bluuebunny/crossref_metadata_2025_split huggingface dataset:
Two Different Water Shutoff Applications in a Poorly Consolidated Sandstone Reservoir with Strong Waterdrive
Authors: Prado M. , Palencia J. , Reyna M. , Fernández I. , Espinoza J. , Rauseo O. 
Published: December 2007

Abstract
This paper describes the design, operation and results of two different water shut-off applications in a field located in Southern Venezuela. The production mechanism of the main reservoirs of the studied field is strong water drive. The presence of the active aquifer, the geological complexity and the high drawdown produced by the electric submersible pumps, it has abruptly increased the water-oil ratio causing premature shutting.
The limitations of the traditional water shut-off applications in this field are the slotted liners gravel pack completion of the wells, the high formation permeability and the presence of caverns in the near wellbore due to sand production. A project was proposed to evaluate the gel technology, including the diagnosis of the high water production source and the design of applications to overcome these limitations.
Two mayor causes were detected, water channeling through high permeability strakes at the top of the reservoir where thin shale barriers are present; and rapid coning at the base, where the sand has a higher vertical permeability and the water-oil contact is present.
According to this, two different applications were designed and successfully evaluated in three wells of the field, two of them correctives and the other preventive. Relevant aspects of the design are the use of an elastic gel system of high consistency with easily controlled gelling times; and the use of placement techniques to guarantee the seal of offensive zones and the protection of the productive ones. In the corrective treatments the gelant was injected using mechanical isolation and the total volume was pumped in two batches, while dual injection was carried out in the preventive application. A reduction of 3000 barrels per day of water production was obtained, as well as a substantial increase in the productive life of the three wells.
Development and Field Application of a High Performance, Unstructured Simulator with Parallel Capability
Authors: Shiralkar G. S. , Fleming G. C. , Watts J. W. , Wong T. W. , Coats B. K. , Mossbarger R. , Robbana E. , Batten A. H. 
Published: December 2007

Abstract
We present the development and field application of a high performance, unstructured simulator with parallel capability. The simulator integrates the subsurface with the surface network model. An earlier paper1 described the integrated surface model. This paper emphasizes the subsurface model and multi-field application.
Object oriented concepts are used to gain flexibility, using efficient data structures to retain performance. The reservoir computational domain is composed of "Grids" and inter-grid connection structures that form the basis for parallelization. The Grids are ensembles of cells that are unstructured in general, and need not be contiguous.
Besides unstructured (PEBI) grid simulation capability, this framework also forms the basis for simulating multiple, independently gridded reservoirs, with shared surface facilities, an important business problem. Earlier multireservoir workflows use LGR's in a fixed grid, making changes like adding a new reservoir difficult. Alternately, they use multiple processors with imperfect resolution of inter-reservoir coupling. In this paper, use of grid objects greatly facilitates the workflow; reservoir grids can be easily added or changed. Simultaneous solution of multi-reservoir and facilities system ensures consistent coupling throughout.
Kinetics and Equilibria of Calcium Lignosulfonate Adsorption and Desorption onto Limestone
Authors: Bai B. , Grigg R. B. 
Published: December 2007

Abstract
Equilibria and kinetics are two basic ingredients for the proper understanding of adsorption and desorption processes between surfactants and rocks. The adsorption and desorption of calcium lignosulfonate (CLS), commonly used as a sacrificial agent in surfactant-based EOR processes, has been studied.
Kinetic results showed that adsorption and desorption are both time-dependent, not instant. Both adsorption and desorption were characterized by a biphasic pattern: a fast step followed by a slow step. Apparent adsorption and desorption rate coefficients were determined by a second-order kinetic model. Desorption is a much slower process than adsorption. Desorption is an un-equilibrium process under normal reservoir flow rate conditions.
Equilibrium results show that CLS adsorption and desorption onto limestone can be described well by the Langmuir isotherm over the tested CLS concentration range, and that increasing concentration increases adsorption density. There is significant hysteresis between CLS adsorption and desorption isotherms. Increasing flow rate slightly decreased CLS equilibrium adsorption. Increasing both NaCl and CaCl2 concentrations increased adsorption density; however, CaCl2 had a much greater impact on the adsorption. Increasing pH decreased CLS adsorption onto limestone. The reasons for the effects of the different factors are elucidated in this paper.
Surfactants as Flow Improvers in Water Injection
Authors: Oskarsson H. , Uneback I. , Hellsten M. 
Published: December 2007

Abstract
In many cases it is desirable to increase the flow of injection water when an oil well deteriorates. It is very costly in offshore operation to lay down an additional water pipe to the injection site. Flow improvers for the injection water will thus be the most cost-effective way to increase the flow rate. During the last years water-soluble polymers have also been applied for this purpose. These drag-reducing polymers are however only slowly biodegraded which has been an incentive for the development of readily biodegradable surfactants as flow improvers for injection water.
A combination of a zwitterionic and an anionic surfactant has been tested in a 5.5 inch, 700 m long flow loop containing sulphate brine with salinity similar to sea water. A drag reduction between 75 and 80% was achieved with 200 ppm of the surfactant blend at an average velocity of 1.9 m/s and between 50 and 55% at 2.9 m/s. Due to the self-healing properties of the drag-reducing structures formed by surfactants, these may be added before the pump section - contrary to polymers which are permanently destroyed by high shear forces.
Design and Deployment of Maximum Reservoir Contact Wells With Smart Completions in the Development of a Carbonate Reservoir
Authors: Afaleg N. I. , Pham T. R. , Al-Otaibi U. F. , Amos S. W. , Sarda S. 
Published: December 2007

Abstract
This paper presents an in depth study for a field-wide application of Maximum Reservoir Contact (MRC) wells along with smart well completions complemented by openhole expandable tubular to develop Haradh Increment-3, the southernmost area of the greater Ghawar Field. The reservoir represents a heterogeneous matrix permeability background, with geological discontinuities such as faults, fractures, and stratiform high permeability streaks. An MRC is a multi-lateral horizontal well with more than 5 km. of total contact with the reservoir rock(1,2). This paper illustrates how an MRC well with smart completion was designed with objectives for higher productivity, better pressure transfer between laterals, delay in water encroachment by down hole control, and higher cumulative production. The design was based on highly detailed dual porosity and dual permeability cross-sectional, sector and full field simulation models in addition to field trials.
Interwell Tracer Tests: Lessons Learned From Past Field Studies
Authors: Du Y. , Guan L. 
Published: December 2007

AbstractThe application of interwell tracer tests is becoming increasingly important to the petroleum industry. Interwell tracer tests, as a proven and efficient tool, have been used to investigate reservoir flow performance and reservoir properties that control gas and water displacement processes. Tracer data have been used to reduce uncertainties attributed to well-to-well communications, vertical and horizontal flow, and residual oil saturation.This paper describes the development of interwell tracer tests in the petroleum industry, from the first qualitative tracer test in the 1950s to the latest quantitative tracer test in the 2000s. The results of our study indicate that poor sampling is the most frequently encountered problem that leads to a failure tracer test and only a small number of interwell tracer tests have employed the advanced numerical modeling methods to analyze the test data. In addition, the interwell tracer tests in the petroleum industry are not well studied as hydrology industry. Therefore, the interwell tracer tests interpretation methods deserve to be paid more attention, so that petroleum engineers can take better advantage of the costly interwell tracer tests.
Asphaltene Adsorption Isotherm in the Pores of Reservoir Rock Cores
Authors: Alkafeef S. F. , Smith A. L. 
Published: December 2007

Abstract
New data relating to the adsorption of asphaltenes on rock pore surfaces are reported. The data were obtained from the measurements of the electrokinetic potential of several different sandstone core samples with asphaltenic oils. The adsorption of asphaltene is accompanied by a numerical reduction in the (negative) surface potential of the pore walls, eventually stabilizing at a small positive potential, attributed to the asphaltene itself.
After increasing to around 30% of the pore radius, the asphaltene adsorbed layer thickness stopped growing either with time or with concentration of asphaltene in the flowing liquid. This behaviour is attributed to the effect on the disjoining pressure across the adsorbed layer described by Derjaguin and Churaev1.
Alternative hypotheses involving asphaltene adsorption isotherm have been investigated. A theoretical treatment advanced describing particle adsorption in the same terms as molecular adsorption and the Langmuir isotherm, with the free energy of asphaltene adsorption on the rock surface (modeled on silica), calculated on the basis of van der Waals attraction. Acceptable agreement was obtained with the electrokinetic measurements.
Application of Adaptive Wavelets To Improve Computational Performance of Kriging
Authors: Yuwono I. P. , Susanto A. , Soesianto K. , Tran T. T. 
Published: December 2007

Abstract
Kriging is a geostatistical estimation tool that has widespread applications in environmental, hydrologie, and petroleum applications. Kriging requires solution of a linear system of equations, often called the kriging or normal equations. The speed of this matrix inversion is dependent on the size of the kriging system; more input data results in larger kriging matrix which takes longer to invert.
Wavelet transform, due to its compact support and orthogonality property of the basis functions, holds some promise to improve computational performance of kriging. An interesting property of wavelet is that the wavelet transform of a dense matrix gives rise to a sparse matrix. The CPU cost of inverting the transformed sparse matrix can be much less than that for the original dense matrix, depending on the degree of sparsity and the bandwidth of the transformed matrix.
This paper presents a study on the application of wavelet transform to improve the computational performance of kriging. Conventional "off-the-shelf wavelets and wavelets derived from an adaptive process were used and their relative performances are documented.
Fit-for-Purpose Production Logging: Memory or Real-Time?
Authors: Al-Muthana A. S. , Ma S. , Al-Hajari A. A. , Aboelnaga S. 
Published: December 2007

Abstract
Memory production logging (M_PL) with slick-line offers some advantages over real-time production logging with electric line which include simpler control or management of well pressure, a smaller footprint for operating equipment, and in general, less cost. Thus, it is inimitable for wells with high flowing wellhead pressure such as deep gas wells and wells with rig-up space restrictions such as small offshore platforms and/or jackets. However, one of the main drawbacks for M_PL is that its data can't be quality controlled in real-time, which is important if real-time decisions need to be made while logging. Therefore, running M_PL is a fit-for-purpose choice and well selection and job planning is critical for the success of running M_PL jobs.
In this study, five field examples of M_PL are presented and compared with well data. These examples include onshore and offshore wells, oil/water and deep gas wells, wells with cased-hole and open-hole completions, and vertical and deviated wells. Recommendations and guidelines of running M_PL are presented.
Souring of Reservoirs by Bacterial Activity During Seawater Waterflooding
Authors: Maxwell S. , Spark I. 
Published: December 2007

Abstract
Waterflooding with seawater for pressure support is to be employed in many of the deepwater Gulf of Mexico fields. Seawater flooding has been employed in the North Sea oilfields for over thirty years and, therefore, this region serves as a valuable source of case histories of the problems that can be encountered. It is now accepted that due to inadequate control of sulfate-reducing bacteria (SRB) the majority of the North Sea seawater floods resulted in souring of the reservoir.
In some cases, hydrogen sulfide concentrations in the production wells have risen to the point where either the well has had to be shut-in or sulfide scavenging chemicals have had to be applied in order to prevent excessive corrosion. Where souring was not predicted, some production systems have had to be upgraded for sour service materials. These remedial actions have resulted in very significant unplanned costs. Although there is no formal published economic data, it is clear that over the history of the North Sea, the cost of lost production and remedial action has been $ 100's millions.
This paper reviews the North Sea experience and discusses the models developed in an attempt to predict reservoir souring. The paper discusses the application of chemical biocides attempted to kill the SRB; the injection of nitrate to stimulate other bacterial populations to compete with the SRB for essential nutrients; and the potential for sulfate removal technologies to reduce sulfate and minimise sulfide production. A strategy for the development of future models to help predict and avoid reservoir souring in future seawater floods is also discussed.
Prediction of Scale Inhibitor Squeeze and Return in Calcite-Bearing Formation
Authors: Kan A. T. , Fu G. , Tomson M. B. 
Published: December 2007

Abstract
Significant progress has been made toward developing a quantitative understanding of the inhibitor/rock interaction. In this study, four common oil field inhibitors (three phosphonates and one polyacrylate) are compared in totally contained squeeze simulation using calcite, a calcite-rich chalk, a calcite and clay containing formation material and a sandstone formation material with predominantly quartz and minimum calcite. Similar inhibitor return behavior was observed in both calcite-rich and low calcite rock, suggesting that calcite is the primary solid responsible for phosphonate retention and clay plays a secondary role in phosphonate retention. The retention of the polymer is much lower than phosphonates. The data show that BHPMP provides the highest squeeze life at MIC &gt; 50 mg/L. DHPMP is the preferred inhibitor at MIC between 1 and 50 mg/L and NTMP is the preferred inhibitor at MIC &lt; 0.3 mg/L. With DTPMP and BHPMP we have found that it is possible to predictably obtain a long and high concentration of inhibitor return. This is exactly what is often needed during, e.g., seawater breakthrough to control barite scale formation. This kind of predictable treatment should be valuable for onshore wells that produce from multiple incompatible zones and to offshore flow assurance issues wherein it is critical to have the ability to control scale during seawater breakthrough. We are presently incorporating these findings into the software for squeeze design, SqueezeSoftPitzer and doing the necessary testing to be certain of the predictability of variations in brine composition and T, P, and TDS.
Microemulsion Reduces Adsorption and Emulsion Tendencies in Bradford and Speechley Sandstone Formations
Authors: Paktinat J. , Pinkhouse J. , Williams C. , Penny G. S. 
Published: December 2007

Abstract
The primary purpose of nonionic surfactants used in well stimulation is to reduce surface tension, contact angle and emulsion tendencies. However, many of these chemicals adsorb rapidly into the surface of the sandstone formation, reducing their effectiveness in reservoir treatments.
This study describes the laboratory and field case studies of various surfactants used in the oilfield. Several different surfactants including ethoxylated linear alcohol, nonyl phenol ethoxylate and a microemulsion system were investigated to determine their adsorption properties when injected into a laboratory sand packed column. A laboratory simulated comparison study of an ethoxylated alcohol and microemulsion was used to determine their water recovery properties from gas wells.
Field data collected from Bradford and Speechley sandstone formations confirms experimental sand packed column and core flow investigations. Reservoirs treated with microemulsion fluids demonstrate exceptional water recoveries when compared with conventional non-emulsifying surfactant treatments. These investigations and presented field data may be used to optimize chemical treatments. The primary objectives of this study are focused to include: Comparison studies of the microemulsion system with conventional ethoxylated surfactants commonly used in the oilfield to determine their adsorption properties into the proppant pack, surface tension and water recovery.Experimental data comparing effectiveness of conventional surfactants and microemulsion in non-emulsification and regain permeability tests.Present case studies where microemulsion treatments have improved water recoveries in treated gas wells.
This paper describes laboratory methods and case histories supporting this investigation. Furthermore, field data collected from several gas wells stimulated in the Bradford and Speechley formations illustrates the microemulsion fluid exhibiting an advantage over the conventional surfactant treatments when water recovery and increased well productivity are of concern to the operator.
Asphaltenes Pipeline Cleanout: A Horizontal Challenge for Coiled Tubing
Authors: Torres C. A. , Treint F. , Alonso C. , Milne A. , Lecomte A. 
Published: December 2007

Abstract
Crude produced in the North of Monagas Estate, East Venezuela, has a high asphaltene content, which comes out of solution in both the wellbore tubulars and pipeline. This can eventually lead to complete plugging of the pipeline. This increases the cost of maintaining production because of the need to periodically remove these organic deposits. In a specific case, 9 km of 8-5/8-in. outside diameter (OD) production pipeline was successfully cleaned out using 2-in. OD coiled-tubing (CT) to regain pipeline production. As there is limited literature or documentation on the use of CT for this specific application, the operator and the service company established a joint team to do the feasibility study and engineering. Some of the key points were; the design of a frame to lay down the injector head, define the entry points along the pipeline, the selection of the bottomhole assembly (BHA), and fluids to use. Other issues were the measurement of stresses (push/pull) on the CT so that the CT could be run as far as possible in the pipeline without damaging either the CT or the pipeline. The pipeline was successfully cleaned, the CT being run seven times from five different entry points in the pipeline. This resulted in savings of USD 1 million for the operator and significantly reduced the time to recover normal production in the pipeline.
Mexico's Influence in the World's Oil and Gas Supply and Demand
Authors: Rojas S. , Saputelli L. , Economides M. 
Published: December 2007

Abstract
As of the end of 2004, the share of natural gas in the total world energy demand was approximately 23% having surpassed coal in 2002 and, for the first time, becoming the number two fuel behind oil. Buoyant estimates suggest that the natural gas market share will increase dramatically by the year 2020.
Natural gas demand will be greatly influenced by the developed economies, namely the United States, Japan and Europe, the emerging energy super-consumer China and the rapidly developing economies of some of the world's most populous nations such as Brazil and Mexico.
This paper focuses on Mexico. Mexico's trillion-dollar economy has resulted in its becoming the second largest US trading partner. The purpose of this work is to generate a framework wherein Mexico can develop its internal energy market and still be a strategic partner for energy with the United States. Strategies such as (a) interconnecting pipelines with the United States, (b) exporting LNG, (c) increasing the gas-to-oil ratio from its existing portfolio, and (d) increasing dry-gas exploration efforts are some of the different options that are considered and outlined in this work.
How Minimum Inhibitor Concentration (MIC) and Sub-MIC Concentrations Affect Bulk Precipitation and Surface Scaling Rates
Authors: Graham A. L. , Boak L. S. , Neville A. , Sorbie K. S. 
Published: December 2007

Abstract
Conventional testing of scale inhibitors (SI) usually focuses only on the inhibition of bulk depositional processes, e.g. in jar tests of inhibition efficiency. In previous work, we have extended the study of inhibition efficiency to examine both bulk and surface depositional processes and their inhibition using scale inhibitors. Where the minimum inhibitor concentration (MIC) is well exceeded, both bulk and surface scaling are prevented. However, we have demonstrated that the presence of an inhibitor, at levels marginally below the MIC, actually enhances surface scale growth over a range of temperatures typically encountered in the production system. Where this precise concentration lies with respect to the MIC is not generally known for scaling systems and it is therefore difficult to predict where potential problems with sub-MIC scale inhibitor levels would occur.
An experimental programme has been conducted to assess the efficiency of PPCA in inhibiting barium sulphate scale formation in the bulk solution and on a metal surface over a range of concentrations and test temperatures. The concentration range tested was chosen (a) to allow identification of the MIC at which both surface and bulk scale formation is controlled and, (b) to establish where potential problems with enhanced surface scaling arise at sub-MIC levels. The results obtained from this study have allowed trends in surface and bulk inhibition to be established and the region of sub-MIC concentrations where surface scaling is enhanced to be identified for three temperatures. We summarise our results using some simple schematic models of the bulk and surface scaling regimes and the corresponding inhibition process.