bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Thorough Investigation of Cleanup Efficiency of Hydraulic Fractured Wells Using Response Surface Methodology
Authors: Ghahri P. , Jamiolahmady M. , Sohrabi M 
Published: June 2011

Abstract
Poor cleanup efficiency of injected fracture fluid (FF) has been considered as one of the main factors contributing to the poor performance of many hydraulically fractured wells (HFWs). Limited parametric studies evaluating the efficiency of FF cleanup have not embarked on a much needed extensive investigation of variation of all pertinent parameters.
In this work we present the results of over 130000 simulations of the process, for a HFW model that was constructed using a reservoir simulator. A computer code has been developed, which automatically, read input data, link the injection and production periods and create the output data. The impact of 16 parameters describing the gas and FF effective permeability of matrix and fracture, pressure drawdown, capillary pressure, and porosity have been studied for two injected FF volume values. Different statistical experimental design methods have been used to sample a reasonably wide range of variation of pertinent parameters. Linear and quadratic response surface models have been used to map the gas production loss (GPL), compared to 100% cleanup case.
The results indicate that GPL is mainly controlled by parameters related to FF cleanup inside the fracture particularly fracture permeability. In some cases increased back flow of FF from matrix into fracture increases GPL. As production continues, the impact of matrix permeability and gas exponent of Corey type relative permeability curve in the matrix become more pronounced. The fracture residual gas saturation and matrix gas end points have negligible effect. The relative importance of pertinent parameters is less for lower FF injection volume and especially at higher production periods. These practical findings can be used to make a better decision on the performance of such costly operations, suggested methods for improving the cleanup efficiency of FF and the optimum fracture design practices.
Hydrajet Fracture Stimulation Technique Used To Rejuvenate Three Wells In Mature Offshore Oil Field Congo - Case History
Authors: Rhodes D , Orski K , N'Gouma C , Guittiene P 
Published: June 2011

Abstract
The Tchendo oil field, located 18 miles off the coast of the Republic of Congo has been operated since 1991, by Total E&P Congo in approximately 100 meters of water.
The wells are deviated (more than 60 degree), completed with production casing as large as 9 5/8", and partially to extensively perforated, with poor to unknown cement quality.
The wells are produced by electrical submersible pumps.
One of the three reservoirs, the Sénonien reservoir, is an intercalation of metric carbonate layers with thicker (20 to 30 meters) but poorer quality sandstones. (0.1 to 10 mD). It is shallow (450 mVSS) and depleted (0.37 psi/ft).
Various attempts to enhance productivity were tested since initial production, including selective or extensive perforation, acid treatments on carbonate layers, and one open hole horizontal well.
However, a large part of the original oil in place still remains in the reservoir.
Therefore, it was decided to evaluate the potential of hydraulic fracturing stimulation treatments to rejuvenate the existing wells.
The well characteristics made conventional methods of hydraulic fracturing either cost prohibitive or impossible.
A first test of the hydrajet propped fracturing technique was performed in 2008, followed in 2010 by two other pilot treatments.
This paper details the lessons learned in using this innovative technique to stimulate the three wells and demonstrates limitations of the technique associated with the existing wellbore conditions. This paper will serve as a guide for revitalizing the Tchendo field and possibly other mature oil fields with low to moderate permeability.
Recent Advancements in Hydrajet Perforating and Stimulation Provide Better Penetration and Improved Stimulation
Authors: Surjaatmadja Jim B. , Gijtenbeek Klaas Van 
Published: June 2011

Abstract
The use of hydrajetting for perforation of wells has been commonplace since the 1960s. During those early years, jetting success was consistently demonstrated. While the quality of hydrajetted perforations is admittedly better, they are generally costly to implement. Horsepower requirements and logistics are a few obstacles associated with this process in terms of cost reduction. With the birth of hydrajet-assisted fracturing (HJAF) methods in the last decade; however, these obstacles were immediately overcome when hydrajet perforating became an integral part of the stimulation process. Hence, the system quickly transposed into an effective, time-saving stimulation treatment method. Within a few years, another hydrajet perforating + frac stimulation process was developed, where coiled tubing (CT) was used for hydrajetting only, and afterward the frac stages were all pumped down the annulus of the CT and the casing, with sand plugs used to seal off after the fracture stimulation treatment to allow more stages of the "hydrajet perf + frac" applications up the well in either vertical or horizontal wells. Soon, an increased level of using hydrajet perforating as a stand-alone service also became far more common.
As these hydrajetting processes become increasingly popular, intensive studies are needed to continually improve the performance of the tools and processes. For example, increased proppant volumes combined with an increased number of fracture stages or more perforations to be placed in one trip quickly mandates creation of higher life-expectancy tools. Improving the performance requires improving the hydrajetting-technology knowledge; in addition, well completions often dictate the size limitation or design of the jetting tool itself, which in turn dictates the pumping limits of the job. Lastly, new jetting technologies might have to be created to define the optimal quality of proppant which should be used in oilfield applications.
This paper offers an in-depth study on improving our jetting expectancies and performances by knowing the various behaviors of abrasives or proppants when they are jetted through nozzles and under other conditions. This data will help us in optimizing the jetting process itself. Results of extensive laboratory tests on different types of proppant are presented which provides a much better understanding of the limitation of various proppant types. Knowing these limitations is a key to successfully using hydrajetting for stimulation purposes or maximizing hydrajet effectiveness when perforating or cutting. Examples of easy-to-use computational tools for such purposes are also presented.
Improved Oil Recovery for Fractured Granite Basement Reservoirs: Historical Lessons, Successful Application, and Possibility for Improvement
Authors: Dang Cuong T. , Chen Zhangxin , Nguyen Ngoc T. , Bae Wisup , Phung Thuoc H. 
Published: June 2011

Abstract
Discovery and development of naturally fractured reservoir has increased dramatically during past 15 years because more fractured reservoirs are being developed as production from conventional reservoirs is declining. Many oil reservoirs in the world are naturally fractured, but relatively little research has been done on the use of advanced oil recovery methods. In addition, very little success has been achieved in increasing the oil production from these complex reservoirs. Some laboratory experiments have been done to investigate the use of IOR methods for fractured reservoir; however, the results of these studies hard to interpret and to apply to field scale predictions. Thus, it is urgent and necessary to collect the experiences from previous successful researches to reduce the risk level.
This study addresses methods and recent advances to enhance oil production in fractured granite basement reservoir of White Tiger field. It is the biggest fractured reservoir up to now on the continental shelf of Vietnam. But, the geological characterization of this reservoir is extremely complex with high uncertainty and challenge in production strategies. Therefore, a numerous of studies were conducted to develop the favorable
IOR techniques including advanced emulsion acidizing stimulation, microbial enhanced oil recovery methods, artificial water buffer, directional drilling application, and gel treatment for basement reservoir. These special approaches were achieved many precious successes in increase the recovery factor from 29% to 44.33% and would be significantly extended the life of reservoir. Regarding to the unique characterization of White Tiger field and lack of experiences of producing in fractured basement reservoir, the lessons learned and experiences gained from past 20 historical years are a worthy case study for both current and future development of NFR in the world.
Translation of New Experimental Test Methods for the Evaluation and Design of Shaped Charge Perforators to Field Applications
Authors: Hardesty J. , Bell M. R. , Clark N. G. , Zaleski T. , Bhakta S. 
Published: June 2011

Abstract
Perforation performance evaluation has come under scrutiny in several recent publications. For most shaped charge perforators sold, performance is evaluated in cement targets, from which downhole performance is extrapolated. This method has been shown to generally over-predict downhole performance, with broad implications for perforating systems and shaped charge design, and well completion design.
Advanced test methodologies are an order of magnitude more complex than the simplified cement penetration tests. This paper details a set of experimental shaped charge development programs with specific geometry and/or flow performance requirements and examples of their corresponding field performance. Tests have been performed with full simulation of single shot perforation, and simplified perforating simulations into stressed rock. Results are reported for shale, sandstone, and high permeability sandstone targets. Designs tested include both conventional and reactive shaped charges.
In one example from 2008-2009, CNX completed fourteen wells using both conventional and reactive perforating systems to evaluate any impact on completion performance. Stimulation and production data have been analyzed for 81 stimulation stages. When comparing wells perforated with reactive shaped charges to conventionally perforated offsets, a reduction in breakdown pressure gradient of between 13% and 29% is observed. Subsequent treating pressures are reduced by 6% to 15%. The wells perforated with reactive shaped charges have also exhibited significantly slower productivity decline over the first nine months.
In addition, near-perforation permeability has been mapped using advanced digital imaging techniques. This allows the grain structure and permeability distribution of a perforated rock target to be accurately measured as a function of radial distance away from the perforation wall and longitudinal position along the perforation tunnel. The paper describes important improvements in our understanding of perforation damage distribution, and provides techniques for use in conjunction with API RP 19B Section 2 and 4 tests to design perforating shaped charges and systems.
Development and Testing of a Perforation Plugging Treatment Designed to Limit Reservoir Crossflow
Authors: Sanders Mark W. , Watson Russell B. , Viste Patrick , Wylie Graeme , Radcliffe Paul 
Published: June 2011

Abstract
Permanently isolating one or more producing zones from another is occasionally required as a means of maximising net flow from a producing well. In this case, zonal isolation is required to minimise the crossflow of a high-temperature depleted, perforated, upper sand section from a lower, higher-pressured zone targeted for future production. Any chemical isolation treatment applied to the upper sand perforations must withstand not only the high temperature involved, but also differential pressures in the region of 300 bar (4,351 psi). Following the treatment, flow would then be initiated from the lower sands by removing an isolating sand plug. By effectively plugging a formation, crossflow between the two producing sections of the well would be minimised, the degree of which would be dependent upon the efficiency of any final perforation seal.
The treatment incorporates specially sized and selected particles designed to invade the matrix permeability, a temperature-triggered bonding agent and ingredients which ensure that the treatment reaches the target. The mixture of the bonding agent and the sized particles creates a well defined seal within the perforation tunnel.
Both the development and testing of the perforation plugging treatment incorporated high-temperature, high-pressure permeability plugging tests in combination with innovative coreflood testing techniques. Detailed analysis of the treatment, cores and perforations with electron microscopy and computed tomography (CT) allowed the initial idea to be tailored and perfected for the specifics of the field application.
This paper will discuss the laboratory development of a perforation plugging treatment designed to limit reservoir crossflow under conditions of high-temperature and high-differential pressures.
Engineered Particle-Size Distribution while Drilling Helps Minimize Wellbore Damage in Sandstone Reservoirs
Authors: Mohamed Monir 
Published: June 2011

Abstract
Inducing formation damage in sandstone reservoirs through poor drilling fluids management can impair well productivity. A detailed mud-management plan that addresses fluid design and particle-size monitoring can help minimize formation damage and improve well productivity. This management plan was demonstrated successfully on 29 wells where the operator implemented an engineered oil-based drill-in fluid (DIF) and a particle-size distribution (PSD) analyzer in the field while drilling the reservoir.
The oil-based DIF was formulated with a 70/30 oil/water ratio and then treated with sized calcium-carbonate bridging agent. The PSD analyzer was used continuously while drilling to monitor and maintain optimal PSD values in the DIF. Maintaining controlled ROP was essential while drilling a reservoir section along with the hourly addition of sized calcium carbonate and efficient solid control equipment running all the time while drilling. Overbalance pressures were also minimized to reduce the risk of differential sticking.
To achieve better bridging results, D90, D50, and D10 particle-size distributions were maintained in the programmed range throughout the entire reservoir section. Upon reaching total depth (TD), the bottomhole assembly was changed and the entire section was reamed to TD. A wiper trip was done to casing shoe then tripped back to bottom without pumping to simulate hole conditions that would occur while running screens.
Once the open hole was deemed in good condition, the well was displaced to a solids-free invert mud maintained at the same density as the DIF. This fluid was circulated over a 265-mesh screen prior to running the screens to ensure all fine sand and excess filter cake had been removed.
Testing results indicated minimum skin damage and good stable production rates.
Acid Placement in Acid Jetting Treatments in Long Horizontal Wells
Authors: Sasongko H. , Zhu D. , Hill A. D. 
Published: June 2011

Abstract
In the Middle East, extended reach horizontal wells (on the order of 25,000 feet of horizontal displacement) are commonly acid stimulated by jetting acid out of drill pipe. The acid is jetted onto the face of the openhole wellbore as the drill pipe is withdrawn from the well. The jetting action helps to remove the drilling fluid filter cake and promote the acid to penetrate into the formation and form wormholes to stimulate the well. However, with very long sections of wellbore open to flow, the acid placement and subsequent wormhole distribution and penetration depths are uncertain.
We have modeled this process using a comprehensive model of acid placement and wormhole propagation in a horizontal well. We presume that the acid jetting tool removes the drilling mud filter cake, so that no filter cake exists between the end of the drill pipe and the toe of the well. Correspondingly, we assume that there is an intact, low-permeability filter cake on the borehole wall between the end of the drill pipe and the heel of the well. The drill pipe is modeled as being withdrawn from the well during the acid jetting treatment, as is done in practice.
The acidizing simulator predicts the distribution of acid and the depths of wormholes formed as functions of time and position during the acid jetting treatment. The model shows that the acid jetting process as typically applied in these wells preferentially stimulates the toe region of the horizontal well. Comparisons of the simulation predictions with published data for acid jetting treatments in such wells showed good general agreement. Based on the simulation study, we present recommendations for improved acid jetting treatment procedures to improve the distribution of acid injected into the formation.
Well Productivity Decline due to Fines Migration and Production: (Analytical model for the Regime of strained particles accumulation)
Authors: Bedrikovetsky Pavel , Vaz Alexandre , Machado Fernando , Zeinijahromi Abbas , Borazjani Sara 
Published: June 2011

Abstract
Well index decline has been widely observed for oil, gas and artesian wells producing the reservoir fines. It has often been explained by the lifting, migration and subsequent plugging of pores by fine particles, which have been observed in numerous core flood tests. In this work, the basic equations for the detachment of fine particles, their migration and size exclusion, causing the rock permeability decline, have been derived. The analytical model, developed for the regime of steady state production with gradual accumulation of strained particles, show the linear skin factor growth vs time and vs the amount of produced reservoir fines.
Pre-Crosslinked Pills Provide Efficient and Consistent Fluid Loss Control
Authors: Gibson Jacob D. , Javora Paul H. , Adkins Mike 
Published: June 2011

Abstract
Solids-free completion brine is the ideal fluid to complete wells employing sophisticated downhole tools with limited metal-to-metal clearances, as well as those requiring sand control operations. Unfortunately, clear brines have no inherent control of fluid loss, leading to poor completion performance, increased formation damage and well control issues, all of which contribute to lost production time. More specifically, fluid engineers have reported greater formation damage due to increased brine-formation interaction while reporting losses as high as 100 barrels per hour. Critical evaluation of these factors coupled with the complexity and cost of today's projects, reinforces the need for chemical systems that immediately and effectively control fluid loss with minimal formation invasion.
Cross-linked pills prepared at the rig site gained industry-wide acceptance by reducing fluid loss to just a few barrels per hour. However, deficiencies of rig-prepared pills occur, such as loss of incompletely cross-linked material into the formation, pre-mature cross-linking that inhibits delivery, significant time needed to make a quality pill, and associated HSE issues that limit the manufacturing of pills at the rig. As a result, researches developed second-generation solids-free FLC pills, which feature pre-cross-linked polymer. This second-generation system provides new dimensions in pill technology that further improve the efficiency and consistency of traditional rig-prepared FLC pills.
This paper presents methodology for using this new class of pre-cross-linked solids-free FLC pills as well as data defining their properties and characteristics including significant reduction in rigsite HSE issues and superior quality control conducted at the manufacturing plant. This paper also presents field case histories demonstrating the use and effectiveness of optimized, fully pre-cross-linked FLC pills ready for immediate use at the rig.
Development of Small Field in Malaysia Using Cost-Effective Open Hole Sandface Completion Technologies – A Case Study
Authors: Safiin N. , Ahmad Mahdzan A. A. , Nik Khansani N. Z. , Ghazali N. M. , Zainal Abidin O. , Zeidan A. A. , Elliot C. , Khalid M. Zaidan , Regulacion R. , Domia P. , Lim P. S. , Abdul Rahim M. F. , Jackson P. 
Published: June 2011

Abstract
Many small oilfields in poorly sorted and highly non-uniform unconsolidated formations with high fines content cannot be developed economically using the preferred sand control method, gravel pack. ‘J’ Field in Malaysia is a small oilfield with marginal economics that was developed successfully using stand-alone screen (SAS), a cost-effective open hole (OH) sand control method. Deployment of SAS in ‘J’ Field does not meet the industry-accepted criteria for sand control methods but provided the operator adequate sand control while fulfilling its economic needs. Recent advances in OH sandface completion technologies such as multi-layer mesh screens, inflow control devices (ICDs), and zonal isolation using swellable packers provided improved performance and reliability of recent SAS installations.
This project marks a few firsts in sand control screen technology: World's first installation of multi-layer mesh screenMulti-layer mesh screen is the current state-of-the-art in premium mesh screen technology. It uses several layers of woven metal mesh filters of gradually decreasing micron rating and diffusion-bonded together, which creates a filter that provides better plugging resistance and solids retention capacity.Malaysia's first installation of tube-type ICDICDs are passive flow control devices that are used in OH horizontal (Hz) wells to delay the onset of water breakthrough and minimize its effect by balancing inflow from toe to heel or between high-perm and low-perm zones. ICDs are integrated with sand control screens for use in unconsolidated formations. Swellable packers are used in ICD completions to provide compartmentalization.
This paper highlights the recent success of utilization of these cost-effective OH sandface completion technologies in the development of ‘J’ Field.
Laboratory and Theoretical Investigation of Size Exclusion Suspension Flow in Rocks
Authors: Chalk P. , Gooding N. , Hutten S. , You Z. , Bedrikovetsky P. 
Published: June 2011

Abstract
Particle transport in suspension flow with pore plugging and particle capture is encountered in a wide range of porous media including reservoir rocks. Based on the particle population balance, a micro scale model accounting for particle size exclusion mechanism and triangular shaped pore throat geometry, has been developed. The steady state case, which corresponds to the initial stage of size exclusion deep bed filtration, allows for an analytical solution. The recovered outlet concentration of suspended particles from this solution is then matched with the measurement from well designed challenge coreflood testing which guarantees net particle-grain repulsion for pure straining condition. The comparison shows good agreement between the modelling result and the laboratory measurement, which also results in the evaluation of pore throat size distribution.