bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of tumor marker HE4 assay on the Elecsys 2010 analyzer
Authors: Ćorić Jozo , Hasanbegović Lejla , Bodulović Aleksandar , Mujić Jasminka
Published: February 2015

Introduction: Whey-acidic protein human epididymis protein 4 (HE4) is a new promising biomarker for epithelial ovarian cancer. The measured HE4 values may depend on the testing procedure used. The aim of this study was to evaluate theMethods: We evaluated a HE4 method on Elecsys 2010 analyzer. The method for quantitative determination of HE4 is direct, competitive chemiluminescent immunoassay. For quality control we use Elecsys PreciControl HE4 1 and 2. HE4 was measure on sera obtained from 56 women ( 20 healthy and 36 with epithelial ovarian cancer).Results: The Roche HE4 assays showed a good linearity (r=0.99) and precision (intrassayed total CV<5%). The median HE4 serum concentrations was significantly higher among EOC patients than healthy females (p<0,05). Elevated levels HE4 were found in 78 % patients with epithelial ovarian cancer.Conclusions: The presented results of the analytical evaluation methods for the determination of HE4 on the Elecsys 2010 analyzer showed an acceptable accuracy and precision.
Early extubation after congenital heart surgery
Authors: Halimić Mirza , Mesihović Dinarević Senka , Begić Zijo , Kadić Almira , Pandur Sanko , Omerbašić Edin
Published: February 2015

Introduction: Despite recent advances in anesthesia, cardiopulmonary bypass and surgical techniques, children undergoing congenital heart surgery require postoperativemechanical ventilation. Early extubation was definedas ventilation shorter than 12 hours. Aim of this study is to identify factors associated with successful early extubation after pediatric cardiac surgery.Methods: The study was performed during period from January 2006 to January 2011 at Pediatric Clinic and Heart Center University Clinical center Sarajevo. One hundred children up to 5 years of age, who have had congenital heart disease, with left–right shunt and obstructive heart disease were included in the study. Patients were divided into two groups: Group I - patients extubated within 12 hours after surgery and Group II - patients extubated 12 or more hours after surgery. Results: The most frequently encountered preoperative variables were age with odds ratio 4% 95%CI (1-7%), Down's syndrome 8.5 95%CI (1.6-43.15), failure to thrive 4.3 95%CI( 1-18). Statistically significant postoperative data included lung disease (reactive airways, pneumonia, atelectasis, pneumothorax) and with odds ratio 35.1 95 %CI (4-286) and blood transfusion with odds ratio 4.6 95%CI (2-12). Blood transfusion (p=0.002) (Wald=9.2) 95%CI (2-12), during as well as after operation procedure has statistically significant influence on prediction time of extubation. Proven markers were age with cut of 21.5 months (sensitivity 74% and specificity 70%) and extracorporeal circulation (ECC) with cut-of 45.5 minutes (sensitivity 71% and specificity 65%).Conclusion: Early extubation is possible in many children undergoing congenital heart surgery. Younger age and prolonged ECC time are markers associated with prolonged mechanical ventilation.
Nurses' Knowledge and Responsibility toward Nutritional Assessment for Patients in Intensive Care Units
Authors: Al Kalaldeh Mahmoud , Shahein Mahmoud
Published: February 2015

Introduction: Nutritional assessment is a prerequisite for nutritional delivery. Patients in intensive care suffer from under-nutrition and nutritional failure due to poor assessment. Nursing ability to early detect nutritional failure is the key for minimizing imparities in practice and attaining nutritional goals. Aim of this article is to examine the ability of Jordanian ICU nurses to assess the nutritional status of critically ill patients, considering biophysical and biochemical measures.Methods: This cross sectional study recruited nurses from different health sectors in Jordan. ICU nurses from the governmental sector (two hospitals) and private sectors (two hospitals) were surveyed using a self-administered questionnaire. Nurses' knowledge and responsibility towards nutritional assessment were examined.Results: A total of 220 nurses from both sectors have completed the questionnaire. Nurses were consistent in regard to knowledge, responsibility, and documentation of nutritional assessment. Nurses in the governmental hospitals inappropriately perceived the application of aspiration reduction measures. However, they scored higher in applying physical examination and anthropometric assessment.  Although both nurses claimed higher use of biochemical measurements, biophysical measurements were less frequently used. Older nurses with longer clinical experience exhibited better adherence to biophysical measurement than younger nurses.Conclusion: Nursing nutritional assessment is still suboptimal to attain nutritional goals. Assessment of body weight, history of nutrition intake, severity of illness, and function of gastrointestinal tract should be considered over measuring albumin and pre-albumin levels.  A well-defined evidence-based protocol as well as a multidisciplinary nutritional team for nutritional assessment is the best to minimize episodes of under-nutrition.
Knowledge, perception, practices and barriers of healthcare professionals in Bosnia and Herzegovina towards adverse drug reaction reporting and pharmacovigilance
Authors: Amrain Maša , Bečić Fahir
Published: February 2015

Introduction: Pharmacovigilance is an arm of patient care. No one wants to harm patients, but unfortunately any medicine will sometimes do just this. Underreporting of adverse drug reactions by healthcare professionals is a major problem in many countries. In order to determine whether our pharmacovigilance system could be improved, and identify reasons for under-reporting, a study to investigate the role of health care professionals in adverse drug reaction (ADR) reporting was performed.Methods: A pretested questionnaire comprising of 20 questions was designed for assessment of knowledge, perceptions, practice and barriers toward ADR reporting on a random sample of 1000 healthcare professionals in Bosnia and Herzegovina.Results: Of the 1000 respondents, 870 (87%) completed the questionnaire. The survey showed that 62.9% health care professionals would report ADR to the Agency for Medicinal Products and Medical Device of Bosnia and Herzegovina (ALMBIH). Most of surveyed respondents has a positive perception towards ADR reporting, and believes that this is part of their professional and legal obligation, and they also recognize the importance of reporting adverse drug reactions. Only small percent (15.4%) of surveyed health care professionals reported adverse drug reaction.Conclusions: The knowledge of ADRs and how to report them is inadequate among health care professionals. Perception toward ADR reporting was positive, but it is not reflected in the actual practice of ADRs, probably because of little experience and knowledge regarding pharmacovigilance. Interventions such as education and training, focusing on the aims of pharmacovigilance, completing the ADR form and clarifying the reporting criteria are strongly recommended.
The significance of psychosocial factors of the working environment in the development of sick building syndrome
Authors: Miškulin Maja , Matić Marina , Beneš Miodrag , Vlahović Jelena
Published: February 2015

Introduction: Sick building syndrome (SBS) is a medical condition in which people in a certain buildings suffer from symptoms of illness or feeling unwell. The aim of this study was to determine the frequency of exposure of the employees of public institutions from the city of Osijek to harmful psychosocial factors of the working environment, to assess whether there is a connection between the exposure to these factors and the incidence of SBS symptoms and to clarify the nature of this connection.Methods: This cross-sectional study was conducted during May 2013 among 178 employees of public institutions in the city of Osijek. An anonymous questionnaire which contained questions relating to demographic data and working status of the participants, their exposure to various harmful psychosocial factors of the working environment and occurrence of certain symptoms of SBS among them was used as a research tool.Results: 96.1 % (171/178) of participants were exposed to harmful psychosocial factors of the working environment. Employees exposed to those factors more frequently expressed symptoms of SBS. The incidence and the number of symptoms of SBS among employees simultaneously grew with the increase of the number of harmful psychosocial factors of the working environment to which they were exposed.Conclusion: The study showed positive connection between the exposure to harmful psychosocial factors of the working environment and the incidence of SBS symptoms, highlighting this issue as a very important subject in the field of occupational medicine and health protection in the workplace.
An extremely rare case of testicular malign neoplasm; alveolar subtype of rhabdomyosarcoma with long term follow-up.
Authors: Ipekci Tumay , Akin Yigit , Hoscan Burak , Tunckiran Ahmet
Published: February 2015

Testicular neoplasm usually occur in men aged between 15 and 35. These are solid organ tumours and also should be operated when there is a suspicious clinical findings. Testis tumours are levelled after histopathology evaluation. The medical, surgical and follow-up strategies of well know testis tumours, such as seminomas, non-seminom germ cell tumours, have been established. In case of testis tumours rare entities may occur as rhabdomyosarcoma.We here presented a rare case of   alveolar subtype of rhabdomyosarcoma in testis with long term follow-up.
Modern treatment of patent ductus arteriosus – single center experience
Authors: Mesihović Dinarević Senka , Kadic Almira , Begić Zijo , Halimić Mirza , Vukas Emina
Published: February 2015

Introduction: Transcatheter closure is a treatment choice for the most children with patent ductus arteriosus (PDA). The closure of the ductus is indicated in any child or adolescent with developed symptoms of significant L-R shunt. The aim of this article is to present our results in 5 years treatment of patients with PDA and their outcome. Methods: From 2009 to 2014, 30 patients underwent a transcatheter closure of PDA at Centre for Heart and Pediatric clinic of Clinical University Centre of Sarajevo. Aortic angiogram was performed to evaluate the size, position, and shape of the duct for selection of appropriate occluder device type and size. All procedures were performed by local team of cardiologists from the Department of Cardiology, Pediatric clinic, with invasive cardiologists team from Sweden and Austria. Echocardiography was repeated at intervals of 24 hours, then 1month, 3 months, and 1 year after the procedure to assess the outcome. Results: Thirty patients underwent transcatheter closure of PDA during the study period. PDA of ≤ 2.0 mm was present in 8 patients and they underwent PDA closure with coils, while 22 patients had PDA diameter  ≥ 2 mm, and they were treated by Amplatzer duct occluder (ADO). Only in 2 (6.2%) patients complications have been observed. The length of hospital stay after the treatment was two to three days. Conclusion: Transcatheter closure of PDA is a modern, safe and efficient method that ensures a faster recovery of the patients, shortens the length of hospitalization.
Increasing Hospital Breastfeeding Rates Through Online Education for Staff Registered Nurses
Authors: Baker Ann , Weideman Yvonne , Facello Debra
Published: February 2015

Background: The Baby-Friendly Hospital Initiative of 2010 recommends the proportion of mothers who breastfeed their babies in the early postpartum period should be at least 75% (Baby-Friendly USA, 2010). The exclusively breastfeeding rate at a community hospital located in the
Appalachian region is 44%, well below the proposed standard. Registered nurses who lack knowledge or exhibit a negative attitude toward breastfeeding, can impede the understanding and skills necessary to empower mothers to effectively breastfeed.

Purpose: This performance improvement
project was designed to determine whether an online educational module was effective in increasing the knowledge and improving the attitudes of nurses working with breastfeeding mothers.

Methods: A pre- and posttest design was used to evaluate nurse’s attitudes and knowledge of
breastfeeding.

Results: The results of the paired-sample t-test indicated a significant increase in the Breastfeeding Initiation Practice scores pre- and posttest. The exclusive breastfeeding rate had a clinically significant change from 44% to 58%.

Conclusion: An online
educational intervention was effective in increasing the knowledge of nurses working with breastfeeding mothers. This efficient and cost-effective intervention may be valuable to hospitals desiring to increase exclusive breastfeeding rates by increasing the knowledge and skill of staff.
Electrical Characterization and Mineralogical Differentiation of a Weathering Cover in the South Cameroon Humid Intertropical Zone using the Self-potential Method
Authors: Atangana Joseph Quentin Yene , Angue Monique Abossolo , Nyeck Brunot , Ndongue Constantin , Tchatat Jules Tchamdou
Published: February 2015

The study presented herein highlights the existence of a diversity of spontaneous sources of electric potential in weathering cover within the inter-tropical humid zone of south Cameroon. The study site presents a spatial mineralogical heterogeneity, which reveals the dominance of gibbsite more generally upslope, transitioning to a residual kaolinite downslope. The spatial characterization of these weathering mantles at the site revealed a general negative correlation between self-potential (SP), elevation, and sand and silt contents, confirming the existence of a dominant SP electrokinetic source. The main electrokinetic source is attributed to the presence of gibbsite, an abundant mineral at well drained relief summits of intertropical landscapes, likely resulting from the intense alteration of kaolinite. The electrofiltration phenomena related to fluid flow in the gibbsitic summit, quite rich in sand and silt, might justify this origin. A separate SP survey carried out in the kaolinitic mantles 5 km away, which lacked gibbsite, but was richer in clay, revealed a positive correlation between SP, elevation, and clay content of the surface horizons. The difference in correlation is attributed to the electrochemical nature of the SP within the second site. Thus, the diversity of sources of SP gives way to formulation of hypotheses on mineralogical differentiation and spatial characterization of lateritic covers.
Ground-truthing Electrical Resistivity Methods in Support of Submarine Groundwater Discharge Studies: Examples from Hawaii, Washington, and California
Authors: Johnson Cordell D , Swarzenski Peter W , Richardson Christina M , Smith Chris G , Kroeger Kevin D , Ganguli Priya M
Published: February 2015

Submarine groundwater discharge (SGD) is an important conduit that links terrestrial and marine environments. SGD conveys both water and water-borne constituents into coastal waters, where these inflows may impact near-shore ecosystem health and sustainability. Multichannel electrical resistivity techniques have proven to be a powerful tool to examine scales and dynamics of SGD and SGD forcings. However, there are uncertainties both in data aquisition and data processing that must be addressed to maximize the effectiveness of this tool in estuarine or marine environments. These issues most often relate to discerning subtle nuances in the flow of electricity through variably saturated media that can also be highly conductive (i.e., seawater).

Three contrasting field sites were examined for this study to assess the effectiveness of electrical resistivity techniques in varying coastal settings by comparing resistivity data to direct salinity and resistivity observations, quantifying changes in lithology and beach geomorphology, and fine-tuning inversion protocols. The three study sites all have substantial (up to 85 cm day−1) submarine groundwater discharge rates, but the hydrologic, oceanographic, and geologic characteristics of the sites are all very different. At a site in Pelekane Bay on the Big Island of Hawaii, seasonal flooding introduces very high concentrations of fine to coarse sediment into the bay. Near-shore circulation is limited in Pelekane Bay, so this newly introduced sediment can become deposited in the bay where it accumulates over time. At a site in Hood Canal, a fjord within Puget Sound, Washington, SGD rates can be high because of the large tidal range, abundant recharge, and steep hydrologic gradients. At Younger Lagoon in northern California, the flow of groundwater towards the coast is much more parsimonious, but here marine processes, including recirculated seawater, are important in controlling the flow of material towards the coast.

Rigorous ground-truthing at each field site showed that multi-channel electrcial resistivity techniques can reproduce the scales and dynamics of a seepage field when such data are correctly collected, and when the model inversions are tuned to field site characteristics. Such information can provide a unique perspective on the scales and dynamics of exchange processes within a coastal aquifer—information essential to scientists and resource managers alike.
Mature Field Revitalization: Resolving Historical-Data Uncertainties for Redevelopment of Mature Fields
Authors: Denney Dennis
Published: February 2015

This article, written by Technology Editor Dennis Denney, contains highlights of paper SPE 81101, "Resolving Uncertainties in Historical Data and the Redevelopment of Mature Fields," by I.S. Agbon, SPE, G.J. Aldana, and J.C. Araque, PDVSA-Intevep, and A.A. Mendoza and M.E. Ramirez, PDVSA-EPM, prepared for the 2003 SPE Latin American and Caribbean Petroleum Engineering Conference, Portof- Spain, Trinidad, 27-30 April.
EOR/IOR: A New Method to Characterize the Size and Shape Dynamics of Asphaltene Deposition
Authors: Bybee Karen
Published: February 2015

This article, written by Assistant Technology Editor Karen Bybee, contains highlights of paper SPE 84893, "A New Method to Characterize the Size and Shape Dynamics of Asphaltene Deposition Process in CO2 Miscible Flooding," by Douglas Fisher, SPE, Alberta Research Council; Nintoku Yazawa, SPE, Japan Natl. Oil Corp.; Hemanta Sarma, SPE, U. of Adelaide; and Marcel Girard, Alex Turta, SPE, and Haibo Huang, Alberta Research Council, prepared for the 2003 SPE International Improved Oil Recovery Conference, Kuala Lumpur, 20-21 October.
EOR/IOR: Displacement Optimization in Hydrocarbon Reservoirs
Authors: Bybee Karen
Published: February 2015

This article, written by Assistant Technology Editor Karen Bybee, contains highlights of paper SPE 81035, "Integrated Global Optimization of Displacement Efficiency in Hydrocarbon Reservoirs," by Daoyong Yang, SPE, U. of Regina; Qi Zhang, U. of Petroleum, China; Yongan Gu, SPE, U. of Regina; and Luhua Li, Tuha Petroleum Exploration & Development Corp., China, prepared for the 2003 SPE Latin American and Caribbean Petroleum Engineering Conference, Port-of-Spain, Trinidad, 27-30 April.
Overview: Mature Field Revitalization (January 2005)
Authors: Lagerlef David
Published: February 2015

Have you ever considered the foresight of the original designers of the mature fields where you have worked? It is often impressive. During the conceptual-design phase, considerations of functional flexibility vs. preinvesting were likely evaluated before deciding how to prepare the field for the future. Significant dividends are realized when this foresight can be incorporated into revitalization projects. Advanced planning for facilities, pipelines, and other infrastructures can reduce the need for significant modifications when implementing revitalization projects. For example, expansion piping runs, production losses, and footprint can be minimized.

It is difficult to eliminate all future obstacles; conflicting interests will inevitably arise. The best economic option is not always the optimal solution for one of the existing facilities or reservoirs, and compromises often have to be made. It is important in these situations to be able to make the most informed decision possible. Quality evaluation tools and data management are critical for determining the economic value of mutually exclusive alternatives. Reliable models and data-retrieval systems can assist present-day engineers in decision making to enable them to take advantage of unexpected revitalization opportunities in a mature field.

Situations can arise, even with the use of advanced planning and quality information, in which there seem to be insurmountable obstacles. The petroleum industry has a track record of meeting such challenges with little hesitation. Difficult deliberations on unanticipated opportunities for a mature field can stimulate impressive and innovative solutions. Our industry is capable of turning the seemingly impossible into reality, which can be crucial in revitalizing a mature field.

Additional Mature Field Revitalization Technical Papers

Available at the SPE eLibrary: www.spe.org

SPE 88604 - A Case Study of a Mature-Field Redevelopment Using Propped Hydraulic Fracturing

SPE 88769 - Maturing Field: A Case History Offshore Abu Dhabi

SPE 89469 - Revitalization of Pilar Field (Sergipe-Alagoas Basin, Brazil) Using Deviated Wells Along Fault Planes—A Successful Experience

SPE 91005 - Through-Tubing Rotary Drilling: A Cost-Effective Method for Sidetracking Wells in Mature Assets
Gas-Injection Pilot in the Hochleiten Field
Authors: Denney Dennis
Published: February 2015

This article, written by Technology Editor Dennis Denney, contains highlights of paper SPE 89356, "Gas-Injection Pilot in the Hochleiten Field," by K. Potsch, SPE, R. Ramberger, SPE, J. Glantschnig, SPE, S. Baumgarthuber, SPE, and F. Gossnitzer, SPE, OMV A.G., prepared for the 2004 SPE/DOE Symposium on Improved Oil Recovery,Tulsa, 17-21 April.

The Hochleiten field, a marginal field north of Vienna, Austria, is highly com-partmentalized and contains very viscous oil. Waterflooding worked only in a part of the reservoir. Poor communication and large pressure differences were observed across the field. A CO2 injection was attempted in an area in which no waterflood had been tried. Use of CO2 improved the inflow capacity of the injector, but oil production from affected wells increased only slightly. To match the actual response of the reservoir, reservoir-model adjustments became necessary. To support the existing reservoir description, an N2-tracer test was initiated to determine the preferred communication paths.

Introduction

The Hochleiten field was discovered in 1973. Production began in 1974. The main reservoir is the Tertiary Lower Sarmatian at a depth between approximately 710 and 800 m subsea. The structure map in Fig. 1 shows that the reservoir is highly compartmentalized with two major, probably sealing, faults. The reservoir is oil bearing, with small gas caps in Sectors A and C.

Approximately 30 wells have been drilled. A waterflood, comprising two wells each in Sectors A and C, was initiated in 1991 with mixed success because of the high level of structural and stratigraphical heterogeneity. Sector B was not included in the waterflood program because the production history did not define fault locations of impermeable layers.

In 1997, a detailed and integrated reservoir study was initiated to understand reservoir behavior. On the basis of new 3D-seismic data, a team of geoscientists and engineers revised the structural and stratigraphic framework of the field, leading to a new reservoir model for dynamic simulation. Several recompletions and infill-drilling locations were identified.

It became evident that lateral-facies changes, as well as reservoir compartmentalization, led to early pressure decline or early water breakthrough. Combining a material-balance model with neural-net-work models in one sector of the reservoir showed that the connectivity between wells and layers generally is poor, and, in particular, water injection at downdip locations could not support the pressure sufficiently in the updip areas of the structure. It also was found that the dissolution of gas increased oil recovery more efficiently than waterdrive alone. Therefore, gas injection is expected to be more efficient than waterflooding to access bypassed oil.
Enhanced Oil Recovery by Steamflooding, Cruse 'E' Field, Trinidad
Authors: Denney Dennis
Published: February 2015

This article, written by Technology Editor Dennis Denney, contains highlights of paper SPE 89411, "Enhanced Oil Recovery by Steamflooding in a Recent Steamflood Project, Cruse 'E' Field, Trinidad," by V. Ramlal, SPE, Petrotrin, prepared for the 2004 SPE/DOE Symposium on Improved Oil Recovery, Tulsa, 17-21 April.

On the basis of the success of the Cruse ‘E’ Pilot steamflood in Trinidad, Petrotrin decided to expand the thermal project. The project was commissioned in January 1996 when steam injection began. In November 1998, environmental concerns in a residential area near the steamflood required project shutdown. This paper discusses the performance of the steamflood during steam injection and during the shutdown period, the operational and economic aspects of the project, and the environmental upgrade conducted to restart the project.

Introduction

The Cruse ‘E’ steamflood is in the Parrylands area of southwestern Trinidad, 8 miles from the town of Point Fortin. It is one of several active thermal projects operated by Petrotrin and is the most recent steamflood developed by the company. The Cruse ‘E’ Expansion steamflood was undertaken following the success of the Cruse ‘E’ Pilot Project. With loan financing from the Inter-American Development Bank (IADB), 28 new patterns were formed by drilling 60 wells and incorporating 35 existing wells in the thermal area. Steam-generation and -distribution equipment and production facilities were installed during 1995, and steam injection began in January 1996. The shallow Cruse ‘E’ sands were ideal for steamflooding, and response was obtained in only 9 months. After 22 months, production reached 1,200 BOPD. For environmental reasons, the flood was shut down in November 1998, and approval was not obtained to restart until March 2002.

Factors that contribute to the success of this project include large reserves of shallow heavy oil (average gravity of 17°API); reliable, adequate supplies of fresh water for injection and natural gas for steam generation; good reservoir continuity within the project limits; 30 years’ accumulated company expertise in enhanced oil recovery; and the success of the pilot project.
Overview: Well Intervention and Control (January 2005)
Authors: Barnett David
Published: February 2015

Advances in well-control theory and practical applications continue to be developed and refined. Some of the most significant advances, and those that often appear in the literature as case histories, are those developed by multidisciplinary teams.

Problems that have plagued the industry for years are being dealt with by teams comprising specialists with expertise in drilling, geology, flu-ids, cementing, and reservoir engineering, to name a few. These problems are not necessarily those that arise solely from deeper drilling, harsh environments, or extreme water depths. They are age-old problems such as shallow gas, sustained casing pressure, and primary well-control procedures (i.e., kick detection and circulation).

Because these problems have been with us so long, partial solutions have been developed that at least allow us to continue drilling and producing, even in notoriously problematic areas. However, the number of unrecognized and mishandled influxes, shallow-gas events, flows after cementing, and producing wells with sustained casing pressure is just an indication that better solutions are needed.

It is encouraging to see the continuing effort from both operators and service companies to improve the materials and methods used to mitigate some of the longstanding well-control problems. This effort is not the typically high-profile, cutting-edge work that garners much of the attention in the industry. It is the practical effort aimed at applying new technology or new solutions to recurring problems.

Additional Well-Intervention and -Control Technical Papers

Available at the SPE eLibrary: www.spe.org

SPE 86706 - Comparison of Quantitative Blowout-Risk-Assessment Approaches

SPE 91009 - Gas Solubility in Synthetic Fluids: A Well-Control Issue

SPE 90427 - Software Simulation and System Design of Dynamic Killing Technique
Microannulus Leaks Repaired With Pressure-Activated Sealant
Authors: Bybee Karen
Published: February 2015

This article, written by Assistant Technology Editor Karen Bybee, contains highlights of paper SPE 91399, "Microannulus Leaks Repaired With Pressure-Activated Sealant," by David W. Rusch, SPE, Seal-Tite Intl.; Fred Sabins, SPE, Cementing Solutions Inc.; and John Aslakson, SPE, W&T Offshore Inc., prepared for the 2004 SPE Eastern Regional Meeting, Charleston, West Virginia, 15-17 September.

Sustained casing pressure (SCP) is a serious problem that is prevalent in most of the oil-producing regions of the world. Annular pressure can be a significant safety hazard and has resulted in blowouts on a number of occasions. SCP is the result of fluid migration in the annulus. The most common path for fluid migration is through channels in the annular cement. An injectable pressure-activated sealant was used to seal channels in the annular cement of several wells in the Gulf of Mexico (GOM).

Introduction

Fluid migration through the annuli of well-bores can result in a condition known as SCP. SCP is pressure that rebuilds in the annulus after being bled down. The integrity of all wellbores deteriorates with age. Cracks and fissures caused by factors related to cement composition, thermal stress, hydraulic stress, and compaction develop in the annular cement. The most significant cause of SCP in outer casing strings is a poor cement bond that results in cracks and annular channels. The cracks and microannulus channels provide a path for high-pressure fluids to migrate. A significant flow of high-pressure fluids can result in an underground blowout or failure of wellbore integrity.
Opening New Exploration Frontiers With the Microflux-Control Method for Well Design
Authors: Bybee Karen
Published: February 2015

This article, written by Assistant Technology Editor Karen Bybee, contains highlights of paper OTC 16622, "Opening New Exploration Frontiers With the Micro-Flux-Control Method for Well Design," by H. Santos, SPE, C. Leuchtenberg, and P. Reid, SPE, Impact Solutions Group, and A. Lage, SPE, Petrobras, originally presented at the 2004 Offshore Technology Conference, Houston, 3-6 May.

The new Microflux-control (MFC) method introduces several features that reduce the risks of conventional drilling, allowing a revision of the current set of well-design criteria. The full-length paper describes these new criteria and shows their benefit in terms of risk reduction and increased operational limits. The MFC method introduces new well-control concepts and addresses pore-pressure uncertainties. This drilling method allows reserves located in challenging areas to be explored more safely and economically.

Introduction

Reserves decline in mature basins has led the oil industry to move into more-challenging environments with increased drilling costs and risks. New drilling techniques need to be developed and used to exploit these new reserves economically.

Because the industry is very conservative, a long time usually is required for changes to be accepted and used to full potential. In many situations where new and advanced techniques are used, a traditional well design still is used with old numbers and concepts. Sometimes, regulatory bodies do not allow use of more-aggressive thinking even when it is based on and supported by successful tests. In other situations, rig contractors may be reluctant to accept the risks on their rigs or there may be insurance restrictions. Ultimately, it is the operator who has to accept and understand the benefits of introducing new techniques so that wells can be drilled to total depth (TD). Having introduced the MFC method in previous publications, the authors concentrate in the full-length paper on the benefits the method can provide in various environments.
Gate-Valve Milling Operation Performed With Coiled Tubing
Authors: Bybee Karen
Published: February 2015

This article, written by Assistant Technology Editor Karen Bybee, contains highlights of paper SPE 96685, "Pioneering ‘Gate Valve Milling’ Operation Performed With Coiled Tubing, Recovers an Important Oil Producer Offshore Brunei," by N.M. Al Araimi, SPE, Brunei Shell Petroleum; B. Gedge, SPE, and K. Burns, Weatherford; and M. Mahajan, SPE, BJ Services, prepared for the 2005 SPE Annual Technical Conference and Exhibition, Dallas, 9-12 October.

Brunei Shell Petroleum offshore Well A was shut in because the 3 1/8-in. master valve on the 5,000-psi monoblock tree was stuck in the closed position because of scale. Two options were considered for recovering the well with well intervention techniques rather than a complete workover and well-kill operation. Because the nearest gate-valve milling machine was in Europe, the valve was milled by use of a coiled-tubing (CT) unit that was on the platform performing a stimulation program on adjoining wells. This operation had been performed only once before, in the North Sea.

During routine wellhead maintenance, the lower master gate valve on Well A was found to be stuck in the closed position, most likely because of a broken stem related to scale buildup and attempts to open the valve. A number of attempts to free the seized valve by turning the wheel handle failed. The lost production caused by this well being offline was 1,260 BOPD, with a monetary loss of U.S. $1.9 million for every 30-day period.

Calcium carbonate scaling tendencies were identified as a likely cause of both the valve seizure and the progressive production decline observed since completion. A hydrochloric acid (HCl) soak treatment was performed, pumping 20 to 25 bbl acid into the wellbore. This treatment did not return the valve to operable service.

The HCl soak treatment was repeated. Because the gate valve was closed, this treatment consisted of a series of 1- to 1.5-bbl acid soak pills that were pumped and left to soak on top of the closed valve. After several hours, each spent pill was displaced through the flow wing outlet. This treatment also was not successful.

An alternative approach was required, and its timing was driven by a compliance need to access and test the subsurface safety valve (SSSV) that was beneath the gate valve. Milling would allow throughbore access to test the SSSV and set plugs to allow tree repair.

Considerations

Use of a gate-valve milling machine has proved to be successful in the past in a number of locations in the world, particularly in geothermal operations, where tree valve seizure is a common occurrence because of the often high scale production and cooling at surface, causing scale precipitation. The problem for this option was that the only unit available was in Europe. To mobilize the unit to Brunei would be expensive and time consuming, and additional equipment like blowout preventers (BOPs) also would have to be mobilized, making this a very expensive option, even if it was sound technically.
Oil and Gas: A Relationship Game
Authors: Donaldson Kevin
Published: February 2015

Guest editorial

Supermajors. Multinationals. Integrated oil companies. These are all terms used to describe the world's largest energy companies. All inspire thoughts of market leadership, control, and power. For many years, that would have been a fair assessment of status. But are things changing?

A recent Financial Times article titled "The New Seven Sisters: Oil and Gas Giants Dwarf Western Rivals" sought to develop an industry consensus regarding the most influential energy companies outside of Organization for Economic Cooperation and Development (OECD) countries. Numerous industry executives were polled and their responses collated. The resulting list included Saudi Aramco, Gazprom, CNPC of China, the National Iranian Oil Company, Petróleos de Venezuela, Petrobras, and Petronas.

These companies are overwhelmingly state-owned and control almost one-third of the world's oil and gas production and more than one-third of its total oil and gas reserves. And the old seven sisters—now four companies as a result of industry consolidation in the 1990s—produce about 10% of the world's oil and gas and hold just 3% of reserves.

So if state-controlled oil companies have the power, does this mean that the international oil companies (IOCs) have had their day in the sun? Are these once-giants of industry now shadows of their former selves, facing a future of begging at the table of the mighty national oil companies (NOCs)? Sensationalists may suggest this to be the case, but not most well-informed industry commentators.

It is a fact, however, that NOCs are more influential today than ever before. Their control over the bulk of global supply, reserves, and projected demand growth inherently gives them economic and political power. But this is not the only reason for their increasing influence on the sector. They also have become much more active in the market.

This increase in activity has been driven by governments asking more of their NOCs as they strive to ensure national security and prosperity. NOCs are, as a result, required to leverage their advantageous energy positions to deliver the infrastructure development (both energy and nonenergy in nature), job creation, energy security, and secondary and tertiary industries their respective governments desire.

New Continues To Need Old

IOCs retain significant influence over the global energy arena, and they collectively represent some of the largest reserves holders, producers, and petrochemical manufacturers operating today. Perhaps more importantly, they are also the technology, intellectual-property, and project-management powerhouses of the industry. As such, IOCs bring a lot to the global oil and gas party. They are here to stay.
A Diverless Retrofit-Tee Hot-Tap GMA-Welding Method
Authors: JPT staff _
Published: February 2015

Technology Update

The basic principle of hot-tapping is to establish a new branch pipeline connection to an existing pipeline while the primary pipeline is under full pressure. This involves connecting the branch pipe, including a valve, to the primary pipeline. Usually, this is accomplished by means of welding or a mechanical clamp connection—cutting a hole in the pipe wall with a machine connected to the valve, retracting the cutting head, closing the valve, and disconnecting and recovering the cutting machine. The pipe branch then may be extended by means of spools and a tie-in to a new pipeline in the normal way. This strategy has been shown to be very cost-effective, compared with alternative methods, including shutdown and tie-in at ambient pressure conditions.

To date, for underwater applications, divers have been used to weld the branch pipe to the primary pipeline, and all installation and cutting operations also have been performed by divers. The cutting machines are essentially marinized versions of standard onshore hot-tap cutting machines and not optimized for the subsea application. This makes it diver-intensive, requiring the training and qualification of diver/welders in advance for the substantial welding job and operation of the cutting machine.

The primary focus of the remote hot-tap project has been the development of a novel design for a diverless installation, combining the use of a remotely installed mechanical clamp, providing the structural integrity and interface with the isolation-valve module and hot-tap cutting tool, and a "seal weld" made by remotely operated hyperbaric gas metal arc (GMA) welding inside the branch pipe (Fig. 1). The intention of the seal weld is not to provide structural capacity as such, but to make a highly reliable, "metal-to-metal" seal meeting at least the same quality standard as that which traditional manually welded hot-taps are meeting today.

The seal-welding qualification program has included work to demonstrate feasibility for up to 2000-m operation and a full, specific program for a potential 145-m application. The programs have included work on mechanical-property characterization and hydrogen pickup, and demonstration of repeatable hyperbaric-GMA-weld quality, even though it is not a structural weld as such. The new remote system will represent a substantial cost reduction because the vessel alone that is used for the remote equipment costs approximately half as much daily as a diver-supported vessel, even before diver-qualification costs are considered. More importantly, the system will extend the capability of the hot-tapping method beyond water depths limited by divers. The remote hot-tap welding tool is shown in Fig. 2.
Pazflor Project Pushes Technology Frontier
Authors: Parshall Joel
Published: February 2015

In its latest campaign to push the deepwater technology frontier on Angola's prolific Block 17, Total has embarked on the Pazflor project. Proceeding under a concession granted by the Angolan national oil company Sonangol, and following upon industry milestones established by Total on the same block at Girassol, Dalia, and Rosa, Pazflor will feature several world firsts for subsea technology, includingFull-field gas/liquid (G/L) separation and liquid boosting systems at the mudlineHybrid boosting pumpsVertical-separator technology

Located approximately 93 miles offshore Luanda and 25 miles northeast of the Dalia complex, in water depths of 2,000 to 3,900 ft, the Pazflor development will bring four fields into production, Perpetua, Acacia, Zinia, and Hortensia, which were discovered between mid 2000 and early 2003 (Fig. 1). The project derives its name from the initial letters of three of those fields (Perpetua, Acacia, and Zinia) and the similar-sounding Portuguese word pasiflor, for passion flower. Thus continues the floral nomenclature on Block 17 established by Girassol (translated: sunflower), Dalia, and the Jasmim and Rosa subsea tiebacks to Girassol.

Like the earlier core developments, Pazflor will be produced by means of a floating processing, storage, and offloading (FPSO) unit. The hull of this processing behemoth will weigh 82,000 tonnes, while its 15 topside modules will weigh an aggregate 37,000 tonnes. Combined, the weight of 119,000 tonnes will make this one of the largest FPSOs in the world. Holding accommodations for 240 persons, the FPSO will process the oil produced by a system of 49 subsea wells that includes 25 producers, 22 water injectors, and two natural gas injectors. The total subsea production system, linked by a network of 109 miles of pipelines and 51 miles of umbilicals, will be spread over a vast expanse of 232 sq miles—some seven times larger than the city of Paris—and have a north/south axis of 19 miles (Figs. 2 and 3). The FPSO will have an oil-processing capacity of up to 220,000 barrels per day (B/D) and storage capacity of 1.9 million barrels, bringing the installed production capacity on Block 17 to more than 700,000 B/D.

The Pazflor project carries a budgeted cost of approximately USD 9 billion. Total, as operator, holds a 40% share in the project, with the remaining interests held by StatoilHydro (23.3%), Esso (20%), and BP (16.7%). Major contracts have been awarded to Daewoo Shipbuilding & Marine Engineering to provide the FPSO; a consortium of SBM and APL to provide the buoy turret offloading system; FMC to provide the subsea separation and production systems; and a consortium of Technip and Acergy to provide the risers, umbilicals, and flowlines.
Technologies Contributing to Increased Recovery
Authors: Bybee Karen
Published: February 2015

This article, written by Assistant Technology Editor Karen Bybee, contains highlights of paper OTC 19418, "Technology Contribution to Increased Recovery," by H. Kjorholt, SPE, A.H. Jorgenvag, SPE, and S. Strom, SPE, StatoilHydro, originally prepared for the 2008 Offshore Technology Conference, Houston, 5-8 May. The paper has not been peer reviewed.

The full-length paper focuses on the past and present strategy of StatoilHydro in developing and implementing improved-oil-recovery (IOR) technologies and lists the technologies that have been key to increased recovery and gives indications regarding the way forward.

Introduction

Increased reserves from IOR activities in mature fields often turn out to be the cheapest and fastest way for an operator to find and develop new hydrocarbons. Technology development is mandatory to increase reserves through IOR.

As an operator, StatoilHydro will not in this setting "sit back" and wait for suppliers to come up with new ideas. They want to define the type of technology required to meet their IOR ambitions and establish partnerships with selected institutes and service providers.

When the technology is deemed necessary by the research and development organization, business assets, and management of the company, the basis for starting a structured research-and-development program is in place. The next phase is to select the supplier. It is believed that the suppliers also will benefit from such cooperation because a successful project will result in a dedicated customer.

Fig. 1 shows how the ultimate recovery in a number of assets has increased since the projects were sanctioned. The average ultimate recovery for all StatoilHydro-operated oil fields today is approximately 50%. The recovery for developments based on dry wellheads is 10 to 12% higher than the recovery in subsea developments. Even though these numbers are high compared to a worldwide average, the objective is to increase recovery by an additional 1 billion bbl, corresponding to a major-field development.

Some important characteristics of IOR volumes in mature fields are the following.Their presence is verified (no exploration in the traditional sense is required).Significant infrastructure is already in place.The knowledge of the reservoir is far better than for new developments.The economic boundary conditions are well known.

The challenge is to get the oil out of the ground with acceptable cost. The key is to develop technologies that can enhance drainage efficiency.

There are no obvious factors such as reservoir properties or drilling challenges responsible for the gap in recovery between subsea and platform developments; it is solely a consequence of the present economic reality of operating subsea vs. from a fixed installation.