bluuebunny/crossref_metadata_2025_split huggingface dataset:
Inhibited Gas Stimulation To Mitigate Condensate Banking and Maximize Recovery in Cupiagua Field
Authors: Franco C. , Zabala R. , Zapata J. , Mora E. , Botero O. , Candela C. , Castillo A. 
Published: June 2014

Abstract
Condensate banking has been identified as one of the most potential damaging mechanism affecting the well productivity in Cupiagua Field. This gas-condensate giant field has reached an average recovery factor of 42% with recovery values of ~60% in some layers of field. The mitigation of condensate banking phenomena, among the other important damaging mechanism currently interacting along the entire productivity zones, has been one of the most relevant stimulation practice in the development strategy.
The mitigation of condensate banking led to optimize common stimulation practices to recover the productivity of gascondensate wells, massive hydraulic fracturing and matrix stimulation with inhibited diesel and alcohol have been the most common practices implemented and optimized to mitigate condensate banking in Cupiagua field.
Since the field is being operated by ECOPETROL (Jun-2010), the mitigation of condensate banking was recognized as one of the most important stimulation challenges to be worked by stimulation team. The effective mitigation of condensate banking is a key to reach and even exceed the production targets set by ECOPETROL short and long term.
This paper describes all the engineering work carried out to implement a new stimulation technique based on the injection of inhibited dry gas. The performed lab job, the simulation runs, the engineering design and the field results are clearly described in the paper, the preliminary results are showing that now we have available a successful stimulation technique to remove and mitigate condensate banking. At the moment this stimulation strategy has been focused in to remove liquid saturation (condensate and water) and organic solids (especially asphaltenes) by incorporating alcohol and surfactants inside the gas stream. Future engineering job will be addressed to find a chemical blend that can improve the gas-treatment life, probably reducing critical liquid saturation or/and reducing the size of no mobile condensate rings.
Experiment and Simulation Study of Proppant Pack Compression
Authors: Ye X. , Tonmukayakul N. , Weaver J. D. , Morris J. F. 
Published: June 2014

Abstract
Realistic laboratory simulation of fractures propped with sand, engineered ceramic proppants, and resin-coated proppants to determine the impact of temperature, stress, and stress cycling on proppant-pack structure and pack permeability is both difficult and expensive. Large, specialized testing equipment and long testing times are required, which can lead to high testing costs. This paper presents a new dynamic compression device (DCD) that permits rapid proppant-pack analysis to optimize proppant selection.
Understanding the mechanical and fluid dynamics of hard granular particle packs subjected to high closure stress and cyclic stress is important for understanding fracture conductivity and the impact of production operations. Few experimental studies have been reported where the compression of proppant with variable stress rates was used that also includes simultaneous direct visualization of the proppant structure.
The DCD imposes a controlled strain on the proppant pack while measuring the stress response, up to a compressive loading of 7,100 psi. Simultaneously, the liquid permeability and a detailed visualization of the proppant-pack structure are acquired. The stress loading and unloading process, performed in either a single or repeated (cycling) protocol, can be performed with precise measurement of the resulting system-level strain. Permeability results obtained using the DCD were comparable to those obtained using standard API linear conductivity determinations. Particle rearrangement by direct visualization during stress cycling was comparable to that predicted by use of a popular, commercial, three-dimensional particle-flow numeric simulator.
The DCD is a small, bench-top device that uses a small proppant sample. It has been demonstrated to be an efficient tool to experimentally determine the impact of closure stress, stress-change rate, proppant-packing properties, and the effect of multiple stress cycles on liquid permeability, while providing direct proppant-pack structure visualization. This new device enables rapid testing to determine the impact of expected downhole production conditions on proppant-pack permeability and permit selection of optimum proppant and proppant coatings.
Dynamic Filtration: Seepage Losses on Tyrihans
Authors: Van Der Zwaag C. H. , Omland T. H. , Vandbakk T. 
Published: June 2014

Abstract
Drilling of the Tyrihans reservoir sections was affected by significant seepage losses. These added up to ~1000 m3 after drilling five wells with 13 reservoir sections, including pilots and laterals, and a total exposed reservoir length of ~15000 m.
In this study, we estimate whether the reported losses can be explained by dynamic filtration mechanisms and related seepage losses. Daily drilling reports were evaluated to reconstruct the downhole drilling environment. Accumulated dynamic and static filter loss periods were calculated. A dynamic filtration HPHT filter press was used to measure dynamic filter losses of laboratory and field samples of the drilling fluid used on Tyrihans. Measurement results were evaluated and extrapolated to field scale. Finally, losses experienced in the field and calculated values were compared.
Results strongly indicate that the reported losses on Tyrihans were dynamic seepage losses and that these losses dominate the total loss volumes clearly. The filtration volumes measured in the laboratory were significantly influenced by the shear rate applied. High shear rates caused a larger dynamic filtration component. There are indications that a reduction of coarse bridging particles during drilling and an increase of finer particles relative to the optimum particle size distribution increases the dynamic filtration component.
Dynamic fluid losses may in magnitude be misinterpreted as lost circulation into microfractures or in developing fracture systems. A correct assessment of the nature of the losses is essential to select an efficient treatment. Elevated downhole and circulation temperatures as well as long reservoir sections creating large filtration areas cause increased dynamic seepage losses. To reduce these losses higher viscosity base oil could be considered in OBM or a less turbulent flow regime should be engineered. The latter can be achieved for example by increasing drilling fluid viscosity, reducing pump rates or choosing a smaller drill pipe diameter. Efforts should be put into maintaining the optimum particle size distribution of filtercake-building bridging particles. Such changes in fluid design should be carefully evaluated, as they can have a negative impact on other fluid parameters such as equivalent circulation density, swab and surge or reduced hole cleaning efficiency. Research should be initiated to develop low-dynamic-loss fluids. This requires a better understanding of dynamic loss mechanisms and the identification and verification of additives that protect filtercakes against shear and erosion.
Fracturing Fluid With Low-Polymer Loading Using a New Set of Boron Crosslinkers: Laboratory and Field Studies
Authors: Williams N. J. , Kelly P. A. , Berard K. G. , Dore’ E. L. , Emery N. L. , Williams C. F. , Mukhopadhyay S. 
Published: June 2014

Abstract
Guar-based crosslinked fluids are most commonly used in hydraulic fracturing to stimulate oil and gas wells. When crosslinked with boron, the fluid not only provides high viscosity, it is also able to recover its rheological properties after being subjected to a mechanical shear. Altough borate crosslinked guar systems are environmentally favorable, the gelled fluids generate a significant amount of insoluble residues upon breaking down with oxidizers or enzymes, commonly known as breakers. The amount of residues formed in the broken fluid is directly related to the type and the quantity of the polymer used. Studies have shown that these residues can cause significant damage to the formation and to the proppant pack conductivity. So it is highly sought-after to formulate an efficient boron-crosslinked fluid system with lower polymer loading without compromising its rheological properties and proppant carrying ability. In addition, the recent global shortage of the guar beans specifically required for the oil & gas industry has driven our efforts further toward this goal.
Studies have shown that crosslinking efficiency is dependent on the availability of the crosslinking sites and the chemical and structural properties of the crosslinkers. Considering these factors two different approaches were taken in order to reduce the polymer loadings of the fracturing fluid: 1) Use of a high yielding, fast hydrating, non-derivatized guar system with appreciably less insoluble materials and 2) Use of a new set of chemically modified boron crosslinkers with higher crosslinking efficiency. This paper will describe the laboratory testing involved in developing this new generation of low-cost, low-polymer, and environmentally responsible fracturing fluids. The fluid is operable in a broad range of temperature and compatible with breakers and additives commonly used in the industry. This system has the capacity to withstand high salinity and high shear rates, and is capable of rapid re-heal, which decreases shear degradation as the fluid is pumped through gravel pack tools. The paper will also discuss our recent fluid testing in preparation for pumping in the Gulf of Mexico.
Pushing the Limits: HT Carbonate Acidizing
Authors: Jimenez Bueno O. E. , Ramirez G. R. , Quevedo Z. M. A. , Resendiz Torres J. T. , Tellez Cisneros F. 
Published: June 2014

Abstract
The Mexico South Region produces more than 520, 000 bopdl from mature carbonate reservoirs. These reservoirs have widely varying reservoir pressures, presence of natural fractures and temperatures up to 350 degF. The extremely high temperatures makes even more challenging the stimulation process with conventional systems resulting in excessive corrosion and very inefficient wormholing.
An innovative solution, considering a chelating agent as treating fluid, has proved to be an effective approach to stimulate these reservoirs. The post treatment production in two different wells showed outstanding results with higher rates than previous treatments and the trend of the production declination was smoothed. This new stimulation solution aided with a good candidate selection has led it to be the preferred solution for HT wells.
Well A was treated with 15.0 m3 of the fluid based on chelating agents as main system, with a solvent preflush and overflush. Previous to this job two stimulation treatments were performed pumping a mixture of conventional acid systems. In both occasions the production increased, however, the production declined to pre-treatment rates in a matter of days. When treated with the new solution the production increased 254 bpd with almost no decrease with time (monitored for three months), indicating a more efficient stimulation treatment, and greatly improved on the economical indicators.
Well B was stimulated with 20.0 m3 of chelating agent fluid after three previous attempts using conventional systems. The production increased 726 bpd. Post-treatment behavior was the same as well A.
Wells A and B showed an increased production of 1.7 KBD with a very limited production declination because of more efficient wormhole creation due to retarded reaction rates allowing a wide contact with the reservoir thus improving production performance, Np and eliminating post-treatment neutralization and testing surface equipment requirements.
A Sequential Polymer Injection Treatment Using RPM: Effects of Multilayer Adsorption of Cationic and Anionic Polymers
Authors: Chung Taemoon , Bae Wisup , Koh Hyunjin , Oh Sangmin , Kim Seungtae , Nguyen Huy X. 
Published: June 2014

Abstract
Relative permeability modifiers (RPMs) have proven to be an effective technology to control water production without significantly damaging hydrocarbon-production potential. Systems most commonly used for this purpose are single solutions of water soluble, high molecular weight polymers that adsorb onto the pore surface and change the flow properties of the porous media. However, these adsorbed polymers are only developed thin single film layer on the pore surfaces, resulting in a moderate success to maximize the water controlling efficiency. Moreover, high molecular weight injecting polymers can cause inaccessible pore volumes (IPVs), resulting in the failure of controlling water production for a long period of time. Because blocking polymer chains in front of IPVs can easily be penetrated due to strong water resistance after the treatment.
To overcome this unsuccessful scenario, this paper presents the laboratory development of a novel polymer injection system, which is a sequential injection of polymers considering ionic characteristic as well as controlling molecular weight, injection volume and concentration.
When cationic and anionic polymers are injected sequentially into a sandstone formation, a first injected cationic polymer induces preferential adsorption onto the negatively charged sandstone pore surfaces. Thereafter, anionic and cationic polymers are injected stepwise. These injecting polymers will be adsorbed and stacked making multiple adsorbed layers by electrostatic interactions, which results in a higher level of hindrance to water flow while still maintaining the minimal effect on hydrocarbon flow. Furthermore, increasing molecular weight and concentration of polymers can be injected sequentially to reduce IPVs. Injection volume can be designed to decrease to simulate maximum water controlling efficiency near wellbore regions.
Experimental results from Berea cores showed that there are improvements in Frrw values (up to 9.29) and Frrw/Frro ratios (up to 3.34) in a sequential injection process compared to conventional single injection processes. Frrw/Frro ratios showed an improving tendency with pore volume injected until the ends of experiments. The obtained results clearly indicate the effectiveness of sequential injection method in verifying improved RPM performance.
Investigation of the Mitigation of Lost Circulation in Oil-Based Drilling Fluids Using Additives
Authors: Guo H. , Voncken J. , Opstal T. , Dams R. , Zitha P. L. 
Published: June 2014

Abstract
Fluid loss control is an essential property of oil based mud (OBM) which can impact the success of drilling operations. The paper presents an investigation of the mitigation of lost circulation in OBM using leak-off control additive. A simple physical model was developed to describe the static filtration process considering the formation and properties of the filter cake. Both HTHP API press and core flow filtration experiments were performed to evaluate the leak-off behavior of OBM. Core filtration experiments were carried with the aid of a CT scanner to monitor the invasion of the filtrate into the sandstone core at time intervals. In the long time limit the model predicts that the fluid loss follows the classical Carter equation, i.e. the leak of volume increases as the square root of time for the static filtration through a filter paper and through the sandstone core. Dual mode filtration diminishes the rate of fluid loss. The model provides also a relation between pressure drop and filtrate rate, which can be used to estimate the permeability of filter cake in the experiment. The leak-off behavior with additive observed in the experiment is well explained by the microstructure of rapid built-up filter cake which is mainly responsible for the control of fluid loss. The role of different components of OBM, e.g. solid particles, emulsion droplets and additives is discussed in the light of our observations.
An Automated Software Workflow To Optimize Gulf of Mexico Lower Tertiary Wilcox Sand Reservoirs
Authors: Dusterhoft R. , Strobel M. , Szatny M. 
Published: June 2014

Abstract
Much has been written about the deepwater Lower Tertiary Wilcox trend in the Gulf of Mexico, which spans hundreds of miles from Alaminos Canyon to Keathley Canyon to Walker Ridge (as well as adjacent areas). The estimated ultimate recoverable oil from these reservoirs is significant: 3 to 15 billion barrels. However, significant technical and reservoir challenges remain because of the water depth (typically greater than 5,000 ft), reservoir depth (typically greater than 20,000 to 30,000 ft below the mud line (BML)), and high pressures (greater than 20,000 psi bottomhole pressure (BHP)). Combining these issues with the thick, low permeability reservoir intervals (more than 1,000 ft thick in the tens of mD) requires new tools as well as new planning and optimization methods.
These new planning tools require system-wide (holistic) integration across multiple domains and completion software applications to produce a truly optimized completion. This type of integration is provided by an automated software workflow. Previous papers have provided details about the benefits derived from the automation of operations, engineering, and production workflows in general. Lower Tertiary Wilcox reservoirs were deemed good candidates by a major service company to implement the automated workflow concept, given the reservoirs’ low productivity index (PI), high-cost wells, high pressure/high temperature (HPHT) technical challenges, and production uncertainty.
This specific workflow seeks to optimize hydraulic fracture design within Lower Tertiary Wilcox reservoirs by stipulating the maximum net present value (NPV) that satisfies all well, completion, and reservoir constraints. Hydraulic fracture design is an example of what is largely a manual process that requires interaction with several software applications to obtain fracture geometry, production constraints, production sensitivity criteria, and NPV scenarios. When the goal is an optimized fracture design, the process is especially arduous because it requires iterative interactions with reservoir simulators, nodal programs, economics models, well tubular design systems, and stimulation design tools to arrive at a suitable design. Enabling coupled simulations technology, this fracture workflow provides a unique holistic combination of tools, which are linked to reflect the actual economic values.
Solving Deep 22" Carbonate Drilling Challenges in Northern Kuwait
Authors: Al Saleh Ali , Shehab Adnan , Al Khaldy Meshal , Portwood Gary , Ghoneim Osama , Maliekkal Harish 
Published: June 2014

Abstract
The operator must drill a deep, vertical 22" hole-section in a HP/HT environment to efficiently tap Jurassic reserves in the North Kuwait gas fields. The borehole starts at approximately 6050ft and continues to 9350ft. Interbedded lithologies encountered include carbonates, sandstones and shales with compressive strength between 6000-25,000psi. The section can take 350hrs to reach total depth (TD).
Historically, the section has been drilled with PDC and rollercone TCI bits. TCI had unacceptable ROP with short life requiring multiple runs. Frictional heat in Mutriba was causing inserts to crack/chip leading to total failure. The abrasive Burgan and Zubair with pyrite were causing extensive insert wear. PDC bits could deliver acceptable ROP, but inconsistent run lengths and vibration induced impact damage were driving up field development costs. Neither bit type could consistently complete the hole section in one run.
To solve problem a forensic investigation of TCI bearing, carbide materials and insert shapes was conducted. The study resulted in new impact resistant carbide grades and unique insert geometries specifically tailored for Middle East carbonate/sandstone drilling. A dynamic twin-sealing system ensures long bearing life. The design was tailored to maximize ROP while retaining a high level of cutting structure durability. The bit was run on RA-414 with outstanding results setting a new Kuwaiti 22" record drilling 3311ft in 335 hours (9.8ft/hr) reaching deep into abrasive Zubair sandstone. It is the most footage drilled by any bit type in the application and the first TCI to penetrate Zubair. It was dull graded 3-5 with all three seals effective in spite of turning two million revolutions. It eliminated multiple bits/trips to complete the hole section reducing rig-time expenditures, bit spend and the expense of a motor required for PDC. With additional modifications, it’s probable the bit will drill the section in one run in the near future.
Used Approaches for Carbonates Acidizing Offshore Brazil
Authors: Pereira A. Z. , da Silva M. G. , da Paixao L. C. , de Oliveira T. J. , Fernandes P. D. 
Published: June 2014

Abstract
Although the new Brazilian carbonate reservoir discoveries represent a huge undertaking, on acidizing terms, many of the challenges faced nowadays are very similar to those found in the old carbonate reservoir fields. Problems like high permeability contrast, heterogeneous porosity distribution and long production intervals have their complexity increased by the completion and production needs. Despite all these problems, the use of conventional approaches, applying basic techniques, has produced good results leaving some time to the development of more specific solutions, once there are still some limitations to overcome. Among those conventional techniques, pilot zones associated with chemical diversion have been intensively used although mechanical diversion has been limited by the completion arrangement.
This paper describes acidizing techniques that have been applied on Brazilian offshore carbonate fields, some observed problems and present some trends related to the development of new acidizing techniques.
Umbilical Deployed Stimulations for Asphaltene Related Damage in Offshore Oil Fields
Authors: Peruzzi T. , Coulon T. , Fauria J. , Frey D. , Marechal H. , Sloan R. 
Published: June 2014

Abstract
In the Deepwater Gulf of Mexico, twelve stimulation jobs were pumped down chemical injection umbilical tubing to remediate suspected asphaltene related productivity decreases. All twelve jobs were done on dry tree wells but the procedures could be adapted for wet tree application.