bluuebunny/crossref_metadata_2025 huggingface dataset:
Innovative Forging Process Allows Safer and Cost Effective Heavy Duty Landing String for Deepwater Applications
Authors: Bordet Laurent , Franchi Jonathan , Granger Scott , Vierke Andre
Published: August 2016

The offshore industry's current trend is driving towards ultra deepwater wells, combined with deeper total depths. In order to be able to set and run larger and heavier casing strings with hook loads approaching or exceeding 2.5 million lbs, an innovative heavy duty landing system has been developed and put on the market.

Such systems must be capable of landing heavy loads while ensuring slip crush resistance. It includes an extended slip with enhanced design (coupled with a new greasing system), a 2.5 million lbs landing carrier and a pipe with a thick walled high strength material section, a light weight tube, and a rotary shouldered connection.

One of the current operational challenges with existing heavy duty landing strings is linked to the positioning of the slips, in particular when using extended slip designs. The limited length of the slips area requires additional time for proper positioning and set up. To address these issues, a new slip proof section design has been developed: the combination of an extended crush proof section and the absence of a heat affected zone in that particular area decreases running time while completely eliminating the risk of setting the slips on a weak point.

The "Spiri-Reinhold pipe crushing" formula has been used to design this system. However, considering the approximation of this model's results, crushing performance has been assessed using the Finite Element Analysis, as well as physical tests performed with a specifically designed pulling unit. These full scale test results have been compared to the ones obtained with both the Finite Element Analysis and the standard "Spiri-Reinhold pipe crushing" formula.
Successful Deployment of Electro-Hydraulic TCP Firing Head Improves Safety and Reduces Rig-Time
Authors: Stolboushkin E.. , Gilliat J.. , Hillis P.. , Zuklic S..
Published: August 2016

The electro-hydraulic firing head features a novel combination of electronic control over a hydraulic firing mechanism. An electronics module senses wellbore pressure and, upon seeing a distinct signal, opens a valve that allows downhole pressure to operate a hydraulic firing mechanism. The hydraulic firing mechanism is extremely reliable, does not have sufficient energy to fire until safely downhole, and is immune to electromagnetic interference. The electronic control system prevents inadvertent pressure applications from prematurely activating the firing head. This combination of electronic control and hydraulic firing in a firing head offers unique and distinct benefits in safety, operational flexibility, and risk reduction.

On a recent job, a TCP assembly with dual electro-hydraulic firing heads (stacked vertically for redundancy) was run below a permanent packer and isolation valve. The electro-hydraulic firing head enabled this deployment to be conducted safely, with reduced risk of NPT, and in a single trip. A hydraulic firing head could not be used in this application due to the risk of pressure communication through the isolation valve during packer setting and testing. The TCP assembly was hung off the packer with a ballistically actuated automatic release. The electro-hydraulic firing head has a detonating cord bypass, allowing it to detonate guns below at the same time as actuating the release above. The availability of this firing head allowed this job to be performed more safely, more efficiently, and with reduced risk of NPT than was previously possible.

This paper will present an overview of the design and features of the electro-hydraulic firing head, discuss the recent successes in utilizing its unique abilities to enable more efficient job plans, and discuss other unique applications for this technology.
Reservoir Protection Strategy and a High Performance Drill-In Fluid for Deepwater Wells in the South China Sea
Authors: Zhao Xin , Qiu Zhengsong , Wang Mingliang , Liu Yunfeng , Chen Ganghua , Liu Shujie , Zhou Jianliang , Xing Xijin
Published: August 2016

The protection of high porosity and high permeability reservoirs has not got enough attentions because the excellent hydrocarbon storage capacity would provide high oil and gas productivity even being damaged to some extent. Deepwater oil and gas reservoirs are mainly high porosity and permeability reservoirs, and the reservoir protection is important because severe reservoir damage will cause an enormous economic loss due to high investment and risk of deepwater operation. A new deepwater gas field in the western part of the South China Sea must be developed soon, and the reservoir protection strategy needs to be studied.

The characteristics of the reservoir were studied by X-ray diffraction, scanning electron microscope, mercury intrusion porosimetry, hot rolling dispersion test and liner swelling test. Furthermore, the water and salinity sensitivities of the reservoir were studied. The results show that the reservoir has high porosity and high permeability with an average porosity larger than 30% and an average permeability higher than 500×10-3 μm. The large pore throats will be easily invaded and plugged by solids in drilling and completion fluid. Therefore, effective temporary-plugging of the pore throats with a wide size range is extremely important. The content of clay mineral is 9% to 19% with approximately 50% mixed-layer illite-smectite, presenting potential borehole instability and reservoir damage risk due to its strong hydration ability. In addition, the reservoir has strong salinity sensitivity and medium-weak water sensitivity. The reservoir protection strategy of drilling and completion fluid related to the properties of the reservoir was proposed. A multi-stage bridge temporary-plugging method was used to prevent the invasion of solids into the pore throats with a wide size range. A highly inhibitive polyamine was selected to inhibit the hydration of clays to maintain wellbore stability and reduce reservoir damage. Because of the requirement of gas hydrate inhibition and density adjustment, a high performance water-based drill-in fluid with formate brines was developed. It has excellent reservoir protection performance with the permeability recovery rate approximately 90%. Meanwhile, it performs well in inhibiting clay hydration, hydrate formation, and has good rheological as well as filtration properties over a wide temperature range from 4 °C to 75 °C.

This work provides theoretical guidance of reservoir protection and a high performance drill-in fluid for the target deepwater gas filed. We hope it will also be useful for the protection of high porosity and high permeability reservoir in other deepwater oil and gas fields.
Investigating the Influence of ESP on Wellbore Temperature, Pressure, Annular Pressure Buildup, and Wellbore Integrity
Authors: Kang Yongfeng , Liu Zhengchun , Gonzales Adolfo , Samuel Robello
Published: August 2016

The electrical submersible pump’s (ESP) impact on wellbore temperatures and integrity is seldom discussed in literature. Most literature discusses ESP run life and failure. The ESP heat dissipation increases the wellbore temperatures. Therefore, direct and indirect thermal-induced stresses are applied to the casings and tubing. At the same time, the trapped annular pressure buildup (APB) also increases, thereby applying additional stress on the casings and tubing. This raises the question—is the safety factor still valid? This is crucial in high-temperature/high-pressure (HT/HP) and deepwater/ultra-deepwater wells that have narrow design margins.

This paper presents studies on the prediction of wellbore temperature and pressure profiles, which account for the ESP heat dissipation effect on APB. The heat dissipation from the ESP electric motor, pump, and cable are considered. Then, the convective and conductive heat transfer through the wellbore are described in a transient wellbore temperature model. The updated temperature profile is then applied, and the APB and tubular stress analysis is revisited.

The model is integrated into an advanced casing and tubing design software platform. Case study results show increasing temperatures along the wellbore. The increased temperatures induce the APB and the strings axial compressive stress increase. In the studied case, the APB increased up to 23.6%. The increased APB induced additional loads on the tubing and casings, which can result in collapse/burst failures. Both theoretical analysis and case studies show that if the original design did not consider the use of ESP, induced APB can cause casing/tubing failure and result in wellbore integrity issues.

The findings indicate ESP heat dissipation does affect the wellbore integrity. Attention should be paid to the possible allocation of ESP in the future to achieve an accurate APB prediction during the modern wellbore completion design and planning phase. The findings are of particular interest in production monitoring and control, wellbore completion, ESP selection, casing/tubing design, and wellbore integrity, especially for mature-field and offshore wells.
Modeling and Simulation of Annular Pressure Buildup APB Management Using Syntactic Foam in HP/HT Deepwater Wells
Authors: Liu Zhengchun , Samuel Robello , Gonzales Adolfo , Kang Yongfeng
Published: August 2016

Annular pressure buildup (APB) in high-pressure/high-temperature (HP/HT) deepwater wells can result in wellbore failure, even during drill-ahead operations. Manufactured to collapse at a specific pressure and installed on the external casing wall, syntactic foam is an economical solution to mitigate APB and protect casing strings in offshore HP/HT wells. This paper focuses on the modeling and simulation of the effects of syntactic foam deformation on APB in casing/tubing annuli.

Syntactic foam is a composite material synthesized by filling a polymer, metal, or ceramic matrix with hollow glass microspheres (HGMSs). Under increasing hydrostatic pressure (HCP), the behavior of the foam material can be described using a HCP-strain curve typically consisting of three regions: linear elastic, plateau, and densification. A multisection linear model was established to express the volumetric strain vs. HCP relationship, which significantly simplifies the APB calculation while still ensuring sufficient accuracy. Analytical correlations were developed for the elastic compressibility and collapse pressure vs. temperature, which can generate feed-in data for the multisection linear model when only limited datasets are available.

A workflow was developed for the simulation of syntactic foam effects on APB in HP/HT wells. The syntactic foam models were implemented and integrated into a commercial casing and tubing design software platform. In a simplified example well, numerical simulation results were found to be consistent with the results from analytical calculation. In a case study of an offshore HP/HT well, numerical simulation demonstrates that syntactic foam is a viable and effective option for APB management. Combined with thermal flow and APB simulators, the implementation of the syntactic foam models enables more accurate casing/tubing load analyses. APB simulation including the effects of syntactic foam can provide valuable information to assist well design engineers in the design of HP/HT deepwater wells with long-term well integrity.
Finite Element Modeling to Determine Perforating Gun Collapse Failure Modes and an Engineered Solution
Authors: Craddock G. G. , Wight Jim , Harive Kevin
Published: August 2016

Three-dimensional (3D) finite element analysis (FEA)-based shock software is the next step in downhole shock modeling. This software uses a finite element and a fluid tool that simulates gun behavior on gun strings and adjoining tools, including perforation and subsequent stress conditions. By examining temporal stress predictions at element locations, failures can be estimated based on these numbers. On a recent perforating operation, there was an undesired event that resulted in a collapse of the spacer section within the perforating string. The event flattened spacers, but did not ruptured them, resulting in not damage to other sections. This event highlights how localized dynamic forces could be over looked in the present 1D industry dynamic modeling software. As part of the planning process, the current industry standard shock software was used to simulate the string and predict the likelihood of failure. The models showed no failure flags; additionally, post-operation models did not predict the downhole events that occurred. As part of the investigation into the events, this modeling shock software was used to provide a more detailed model of the event. These models provide a full 3D representation of the string and allow a much more detailed understanding of the pressures and stresses during the perforating event. The models clearly showed the string design was not optimized for the localized dynamic event and there was a risk of collapse. Pressures were plotted as a function of time at locations on the outside of the spacers, safety spacer, and loaded guns. The results showed pressures outside the spacers, which exceeded static threshold values and lasted for extended durations. Other regions, such as the safety spacer, did not show this effect at above static threshold magnitudes. As well as being able to reproduce the collapse event , work was taken a step further to examine mitigation designs that could be used to help prevent these types of issues. It was possible to test several of these designs using the 3D FEA-based shock software to validate their functionality.
Overcoming the Challenges of Running Large Diameter Casing Through High Inclination Wellbores at Shallow Depths in Deep Water Wells
Authors: Mitchell Sarah , Reagins Deandre
Published: August 2016

Historically, running large diameter surface and intermediate casing in the shallow sections of a well with a high build rate and inclination has proven to be very challenging, with a high risk of getting stuck off bottom. At the same time, with limited drilling margins, it has become important to be able to successfully set large diameter casing under these conditions to enable the well to reach target objectives and/or avoid subsurface hazards.

A comprehensive analysis reveals that a major contributing factor to the difficulty of running large diameter casing is due to the large end loads resulting from the high inherent stiffness of the casing as it is bent through dog-legs or ledges. Finite element analysis indicated that these forces were high enough to cause the shoe to dig in to softer formations, and that the end forces increased substantially as casing size and weight increased, or as dog-leg severity and inclination increased.

A fairly simple solution was identified: a composite flexible shoe run at the bottom of the casing reduced the side loads at the bottom of the casing when running into the hole. Effective communication and cooperation between designer and operator allowed for a product that was thoroughly tested and examined from an operational standpoint to identify risks and address possible failure modes. Smaller tools were also proven out in higher build rate horizontal wells prior to running in a higher cost deepwater environment.

Several case histories are presented that demonstrate the ability to run 18, 16, and 14-inch casing smoothly to target depth through build sections with doglegs of more than 4°/100ft, in soft formations, and to inclinations of more than 60° using a composite flexible casing shoe.

The ability to reliably set large diameter casing through build sections and into high inclination wellbores expands the envelope of design possibility when planning deepwater wells.
First Deepwater MPD Operation in the Gulf of Mexico: Challenges and Lessons Learned
Authors: Samuel Nishanth , Santos Helio , Valluri Sandeep
Published: August 2016

In the Gulf of Mexico, the Paleogene play presents challenges in narrow drilling margins. To overcome the challenges, a fully integrated Managed Pressure Drilling (MPD) packaged system was incorporated into a deepwater drill ship. The MPD system was designed to drill a deepwater, high pressure / high temperature well in the Gulf of Mexico. This paper will explain the lessons learned, the challenges and improvements carried out through the use of the MPD system in three key areas: advanced wellbore pressure modeling, downhole characteristics fingerprinting using downhole data and the MPD equipment. A full MPD system was designed to comply with all new government regulations and its performance proven through successful cased hole and open hole testing. Upon government approval, the new system was used to drill the well in full MPD conditions, where the mud weight (MW) was brought below pore pressure and the well was balanced with applied surface back pressure. Throughout the well, there were numerous lessons learned in three key areas: wellbore hydraulics modeling, downhole characteristics provided by PWD data, & the MPD equipment. An advanced wellbore pressure model was needed to accurately maintain the appropriate downhole pressure through the application of surface backpressure. The system used this model to perform simulations and applied the results of those simulations to control the surface equipment. Downhole Pressure While Drilling (PWD) data provided verification of the modeling results and applied surface back pressure as the well was drilled. Challenges faced during the operation included pressure compensation due to swab and surge as a result of pipe movement, and fluid inertia coupled with compressibility of the mud. The downhole characteristics of the well were tracked through PWD data, which was important in compensating the backpressure during connections and drilling. Further, the downhole data were consistently used to fine-tune and adjust the applied back pressure to ensure the well did not go underbalanced during these operations. Continuous improvement during operations also led to increased reliability of the MPD equipment.
Drilling Through Salt Formations: A Drilling Fluids Review
Authors: Amer A.. , Dearing H.. , Jones R.. , Sergiacomo M..
Published: August 2016

In many deepwater plays around the world, salt formations overlie prolific reservoirs containing billions of barrels of oil. Drilling into these reservoirs requires the successful penetration of the challenging salt layers. Based on experiences in key deepwater basins, this paper reviews the fluids and techniques used to drill through salt formations.

Salt formations are unique. Salt has little porosity and permeability. It can flow plastically through other geological rock beds under stress with "salt creep" resulting in wellbore size reduction and casing collapse. Salt can also dissolve in water necessitating the salinity of a water-based fluid be kept near or at saturation to avoid or minimize wellbore enlargement that can lead to poor cementing of the casing and deficient zonal isolation.

In spite of the aforementioned issues, salt formations are drilled successfully around the world, and drilling fluids play a vital role in a successful drilling operation. A downhole simulator cell (DSC) has been found to be a key tool in assessing the effect of drilling fluids on salt formations by drilling salt cores at in-situ conditions of temperature and pressure while monitoring the core and fluid interactions.

This paper combines a downhole simulation cell (DSC) testing and data from previous literature to provide a comprehensive overview of drilling fluids interactions with salt formations. This dialogue combines the experiences of drilling salt as seen from a drilling fluids perspective into one publication.

Three generalized fluids are evaluated: riserless water-based fluid (WBF), high-performance water-based fluid (HPWBF), and synthetic-based fluid (SBF). Performance criteria used to evaluate fluids include rates of penetration (ROP), hole cleaning, wellbore stability and washout minimization. Environmental compliance and system strengths and limitations are outlined. Topics include evaporite mineral types and drilling challenges including exit strategies and tar beds.
The Development and Qualification of a Novel Proppant System to Enhance Performance of High Rate Soft Sand Water Injection Wells With Cased Hole Sand Control Completions
Authors: Whaley K.. , Rickman R.. , McClelland K.. , Decker T.. , Murillo R.. , Candella J.. , Roper T.. , Johnson D..
Published: August 2016

With the rapid increase in number of major development projects in soft sand reservoirs in the last 20 years the industry has had to develop a range of sand control completion technologies to deliver high rate, reliable wells to support the production and injection. Sand control completion systems for production wells are generally mature and are broadly speaking typically successful. The development of reliable sand control systems for water injections wells has however typically proven to be significantly more challenging and this has impaired the economics of multiple projects by either necessitating the installation of more water injection wells, the periodic remedial repair of existing injection wells or suffer the inevitable impact on production rates and reserves recovery.

In many locations Cased Hole Fracpack (CHFP) or Gravel Pack (GP) completions have proven to have the capability to deliver high rate water injection wells. However, their long term reliability is often compromised due to the loss of the annular pack proppant when injecting water above formation fracture pressure. The loss of the annular pack proppant compromises the sand control system and reduced injection rates and formation fill in the wellbore typically soon follow.

In order to address this issue of annular proppant pack loss, a project was initiated to develop and qualify a proppant system that would remain immobile in the casing to screen annulus of CHFP/GP completions over life of well even when injecting water at high rate (in excess of 30,000 bbl/day) above formation fracture pressure.

Potential solutions from both inside and outside the oil and gas industry were reviewed and put through a rigorous program of lab based screening tests. Successful products progressed to the second stage qualification process of further lab scale and larger yard scale testing.

The final phase of the qualification process involved taking the preferred proppant product, a new generation resin coated proppant activated by a combination of a chemical activator additive in the fracturing fluid and temperature, and performing two onshore field trial operations which included several months of high rate water injection. The first installations of the new proppant product in deep water injection wells are expected from 2016 onwards.

One of the main challenges in the program was how to demonstrate suitability for both the installation process and life of well down hole service conditions in the lab and yard environment in a short time frame. This demanded the development and construction of a wide range of novel test procedures and apparatus. The results of this qualification and testing program will be discussed in this paper.
Physical and Mechanical Properties of Field-Generated Foam Cements: Implications for Cement Property Prediction and Modeling
Authors: Gieger Connor , Fazio James , Spaulding Richard , Kutchko Barbara , DeBruijn Gunnar
Published: August 2016

Properties of foam cement are of particular importance to the zonal isolation and mechanical integrity of wellbore cements used in offshore applications. This paper presents an assessment of physical and mechanical properties of field generated foam cements. These properties are measured to determine the performance of cements generated at field conditions, and for comparison with data sets obtained from laboratory-generated cement. These measured properties are also integral data for the development of empirical relationships used to estimate the properties of cements existing in the wellbore.

Measurements of mechanical properties include both dynamic and static testing methods. Dynamic testing of Young's modulus, Poisson's ratio, and other mechanical and physical properties are performed under cyclic effective pressures from 6 – 48 MPa. Dynamic measuring practices utilize ultrasonic velocity measurements at 4 MPa intervals during pressure cycling. Static methods perform strain measurements under uniaxial loading, and are used for strength analysis and comparison with dynamic measurement results. Laboratory-generated cements were mixed according to API-RP-10B-2 and 10B-4, using a Class H Portland cement system. Field-generated samples were obtained from industry collaborators.

Results indicate irreversible changes to permeability and Young's modulus over the course of pressure cycling. These systematic variations provide insight into how foam cement properties may be altered when exposed to pressure variations within the wellbore. Empirical relationships are developed between parameters such as compressive strength, permeability, porosity, p-wave velocity, and Young's modulus for foam cements using linear and non-linear least-squared regression analysis. Preliminary empirical relationships show strong associations between compressive strength and each of the various properties of interest. This is a promising development in efforts to predict the properties of in-situ cements.

This assessment of mechanical and physical properties of field-generated foam cement provides an in-depth look at cements generated at simulated in-situ pressure conditions. A comparison of field- and lab-generated cement properties provides information about how representative lab-generated cements are of typically-unavailable field samples. The empirical relationships reported in this study may help to provide, using the few measured properties of placed cements, a method of estimating physical and mechanical properties. This information is intended to aid cement design and wellbore planning for more reliable wellbores.
Gravel Packing Fluid for HP/HT Environment
Authors: Prakash Chetan , Rama Mallikarjuna Shroff , Garaje Sunil
Published: August 2016

An aqueous-based linear gel composition comprising diutan gum and an environmentally acceptable stabilizer has been developed for gravel packing applications. This aqueous-based gel works at elevated temperatures greater than 300°F. The rheological properties of these linear gels are particularly useful in gravel packing operations that involve shunt tubes. This paper presents laboratory studies that demonstrate the gel's thermal stability, rheological properties, minimal formation damage characteristics, and suitability for gravel packing operations.

Linear diutan gels exhibit excellent sand-suspension characteristics, even when they have relatively low viscosity because of their hyper-branched structure. However, their use at temperatures greater than 270°F can be challenging because of limited thermal stability. A new fluid composition that comprises a biodegradable, environmentally acceptable gel stabilizer was developed to address this issue. Thermal stability and rheological properties were studied using a Chandler Engineering® viscometer at elevated temperatures and various shear rates between 5 and 1021 s−1. The sand-suspension characteristic was studied using a high-pressure/high-temperature (HP/HT) autoclave. Formation damage characteristics caused by fluid invasion were studied by measuring regain permeability after coreflooding.

The results show the thermal stability of linear diutan gel improved from 270 to 310°F when the gel stabilizer was added. This fluid was stable up to 4 hours and exhibited excellent shear-rehealing properties at 310°F. The fluid rheology profile at various shear rates is in accordance with the criteria necessary for gravel packing operations that use shunt tubes. The fluid could suspend proppant/sand for 1 hour at 310°F with less than 20% settling. The gel stabilizer helped to improve thermal stability and sand-suspension characteristics by scavenging oxygen dissolved in the fluid and quenching the radicals generated at higher temperatures. The fluid was compatible with completion brine, crude oil, and oil-based drilling mud. Therefore, it could be used in nonaqueous fluid-pack completions. It showed more than 90% regain permeability, which suggests a clean break of gelling agent and low damage to the formation rock.

The good thermal stability and sand-suspension properties of the fluid system using the biodegradable, environmentally acceptable gel stabilizer make it a good choice for gravel packing operations in HP/HT reservoirs. The low-residue fluid property helps to ensure economical production rates.
A Look at Processes Impacting Foamed Cements
Authors: Kutchko Barbara , Crandall Dustin , Spaulding Richard , Gill Magdalena , Moore Johanthan , Gieger Connor , Haljasmaa Igor , Benge Glen , Maxson Joe
Published: August 2016

This paper presents the results of a joint industry study with the American Petroleum Institute (API) and the National Energy Technology Laboratory (NETL) to assess three sets of field-generated foamed cement at in-situ conditions using surface operations. In this data set, industrial bottled N2 gas was used to generate the field samples versus the cryogenic nitrogen in previous tests. The advantage in using bottled N2 was the ability to mix and pump at lower rates while maintaining an accurate nitrogen delivery, thus allowing collection of low quality foamed cement samples. Foam quality is a measure of the ratio of gas to slurry. Additionally a static capture manifold or split manifold was used for the foam capture which allowed for foam isolation while maintaining the defined rates and pressures. This also gave the ability to maintain the capture pressure during transfer of the samples to the pressurized containers. A foam accumulator chamber was added to the static capture manifold and was charged with foam and subsequently displaced with N2 while filling the sample cylinder.

This paper presents results of X-ray Computed Tomography scans of the constant pressure sample cylinders which showed that collection processes have a dramatic influence on the structure of the cured foamed cement. Physical properties such as porosity and permeability, were also measured and indicate a strong relationship between foam quality and homogeneity of the samples. This research will ultimately offer the ability to predict the behavior of foamed cements under in situ conditions when compared to laboratory generated foamed cements.
Relating Cement Additive Performance to Mix Water Composition for Deep Water and Salt Zone Applications
Authors: Reddy B. R. , Contreras Elizabeth Q. , Boul Peter J.
Published: August 2016

Achieving quality cement performance in deep water wells with large amounts of salt present requires fundamental understanding of the salt effects on the interactions of cement additives with cement on the slurry performance. Many problems encountered later in the life of the well can be traced to slurry performance issues during placement and the initial setting process. Cement slurry designs for an oilwell can range from simple to highly complex depending on the geology, lithology, placement logistics, wellbore conditions and long-term performance. Logically designed cement slurry formulations and dependable additive behavior are critical to meeting cement performance requirements. Formulations can include mineral admixtures added in substantial quantities and additives in smaller (<2% by weight of cement) quantities. The performance of the additives in cement slurries depends strongly on competitive adsorption on cement and mineral surfaces. Adsorption interactions are directly influenced by downhole temperature, the nature of the formation, and the mix water composition. These aspects underline the need for understanding additive interactions with cement under wellbore conditions.

Of particular relevance to deep water cementing is the performance of additives in sea water containing monovalent and divalent salts with chloride and various other anions present in amounts close to 4% by weight. The problem of additive performance becomes even more of a concern when cement is placed against salt formations. High ionic strength of sea water or of a sea/fresh water slurry placed against a salt formation, can compress the electrical double layer of cement clinker particles, alter chain conformations of ionically charged or hydrophobically modified polymeric additives, or change the solubility of additives. Additives may perform extremely well in fresh water slurries, but may perform poorly in slurries with high salt content. Additionally, the salt itself can affect cement performance. For example, sodium chloride is a set accelerator in small quantities (≤13% by weight of cement) while it functions as a retarder in large quantities.

The objective of this presentation is to gain molecular level understanding of relationships among additives based on chemical structures, adsorption onto cement surfaces, and the mix water ionic strength.

In this study, typical additives for dispersion and retardation are contacted with Portland cement in deionized water, synthetic sea water, water containing 2% to saturation level of NaCl or divalent salts in a formation brine. The reactions were analyzed by isothermal calorimetry, UV/Visible spectroscopy and rheology. The interpretation and implications of laboratory results are presented.
Integrated Drilling Strategy Leads to Successful Execution of the First Highly Deviated Deep Water Well in Mexico
Authors: Przhegalinsky I.. , Briceno Colmenares C. J. , Ramirez Amayo O. O. , Jimenez G. Malpica
Published: August 2016

The first highly deviated Deep Water well with an inclination up to 80° was drilled in Mexico. A strategy developed in collaboration with the owner and Directional Drilling contractor allowed to safely drill the well within AFE and reach all planned objectives.

In order to maximize production, avoid geological risks and optimize utilization of existing subsea infrastructure the Deep Water well (with water depth over 3000ft) was designed with inclination reaching 75°, demanding dog leg severity (2.5°/100ft) and several sections to be enlarged while drilling.

Being the first well with such high angle in Mexican Deep Water, Lakach-52 did not have much of a reference. Many design and operational issues had to be solved for the first time.

Besides problems typical for highly deviated wells, such as hole cleaning, wellbore stability, high ECD, etc., potential issues were anticipated with a kick off from vertical in very soft formation, perform directional work within interbedded formations and a zone of conglomerates, pass between faults and simultaneously enlarge the hole.

Additionally, a number of factors were taken into account in order to design the well: existing subsea infrastructure, local practices, geological/geomechanical risks, operational risks (direction, S&V, stuck pipe, etc.)

In order to ensure flawless performance and address all potential issues, the service company ran the project under integrated management roof. A special communication protocol/structure was designed in order to optimize the decision making process than response time. A specific project drilling strategy was developed for each stage of the well construction process.

All BHAs as well as drilling parameters were designed using the following approach: fit to purpose BHA tendency, bending stresses below critical, minimum shocks and vibrations and optimized hydraulics.

As a result, the well was successfully drilled within AFE curve, all given targets were successfully achieved. All sections were drilled with ROP faster than planned. The conductor was jetted and the following section was drilled ahead using a straight motor with a minimum deviation from verticality 0.26° The kick off successfully performed at very shallow depth and very soft formation with push the bit Rotary Steerable system. The 17 ½" × 20" section was drilled successfully in 1 run. Inclination was built to 30°. The 14 ½"x 17 ½" section was the most challenging section. 3 BHAs were used to drill the section. Optimization of the BHA allowed to eliminate shocks & vibrations and reach drilling objective within the given tolerance, despite the geological complications and demanding well profile. The 12 ¼" section was drilled successfully to TD and the required LWD logs were obtained in the reservoir at 75° of inclination.
Real-Time Health Monitoring of Top Drives for Offshore Operations Using Physics Based Models and New Sensor Technology
Authors: Pournazari Parham , Adams Douglas , Ashok Pradeepkumar , Oort Eric van , Holliday Keith
Published: August 2016

The top drive is a critical piece of equipment in well construction. When the top drive fails, drilling halts and operations are suspended until the machine is fixed, at considerable cost to all parties. Literature and survey data reveal that top drive failure is among the leading causes of hardware-related non-productive time (NPT) on drilling rigs. The objective therefore is to detect a failing top drive hours or even days before it can no longer function effectively, and pro-actively maintain it before catastrophic failure takes places. In this paper, three separate health monitoring techniques are considered for a top drive: thermal analysis, vibration analysis, and oil analysis. Appropriate sensors are suggested for each of the three analyses, and are described in this paper. The paper also details a thermal model and a fault detection algorithm used to monitor the lubrication and electric motor subsystems of an AC electric top drive. These algorithms have been implemented and deployed in the field. Since no faults have occurred to date in the top drives on which these algorithms have been deployed, simulation results are presented for artificially induced faults. The advantages and disadvantages of other relevant sensor technologies and methodologies are studied and discussed. It is shown that the upfront cost of the sensors and the data acquisition system can easily be recouped by preventing one to two top drive failures. Additionally, the thermal analysis method described can be conducted with the existing sensor suite available on most top drives. This novel methodology can be easily implemented without the need for complex sensors, and is expected to make a meaningful, positive contribution to lowering NPT associated with rig hardware failures.
Invert Emulsion Fluid for Alpha Beta Gravel Packing - Laboratory Development and Successful Yard Test
Authors: Panamarathupalayam Balakrishnan , Khvostichenko Daria , Phatak Alhad , Zhang Joyce , Green Sarah , Gadiyar Balkrishna , Lecerf Bruno , Allogo Clotaire-Marie Eyaa
Published: August 2016

This paper describes the development and qualification of an oil-based gravel pack carrier fluid. The fluid is a water-in-oil emulsion prepared with base oil, brine, and emulsifier. Densities up to 13.6 lbm/galUS can be achieved using oil-to-brine ratios between 45:55 and 60:40. This oil-to-brine ratio range is such that the fluid exhibits low viscosity and Newtonian rheology, making it suitable for alpha/beta gravel pack placement. Extensive laboratory testing was performed to characterize fluid properties at various temperatures and oil-to-brine ratios. Performed in 4-in pipe, tests evaluated pressure drops at rates of up to 15 bbl/min, which revealed that the friction pressure generated by this fluid matches established empirical correlations for Newtonian fluids in turbulent flow. Finally, a full-scale yard test was performed to demonstrate that the fluid can be mixed using standard mixing equipment and used to successfully place alpha/beta gravel packs.
Effect and interaction study of acetamiprid photodegradation using experimental design
Authors: Tassalit Djilali , Chekir Nadia , Benhabiles Ouassila , Mouzaoui Oussama , Mahidine Sarah , Merzouk Nachida Kasbadji , Bentahar Fatiha , Khalil Abbas
Published: August 2016

The methodology of experimental research was carried out using the MODDE 6.0 software to study the acetamiprid photodegradation depending on the operating parameters, such as the initial concentration of acetamiprid, concentration and type of the used catalyst and the initial pH of the medium. The results showed the importance of the pollutant concentration effect on the acetamiprid degradation rate. On the other hand, the amount and type of the used catalyst have a considerable influence on the elimination kinetics of this pollutant. The degradation of acetamiprid as an environmental pesticide pollutant via UV irradiation in the presence of titanium dioxide was assessed and optimized using response surface methodology with a D-optimal design. The acetamiprid degradation ratio was found to be sensitive to the different studied factors. The maximum value of discoloration under the optimum operating conditions was determined to be 99% after 300 min of UV irradiation.
Improvement and prediction of OSA system performance in sludge reduction through integration with thermal and mechanical treatment
Authors: Nazif Sara , Mehrdadi Naser , Zare Sajad , Mosavari Sarvenaz
Published: August 2016

The oxic–settling–anoxic (OSA) process is one of the sludge production reduction methods in the activated sludge process. In this method, sludge is stored in an anaerobic tank within the sludge return line before entrance into an aeration tank. Due to this method's flexibility in application to operating treatment plants and not being energy-consuming, its application is developing. In this research, the improvement of the OSA process is investigated via thermal and mechanical treatment in a sequencing batch reactor (SBR). A pilot-scale reactor and domestic wastewater are used. Sludge was subjected to high temperature in an anaerobic tank using a heat transformer and it was subjected to mechanical shear through mechanical mixing in the anaerobic tank. Different temperatures and voltages were tested. The OSA process reduced sludge production by 24% while the chemical oxygen demand (COD) removal rate decreased from 90% to 86%. Thermal treatment combined with the OSA process caused a maximum of 46% sludge production reduction. However temperatures above 90 °C are not recommended due to a high level of decrease in COD removal. Mechanical mixing in combination with the OSA process led to 34% sludge production reduction. The effluent quality is not affected by the OSA process itself but is slightly reduced by thermal treatment and mechanical mixing. Therefore, for reaching the maximum sludge reduction in OSA plus thermal and mechanical treatment it would be necessary to evaluate the effect of different sets of parameters on effluent quality beside the sludge reduction. For this purpose multi-layer perceptron artificial neural network models are developed to predict the effluent total suspended solids and COD removal efficiency as well as sludge production rate. The models perform well and would be useful tools in determining the optimal set of system operation parameters.
The Mystery of the Lord’s Nativity in the Sermons of Leo the Great
Authors: Jasiewicz Arkadiusz
Published: August 2016

Jednym z piewców misterium Bożego Narodzenia był papież, św. Leon Wielki. Znamy dobrze działalność św. Leona dzięki jego przepięknym kazaniom – zachowało się ich niemal sto, zapisanych wspaniałą i jasną łaciną, oraz dzięki jego listom – ok. stu pięćdziesięciu. Wśród jego kazań znajdujemy te, które najbardziej nas interesują: na Narodzenie Pańskie (11 mów) i na Objawienie Pańskie (8 mów). Z tego materiału źródłowego staram się przybliżyć główne myśli naszego autora dotyczące misterium Bożego Narodzenia. Najpierw zatrzymuję się na duchowych owocach Tajemnicy Wcielenia, następnie ukazuje przyjście Pana jako objawienie się Miłosierdzia Bożego, a przy końcu wskazuję na postawę, jaką człowiek powinien zająć wobec tajemnicy Bożego Narodzenia. Tak streszcza swoją naukę: „Uciekając się bowiem znowu do miłosierdzia Bożego – co w tak niewysłowiony sposób ku nam zstąpiło, że Stwórca ludzi zechciał stać się człowiekiem – poznajemy siebie w Tym, któremu Boską część oddajemy” (Na Narodzenie Pańskie 8).
The Economy of Salvation According to 2 Tm 1 : 9–10
Authors: Wilk Janusz
Published: August 2016

Artykuł podejmuje analizę hymniczno-liturgicznego dwuwiersza, który porusza trzy aspekty tematyczne: odkupienie człowieka przez Boga (w. 9a); odwieczne postanowienie zbawienia człowieka przez Jezusa Chrystusa (w. 9b) oraz skutki odkupienia – nowe, nieprzemijające życie (w. 10). 2 Tm 1, 9–10 eksponuje zbawienie jako łaskę Boga wobec człowieka, który w żaden sposób nie mógł sam zainicjować lub zrealizować tego dzieła. Człowiek jednakże mógł i wciąż może przyjąć lub odrzucić jego skutki. Studium 2 Tm 1, 9–10 wskazuje również na semantyczną i tematyczną integralność tego dwuwiersza z całą perykopą 2 Tm 1, 6–14. Nie tylko nie przerywa on głównej myśli całej wypowiedzi (wierność i wytrwałość w służbie Ewangelii), ale stanowi jej szczegółowe wyjaśnienie, wskazując, czym jest Ewangelia, dla której warto przyjąć cierpienie wiążące się z niedalekim męczeństwem lub też z codzienną, systematyczną i uciążliwą pracą związaną z przepowiadaniem Dobrej Nowiny o zbawieniu człowieka dokonanym przez Boga w osobie Jezusa Chrystusa.
Utility of the intensive care unit in patients undergoing microvascular decompression: a multiinstitution comparative analysis
Authors: Lawrence Jesse D. , Tuchek Chad , Cohen-Gadol Aaron A. , Sekula Raymond F.
Published: August 2016

OBJECTIVE

Use of the ICU during admission to a hospital is associated with a significant portion of the total health care costs for that stay. Patients undergoing microvascular decompression (MVD) for cranial neuralgias are routinely admitted postoperatively to the ICU for monitoring. The primary purpose of this study was to compare complication rates of patients with and without a postoperative ICU stay following MVD. The secondary intents were to identify predictors of complications, to analyze variables of health care resource utilization, and to estimate the cost of postoperative management.

METHODS

The authors performed a retrospective comparative analysis of consecutive patients undergoing MVD at 2 institutions. A total of 199 patients without a postoperative ICU stay from Institution A and 119 patients with an ICU stay from Institution B were reviewed. Inclusion criteria included any adult (i.e., 18 years of age or older) undergoing MVD for trigeminal neuralgia, hemifacial spasm, glossopharyngeal neuralgia, or geniculate neuralgia. Patients with incomplete medical records were excluded. Medical comorbidities, intraoperative variables, complications, postoperative interventions, and variables indicating health care resource utilization were reviewed.

RESULTS

The study compared 190 patients without a postoperative ICU stay from Institution A with 90 patients with an ICU stay from Institution B. Seven patients without an ICU stay and 5 patients with an ICU stay experienced complications after surgery (p = 0.53). Multivariate analysis identified coronary artery disease to be a predictor of complications (p = 0.037, OR 6.23, 95% CI 1.12–34.63). Patients from Institution A without a postoperative ICU stay had a significantly shorter length of stay, by approximately 16 hours (p < 0.001), and received less postoperative imaging (p < 0.001, OR 14.39, 95% CI 7.75–26.74) and postoperative diagnostic testing (p < 0.001) than patients from Institution B with an ICU stay. Estimated cost savings in patients without an ICU stay and 1 less day of inpatient recovery was calculated as $1400 per patient.

CONCLUSIONS

Selective versus routine use of ICU care as well as postoperative imaging and diagnostic testing may be safe after MVD and can lead to a reduction in overall health care costs.