bluuebunny/crossref_metadata_2025 huggingface dataset:
Sildenafil Prevents and Reverses Transverse-Tubule Remodeling and Ca
2+
Handling Dysfunction in Right Ventricle Failure Induced by Pulmonary Artery Hypertension
Authors: Xie Yu-Ping , Chen Biyi , Sanders Philip , Guo Ang , Li Yue , Zimmerman Kathy , Wang Lie-Cheng , Weiss Robert M. , Grumbach Isabella M. , Anderson Mark E. , Song Long-Sheng
Published: December 2011

Right ventricular (RV) failure (RVF) is the main cause of death in patients with pulmonary artery hypertension (PAH). Sildenafil, a phosphodiesterase type 5 inhibitor, was approved recently for treatment of PAH patients. However, the mechanisms underlying RV contractile malfunction and the benefits of sildenafil on RV function are not well understood. We aimed to investigate the following: (1) the ultrastructural and excitation-contraction coupling alterations underlying PAH-induced RVF; (2) whether the ultrastructural changes are reversible; and (3) the mechanisms underlying the therapeutic benefits of sildenafil in PAH-RVF. We used a single injection of monocrotaline in Wistar rats to induce pulmonary vascular proliferation, which led to PAH and RVF. RV myocytes displayed severe transverse (T)-tubule loss and disorganization, as well as blunted and dys-synchronous sarcoplasmic reticulum Ca
2+
release. Sildenafil prevented and reversed the monocrotaline-induced PAH and LV filling impairment. Early intervention with sildenafil prevented RV hypertrophy and the development of RVF, T-tubule remodeling, and Ca
2+
handling dysfunction. Although late treatment with sildenafil did not reverse RV hypertrophy in animals with established RVF, RV systolic function was improved. Furthermore, late intervention partially reversed both the impairment of myocyte T-tubule integrity and Ca
2+
handling protein and sarcoplasmic reticulum Ca
2+
release function in monocrotaline-treated rats. In conclusion, PAH-induced increase in RV afterload causes severe T-tubule remodeling and Ca
2+
handling dysfunction in RV myocytes, leading to RV contractile failure. Sildenafil prevents and partially reverses ultrastructural, molecular, and functional remodeling of failing RV myocytes. Reversal of pathological T-tubule remodeling, although incomplete, is achievable without the regression of RV hypertrophy.
Effectiveness of a School-based Fluoride Mouthrinse Program
Authors: Divaris K. , Rozier R.G. , King R.S.
Published: December 2011

The aims of this study were to estimate the caries-preventive effects of a school-based weekly fluoride mouthrinse (FMR) program and to determine whether its effectiveness varied by school-level caries risk. We used clinical and parent-reported data for 1,363 children in grades 1 through 5 from a probability sample of North Carolina (NC) schoolchildren. Children’s caries experience was measured using decayed and filled primary (d2,3fs) and total (d2,3fs+D2,3MFS) tooth surfaces. Program participation was quantified using ‘FMR years’. To estimate caries risk at program entry, children were matched with NC kindergarten-surveillance data representing school-level mean untreated decay (low-risk school: < 1 and high-risk school: ≥ 1 untreated carious teeth). Mean d2,3fs was 4.1 [95% confidence limits (CL) = 3.7, 4.5]. Overall, each ‘FMR year’ was associated with weak reduction of caries prevalence in the primary [prevalence ratio (PR) = 0.98; 95% CL = 0.90, 1.06] and the mixed dentition (PR = 0.98; 95% CL = 0.91, 1.05). We found a trend toward a larger caries-preventive benefit among children in high-risk schools compared with those in low-risk schools ( i.e., 55% vs. 10% caries reduction for 5 to 6 yrs of FMR participation compared to none). Although this difference was not confirmed statistically, our results indicate that children in high-risk schools, as identified by school-level surveillance data, may experience substantial caries-preventive benefits from long-term FMR participation.
An Evaluation of Intimate Partner Violence Intervention With Incarcerated Offenders
Authors: Connors Angela D. , Mills Jeremy F. , Gray Andrew L.
Published: December 2011

The following study is an evaluation of the Moderate Intensity Family Violence Prevention Program (MIFVPP). The sample consisted of 298 male federal offenders who participated in the MIFVPP while incarcerated or on release within the community. Participants were assessed pre-, mid-, and postprogram using an assessment battery consisting of self-report questionnaires and facilitator-rated evaluation scales. Results of the study found uniform and significant ( p < .001) improvement for pre and post program change in the self-report questionnaires and in the facilitator ratings. A positive improvement in motivation, whether assessed by the participant or facilitator, was associated with improvement in program outcomes and significant within, between, and interaction effects were found when participant program performance over time was compared among grouped postprogram ratings of motivation. The implication for the efficacy of addressing offender motivation to change in intimate partner violence (IPV) interventions is discussed.
Bullying Among Adolescents in North Cyprus and Turkey
Authors: Bayraktar Fatih
Published: December 2011

Peer bullying has been studied since the 1970s. Therefore, a vast literature has accumulated about the various predictors of bullying. However, to date there has been no study which has combined individual-, peer-, parental-, teacher-, and school-related predictors of bullying within a model. In this sense, the main aim of this study was to test a multifactor model of bullying among adolescents in North Cyprus and Turkey. A total of 1,052 adolescents (554 girls, 498 boys) aged between 13 and 18 ( M = 14.7, SD = 1.17) were recruited from North Cyprus and Turkey. Before testing the multifactor models, the measurement models were tested according to structural equation modeling propositions. Both models indicated that the psychological climate of the school, teacher attitudes within classroom, peer relationships, parental acceptance-rejection, and individual social competence factors had significant direct effects on bullying behaviors. Goodness-of-fit indexes indicated that the proposed multifactor model fitted both data well. The strongest predictors of bullying were the psychological climate of the school following individual social competence factors and teacher attitudes within classroom in both samples. All of the latent variables explained 44% and 51% of the variance in bullying in North Cyprus and Turkey, respectively.
Sexual Assault Nurse Examiners’ Perceptions of Their Relationship With Doctors, Rape Victim Advocates, Police, and Prosecutors
Authors: Maier Shana L.
Published: December 2011

In response to the negative and inefficient treatment of rape victims by emergency room personnel, the first Sexual Assault Nurse Examiner (SANE) programs began in the late 1970s. While SANEs, doctors, rape victim advocates, police officers and prosecutors work together to ensure the most comprehensive and sensitive care of rape victims, they all have very different roles and objectives. This research explores SANEs’ perceptions of their relationships with other professionals who treat or interact with rape victims. Data from interviews with 39 Sexual Assault Nurse Examiners from four East Coast states indicate positive relationships are marked by open communication, respect shown towards SANEs as well as rape victims, and a sense of appreciation among SANEs. On the contrary, negative relationships result when SANEs believe police treat victims poorly, when advocates overstep boundaries and question SANEs about evidence collection or the exam, and when prosecutors fail to properly prepare them to testify during a trial.
Intimate Partner Violence Perpetration by Court-Ordered Men
Authors: Hall Jeffrey E. , Walters Mikel L. , Basile Kathleen C.
Published: December 2011

This study continues previous work documenting the structure of violence perpetrated by males against their female intimate partners. It assesses the construct validity of a measurement model depicting associations among eight subtypes of perpetration: moderate physical violence, severe physical violence, forced or coerced sexual violence, sexual violence where consent was not possible, emotional/verbal psychological abuse, dominance/isolation psychological abuse, interactional contacts/surveillance related stalking, and stalking involving mediated contacts. Data were obtained from a sample of 340 men arrested for physical assault of a female spouse or partner, and court ordered into batterer intervention programs. Men were surveyed before starting the intervention. Confirmatory factor analyses (CFA) supported the validity of model as evidenced by good model to data fit and satisfaction of requirements for fit statistics. In addition, the eight factor solution was characterized by a slightly better model to data fit than a four factor higher order solution described in the author’s previous work. Latent variable correlations across the broader categories of intimate partner violence (IPV) revealed that the violence subtypes were mostly moderately positively correlated and ranged from .381 (emotional/verbal psychological abuse with interactional contacts/surveillance related stalking) to .795 (dominance/isolation psychological with abuse with forced sex). Future studies should determine whether there are distinct risk factors and health outcomes associated with each of the eight IPV perpetration subtypes and identify possible patterns of co-occurrence.
Victims’ Influence on Intimate Partner Violence Revictimization
Authors: Kuijpers Karlijn F. , Van der Knaap Leontien M. , Winkel Frans Willem
Published: December 2011

Research has reported that not only characteristics of the perpetrator but also characteristics of the victim influence risk for intimate partner violence (IPV). This would suggest that prevention of repeat abuse could benefit from a focus on both perpetrator and victim characteristics. Knowledge on factors that are within victims’ sphere of influence is important because a focus on victim characteristics can help victims to take control of their situations and can thereby empower them. Dynamic victim-related factors are most relevant here as these are factors that can be changed or improved, in contrast to unchangeable static factors. Surprisingly, however, little is known about how victim-related factors affect risk for revictimization of IPV. The current study was conducted among a Dutch sample of 156 female, help-seeking IPV victims. The aim was to examine to what extent prior IPV and, in particular, dynamic victim-related factors influence risk for future IPV. In accordance with the models articulated by Foa, Cascardi, Zoellner and Feeny, we studied how the three key factors from their models—partner violence, victims’ psychological difficulties, and victims’ resilience—related to risk for IPV revictimization. Results provide support for several key factors (partner violence and victims’ psychological difficulties) and, moreover, show which victim-related factors contribute to revictimization risk above and beyond the influence of prior violence committed by a partner against the victim (i.e., victims’ prior IPV victimizations). Findings are discussed in terms of recommendations for practice and future research.
Repetition, Power Imbalance, and Intentionality
Authors: Cuadrado-Gordillo Isabel
Published: December 2011

The criteria that researchers use to classify aggressive behaviour as bullying are ‘ repetition’, ‘ power imbalance’, and ‘ intent to hurt’. However, studies that have analyzed adolescents’ perceptions of bullying find that most adolescents do not simultaneously consider these three criteria. This paper examines adolescents’ perceptions of bullying and of the different forms it takes, and whether these perceptions vary according to the teen’s role of victim, aggressor, or witness in a bullying situation. The data acquisition instrument was a questionnaire applied to a sample of 2295 teenagers. The results show that none of these three groups considered the criterion of repetition to be important to define bullying. A further conclusion was that both aggressors and witnesses used the criteria of ‘ power imbalance’ and ‘ intent to hurt’ to identify a situation of bullying, although the aggressors placed especial emphasis on the superiority of power over the victim, while the witnesses emphasized the intent to hurt the victim. One noteworthy finding was that victims do not consider the factor ‘ power imbalance’. The factor that determined their perceptions was the ‘ intent to hurt’. Finally, some modes of bullying were seen as forms of typical teen social interactions, and the perception depended significantly on the adolescent’s role as aggressor, victim, or witness.
Soliciting and Using Input During Organizational Change Initiatives
Authors: Lewis Laurie K. , Russ Travis L.
Published: December 2011

Scholars have documented many benefits of participatory processes during change including minimizing participants’ resistance, increasing their satisfaction, and strengthening their perceptions of control. Ironically, evidence also suggests that participative communication approaches are underused. This study explores implementers’ solicitation and use of stakeholder input during change processes. Twenty-six implementers from different organizations were interviewed and their responses were transcribed and thematically analyzed. Four general approaches to soliciting and using input were groundedly developed from these data. Findings suggest that the interviewees in this study tend to favor the “restricted” and “advisory” approaches to input solicitation and use. In the restricted model, implementers were highly selective about who was asked for input and aimed to disregard negative feedback. In the “advisory” approach, implementers solicited input more widely however were mixed in the degree to which negative feedback was used to make modest improvement in the change initiative.
Acculturation Phenomena Experienced by the Spouses of Korean International Students in the United States
Authors: Kim Junhyoung
Published: December 2011

I explored the ways in which Korean international students’ spouses perceived and coped with the challenges associated with the adaptation process. I used in-depth interviews to examine how they dealt with life challenges, barriers, and coping strategies associated with acculturative stress. Three themes were identified: challenging life experiences and barriers as immigrants, the experience of emotional and psychological distress and stress, and new identified family structures. Two coping strategies used with acculturative stress were addressed: the recognition of personal strength and involvement in meaningful activities. I found that purposeful and meaningful activities associated with volunteerism, as well as cultural values and beliefs, played important roles in coping with stress. Further investigation into the role of meaningful activities for immigrants is necessary to have a better understanding of the phenomenon.
From Bridges to Trading Zones in Organizational Culture and Institutional Research
Authors: Morrill Calvin
Published: December 2011

Scholarship on organizational culture and institutional analysis differ in their intellectual origins, modal research methods, and mechanisms explaining stability and change. At the same time, these two traditions share an underlying concern with systems of meaning. Against this backdrop the conto the symposium used two strategies to write across the boundaries separating cultural and institutional analysis. The first strategy involved developing common meta-theoretical languages and the second focused on identifying research problems and questions in scholarly “trading zones” where approaches drawn from both cultural and institutional perspectives can be developed. Trading zones suggest certain advantages in working across scholarly traditions with respect to problem scale, theoretical scope, methodology, and graduate education.
Effect of Prostaglandin E1 on Pulmonary Arterial Hypertension Following Corrective Surgery for Congenital Heart Disease
Authors: Dong Ming-Feng , Ma Zeng-Shan , Ma Sheng-Jun , Chai Shou-Dong , Tang Pei-Zhe , Yao Dao-Kuo , Wang Lexin
Published: December 2011

Objective:

To evaluate the therapeutic effects of prostaglandin E1 (PGE1) on residual pulmonary arterial hypertension (PAH) after corrective surgery for congenital heart disease.

Methods:

Thirty-one patients with postoperational PAH were randomly divided into control group (n = 15) and PGE1 group (n = 16, 6 courses of intravenous PGE1 plus conventional therapy). Mean pulmonary arterial pressure (MPAP), right ventricular ejection fraction (RVEF), and left ventricular ejection fraction (LVEF) were measured by echocardiography before and 3, 6, and 12 months after the treatment. Arterial oxygen pressure (Pao2) was monitored.

Results:

In both groups, MPAP decreased and RVEF, LVEF, and Pao2 increased at 6 and 12 months following surgery. In the PGE1 group, the MPAP (32.2 ± 5.2 vs 40.2 ± 5.1 mm Hg; P = .008) was lower and RVEF (66.6% ± 6.5% vs 54.9% ± 2.1%; P = .019), LVEF (65.9% ± 3.9% vs 53.5% ± 5.1%; P = .031), and Pao2 (94.3% ± 11.2% vs 93.1% ± 11.3%; P = .009) was higher than in the control group 12 months after the surgery. Four patients (26.7%) in the control group died of pulmonary hypertension crisis, but there was no death in the PGE1 group ( P = .029). Cumulative survival rate in the control group were 86.7%, 80%, 73.3%, and 73.3% at 1, 2, 3, and 5 years, respectively.

Conclusions:

Intravenous PGE1 therapy after corrective surgery for congenital heart disease was associated with a reduction in mean pulmonary arterial pressure and a lower risk of death.
Patient Preference for Emergency Care
Authors: DeLia Derek , Cantor Joel C. , Brownlee Susan , Nova Jose , Gaboda Dorothy
Published: December 2011

The authors use a statewide survey to examine care seeking behavior in the emergency department (ED). Most patients who go to the ED (69.3%) do so mainly for conditions they believe are urgent. Time before seeking ED care is highly variable from immediately (28.7%) to more than 1 week (7.0%) and is only weakly related to the perceived urgency of medical condition. Healthier individuals initiate ED care more rapidly than sicker patients. In retrospect, 80.4% of patients would go to the same ED if they had the same medical episode but this percentage falls substantially with increased ED waiting time. Subject to some limitations uncovered in model specification tests, the study highlights several correlates of ED care seeking behavior that may be useful for designing strategies to divert some patients away from the ED. It also raises larger questions, however, about whether diversion is optimal from patient and health system perspectives.
Determinants of patient satisfaction in ambulatory oncology: a cross sectional study based on the OUT-PATSAT35 questionnaire
Authors: Thanh Vân France Nguyen , Bosset Jean-François , Monnier Alain , Fournier Jacqueline , Perrin Valérie , Baumann Cédric , Brédart Anne , Mercier Mariette
Published: December 2011

Background

The aim of this study was to identify factors associated with satisfaction with care in cancer patients undergoing ambulatory treatment. We investigated associations between patients' baseline clinical and socio-demographic characteristics, as well as self-reported quality of life, and satisfaction with care.

Methods

Patients undergoing ambulatory chemotherapy or radiotherapy in 2 centres in France were invited, at the beginning of their treatment, to complete the OUT-PATSAT35, a 35 item and 13 scale questionnaire evaluating perception of doctors, nurses and aspects of care organisation. Additionally, for each patient, socio-demographic variables, clinical characteristics and self-reported quality of life using the EORTC QLQ-C30 questionnaire were recorded.

Results

Among 692 patients included between January 2005 and December 2006, only 6 were non-responders. By multivariate analysis, poor perceived global health strongly predicted dissatisfaction with care (p < 0.0001). Patients treated by radiotherapy (vs patients treated by chemotherapy) reported lower levels of satisfaction with doctors' technical and interpersonal skills, information provided by caregivers, and waiting times. Patients with primary head and neck cancer (vs other localisations), and those living alone were less satisfied with information provided by doctors, and younger patients (< 55 years) were less satisfied with doctors' availability.

Conclusions

A number of clinical of socio-demographic factors were significantly associated with different scales of the satisfaction questionnaire. However, the main determinant was the patient's global health status, underlining the importance of measuring and adjusting for self-perceived health status when evaluating satisfaction. Further analyses are currently ongoing to determine the responsiveness of the OUT-PATSAT35 questionnaire to changes over time.
Influence of retinoblastoma-related gene silencing on the initiation of DNA replication by African cassava mosaic virus Rep in cells of mature leaves in Nicotiana benthamiana plants
Authors: Bruce Gareth , Gu Mei , Shi Nongnong , Liu Yule , Hong Yiguo
Published: December 2011

Background

Geminiviruses mainly infect terminally differentiated tissues and cells in plants. They need to reprogramme host cellular machinery for DNA replication. This process is thought to be mediated by inactivation of cell-cycle repressor proteins and by induction of host DNA synthesis protein expression through actions of the geminviral replication initiator protein (Rep).

Findings

Exploiting a Nicotiana benthamiana pOri2 line, which is transformed with a transgene consisting of a direct repeat of the African cassava mosaic virus (ACMV)-replication origin (Ori) flanking a non-viral DNA region, and virus-induced RNA silencing (VIGS), the impact of host gene expression on replication of the ACMV-derived replicon was investigated. The ACMV Rep trans-replicated the viral episomal replicon in leaves of young but not older pOri2 plants. Upon VIGS-mediated down-regulation of N. benthamiana NbRBR1, the retinoblastoma-related protein gene coding for a negative cell-cycle suppressor, recovered the ability of ACMV Rep for trans DNA replication, whereas the silencing of NbPCNA coding for the sliding clamp of DNA polymerase had no effect.

Conclusions

These results suggest that the cellular machinery for DNA replication in differentiated tissues of older leaves cannot be reprogrammed by Rep alone but may need other uncharacterised viral and plant factors.
The Alzheimer's β-secretase enzyme BACE1 is required for accurate axon guidance of olfactory sensory neurons and normal glomerulus formation in the olfactory bulb
Authors: Rajapaksha Tharinda W , Eimer William A , Bozza Thomas C , Vassar Robert
Published: December 2011

Background

The β-secretase, β-site amyloid precursor protein cleaving enzyme 1 (BACE1), is a prime therapeutic target for lowering cerebral β-amyloid (Aβ) levels in Alzheimer's disease (AD). Clinical development of BACE1 inhibitors is being intensely pursued. However, little is known about the physiological functions of BACE1, and the possibility exists that BACE1 inhibition may cause mechanism-based side effects. Indeed, BACE1-/- mice exhibit a complex neurological phenotype. Interestingly, BACE1 co-localizes with presynaptic neuronal markers, indicating a role in axons and/or terminals. Moreover, recent studies suggest axon guidance molecules are potential BACE1 substrates. Here, we used a genetic approach to investigate the function of BACE1 in axon guidance of olfactory sensory neurons (OSNs), a well-studied model of axon targeting in vivo.

Results

We bred BACE1-/- mice with gene-targeted mice in which GFP is expressed from the loci of two odorant-receptors (ORs), MOR23 and M72, and olfactory marker protein (OMP) to produce offspring that were heterozygous for MOR23-GFP, M72-GFP, or OMP-GFP and were either BACE1+/+ or BACE1-/-. BACE1-/- mice had olfactory bulbs (OBs) that were smaller and weighed less than OBs of BACE1+/+ mice. In wild-type mice, BACE1 was present in OSN axon terminals in OB glomeruli. In whole-mount preparations and tissue sections, many OB glomeruli from OMP-GFP; BACE1-/- mice were malformed compared to wild-type glomeruli. MOR23-GFP; BACE1-/- mice had an irregular MOR23 glomerulus that was innervated by randomly oriented, poorly fasciculated OSN axons compared to BACE1+/+ mice. Most importantly, M72-GFP; BACE1-/- mice exhibited M72 OSN axons that were mis-targeted to ectopic glomeruli, indicating impaired axon guidance in BACE1-/- mice.

Conclusions

Our results demonstrate that BACE1 is required for the accurate targeting of OSN axons and the proper formation of glomeruli in the OB, suggesting a role for BACE1 in axon guidance. OSNs continually undergo regeneration and hence require ongoing axon guidance. Neurogenesis and the regeneration of neurons and axons occur in other adult populations of peripheral and central neurons that also require axon guidance throughout life. Therefore, BACE1 inhibitors under development for the treatment of AD may potentially cause axon targeting defects in these neuronal populations as well.
Exceptionally preserved fossil insect ears from the Eocene Green River Formation of Colorado
Authors: Plotnick Roy E. , Smith Dena M.
Published: December 2011

Tympanal ears in insects are important for both intraspecific communication and for the detection of nocturnal predators. Ears are thought, based on modern forms, to have originated independently multiple times within insects and can be found on multiple regions of the body. Here we describe and document the exceptionally well preserved tympanal ears found in crickets and katydids from the Eocene Green River Formation of Colorado, which are virtually identical to those seen in modern representatives of these groups. These specimens are among the best preserved insect ears in the fossil record and establish the presence of ears in two major clades of Orthoptera 50 million years ago. Also discussed and evaluated are previously described insect ears from the Mesozoic and the implications of the findings of the present study for studying the evolution of ears within insects.
Smart E&P Collaboration Centers: Design, Technology Support, and Lessons Learned
Authors: Al-Qahtani Adel A. , Hogg Martin F. , Lau Kenneth K. , Al-Naser Naser A.
Published: December 2011

The application and adoption of collaboration centers in the exploration and production (E&P) industry have increased significantly in the past decade. The benefits of collaboration-center use have been clearly identified including the delivery of cost-effective and fully integrated multidiscipline field, reservoir, and well management decisions.

Saudi Aramco has established a number of collaboration centers that directly capitalize on large-scale, multidiscipline, value-added technical and business collaborations. These centers, for instance, cover areas of exploration, geosteering, real-time drilling, field development, and production and intelligent-field management. Tangible economic and technical benefits of such collaboration encompass improved recovery, improved technical workflows, technology innovation, enhanced staff-skill-set development, and significant reduction of critical field-development-study cycle times. This paper outlines Saudi Aramco's experience from 5 years of using multidiscipline collaboration centers with a focus on facility design, technology (software and hardware) support, and lessons learned.

Advances in interactive, high-performance technology solutions (hardware and software) and easy-to-use visual communication technologies present additional opportunities to extend and enhance the value-added impact of collaboration centers, including virtual collaboration. The need for physical, localized centers will be discussed, compared, and evaluated in the context of virtual-collaboration-center potential. The paper presents a "checklist" methodology for collaboration-center design, layout, support, and maintenance incorporating the challenges of continuous technology advancement and multidiscipline project complexity.
Simulation on the Method of Determining Remaining Oil Saturation by Measuring Dual Pulsed Neutron Parameters
Authors: Feng Zhang , Chao Yuan , Juntao Liu , Shuang Hou , Yan Sun
Published: December 2011

The parameters of C/O ratio and Sigma based on pulsed neutron source can be obtained at the same time in one logging, which utilizes a special pulse and measurement timing design to record inelastic, capture gamma ray spectra and gamma ray time spectrum at the far and near detector. By combining dual parameters for determining oil, water and gas saturation, it can resolve the problem no way to distinguish gas and water only using C/O, oil and fresh water only using Sigma, in addition, it can determine saturation under the condition of unknown borehole porosity information. By theoretical analysis and Monte Carlo simulation method, the gamma ray time spectrum after repetitive pulse of neutron emission can still meet the exponential decay law, and repetitive pulse before neutron lifetime measuring can raise gamma count rate of time spectrum 3 to 5 times, therefore, the dual parameters measured simultaneously in one logging are feasible. Through dual parameters of C/O ratio and Sigma, the C/O data is cross plotted against Sigma data and then to determine oil, water and gas saturation. By using Monte Carlo method to set up computation model, inelastic gamma spectrum, capture gamma spectrum and time spectrum under certain borehole and formation conditions can be simulated, and the logging response is given when determining oil, water and gas saturation by using cross plot technique of C/O and Sigma. In addition, the influence of lithology, porosity, shale content, borehole size, formation water salinity and gas density on determining saturation were simulated, and it will provide response relation for determining oil saturation by dual parameters of C/O ratio and Sigma.
Multi-Million Cell SAGD Models - Opportunity For Detailed Field Analysis
Authors: Akram Farrukh
Published: December 2011

Canada has the world’s largest deposits of ultraheavy oil and bitumen, estimated at 2.5 trillion barrels. Thermal recovery processes such as CHOPS (cold heavy-oil production with sand), SAGD (steam-assisted gravity drainage), and CSS (cyclic steam stimulation) have been successfully employed and promise good recovery for these oil sands. SAGD, however, is a relatively new technology and most of these projects are struggling to reach their expected production rates.

SAGD recovery shortcomings are mostly related to geological aspects of the reservoirs that were not fully understood initially, and reservoir simulation studies are being conducted to improve the understanding of reservoir response to steam injection. As operators are gaining experience with the SAGD process, it is becoming clear that oil sands are anything but homogenous and have tremendous variations in key geological and reservoir properties.

Building models for thermal simulation is significantly more complex than building them for conventional simulations, requiring more computing power, more iteration, and more memory. To capture the details of heterogeneity in a thermal reservoir simulation model, a very fine-scale grid is required. Also, a full-field model is required to appropriately understand the interplay of steam chambers for adjacent well pairs.

The results gained by combining both full-field and thermal simulation results into a multimillion-cell model more accurately represent the geological heterogeneity and movement of steam along the wellbores. The methodology presented in this paper uses advanced simulator and computing technology for this purpose. The model preserves the extreme detail required for accurate interpretation and prediction, enabling testing of sensitivity for multiple operational parameters such as injection pressures and limiting flow pressures.

A unique well-placement design is chosen that allows for greater sweep efficiency and flexibility in well placement. Advanced computing technology enables the large model to be run in a fraction of the time required by conventional techniques, enforcing greater accuracy in results and preserving the true behavior of the steam flow. To reduce the uncertainty of operational parameters, a sensitivity plot is provided to describe the parameters that have the most impact on the SAGD behavior.

The methodology presented here allows for uncertainty and sensitivity analysis using a multimillion-cell model, bridging the gap between geology and engineering and instilling greater confidence in the results of the reservoir simulation study. The ultimate objective is to acquire more accurate results so that the expected SAGD production rates can be achieved through optimization of technology and processes.
Optimal Soak Time for Cyclic Steam Stimulation of a Horizontal Well in Gravity Drainage Reservoirs
Authors: Wu Z. , Vasantharajan S.
Published: December 2011

In an earlier work, we presented a new, semi-analytical gravity drainage model to predict oil production of a horizontal well under cyclic steam stimulation. In this paper, the model for the horizontal well is extended from the gravity drainage representation to more accurately predict performance during the cyclic steam stimulation. The water–vapor equilibrium in the cylindrical chamber created by injected steam in the vicinity of the well, heat losses to surrounding oil, formation during the steam soaking stage, and oil production are now included in the modified model. The computation procedure consists of solving the transient heat conduction equations to obtain the temperatures in the chamber and surrounding oil during the soak period and determining the temperature decline during the oil production phase. By using the proposed model, one can optimize the soak time to maximize the cumulative oil production. A case stud is presented to illustrate this capability.

Sensitivity studies have also been conducted to better understand the impact of steam quality and steam injection volumes on well performance. The proposed model is employed on an example application to enhance cumulative oil production.
Modeling of a New Field Development Plan for a Giant Offshore Oilfield in the UAE
Authors: Bachar S. , Obara H. , Watanabe M.
Published: December 2011

A modeling study was undertaken to optimize the subsurface development of a giant offshore oil field in the UAE, using the concept of artificial islands. The new development plan capitalized on many advantages of artificial island in terms of surface and subsurface flexibility [Ref.1].

The main objective of this paper is to present the dramatic changes in a field development plan (FDP) which have been achieved by incorporating the concept of Maximum Reservoir Contact (MRC) wells and Geologic Drainage Area (GDA) for development of reservoir G. This revised FDP was the result of evaluating various development options for reservoir G and incorporating learning from sector model through a workflow which was established for this purpose.

In this paper, we describe multiple field development options which have been evaluated for reservoir G through full field modeling and sector model sensitivity studies. Recommendations are made for the optimal development plan. The recommended development plan (referred to as the Island Option) is tailored to the geologic description of the reservoir and uses 3 km maximum reservoir contact (MRC) wells in addition to shorter MRC wells, enabled by drilling wells from islands instead of conventional drilling and production towers ("WHPTs"). Key elements of the island development plan are that it:Is based on a variably spaced, line drive pattern floodHonors the reservoir geology and current oil saturation distributionUses ~3 km MRC wells with closer spacing (~0.5 to 1 km) in place of the current 500 m to 1 km WHPT wells in areas of the reservoir with low permeabilityUses ~1 km MRC wells with larger spacing (~1 to 1.5 km) in areas of the reservoir with high permeabilityPerforms better than the predecessor development plan (referred to as WHPT Option) in terms of plateau duration and ultimate recovery

The recommended plan for reservoir G is the Island Option, which calls for drilling 79 new wells compared to the WHPT Option which would have required 140 new wells. The new wells in the island development plan are a mix of 3 km MRC wells, 1 km horizontal wells and vertical wells. The MRC wells are oriented in a northwest-southeast direction to be aligned with the predominant fault direction in the field, reducing the risk of poor areal sweep because of water breakthrough resulting from wells intersecting faults.
Permeability Characterization of a High-K Dolomitized Interval: A Case Study from an Early Cretaceous Carbonate Reservoir of a Giant Oil Field, Offshore Abu Dhabi, United Arab Emirates
Authors: Yamamoto K. , Al-Zinati O. , Ottinger G. , Edwards E. , Kompanik G. , Al-Ameri M. B.
Published: December 2011

This paper presents an approach for permeability characterization of a thin, high-K dolomitized interval based on application of depositional and diagenetic concepts. The interval is 3.5 feet in average thickness and has higher permeability values than surrounding limestones. It is an important drilling target and the permeability shows significant heterogeneity vertically and laterally which impacts future well placement and completion designs of long laterals. Detailed core observations from 85 wells suggests that the intensity of dolomitization is laterally variable at an inter-well scale, but that there is a clear vertical trend of dolomite content increasing towards the middle part of the interval at each well location. The dolomitization is often concentrated within the grain-dominated facies and, in general, it leads to increased permeability. However, in some instances it can result in an intense overdolomitization yielding degraded reservoir quality. Permeability can also be improved in some areas by leaching of non-dolomitized material, particularly in the crestal area of the field.

Core and petrographic observations combined with plug analysis data suggest that the dolomitized zone can be divided into three sublayers and characterized by two rock types: Dolostone with well-developed intercrystalline pores (high-K) and highly overdolomitized dolostone that occur in the middle sublayer.Calcareous dolostone characterized by weaker dolomitization and/or dissolution that are in the upper/lower sublayers. This rock type is also occasionally assigned to the middle sublayer where dolomitization is locally weak.

Regression analyses of plug porosity-permeability values are characterized by one regression line for the dolostone rock type, which represent a higher permeability trend (Trend 1) that contrasts the calcareous dolostone rock type (Trend 2).

The proposed fine-scale layering scheme and rock typing can be used to model the vertical and lateral petrophysical heterogeneity and permeability contrasts of the high-K dolomitized interval.
Development of A Fast Auxiliary Subspace Pre-conditioner for Numerical Reservoir Simulators
Authors: Hu Xiaozhe , Liu Wei , Qin Guan , Xu Jinchao , Zhang Zhensong
Published: December 2011

Abstract The Fast Auxiliary Space Preconditioning (FASP) method is a general framework for constructing effective preconditioners for solving discretized partial differential equations (PDEs). By constructing appropriate auxiliary spaces, FASP transforms a complicated problem into a sequence of simpler solver-friendly systems. In this paper, we present a new FASP preconditioner for petroleum reservoir simulations. According to the analytic characteristics for the pressure and saturation variables in the black oil model, we choose appropriate auxiliary spaces for different parts of the Jacobian systems arising from the fully implicit method (FIM) with coupled implicit wells. By combining the new preconditioner with Krylov subspace methods (such as the GMRes method), we construct an efficient and robust solver, which can be easily generalized to more complicated models like the modified black oil model for simulating polymer flooding. Preliminary numerical experiments demonstrate the advantages of this new preconditioner. Introduction The solution of the linear system of equations arising from fully implicit method for a large scale reservoir simulation has many challenges. Very often more than 80% of CPU time in fully implicit reservoir simulation is usually spent on solving Jacobian systems resulting from the Newton linearization. These linear systems are large, sparse, highly nonsymmetric and ill-conditioned. The Krylov subspace methods1, such as BiCGstab and GMRes, are efficient iterative methods for these Jacobian systems. Since these iterative methods do not converge very well by themselves, many preconditioners have been proposed over the years. They mainly fall in two categories: (i) purely algebraic preconditioners and (ii) preconditioners based on the different properties of the variables. In the category (i), there are, for example, point-wise incomplete lowerupper factorization (ILU) methods2, 3, 4, 5, block ILU methods6, 7, nest factorization methods8, 9, and SVD-reduction methods10. In the category (ii), on the other hand, the methods are based on the understanding that pressure variables and saturation variables have different PDE properties; the representative examples are the Combinative method11, Constrained Pressure Residual (CPR) method12, 13, and multi-stage methods14, 15, 16.
Stabilizing Fracture Faces in Water-Sensitive Shale Formations
Authors: Weaver J. D. , Nguyen P. D. , Loghry R. A.
Published: December 2011

Fracturing water-sensitive shale formations with water-based fracturing fluids requires special attention to minimize the destabilization of high-clay-content shale formations. The reaction of water with clay minerals can result in clay swelling, dispersion, and flocculation. Failure to prevent these effects can lead to fracture-face softening and sloughing, resulting in significant loss of fracture conductivity.

The use of chemical additives designed to minimize the effect of water-based fluids on clay minerals is a well-established technology for formation-matrix treatment of high-permeability formations where fluid leakoff during a treatment is significant. Because shale formations exhibit permeabilities in the nanodarcy (nD) range, high fluid loss and matrix treatment is not the dominate concern. Typical pore-throat diameters in shale can be in the nanometer (nm) range, and actual molecular size becomes paramount.

A variety of additives are advertised to prevent clay damage, but little information is provided explaining how they work, how to select the appropriate product, and how to optimize the treatment. This paper presents a comparative study, including many of the currently available clay-control materials tested on a variety of simulated and actual shale-formation materials.

Chemical mechanisms describing how these products function to stabilize clay minerals and how these mechanisms control the duration they remain in the formation to provide protection to the clay minerals are also presented to enhance the general understanding of product selection, capability, and limitations. A review of current laboratory-testing methods used to make recommendations, including limitations and precautions, is included.
Fracture Height Containment in the Stimulation of Oriskany Formation
Authors: Vatsa Tushar , Wang John Yilin
Published: December 2011

The Oriskany formation has been a prolific producer of natural gas in the Appalachian basin since 1930s. Lot of production wells have been converted to gas storage wells for the ease of operation. Natural gas storage industry is a vital part of North American energy driven economy because of the fluctuation in seasonal demand and in maintaining the reliability of supply needed to meet the demands of the consumer. However, the storage wells suffer from an annual deliverability loss of 5% owing to the various damage mechanisms.

A lot of work pertaining to the issue of identification of damage mechanisms, and subsequent development of stimulation technology in order to mitigate the damage and restore the wells deliverability has been done in a joint effort between The Gas Research Institute, Department of Energy, American Gas Association and the various other operator companies involved in the storage industry. Operators mostly rely on traditional methods such as blowing, washing, reperforating, acidizing, infill drilling to restore wells deliverability. These traditional methods do provide short term benefits but the longevity is not sustained and the overall situation remains same. Hydraulic fracturing is not preferred in terms of legitimate concerns over excessive vertical height growth, long fracture fluid clean up times, lack of expertise and cost.

This research study was carried out to understand the various damage mechanisms affecting the Oriskany wells, with a focus on gas storage wells. I then developed a dataset of reservoir properties, rock properties and fracture treatment data for Oriskany based on a complete literature review and calculations from a sonic log. New stimulation methods were developed based on a systematic parametrical study on the type of fracture fluids, injection rate, types of proppant, treatment volume, reservoir pressure and treatment schedule. These new methods lead to increased well deliverability, fracture height containment and higher average fracture conductivity.
Drilling, Production, Intervention Milling Tool - Records Achieved in Milling of Cemented Tubulars, a Technological Standout with Real Field Results
Authors: Fisher Jerry , Bailey Tom , Bansal R. K. , Haq Mohammed A.
Published: December 2011

The scenario of having drill string or work string cemented up in plugging or squeezing operations is a real occurrence and if the right procedures are not followed, then the intervention process can be lengthy, time consuming with increased costs to the operator. The intervention techniques for drill pipe or work string can be either washing over or milling it out. During wash-over operations when the cemented tubular is eccentric to the casing, and little progress is made, milling the cemented tubular is the best option. Using conventional junk mills, the rates of penetration (ROP) achieved are significantly lower and the over-all mill life is between 10-50 ft before the mill cores out. This paper describes a new cemented tubular mill designed and ruggedly constructed to mill wellbore tubulars that are internally and externally cemented. With its enhanced geometry, this mill has exceeded the rate-of-penetration performance of standard crushed-carbide and/or insert-dressed mills. This paper also describes real field results in details - both with correct application as well as results of incorrect applications.

As always, the objective of this paper is to disseminate technical information within the SPE guidelines.