bluuebunny/crossref_metadata_2025_split huggingface dataset:
Application of Imaging X-Ray Photoelectron Spectroscopy (IXPS) to Pore Surface Analysis
Authors: Hill P.I. , Hughes C.R. , Isaac K.P. , Jordan M.J. , Hazell L. 
Published: December 2007

Abstract
Imaging X-ray Photoelectron Spectroscopy (IXPS) has been evaluated for its application to derive information on scale inhibitor distribution directly, and the wettability of pore surfaces indirectly, from a number of North Sea reservoir core samples. The technique derived elemental composition of an area of approximately 2 × 3 mm, with more detailed image mapping for individual elements over an area of 700 m.
An hexaphosphonate inhibitor was applied by both adsorption and precipitation methods. Phosphorous, a major component of the inhibitor, was only detected in the precipitated treated core. The level of detection though was below that necessary for more detailed mapping of inhibitor distribution. At this stage of the evaluation IXPS was found not to be appropriate for deriving detail of inhibitor distribution, however, results of this evaluation indicate that surface carbon distribution (wettability) is clearly affected by inhibitor treatment.
IXPS has also been used to compare different core cleaning and conditioning treatments of oil wet North Sea reservoir core samples. Results show that hot solvent cleaned core has a reduced mean carbon surface composition density relative to core that has been mild solvent cleaned. This confirms the removal of significantly more oil by hot solvent cleaning, indicating that core surface wettability characteristics are modified differently by different treatments, even though both treatments are thought to preserve an oil wet state.

Introduction
Wettability of reservoir rock is a critical parameter in reservoir characterisation Reservoir management and the understanding of oil recovery mechanisms require data on wettability, especially as it affects relative permeability and influences the effectiveness of production operations, e.g., surfactant-inhibitor treatments against scale formation. Current techniques for the measurement of wettability are unreliable and can take many months to complete. IXPS can derive such information rapidly.
IXPS also has potential to be implemented to a number of wider applications during reservoir evaluation. It can derive information on the distribution of elements which may relate to core mineralogy or from chemical treatments applied i.e. scale inhibitors.

Objectives
To evaluate the effects of different core cleaning methods on wettability.
To evaluate the application of surface analysis for mapping inhibitor distribution.
To evaluate the use of surface analysis to correlate 'wettability' and/or inhibitor distribution with reservoir framework mineralogy.
Rheological Responses to Variations in Aqueous-Based Zirconium Crosslinker Chemistry
Authors: Harry David N. , Moorhouse Ralph , Matthews Les , Chen Gong 
Published: December 2007

Abstract
Aqueous based zirconium crosslinked fracturing fluids have seen widespread service since the early 1980's. Today, zirconium crosslinkers are used with many types of polymer solutions, across a pH range of from less than 1 to greater than 12. at bottom-hole temperatures of from less than 100F to greater than 400F. There is no doubt among workers in the field that the same zirconium crosslinked fracturing fluid is not suitable for such a wide range of applications, and, yet, there has yet to be published a systematic evaluation of the impact first order changes in the composition of zirconium crosslinkers have on rheological performance. This study endeavors to provide such a systematic evaluation.
Aqueous-based zirconium crosslinked systems can be made with a wide range of functionality to meet specific performance needs. In hydraulic fracturing fluid systems utilizing zirconium crosslinked guar or guar derivatives, changes in the crosslinker due to differences in the zirconium raw material source, the ligand to metal ratio, cation type, and pH of the system cause significant differences in rheological performance. In particular, crosslink time, temperature and stability at temperature (for a given shear regime) can be controlled by manipulation of the aforementioned factors. This study presents a systematic evaluation of these factors and discusses how an understanding of their interrelationships is essential in predicting performance of a crosslinker or designing a new fluid system.
Zirconium Additive Improves Field Performance and Cost of Biopolymer Muds
Authors: Burrafato G. , Guameri A. , Lockhart T. P. , Nicora L. 
Published: December 2007

Abstract
Novel inhibited biopolymer muds are reported that provide both environmental compatibility and excellent performance in drilling reactive shales. These muds employ the new dispersing agent zirconium citrate (ZrC) which provides effective rheology control for the build-up of low density solids in the mud. Laboratory experiments on Xanthan gum and Scleroglucan biopolymer field muds demonstrate the exceptional thinning power of ZrC compared to other deflocculants. Results from the application of ZrC for rheology control in Scleroglucan-potassium muds are given for two wells drilled in southern Italy. In both wells, the use of ZrC strongly reduced the need for mud dilution, compared to previously drilled wells, and proved an effective means for stabilizing rheology during stopped circulation. On account of the sharply-reduced mud volumes required, use of ZrC reduced total fluid costs by 26 and 44% for these wells.
A Simple Method for Determination of Radius of Investigation for Non-Newtonian Fluids and Other Non-Ideal Systems
Authors: Wang Xinhai , Ma Shouxiang 
Published: December 2007

Abstract
Transient pressure testing is an important tool in obtaining reservoir information. Information derived from transient tests is useful only to those portions of the reservoir in which flow has occurred during the test. Thus, determination of radius of investigation (ROI) is essential. The most commonly used ROI equations were derived for Newtonian fluids Darcy flow in a homogeneous formation. Limited information of ROI is available for systems involved with non-Newtonian fluids or non-Darcy flow which could be important in polymer flooding or production of gas wells.
ROI was determined in this paper by combining material balance equation and pressure distribution at any given testing time. This method of determining ROI was applied to non-Newtonian power-law fluids Darcy flow and Newtonian fluids non-Darcy flow in both homogeneous and composite formations.
Main observations from this study included that for non-Newtonian power-law fluids:ROI was compared with a literature ROI model which is applicable in the range of 0&lt;n&lt;1. Within {0,1}, the two models give consistent results with the difference being zero at about n=0.6. The applicable range for the new model however is n 0 9.When n&lt;1, ROI increases with flow rate, q, while n&gt;1, ROI decreases with increase in q. At n=1, ROI is independent on q.Difference between original formation permeability, k, and the permeability around wellbore, kA, has a significant effect on ROI if kA/k&lt;1.
The effect of kA /k on ROI increases with n, kA/k has minor effect on ROI if kA/k&gt;1. For Newtonian fluids non-Darcy flow,ROI is dependent on flow rate,ROI is less than that for Darcy flow, andROI decreases with increase in turbulent factor.

Introduction
Radius of investigation (ROI) is used to estimate the time required to test the desired area in a formation. The most commonly used radius of investigation, ri, was obtained by van Poollen,1 ri,P, by assuming that a Newtonian fluid flows in a uniform, homogeneous, and isotropic formation under the conditions of Darcy flow. (This is referred as ideal systems.)
Equation 1
where k is the formation permeability, f porosity, µ Newtonian fluid viscosity, Ct total compressibility, t testing time, and E1 is a unit conversion factor. A detailed review and discussion of Eq. 1 was given by Johnson.2
Consistent units should be used in Eq. 1 and all the following equations in this study. However, direct application of these equations could be difficult. Therefore a unit conversion factor, E, is included for the more convenient field units. If the parameters in Eq. 1 have the units as shown in Table 1, E1 is equal to 0.016238.
Numerous pressure transient studies for non-Newtonian fluids3–6 and high flow rate non-Darcy flow7–9 have been reported. However, limited information on ROI was available for systems involved with (1) non-Newtonian fluids, (2) non-Darcy flow, and (3) non-homogeneous porous media.
Pre and Post Gravel Pack Pressure Transient Testing of Layered Reservoir Wells
Authors: Al-Haddad S. , Hebert J. , Arbaugh R. , McKnight D. 
Published: December 2007

Abstract
Permeability and skin factor can be misestimated from well testing data taken after completing wells in layered reservoirs. Results presented in this paper are based on field data and numerical simulation work on two wells in an offshore Louisiana field.
Testing results taken after completing the first well in the field with a gravel pack, gave considerably lower than expected permeability results that could have jeopardized the future development of the field. Well performance analysis based on pre-gravel pack flow, as well as investigation of existing well log data, indicated the possibility of a layer of higher permeability within the tested interval. In consideration of this analysis, a decision was made to proceed with the drilling of a second well in the field and perform a pre-gravel pack test to obtain original reservoir data. Then, the completion design for the second well and the treatment strategy for the first well would be based on the proposed pre-gravel pack test results of the second well.
The pre-completion impulse testing of the second well, drilled to the same reservoir, gave a higher calculated permeability than the first well, confirming our expectation. A new completion design was proposed and implemented on the second well. Post-completion transient testing indicated that the second well completion maintained communication with the higher permeability layer allowing the evaluation of the well completion skin. The new reservoir permeability then used in reservoir simulation resulted in a more reliable field production performance prediction and evaluation. Well log data, well test data, completion design, and reservoir simulation results are presented in this paper.
An Organized Approach Toward Remediation of Salt-Affected Soils at E & P Sites
Authors: Carty D. J. , Priebe W. F. , Swetish S. M. , Crawley W. W. 
Published: December 2007

Abstract
Strategy and tactics for remediation of salt-affected soils at exploration and production (E&P) sites continue to challenge the petroleum industry. Although substantial refinement of remediation technology is still required, an adequate database currently exists for the remediation of most sites. Permanent remediation (complete cure) requires correct measurement (examination), interpretation (diagnosis), and selection and application of the appropriate technology (prescription) for the specific physical, chemical, and cultural condition of each unique site (patient). Differences among spill circumstances include the volume and concentration of produced water spilled, the soil's texture, slope, stratification, erodibility, mineralogy, chemical characteristics, vegetation status, and drainage characteristics, as well as seasonal water table variation, site meteorological conditions, and corporate, regulatory, and landowner constraints. A decision-tree incorporating these and other variables will be presented in a forthcoming publication. Major factors of concern and emerging technologies are highlighted in this paper. Society of Petroleum Engineers, (SPE) members are invited to join in forming a national technical support network to provide a comprehensive and readily available database with which the petroleum industry can better examine, diagnose, prescribe, and cure salt-affected soil "patients."
Progressing Cavity (PC) Pump Design Optimization for Abrasive Applications
Authors: Delpassand Majid S. 
Published: December 2007

Abstract
The progressing cavity (PC) pump is well established as the pump of choice for handling abrasive solids. PC pump design can be optimized to achieve the best wear performance available for a given size. The wear optimization of the PC pumps is achieved through geometric design for minimum internal fluid velocities and by selecting proper materials of construction.
Wear causes PC pump failure by gradually reducing the volumetric efficiency and increasing pump slippage. This paper focuses on the parameters that influence pump wear, describes wear mechanisms, reviews design techniques for wear optimization, and presents field data to support some of the claims.
A Successful Water Shut Off. A Case Study from the Statfjord Field
Authors: Børeng Raymond , Svendsen Ove Birger 
Published: December 2007

Abstract
Gel is considered to have an interesting potential for water shut off applications, especially in fields having natural shale barriers and large permeability variations and/ or where reduction in tubing/ casing diameter is not wanted. This paper describes a case study from the Statfjord Field where polymer silicate gel was used to build up experience for water shut off applications of the lower producing interval in a well that produced from two intervals. The intervals where separated by 5m in 9 5/8" casing and located at approximately 3100 m.
The primary objective was to shut off water and secondly to evaluate gel technolog)'. Mechanical techniques and gel technology were considered as means of achieving the objectives. Both required the use of 2" coiled tubing in a live well (Fig. 14). Gel technolog)' was selected since diameter restriction in the casing was not wanted due to potential later perforations deeper into the well combined with desire of qualifying the technolog)' and related techniques.
This paper reports some of the results achieved in the laboratory, and give references to papers where the laboratory techniques and results are given, refs. 1 through 5. The pre planning and the laboratory' testing for finding a suitable gel formulation was also performed in collaboration with a service company.
Therefore this paper focuses mostly on the well performance, placement of plugs in the well by wireline and coiled tubing, pumping of the gel solution through the coiled tubing and into the lower perforation interval and evaluation of results.
The operation has been an economical success. After water isolation from the lower interv al, the well has produced oil with a gross value of 15 mill. U.S.$ in 6 months and the operation had a pay back time of 50 days.
Numerical Simulation of Steamflood Efficiency Improvement Through Use of Hydraulic Fracturing Technology
Authors: Manrique J. F. , Mukherjee H. , Mach J. 
Published: December 2007

Abstract
We present the use of fracturing technology to accelerate performance and improve ultimate recovery in heavy oil reservoirs. The applicability and efficiency of this approach were investigated by means of numerical simulation. A fully implicit 3-D thermal simulator was used to model the heat transfer efficiency and productivity enhancement when using this approach. Different scenarios were modeled for wells with horizontal and vertical fractures. This technology may be especially suitable for thinner reservoirs, dipping reservoirs and steam distillation drives.
The "heat plane source" concept is presented in this paper to explain the advantages of fractured steam injectors for improvement of thermal recovery processes. During steam injection, heat convection and gravity effects become dominant in the near wellbore area causing excessive heat losses and poor recovery. We suggest an approach that will minimize convection override of the oil while creating a more efficient and stable steam drive.
Numerical results suggest that production response of current steamflood operations can be improved by inclusion of hydraulic fractures. Additional advantages observed for fractured injectors suggested a modified injection schedule that improves productivity and steam allocation for neighboring projects. This results in a faster return of investment and substantial increase in cash flow during the early life of the project. The economic benefits were evaluated by incorporating the production response into an economic model that maximizes the Return of Investment and Net Present Value.
Evaluation of Particulate and Hydrocarbon Fracturing Fluid-Loss Additives Under Dynamic Conditions
Authors: McGowen James M. , Vitthal Sanjay 
Published: December 2007

Abstract
This paper presents the results of an industry consortium established to understand and allow modeling of the fluid-leakoff process in hydraulic-fracturing applications. Fluid-loss data was measured with a state-of-the-art experimental setup that included fluid preconditioning loops for high-shear and low-shear regimes and a novel cell design that minimizes flow irregularities. Previous papers 1,2 have presented the effects of experimental designs, shear rate, permeability, and pressure on the fluid loss of water-based systems with no fluid-loss control aids. This paper presents the results of experiments that used linear hydroxypropylguar (HPG) gel and HPG/borate fluid systems with various types of hydrocarbon and/or particulate fluid-loss additives in similar testing procedures.
This study has found that each fluid-loss additive has an optimum performance range that depends on the fluid type and core permeability. Hydrocarbon fluid-loss additives, even at low concentrations (0.5% by volume), were found to be effective in reducing the filter-cake permeability of crosslinked gel systems in low-permeability cores (less than 10 md). Unless effective particulate fluid-loss additives were also used, hydrocarbon additives were ineffective in reducing the spurt loss or the filter-cake permeability in higher-permeability cores. Since hydrocarbon additives principally work on reducing the filtercake permeability, they exhibited more shear-rate sensitivity than "neat" fluids. However, in contrast to the pressure-independent behavior of neat fluids, the fluid-loss coefficients with hydrocarbon additives increases with pressure.
Particulate fluid-loss additives were very effective in reducing spurt loss, especially for low-viscosity fluids. Inert and oil-soluble materials out-performed most water-soluble particu lates, particularly in higher-permeability formations. An investigation of the particulate particle size indicated that the optimum particulate size distribution must incorporate particles one to two times larger than the peak core pore size. Shear rate did not alter the particulates' effectiveness in controlling spurt loss; however, it did affect the filter-cake properties (Cw and vn values) in most situations similar to neat fluids. The addition of particulates did not change the compressibility of filter cakes that was observed earlier with neat fluids. The spurt loss with inert particulate additives was relatively independent of pressure, in contrast to the pressure-dependent spurt loss of neat fluids.
Understanding Proppant Closure Stress
Authors: Schubarth S. K. , Cobb S. L. , Jeffrey R. G. 
Published: December 2007

Abstract
The effect of closure stress on fracture conductivity has been well documented by laboratory measurement. Common industry practice for estimating closure stress on proppant in the field is to subtract flowing bottomhole pressure from the estimated in-situ stress of the pay interval fractured. This paper proposes that the closure stress on proppant in a fracture can be significantly higher than common estimations due to the influence of the bounding layers and the elastic response of the formation acting on the proppant. In this paper we will review past literature on fracture propagation, fracture conductivity and proppant placement and demonstrate the impact that increased proppant stress due to bounding layers can have on fracture conductivity and ultimately production.
Effects of Pressure Drop in Horizontal Wells and Optimum Well Length
Authors: Penmatcha V. R. , Arbabi S. , Aziz K. 
Published: December 2007

Abstract
As the length of a horizontal well is increased, its contact with the reservoir increases. But at the same time, the resistance to flow in the well also increases, which has a direct negative effect on the productivity of the well. The overall performance of a horizontal well depends on the balance of these two opposing factors. No reliable tools are currently available that account for both these factors in the evaluation of horizontal well performance. A semi-analytical well-model is developed which can quantify the effects of both single phase oil and two-phase oil/gas flow pressure loss in the well on the overall well performance. The model is quite flexible and can incorporate any friction factor correlation. A methodology is developed to show the effects of various reservoir, fluid and well parameters on well productivity. We demonstrate that ignoring frictional effects could lead to unrealistically higher production estimates and low breakthrough times for water or gas. As a result of pressure drop in the well, breakthroughs occur first at the heel of the well. A methodology is also developed to calculate the optimum horizontal well length.
Measured Rodstring/Tubing Wear and Associated Side Loading
Authors: Long Scott W. , Bennett Donald W. 
Published: December 2007

Abstract
Ever since the first installation of steel sucker rods in production tubing, the Petroleum Industry has been aware of rod string and tubing wear. The associated rod string and tubing wear with this artificial lift system continues to have an impact on the ability to economically produce oil and gas.
The downstroke phenomenon of sucker rod string compression, buckling, sucker rod/tubing contact and associated sucker rod/tubing wear is becoming more clearly defined (see References 1,2, and 3) throughout the petroleum industry.
This paper will provide the Petroleum Industry with a more accurate understanding of sucker rod and tubing wear resulting from sucker rod side loading initiated by downstroke sucker rod buckling. This paper will present a description of test equipment and test parameters resulting in the following: Calculated cycles to 100% tubing wall loss vs. side loading.Calculated cycles to 100% sucker rod diameter loss vs. side loading.Calculated cycles to 100% sinkerbar diameter loss vs. side loading.
A better understanding of sucker rod and tubing wear will provide the Industry with better sucker rod string design guidelines. Use of these guidelines can reduce costly sucker rod and tubing wear and failures that impact the ability of the Petroleum Industry to economically produce oil and gas.