Pore Pressure Prediction in Sandstone Using a Lateral Transfer Approach

Accurate pore pressure prediction is required to determine reliable static mud weights and circulating pressures, necessary to mitigate the risk of influx, blowouts and borehole instability. To accurately estimate the pore pressure, the over-pressure mechanism has to be identified with respect to the geological environment. One of the most widely used methods for pore pressure prediction is based on Normal Compaction Trend Analysis, where the difference between a ‘normal trend' and log value of a porosity indicator log such as sonic or resistivity is used to estimate the pore pressure. This method is biased towards shales, which typically exhibit a strong relationship between porosity and depth. Overpressure in non-shale formations has to be estimated using a different method to avoid errors while predicting the pore pressure. In this study, a different method for pore pressure prediction has been performed by using the lateral transfer approach. Many offset wells were used to predict the pore pressure. Lateral transfer in the sand body was identified as the mechanism for overpressure. This form of overpressure cannot be identified by well logs, which makes the pore pressure prediction more complex. Building a 2D geomechanical model, using seismic data as an input and following an analysis methodology that considered three type of formation fluids - gas, oil and water in the sand body, all pore pressure gradients related to lateral transfer for the respective fluids were evaluated. This methodology was applied to a conventional reservoir in a field in Colombia and was helpful to select the appropriate mud weight and circulating pressure to mitigate drilling risks associated to this mechanism of overpressure. Seismic data was critical to identifying this type of overpressure mechanism and was one of the main inputs for building the geomechanical earth model. This methodology enables drilling engineers and geoscientists to confidently predict, assess and mitigate the risks posed by overpressure in non-shale formations where lateral transfer is the driving mechanism of overpressure. This will ensure a robust well plan and minimize drilling/well control hazards associated with this mode of overpressure.

The prevalence and risk factors of low back pain among the nurses at Sardjito Hospital, Yogyakarta, Indonesia

Background: The study aimed to identify the prevalence and risk factors of LBP among the nurses at Sardjito Hospital. Method: A cross-sectional study was conducted in Sardjito Hospital Yogyakarta. LBP was measured in nurses who had work for one year using the Keele Start Back Screening Tool (KSBT) and Orebro Musculoskeletal Pain Questionnaire (OMPQ). A simple and multiple logistic regression was used for analysis. Results: Of 800 valid subjects, 324 (40.5%) have the history of LBP complaint, 88.9% were suffering the pain during the data collection. The most significant variables are the history of previous spinal complaints (p = 0.00), slide board use for lateral transfer (p=0.010), gender (p=0.026) and current work place (p=0.019). Nine of the 288 patients of LBP have high risk in line with the KSBT stratification, while 22 of 288 patients have High Estimated Risk of Future Work Disability that agrees with the stratification of performance prognosis using OMPQ. Conclusion: The prevalence of LBP among the nurses at Sardjito Hospital reaches 40.5%, with 88.9% of whom still suffer from pain during the data collection. The risk factors of LBP among the nurses are previous spinal complaint, tools for lateral transfer, work place and gender. Key words: Risk factor; Lower back pain; Nurses; Pain; Prevalence Citation: Mahmud, Sri R, Iqbal MR, Lukman WA, Sri HN. The prevalence and risk factors of low back pain among the nurses at Sardjito Hospital, Yogyakarta, Indonesia. Anaesth. pain intensive care 2021;25(1):19–26; DOI 10.35975/apic.v25i1.1432 Received: 13 November 2020, Reviewed: 18 November 2020, Accepted: 16 December 2020

Δ14C PEAKS APPEARING IN EARLYWOOD AND LATEWOOD TREE RINGS (AD 770–780) IN NORTHEASTERN ARIZONA

ABSTRACT The AD 775 peak in Δ14C (henceforth, M12) was first measured by Miyake et al. and has since been confirmed globally. Here we present earlywood and latewood Δ14C values from tree rings of pinyon pine (Pinus edulis) from Mummy Cave, Canyon de Chelly National Monument, Chinle, Arizona, USA, for the period AD 770–780. These data reconfirm the timing of M12 and show a small rise in Δ14C in AD 774 latewood. Allowing for the delay in lateral transfer of radiocarbon produced at high latitude, this suggests that 14C peak production occurred in late winter or spring of AD 774. Additionally, Δ14C decreased slightly in the earlywood of AD 775 and increased in the latewood of AD 775 to a higher level than that observed in AD 774.

Mapping the past, present and future research landscape of paternal effects

Although in all sexually reproducing organisms, an individual has a mother and a father, non-genetic inheritance has been predominantly studied in mothers. Paternal effects have been far less frequently studied, until recently. In the last five years, research on environmentally induced paternal effects has grown rapidly in the number of publications and diversity of topics. Motivations for studies into paternal effects are also diverse. For example, from the ecological and evolutionary perspective, paternal effects are of interest as facilitators of response to environmental change and mediators of extended heredity. Medical researchers track how paternal pre-fertilization exposures to factors, such as toxins, trauma or diet, influence offspring health. In consequence, literature on paternal effects is large and disparate. Here, we systematically review and synthesize this heterogeneous field to help fostering connections between areas of knowledge that develop in parallel, but which could benefit from the lateral transfer of concepts and methods.