Application of Machine Learning Algorithms in Hydrocarbon Exploration and Reservoir Characterization

This dissertation presents novel approaches to evaluate complex seismic and well-log data using machine learning algorithms with examples from two different hydrocarbon fields. The applicability of these algorithms for predicting and classifying direct or indirect hydrocarbon indicators are assessed and compared to knowledge-driven methods. The efficacy of the various techniques leads to recommendations for utilizing machine learning algorithms in well planning or later cycle hydrocarbon-field development. In the first study in this dissertation, application of a model-based artificial neural network is compared to the performance of a prestack simultaneous inversion method in predicting hydrocarbon presence in the Heidrun Field, offshore Norway. Low-frequency initial models were used to create 3D Poisson’s ratio models to reflect the fluid within this field and the results were compared based on the accuracy and generalization power of the two methods. The results of both methods confirmed Poisson’s ratio to be a good direct hydrocarbon indicator within the wells used from this field. The direct dependency of the inversion method on the provided input constraints, however, can raise the risk for well planning decisions beyond the known zones. The generalize regression neural network results better matched the observations at the training wells and provided a lower risk of false discoveries in delineating favorable zones beyond the drilled wells. The second study was conducted with the aim of classifying different facies from well logs in wells of the Heidrun Field and in the Kupe Field, offshore New Zealand. Different machine learning approaches were utilized in this study and to investigate quantitatively and qualitatively the accuracy and stability of their predictions. Both supervised methods could successfully predict hydrocarbon-bearing units, with the bagged tree algorithm having a higher overall, and hydrocarbon-related, accuracy rate. Application of the bagged-tree algorithm showed a very low false discovery rate for oil sands and no false discoveries for gas sands in the Heidrun Field. A misclassification of oil sands as brine sands in one Heidrun well is in agreement with relatively high Poisson’s ratios as discussed in the first study. Qualitative investigations of Kupe Field results also demonstrated accurate prediction of hydrocarbon-bearing units, including a shaly hydrocarbon sand class defined for low-quality reservoir sands. Hydrocarbon shows reported in one well that were not predicted by the algorithm, in fact, occur in a very low-porosity section of the reservoir that was not identified as reservoir in reports either. In the last study, the classifications of the litho-fluid facies were extended to three dimensional models using two machine learning methods and were compared with a knowledge-driven approach. The results were examined through a probabilistic approach to reflect the uncertainty of the predicted classes. The probabilistic neural network and the bagged-tree algorithm successfully predicted the variations of litho-fluid facies, especially for hydrocarbon units. Both methods predicted gas sands in certain parts of the field, away from control points, with similar form and lateral dimension. By comparing the results in predicting oil sands and shale, we interpret the bagged-tree method to be more adherent to the known parameters set by the interpreter, such as the OWC and the target classes. Predictions from the probabilistic neural network, however, can deviate from the target facies even close to the wells on which it has been trained. The efficiency of machine learning techniques in increasing the prediction accuracy and decreasing the procedure time, and their objective approach toward the data, make it highly desirable to incorporate them in seismic data analyses. Along with the emphasis on the application of machine learning techniques in the study of subsurface properties, this dissertation presents frameworks for utilizing these techniques as new tools for the interpreter, not as a replacement. The knowledge of the data analyst about the field, and the selection and preparation of the attributes and application of the appropriate algorithm are all crucial factors in this procedure.Release after 01/24/201

Adapting an intervention of brief problem-solving therapy to improve the health of women with antenatal depressive symptoms in primary healthcare in rural Ethiopia

Background: Evidence-based brief psychological interventions are safe and effective for the treatment of antenatal depressive symptoms. However, the adaptation of such interventions for low- and middle-income countries has not been prioritised. This study aimed to select and adapt a brief psychological intervention for women with antenatal depressive symptoms attending primary healthcare (PHC) in rural Ethiopia. Methods: We employed the Medical Research Council (MRC) framework for the development and evaluation of complex interventions. Alongside this, we used the ADAPT-ITT model of process adaptation and the ecological validity model (EVM) to guide content adaptation. We conducted formative work, comprising a qualitative study, a series of three participatory theories of change workshops and an expert adaptation workshop to assess the needs of the target population and to select an intervention for adaptation. The adaptation process followed a series of steps: (1) training Ethiopian mental health experts in the original South African problem-solving therapy (PST version 0.0) and an initial adaptation workshop leading to PST Version 1.0. (2) Version 1.0 was presented to perinatal women and healthcare professionals in the form of a ‘theatre test’, leading to further adaptations (version 2.0). (3) Local and international stakeholders reviewed version 2.0, leading to version 3.0, which was used to train 12 PHC staff using clinical cases. (4) Finally, feedback about PST version 3.0 and its delivery was obtained from PHC staff. Results: In the first step, we modified case examples and terminology from the South African model, introduced an in-session pictorial flipchart for this low literacy setting, and added strategies to facilitate women’s engagement before translating into Amharic. In the second step, adaptations included renaming of the types of problems and inclusion of more exercises to demonstrate proposed coping strategies. In the third step, the components of motivational interviewing were dropped due to cultural incongruence. In the final step, refresher training was delivered as well as additional training on supporting control of women’s emotions to address PHC staff training needs, leading to the final version (version 4.0). Conclusion: Using a series of steps, we have adapted the content and delivery of brief PST to fit the cultural context of this setting. The next step will be to assess the feasibility and acceptability of the intervention and its delivery in antenatal care settings

Pregnant women and health workers’ perspectives on perinatal mental health and intimate partner violence in rural Ethiopia: a qualitative interview study

BackgroundMental health conditions are common during the perinatal period and associated with maternal, foetal, and neonatal morbidity and mortality. There is an established bidirectional relationship between mental health conditions and intimate partner violence (IPV), including during and after pregnancy. Mean lifetime prevalence of physical, sexual or emotional IPV exposure among women in rural Ethiopia is estimated to be 61% and may be even higher during the perinatal period. We aimed to explore the perspectives of women and antenatal care (ANC) health workers on the relationship between all types of IPV and perinatal mental health, to inform the adaptation of a psychological intervention for pregnant women experiencing IPV in rural Ethiopia.MethodsWe conducted in-depth qualitative interviews with 16 pregnant women and 12 health workers in the Gurage zone of the Southern Nations, Nationalities and People’s Region of Ethiopia, between December 2018 and December 2019. We conducted thematic analysis of English-translated transcripts of audio-recorded Amharic-language interviews.ResultsParticipants contextualised IPV as the primary form of abusive treatment women experienced, connected by multiple pathways to emotional and bodily distress. Patriarchal norms explained how the actions of neighbours, family, community leaders, law enforcement, and government agents in response to IPV often reinforced women’s experiences of abuse. This created a sense of powerlessness, exacerbated by the tension between high cultural expectations of reciprocal generosity and severe deprivation. Women and health workers advocated a psychological intervention to address women’s powerlessness over the range of difficulties they faced in their daily lives.ConclusionsWomen and health workers in rural Ethiopia perceive multiple, interconnected pathways between IPV and perinatal emotional difficulties. Contrary to expectations of sensitivity, women and health workers were comfortable discussing the impact of IPV on perinatal mental health, and supported the need for brief mental health interventions integrated into ANC

Viewpoint: WHO world mental health surveys international college student initiative: implementation issues in low‐ and middle‐income countries

The university system and students are rapidly growing and changing in low‐ and middle‐income countries (LMICs). This growth can facilitate enhanced national productivity yet it can also bring potential risks to student mental health. The World Mental Health Surveys International College Student (WMH‐ICS) initiative could increase information and support in a relatively low‐cost manner for university students in LMICs—a group that is particularly vulnerable to mental health problems and who live in an environment where few targeted resources may be available. Effective implementation of the WMH‐ICS initiative, however, requires long‐term planning and consideration of the specific challenges present in LMIC settings. Planning as to what types of interventions would be needed and achievable in the next 10 to 15 years and consideration of local issues related to uptake, acceptability, appropriateness, feasibility, fidelity, and sustainability from the very beginning would be needed to ensure that the initiative would be useful in the future

Brief problem-solving therapy for antenatal depressive symptoms in primary care in rural Ethiopia:protocol for a randomised, controlled feasibility trial

BACKGROUND: Despite a high prevalence of antenatal depression in low- and middle-income countries, there is very little evidence for contextually adapted psychological interventions delivered in rural African settings. The aims of this study are (1) to examine the feasibility of procedures for a future fully powered efficacy trial of contextually adapted brief problem solving therapy (PST) for antenatal depression in rural Ethiopia, and (2) to investigate the acceptability, fidelity and feasibility of delivery of PST in routine antenatal care.METHODS: Design: A randomised, controlled, feasibility trial and mixed method process evaluation.PARTICIPANTS: Consecutive women attending antenatal clinics in two primary care facilities in rural Ethiopian districts. Eligibility criteria: (1) disabling levels of depressive symptoms (Patient Health Questionnaire (PHQ-9) score of five or more and positive for the 10th disability item); (2) gestational age 12-34 weeks; (3) aged 16 years and above; (4) planning to live in the study area for at least 6 months; (5) no severe medical or psychiatric conditions.INTERVENTION: Four sessions of adapted PST delivered by trained and supervised antenatal care staff over a maximum period of eight weeks.CONTROL: enhanced usual care (EUC).SAMPLE SIZE: n = 50. Randomisation: individual randomisation stratified by intimate partner violence (IPV). Allocation: central phone allocation. Outcome assessors and statistician masked to allocation status. Primary feasibility trial outcome: dropout rate. Primary future efficacy trial outcome: change in PHQ-9 score, assessed 9 weeks after recruitment.SECONDARY OUTCOMES: anxiety symptoms, trauma symptoms, intimate partner violence, disability, healthcare costs at 9 weeks; postnatal outcomes (perinatal and neonatal complications, onset of breast feeding, child health) assessed 4-6 weeks postnatal. Other trial feasibility indicators: recruitment, number and duration of sessions attended. Audio-recording of randomly selected sessions and in-depth interviews with purposively selected participants, healthcare providers and supervisors will be analysed thematically to explore the acceptability and feasibility of the trial procedures and fidelity of the delivery of PST.DISCUSSION: The findings of the study will be used to inform the design of a fully powered efficacy trial of brief PST for antenatal depression in routine care in rural Ethiopia.TRIAL REGISTRATION: The protocol was registered in the Pan-African clinical trials registry, (PACTR): registration number: PACTR202008712234907 on 18/08/2020; URL: https://pactr.samrc.ac.za/TrialDisplay.aspx?TrialID=9578

Adapting brief problem-solving therapy for pregnant women experiencing depressive symptoms and intimate partner violence in rural Ethiopia

OBJECTIVE: To adapt an evidence-based psychological intervention for pregnant women experiencing depressive symptoms and intimate partner violence (IPV) in rural Ethiopia.METHOD: We conducted a desk review of contextual factors in Sodo, Ethiopia, followed by qualitative interviews with 16 pregnant women and 12 antenatal care (ANC) providers. We engaged stakeholders through participatory theory of change (ToC) workshops, to select the intervention and articulate a programme theory. We used "ADAPT" guidance to adapt the intervention to the context, before mapping potential harms in a "dark logic model".RESULTS: Brief problem-solving therapy developed for South Africa was the most contextually relevant model. We adapted the delivery format (participants prioritised confidentiality and brevity) and training and supervision (addressing IPV). Consensus long-term outcomes in our ToC were ANC providers skilled in detecting and responding to emotional difficulties and IPV, women receiving appropriate support, and emotional difficulties improving. Our dark logic model highlighted the risk of more severe IPV and mental health symptoms not being referred appropriately.CONCLUSION: Although intervention adaptation is recommended, the process is rarely reported in depth. We comprehensively describe how contextual considerations, stakeholder engagement, programme theory, and adaptation can tailor psychological interventions for the target population in a low-income, rural setting

Service user and caregiver involvement in mental health system strengthening in low- and middle-income countries: systematic review

The involvement of mental health service users and their caregivers in health system policy and planning, service monitoring and research can contribute to mental health system strengthening, but as yet there have been very few efforts to do so in low- and middle-income countries (LMICs). Methods This systematic review examined the evidence and experience of service user and caregiver involvement in mental health system strengthening, as well as models of best practice for evaluation of capacity-building activities that facilitate their greater participation. Both the peer-reviewed and the grey literature were included in the review, which were identified through database searches (MEDLINE, Embase, PsycINFO, Web of Knowledge, Web of Science, Scopus, CINAHL, LILACS, SciELO, Google Scholar and Cochrane), as well as hand-searching of reference lists and the internet, and a snowballing process of contacting experts active in the area. This review included any kind of study design that described or evaluated service user, family or caregiver (though not community) involvement in LMICs (including service users with intellectual disabilities, dementia, or child and adolescent mental health problems) and that were relevant to mental health system strengthening across five categories. Data were extracted and summarised as a narrative review. Results Twenty papers matched the inclusion criteria. Overall, the review found that although there were examples of service user and caregiver involvement in mental health system strengthening in numerous countries, there was a lack of high-quality research and a weak evidence base for the work that was being conducted across countries. However, there was some emerging research on the development of policies and strategies, including advocacy work, and to a lesser extent the development of services, service monitoring and evaluation, with most service user involvement having taken place within advocacy and service delivery. Research was scarce within the other health system strengthening areas. Conclusions Further research on service user and caregiver involvement in mental health system strengthening in LMICs is recommended, in particular research that includes more rigorous evaluation. A series of specific recommendations are provided based on the review

Stress and functional neurological disorders: mechanistic insights

At the interface between mind and body, psychiatry and neurology, functional neurological disorder (FND) remains poorly understood. Formerly dominant stress-related aetiological models have been increasingly challenged, in part due to cases without any history of past or recent trauma. In this perspective article, we review current evidence for such models, and how research into the role of traumatic stress in other disorders and the neurobiology of the stress response can inform our mechanistic understanding of FND. First, we discuss the association between stress and the onset or exacerbation of a variety of physical and mental health problems. Second, we review the role of hypothalamic-pituitary-adrenal axis dysfunction in the neurobiology of ill-health, alongside evidence for similar mechanisms in FND. Third, we advocate a stress-diathesis model, in which biological susceptibility interacts with early life adversity, where FND can be precipitated by traumatic events later in life and maintained by psychological responses. We hypothesise that greater biological susceptibility to FND is associated with less severe remote and recent stress, and that FND precipitated by more severe stress is associated with lower biological vulnerability. This would explain clinical experience of variable exposure to historical and recent traumatic stress among people with FND and requires empirical investigation. A testable, evidence-based stress-diathesis model can inform nuanced understanding of how biological and psychological factors interact at the individual level, with potential to inform personalised treatment pathways. Much-needed research to establish the aetiology of FND will enhance clinical care and communication, facilitate effective treatment and inform prevention strategies

Adapting brief problem-solving therapy for pregnant women experiencing depressive symptoms and intimate partner violence in rural Ethiopia

OBJECTIVE: To adapt an evidence-based psychological intervention for pregnant women experiencing depressive symptoms and intimate partner violence (IPV) in rural Ethiopia.METHOD: We conducted a desk review of contextual factors in Sodo, Ethiopia, followed by qualitative interviews with 16 pregnant women and 12 antenatal care (ANC) providers. We engaged stakeholders through participatory theory of change (ToC) workshops, to select the intervention and articulate a programme theory. We used "ADAPT" guidance to adapt the intervention to the context, before mapping potential harms in a "dark logic model".RESULTS: Brief problem-solving therapy developed for South Africa was the most contextually relevant model. We adapted the delivery format (participants prioritised confidentiality and brevity) and training and supervision (addressing IPV). Consensus long-term outcomes in our ToC were ANC providers skilled in detecting and responding to emotional difficulties and IPV, women receiving appropriate support, and emotional difficulties improving. Our dark logic model highlighted the risk of more severe IPV and mental health symptoms not being referred appropriately.CONCLUSION: Although intervention adaptation is recommended, the process is rarely reported in depth. We comprehensively describe how contextual considerations, stakeholder engagement, programme theory, and adaptation can tailor psychological interventions for the target population in a low-income, rural setting