing bacteria (SRB) in oilfield systems can create safety, environmental and operational problems such as microbiologically influenced corrosion (MIC), solids production and biogenic hydrogen sulfide (H2S) generation. A previously reported study showed that a group of structurally-related derivatives of 9,10-anthraquinone at micromolar concentrations effectively inhibits the process of sulfate respiration in SRB without having a bactericidal effect on the bacteria. This new technology was field tested in a California oilfield produced water injection system. Acrolein was being used daily as a biocide in this system to control the generation of iron sulfide solids resulting from SRB activity. The new treatment protocol field tested combined reduced frequency slug treatments of acrolein with treatments of a soluble form of anthraquinone. Laboratory studies were performed in conjunction with the field trial to confirm that laboratory evaluations of the anthraquinone treatments could relate to actual field usage. This paper describes the water injection system, the treatment program and presents the results of monitored parameters, including H2S concentrations, total suspended solids, SRB levels and anthraquinone residuals from three treatment periods and a control period. The synergistic effect of the two chemicals allowed for an extension of the time between acrolein treatments from one day to greater than one week while maintaining acceptable water injection quality.
High-Density Monomer System for Formation Consolidation/Water Shutoff Applications
Authors: Eoff Larry , Funkhouser Gary P. , Cowan Mike 
Published: December 2007

Abstract
This paper describes a monomer system for formation consolidation in deepwater applications. In deepwater wells, shallow zones may have pore pressures close to fracturing pressures. In these situations, lost circulation or flowing zones can be difficult to control and can lead to a complete loss of the well.
Hydroperoxide and azo initiators were used for polymerizing solutions of 2-hydroxyethyl acrylate in aqueous solutions of sea salt, sodium chloride (NaCl), calcium chloride (CaCl2), calcium bromide (CaBr2), and zinc bromide (ZnBr2) with densities from 8.6 to 17.5 lbm/gal. These monomer solutions undergo controlled polymerizations in the formation to yield stiff plugs that can withstand high differential pressures. A similar monomer system has been used for water shutoff applications, but had never been formulated in heavy brines or used in the cool temperatures (50° to 60°F) typical of the shallow water-flow zones. Using a high-density consolidation fluid would be advantageous in shallow water-flow zones. This fluid could be spotted over the problem zone and allowed to flow into the zone because of the hydrostatic pressure. This fluid would allow the treatments to be used in wells where high-pressure injection into the formation is not an option. Before this work, no high-density fluids were available for these applications.
Various data are shown describing the system's development, including gel-time curves and compressive strengths of consolidated sandpacks. Factors affecting the performance and application of the system are discussed.
Treatment of Salt Affected Soil in the Oil Field
Authors: Mishra Surendra K. , Evans William J. , Lacik John I. 
Published: December 2007

Abstract
Soils, drill cuttings and other solid wastes which are exposed to high levels of salt through spillage from drilling and producing operations, pipe line breaks or leaks, become saturated with sodium. Although the EPA and the industry have demonstrated that the vast majority of such wastes are non-hazardous, in actuality, they have an adverse impact on the fertility of the soil.
The degree of salt saturation is influenced by the soil mineralogy. Many native soils containing high montmorillonitic clays have the capacity of adsorbing sodium species in their crystal structure. Sodium adsorbed montmorillonitic clays being dispersed affect the physical structure of soil and, in turn, adversely influences its permeability. High salt content of soil also has a profound influence on its osmotic pressure. Consequently, it has a detrimental influence on the health of the commercial crops or native vegetation.
The physical structure of the soil can be chemically modified, allowing improved drainage of undesirable salt species. To store its physical structure and to make it permeable, the industry has practiced cationic amendment of sodium contaminated soil. Traditionally used gypsum, being sparsely soluble in water is unable to provide a readily available source of cationic species for amendment. A carefully designed product containing readily available cationic source along with other nutrients for the growth of vegetation has been highly successful. Field results from various geographical locations with different soil composition and degree of contamination showing rapid reductions in the sodium contents and, in turn, also having a dramatic effect on the restoration of vegetation are discussed in this paper.
Study on Design of Extended Reach Well Trajectory
Authors: Ma Shanzhou , Huang Genlu , Zhang Jianguo , Han Zhiyong 
Published: December 2007

Abstract
This paper presents three main principles on the design of extended reach drilling well trajectory. The profile of build up section is optimized within nine types of shapes. The results show that sideway curves, curvature decreasing curve and circular arc are better than others. The influences of kick off point, maximum build up rate or hold angle on torque and drag and well length of three kinds of optimum curves are discussed. The results obtained are important guidelines for design of extended reach well trajectory.
P. 233
An Optimum Method of Early-Time Well Test Analysis -- Genetic Algorithm
Authors: Yin Hongjun , Zhai Yunfang 
Published: December 2007

Abstract
Conventional type curve fitting analysis of early-time transient pressure data influenced by wellbore storage effects can yield non-unique results due to similarity in the shape of the curves. In order to alleviate this problem, this paper proposed an optimum method based on adaptive genetic algorithm (AGA). This is a robust approach to get early-time well test interpretation. It is superior to the non-linear regression algorithms and standard genetic algorithm. Initial estimates of the parameters and operator probability (crossover and mutation probability) need not be specified. The diversity of the population and the convergence capacity of the GA can be maintained by using the adaptively varying probabilities of crossover and mutation depending on the fitness values of the solutions. By this way the optimum reservoir parameters can be obtained. Applicability of the proposed methods is demonstrated by analyzing a field example.
P. 265
Successful Application of Multistage Acid Fracturing Technology in Changqing Gas Field
Authors: Liu Hailang , Zhao Zhenfeng 
Published: December 2007

Abstract
The Ordovician carbonate reservoirs are heterogeneous with low formation pressure, low permeability in Changqing gas field. Multistage Acid Fracturing is a key technology for further stimulation in this field. This paper presents the technique mechanism, suitability analysis, lab experiments evaluation, optimization of key parameters, application results, and so on of this technology.
P. 323
Pressure Transient Analysis for Relaxation Model of Non-Newtonian Visco-elastic Flow in Fractal Reservoir with Wellbore Storage and Skin Effect
Authors: Tong Dengke , Chen Qinlei , Ge Jiali 
Published: December 2007

Abstract
The majority of the conventional pressure-transient models assume that permeability and porosity of a formation is invariant in space. Moreover, fluid flow in reservoir is Newtonian fluids or non-Newtonian power-law fluids. Such an assumption gives good results in many situations; but the geological complexity of units and/or non-Newtonian relaxation characteristics of visco-elastic fluids may make these assumptions of dubious value. The purpose of this study is to explore flow analysis of non-Newtonian visco-elastic fluids with relaxation property in reservoir that are not amenable to the conventional approach.
In the study, we present a pressure-transient radial relaxation flow model of non-Newtonian visco-elastic fluids in fractal reservoir considering the effect of wellbore storage and skin factor. Analytical solution and asymptotic solution in real space are obtained by using Laplace transform for a constant- rate condition at a single well in an infinite reservoir. The flow behavior of non-Newtonian visco-elastic fluids is also analyzed by using numerical inversion scheme of Laplace transform. We discuss pressure response of changing spectral dimension and rheological parameters. Conventional model (hornogenous reservoir, Newtonian fluids) is a special case of above model. The results obtained in the study extend previous pressure transient analysis for single phase Newtonian flow in a 2-D cylindrical system to reservoir of arbitrary fractal dimension and visco-elastic fluids of rheological parameters.
P. 343
Effect of Porous Medium Adsorption on Percolation Law of Condensate-gas Mixture
Authors: Du Jianfen , Li Shilun , Sun Lei 
Published: December 2007

Abstract
The condensate-gas mixture flowing process takes place in the porous media of deep strata. Owing to their giant specific area, the porous media are of a relatively strong adsorption capacity and the fluid exists as two states, i.e. adsorption state and free state. According to the basic theories of multiphase flow and the acting mechanisms of porous medium adsorption, a research approach of percolation law which contains the effect of the mixed gas, which is adsorbed on the surface of porous media under formation conditions, is proposed. A corresponding mathematical model is set up too. Through an example calculation, the effect of porous medium adsorption on percolation law is analyzed. It is concluded that the effect of porous medium adsorption on the flowing process of condensate-gas mixture is of objective reality and can't be neglected.
P. 459
Research and Application of Metal Complex - Amphoteric Polymer Drilling Fluid
Authors: Yabin Niu , Daming Zhang , Hongzhang Xiao , Wumuxi Zheng , Jian Li 
Published: December 2007

Abstract
Amphoteric polymer and MMH drilling fluid systems have been widely applied in oil fields in recent years with good benefits. The applications have shown the advantages and disadvantages of the two drilling fluid systems. Based on the analysis and research of molecular structure and mechanism of the two kinds of additives in drilling fluid, the molecular structures of new polymers, metal complex - amphoteric polymers PMHA, JMHA, are designed and researched. The new products have properties of both amphoteric polymer and MMH, that is, high inhibition, high thixotropic, stable drilling fluid rheological, excellent filtrate control ability and the ability of protecting production formation from damage. Applications in Zhongyuan, Jiangsu and Liaohe oilfields showed that it increased drilling rate, decreased the trouble under well bore and the enlargement rate of well diameter. The metal complex-amphoteric polymer products have good compatibility with other additives. The drilling fluid system formulated by these products has stable rheological properties with low cost. Now the drilling fluid system has been successfully applied in vertical, directional, deep and slim hole wells in China's oil fields. Taking advantage of the metal complex - amphoteric polymers, we have formulated drilling mud systems, such as the fresh water mud, high-density mud with high salinity, slim hole drilling fluid and completion fluid.
Research on Utilization Shallow Structure to Construct Underground Natural Gas Storage
Authors: Li Jianzhong 
Published: December 2007

Abstract
The constructed underground natural gas storage in the world can be divided into four types according to the storage style. This paper presents successful experience of foreign countries and by which to specify standards and conditions for utilizing shallow structures to construct underground natural gas storage in China. Two shallow structures discovered in Northern Jizhong area have been optimized and evaluated as the initial storage target in combination with the fact of supplying natural gas from Shanbei gas field to Beijing. The storage capacity of two shallow structures can meet the requirement of emergency and adjust the peak value seasonably. It can provide reference value to the decision of constructing underground natural gas storage in Beijing and Tianjin area, and it can be also applied to the similar project in other areas in China in the future.
P. 551
NMR Logging Studies of Igneous Reservoir by the Aid of Core Analysis on Linpan Area Shengli Oilfield
Authors: Lu Fenggen , Zhao Wenjie , Wu Jingli , Wang Weimin , Liu Wei , Sun Dianging , Li Pei 
Published: December 2007

Abstract
Linpan area of Shengli oilfield is rich in igneous reservoirs. The formation is hard to be evaluated by conventional logging methods because of complex lithology characters of the rocks. Nuclear Magnetic Resonance Imaging Logging (NMRIL), which can provide formation porosity, permeability, moveable fluid, has many advantages over other logging methods. It gives us a completely new method to evaluate igneous formation. In this paper we demonstrate an NMRIL interpretation method that combines NMR logging data with core analysis. Big size igneous cores with different lithology were selected for laboratory analysis. Their relationships among porosity, permeability, moveable fluid index, T2 distributions, and NMR signal have been analyzed and discussed. Logging data were precisely interpreted using our own software that allowed many more T2 points to be calculated from NMR echo data.
P. 557
Deliverability Enhancement of High-Volume Oriskany Gas Storage Wells Using Foamed Acid as a Damage Removal Medium
Authors: Fontaine James S. , Rouze Scott G. 
Published: December 2007

Abstract
As gas storage wells age over time they are susceptible to processes having negative impact on deliverability. The GRI study of 1993 determined that on a national average, 5% of storage deliverability capacity is lost per year.
This paper will discuss the successful use of foamed acid as a stimulation fluid in Oriskany gas storage wells in the Wharton Gas Storage Field in north-central Pennsylvania. Case histories of three treatments performed and the impact upon deliverability will be presented. Two of these treatments were performed on wells damaged during re-work projects and one was performed on a well suffering from a large decline in deliverability.
Reservoir Simulation and Analysis of the Sciota Aquifer Gas Storage Pool
Authors: Sawyer Walter K. , Zuber Michael D. , Bues Allen D. 
Published: December 2007

Abstract
This paper presents the results of a reservoir simulation study of the Sciota aquifer gas storage field in McDonough County, Illinois. The field has been in operation since the early 1970's and is currently operating with 12 injection wells and five observation wells. The field is operated by the Central Illinois Public Service Company, now part of AmerenCIPS.
The objectives of this study were to (1) build a computer database of all historical pressure and injection/withdrawal data, (2) determine inventory volumes over time, (3) determine the cause of the low working-gas to base-gas ratio, and (4) determine if field deliverability could be improved.
In this study, weekly injection/withdrawal data and daily wellhead pressure data were first computerized and analyzed to evaluate past reservoir performance. Analysis of the injection/withdrawal data indicated a cumulative net gas injection of about 4.7 Bscf from November 1972 to July 1997. However, the average working gas was only about 0.3 Bscf for the last nine storage cycles, giving a working-gas to base-gas ratio of only about 6.4 %.
Analysis of the wellhead pressure data indicated that the wells were loading up with water during each withdrawal period. Using all available reservoir and geology data, we constructed a two-phase gas-water model of the Sciota storage pool and history matched the injection/withdrawal on a monthly basis from 1972 to 1997. We determined that the working gas could possibly be increased threefold from 0.3 Bscf to 1 Bscf by maintaining lower bottomhole pressures during withdrawal.