Stress-sensitive Model Research Articles

Stress sensitivity in women with a history of recurrent versus first-episode major depression.

Approximately 50 % of people who recover from an initial episode of major depressive disorder (MDD) experience a recurrence, and the risk for recurrence increases with each additional episode. Consistent with the stress sensitization model, there is evidence that whereas initial MDD onsets are often preceded by major negative life events, recurrences are often triggered by more minor events. However, it is unclear whether this is due to increased frequency of minor life events, increased reactivity to these events, or both. The current study examined these questions in a community sample of 227 adult women with a history of recurrent MDD (rMDD, n = 77), first-episode MDD (fMDD, n = 38), or no history of MDD (n = 112). Women were assessed at baseline and every six months for two years (5 assessments total). Throughout the follow-up, major and minor life events were assessed using contextual threat interviews and depressive symptoms were assessed using a self-report questionnaire. Regarding event frequency, minor events were more common than major events, and the rMDD group experienced more negative events overall (both major and minor) than the never depressed group but not the fMDD group. Regarding stress reactivity, results of linear mixed modeling revealed that whereas all three groups exhibited similar increases in depressive symptoms following major events, only women in the rMDD group experienced significant increases in depressive symptoms following minor events. These findings show that not only are women with rMDD living in more stressful contexts, but they are also more reactive to minor stressors, increasing risk for future depression.

Mutual Inductance Model of the Mechanical Stress Sensitivity of the Power Transformer Functional Parameters

The mutual inductance model enables testing the behavior of power transformers under different operation conditions, especially under the environmental influences on the transformer’s core. This paper presents the investigation results of the stress dependence of the magnetic relative permeability of the power transformer. It was observed that under tensile mechanical stresses up to 98 MPa applied to the core, the transformer input current amplitude increases by almost 67%, whereas the transformer's reactive power increases by 53%. In industrial systems, such changes can potentially lead to unwanted power system shutdowns due to overloading. This effect should be considered during the development of critical power systems.

Adverse Childhood Experiences, Perceived Discrimination, and Mental Health in Sexual and Gender Minoritized Adults: Comparing Stress Accumulation and Stress Sensitization Models.

Purpose: The purpose of this study was to assess the relationship between adverse childhood experiences (ACEs) exposure, perceived discrimination, and anxiety and depressive symptoms in sexual and gender minoritized (SGM) adults in the United States. Methods: Respondents (n = 4445) from a national Qualtrics research panel completed a web-based survey. Guided by the stress proliferation (mediation model) and stress sensitization (moderation model) models, we examined the relationships between ACEs and perceived discrimination and the severity of anxiety and depressive symptoms in adulthood. Results: Cumulative ACEs exposure was positively associated with everyday discrimination scale (EDS) scores. ACEs and EDS scores had a significant direct association with anxiety and depressive symptoms. We found support for EDS as a mediator for anxiety (β = 0.12, p < 0.001) and depressive symptoms (β = 0.14, p < 0.001) and for ACEs as a moderator of the relationship between EDS and anxiety (β = -0.04, p = 0.004) and depressive (β = -0.05, p = 0.001) symptoms. Conclusions: These findings suggest that both stress proliferation and stress sensitization likely contribute to disparities in anxiety and depressive symptoms in SGM adults. This finding supports the integration of social safety and minority stress perspectives regarding health disparities in SGM populations. Exposure to early life adversity likely alters neurodevelopment, which in turn increases awareness of the lack of social safety in adulthood, reduces capacity to cope with minority stress exposure, and ultimately contributes to increased anxiety and depressive symptoms. Prevention efforts should focus on building positive and compensatory childhood experiences.

Stress proliferation in ethnoracial disparities of mental health among U.S. sexual minority adults.

Non-White sexual minorities experience disproportionate adverse childhood experiences (ACEs) and adulthood discrimination, as compared to their White or heterosexual counterparts. These stressors lead to increased psychological distress and worsened clinical outcomes, including suicidality. Minority stress theory posits that systemic marginalization, as experienced by minoritized individuals, leads to distress. Intersectionality theory suggests that marginalization compounds over time for individuals with intersectional minority identities. Yet, the mechanisms underlying the stress proliferation process for individuals with intersectional minority identities remain largely unexamined. The present study used nationally representative data of sexual minority individuals (n = 1,518, Mage = 31 years, ethnoracial minority = 38.7%, female and gender minority = 50.6%) to investigate the relations among ethnoracial minoritization, ACEs, discrimination, distress, and self-injurious/suicidal outcomes. We proposed a novel integration of minority stress, intersectionality, and stress proliferation theories. Via longitudinal mediation, we tested models of stress persistence, stress accumulation, and stress sensitization. Our results confirmed disparities between White versus non-White sexual minorities on ACEs, discrimination experiences, and psychological distress. We found support for the stress persistence and the stress accumulation models, but not the stress sensitization model. Moreover, we found distress and discrimination were associated with future nonsuicidal self-injurious behaviors and suicidal outcomes, highlighting the deleterious consequences of intersectional minority stress proliferation. Our results support our proposed theory of intersectional minority stress proliferation where ethnoracial and sexual minoritization intersect and beget disproportionate ACEs, which in turn contribute to accumulation and persistence of psychological distress and discrimination experiences in adulthood. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Characterizing permeability-porosity relationships of porous rocks using a stress sensitivity model in consideration of elastic-structural deformation and tortuosity sensitivity

Clarifying the relationship between stress sensitivities of permeability and porosity is of great significance in guiding underground resource mining. More and more studies focus on how to construct stress sensitivity models to describe the relationship and obtain a comprehensive stress sensitivity of porous rock. However, the limitations of elastic deformation calculation and incompleteness of considered tortuosity sensitivity lead to the fact that the existing stress sensitivity models are still unsatisfactory in terms of accuracy and generalization. Therefore, a more accurate and generic stress sensitivity model considering elastic-structural deformation of capillary cross-section and tortuosity sensitivity is proposed in this paper. The elastic deformation is derived from the fractal scaling model and Hooke's law. Considering the effects of elastic-structural deformation on tortuosity sensitivity, an empirical formula is proposed, and the conditions for its applicability are clarified. The predictive performance of the proposed model for the permeability-porosity relationships is validated in several sets of publicly available experimental data. These experimental data are from different rocks under different pressure cycles. The mean and standard deviation of relative errors of predicted stress sensitivity with respect to experimental data are 2.63% and 1.91%. Compared with other models, the proposed model has higher accuracy and better predictive generalization performance. It is also found that the porosity sensitivity exponent α, which can describe permeability-porosity relationships, is 2 when only elastic deformation is considered. α decreases from 2 when structural deformation is also considered. In addition, α may be greater than 3 due to the increase in tortuosity sensitivity when tortuosity sensitivity is considered even if the rock is not fractured.

Stress begets stress: The moderating role of childhood adversity in the relationship between job stress and sleep quality among nurses

Nurses exhibit considerable variations in sleep quality and experience high job stress levels. Distal factors, such as childhood adversity, and proximal factors, both influence sleep quality. We investigated the moderating role of childhood adversity with job stress and sleep quality, and whether this aligns with the stress-sensitization or stress-amplification models. The impact of job stressors' total score and its dimensions on sleep quality was analyzed using traditional linear regression models and the extreme gradient boosting machine learning algorithm. The hierarchical regression examined the moderating role of childhood adversity in the relationship between job stress and sleep quality. An interactive tool was used to visualize the results. Among the dimensions of job stress, "time allocation and workload" strongly correlated with sleep quality, followed by "nursing profession and work problems," "patient care issues," "management and interpersonal problems," and "working environment and equipment problems." The moderating role of childhood adversity in the relationship between different dimensions of job stressors (except working environment and equipment problems) and sleep quality aligns with the stress-sensitization model. This study was susceptible to recall bias and objective sleep data were unavailable. Cross-sectional study design was used, thus limiting causal inferences. Finally, the moderating effect of childhood adversity on subsequent stress among nurses remains unclear. Childhood adversity and job stress were integrated into a stress-sensitization model, providing a nuanced and specific examination of sleep quality. Healthcare policymakers should focus on job stress and childhood adversity, improve nurses' sleep quality, and ultimately benefit patient care and outcomes.

Micromechanism and mathematical model of stress sensitivity in tight reservoirs of binary granular medium

Research on reservoir rock stress sensitivity has traditionally focused on unary granular structures, neglecting the binary nature of real reservoirs, especially tight reservoirs. Understanding the stress-sensitive behavior and mathematical characterization of binary granular media remains a challenging task. In this study, we conducted online-NMR experiments to investigate the permeability and porosity evolution as well as stress-sensitive control mechanisms in tight sandy conglomerate samples. The results revealed stress sensitivity coefficients between 0.042 and 0.098 and permeability damage rates ranging from 65.6% to 90.9%, with an average pore compression coefficient of 0.0168–0.0208 MPa−1. Pore-scale compression occurred in three stages: filling, compression, and compaction, with matrix pores playing a dominant role in pore compression. The stress sensitivity of binary granular media was found to be influenced by the support structure and particle properties. High stress sensitivity was associated with small fine particle size, high fines content, high uniformity coefficient of particle size, high plastic deformation, and low Young's modulus. Matrix-supported samples exhibited a high irreversible permeability damage rate (average = 74.2%) and stress sensitivity coefficients (average = 0.089), with pore spaces more slit-like. In contrast, grain-supported samples showed low stress sensitivity coefficients (average = 0.021) at high stress stages. Based on the experiments, we developed a mathematical model for stress sensitivity in binary granular media, considering binary granular properties and nested interactions using Hertz contact deformation and Poiseuille theory. By describing the change in activity content of fines under stress, we characterized the non-stationary state of compressive deformation in the binary granular structure and classified the reservoir into three categories. The model was applied for production prediction using actual data from the Mahu reservoir in China, showing that the energy retention rates of support-dominated, fill-dominated, and matrix-controlled reservoirs should be higher than 70.1%, 88%, and 90.2%, respectively.

청소년 성폭력 피해경험자의 과거 중복학대 경험과 정신건강 －스트레스 민감성 모델(Stress Sensitization Model) 검증－

청소년 성폭력 피해경험자의 과거 중복학대 경험과 정신건강 －스트레스 민감성 모델(Stress Sensitization Model) 검증－

Nurture outpaces nature: fostering with an attentive mother alters social dominance in a mouse model of stress sensitivity.

Maternal care is critical for epigenetic programming during postnatal brain development. Stress is recognized as a critical factor that may affect maternal behavior, yet owing to high heterogeneity in stress response, its impact varies among individuals. We aimed here to understand the connection between inborn stress vulnerability, maternal care, and early epigenetic programming using mouse populations that exhibit opposite poles of the behavioral spectrum (social dominance [Dom] and submissiveness [Sub]) and differential response to stress. In contrast to stress-resilient Dom dams, stress-vulnerable Sub dams exhibit significantly lower maternal attachment, serum oxytocin, and colonic Lactobacillus reuteri populations. Sub offspring showed a reduced hippocampal expression of key methylation genes at postnatal day (PND) 7 and a lack of developmentally-dependent increase in 5-methylcytosine (5-mC) at PND 21. In addition, Sub pups exhibit significant hypermethylation of gene promoters connected with glutamatergic synapses and behavioral responses. We were able to reverse the submissive endophenotype through cross-fostering Sub pups with Dom dams (Sub/D). Thus, Sub/D pups exhibited elevated hippocampal expression of DNMT3A at PND 7 and increased 5-mC levels at PND 21. Furthermore, adult Sub/D offspring exhibited increased sociability, social dominance, and hippocampal glutamate and monoamine levels resembling the neurochemical profile of Dom mice. We postulate that maternal inborn stress vulnerability governs epigenetic patterning sculpted by maternal care and intestinal microbiome diversity during early developmental stages and shapes the array of gene expression patterns that may dictate neuronal architecture with a long-lasting impact on stress sensitivity and the social behavior of offspring.

Gene-environment interplay in internalizing problem behavior.

Behavior genetic methods are useful for examining mechanisms underlying the interaction between genetic and family environmental factors of internalizing problem behavior (INT). Previous twin studies, however, have shown little consistency in interaction patterns, depending on type and operationalization of measured environments. The aim of the current study was to explore different gene-by-environment interaction patterns among different family-level environmental risk factors and resources known to correlate with INT. Using an empirical-based approach, we combined various indicators of the family environment to derive four dimensions: positive parenting, negative parenting, lack of parental resources, and socioeconomic status. We then used a genetically informed design of twins raised in the same family to test whether interaction patterns followed a diathesis stress or vantage sensitivity model formulation. The sample consisted of 2,089 twin pairs and their families from two twin birth cohorts (ages 11 and 17) participating in Wave 1 of the German TwinLife study of social inequalities. In line with a vantage sensitivity pattern of interaction and with the bioecological model of development (Bronfenbrenner & Ceci, 1994), evidence for a general mechanism of gene-environment interaction with increasing nonshared environmental variance for more adverse and less propitious family conditions was found. In preadolescence, parenting behavior had a greater moderating influence on INT compared to general family conditions like socioeconomic status. Interventions for INT that directly involve parents, thus, may be more important in preadolescent populations whereas individual interventions for adolescents may be more successful if they are adapted to different levels of socioeconomic status. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Diffusive Leakage Through Existing and/or Induced Microfractures in the Caprock of CO2 Storage System

Summary Safe sequestration of CO2 in subsurface formations requires a caprock that inhibits the unwanted flow of the stored fluids. However, the preexisting fractures and the induced fractures initiated by overpressure and thermal stresses may act as potential leakage pathways. In this study, we describe a physical problem where the caprock with tiny embedded microfractures is subjected to overpressurization at the storage layer. The average effect of the existing and induced fractures is accounted for by employing a spatially variant permeability field. Also, the alteration of effective local stress is considered by applying Pedrosa’s stress-sensitive model. The coupled model for the pressure diffusion in the caprock and monitoring aquifer is solved using a general Bessel function solution and Laplace transform. The nonlinearity due to stress sensitivity was attenuated by Pedrosa’s transform, and a perturbation solution was obtained. The obtained solution was verified analytically and compared against classical solutions. The spatial variability of the caprock permeability field is effectively represented by the caprock’s two endpoint permeability values, storage/caprock interface permeability, and caprock/monitoring aquifer interface permeability. The ratio between the caprock’s two endpoint permeability values, intactness ratio, is observed to decrease with the increase in the permeability modulus, indicating permeability enhancement due to pressure buildup in the caprock. We identified that the temporal change in the spatially variant permeability field due to stress sensitivity is negligible. The results revealed that all averaging methods underestimate the pressure inside the caprock compared to a spatially variant case. This underestimation is minimum at the interface of caprock and monitoring formation for the harmonic average. The pressure evolution in the monitoring aquifer shows an overestimation of pressure when arithmetic and geometric average permeabilities are considered, while the results obtained using a harmonic average are similar to those of the spatially variant case. The reported work is unique as it accounts for pressure diffusion through preexisting and induced fractures and provides a coupled solution for pressure evolution in monitoring aquifers. This analytical model can be extended for double porosity formations.

Associations of childhood and adult adversity with daily experiences in adulthood

AbstractData from 213 adults were analysed to test the stress accumulation and stress sensitization models as they relate to daily mood, health behaviours and social interactions. Adults reported on childhood adversity, past year adversity, and daily experiences on 14 evenings. Results largely supported the stress accumulation and not stress sensitization model such that childhood and past year adversity had independent but not synergistic effects on daily experiences. Both adversity measures were independently associated with greater daily negative affect and negative affect variability. Childhood adversity independently associated with greater mean variability in daily positive affect. Past year adversity was associated with more daily social activities, greater odds of reporting interpersonal tension at least once, and daily tension. Although childhood adversity was associated with greater odds of sharing about one's day at least once, past year adversity was associated with more daily sharing and childhood adversity with less. Both measures were unrelated to daily health behaviours except childhood adversity was associated with lower odds of being a current drinker. The only support for the stress sensitization model was number of daily cigarettes among smokers. Our findings suggest childhood and recent adversity independently relate to adults' daily experiences and should be considered jointly.

STRESS SENSITIVITY ANALYSIS OF FRACTAL POROUS MEDIA BASED ON THE ELASTO-PLASTIC THICK-WALLED CYLINDER MODEL

The stress-dependent flow and transport behaviors of porous media are ubiquitous in various scientific and engineering applications. It has been shown that the change of effective stress has important effects on the permeability and porosity of porous media. In this paper, a new stress sensitivity model for porous media is developed based on the fractal theory and the elasto-plastic thick-walled cylinder model. The proposed model is able to predict the elasto-plastic deformation of the fractal porous media under loading–unloading stress cycles, which plays a crucial role on the permanent variations of the permeability and porosity. It is found that the permeability of stress-sensitivity porous media is related to the capillary fractal dimension, capillary fractal tortuosity dimension, minimum and maximum capillary diameters, Young’s modulus and Poisson’s ratio of capillary. Each parameter has a clear physical meaning. The validity of the developed fractal model is verified by comparing the model predictions with the available experimental data.

Experimental study and production model of multiscale stress sensitivity in tight oil reservoirs

ABSTRACT Stress sensitivity is an inevitable issue in the depletion exploitation of tight oil reservoirs, especially in the reformed multiscale region. Through a series of improved laboratory experiments, the stress sensitivity characteristics of multiscale media were thoroughly evaluated based on the primitive effective stress. Furthermore, based on the nonlinear seepage theory and equivalent seepage resistance method, a corresponding multiscale production prediction model of vertical wells in tight oil reservoirs with stress sensitivity established. The results showed that the decline in permeability of main fracture rock (12.86%) was more than twice that of the microfracture rock (5.25%), which was approximately four times that of the matrix rock (3.32%) in the selected pressure range. In addition, there was a fine power function relationship between permeability variation and effective stress in multiscale representative media. Compared with the actual daily production and cumulative production of the coring well, the production curve fitting of the proposed multiscale model was 91.25%, which was reliable to guide the development scheme design in the target block of tight oil reservoirs.

Sensitization or inoculation: Investigating the effects of early adversity on personality traits and stress experiences in adulthood.

Cumulative evidence has been found for the associations between personality traits and stress experiences in adulthood. However, less is known about the moderating mechanisms underlying these associations. The present study tested whether the stress sensitization and stress inoculation hypotheses could be applied to the relationship between early adversity and personality in adulthood. Specifically, we tested the linear and curvilinear relations between early adversity (measured retrospectively) and adulthood personality traits, as well as the linear and curvilinear moderating effects of early adversity on the associations between adulthood stress and personality traits. Samples of older adults from the Health and Retirement Study (HRS; N = 6098) and middle-aged adults from the Midlife in the United States Survey (MIDUS; N = 6186) were used. Across the two samples, positive linear associations were found between retrospective early adversity and neuroticism. The results also suggested significant linear effects of early adversity on the association between ongoing chronic stressors and neuroticism such that individuals with moderate exposure to early adversity showed stronger associations between ongoing chronic stressors and neuroticism. Results from the current research were more in line with the stress sensitization model. No support was found for the stress inoculation effects on personality.

The disparate impact of COVID-19 on the mental health of female and male caregivers.

Caregiver mental health is crucial to the wellbeing of children. This is most apparent when caregivers face high levels of stress or life adversity. To study this phenomenon in the current global context, this study examined the relation between stress/disruption from the COVID-19 pandemic and the mental health of female and male caregivers. Pre-pandemic childhood adversity was considered as a moderator of this association. A multi-national sample (United Kingdom, 76%; United States, 19%; Canada, 4%, and Australia, 1%) was recruited in May 2020, of whom 348 female and 143 male caregivers of 5-18 year-old children provided data on the constructs of interest. At this time, caregivers reported on their history of adverse childhood experiences (ACEs) and COVID stress/disruption. About two months later (July 2020) caregiver mental health was evaluated. We examined differences between female and male caregivers on ACEs, COVID stress/disruption, and mental health (distress, anxiety, substance use, and posttraumatic stress). Main and interactive effects of ACEs and COVID stress/disruption on each mental health outcome were examined. Female caregivers reported higher COVID stress/disruption, more ACEs, and greater distress, anxiety, and posttraumatic stress symptoms compared to male caregivers. Among female caregivers, higher COVID stress/disruption and more adverse childhood experiences (ACEs) independently predicted all mental health outcomes, consistent with a stress accumulation model. Among male caregivers, a pattern of interactions between COVID stress/disruption and ACEs suggested that the effects of COVID stress/disruption on mental health was stronger for those with higher ACEs, especially for substance use, consistent with a stress sensitization model. Higher levels of stress and mental health difficulties among female caregivers suggests a disproportionate burden due to pandemic-related disruption compared to male caregivers. Findings speak to the disparate effects of COVID-19 on the mental health of female compared to male caregivers, and the role of pre-existing vulnerabilities in shaping current adaptation.

Experimental Research on Dynamic Variation of Permeability and Porosity of Low-Rank Inert-Rich Coal Under Stresses.

The effective stress variation can cause permeability change during coalbed methane (CBM) production. At the same time, macerals have an important influence on the stress sensitivity of coal reservoirs. To investigate the low-rank inert-rich coal permeability dynamic response to effective stress during the production of CBM, eight low-rank coal samples were collected from the Huanglong coalfield, China, and the dynamic changes in helium permeability and porosity were tested under conditions in which the effective stress changed from 0, 15, to 0 MPa. Then, the permeability dynamic change, stress sensitivity control mechanism, and their influence on the development of low-rank CBM are discussed. The results show that with the increase in effective stress, the permeability and porosity of coal samples decrease in the form of negative exponents. During the process of effective stress increase, the permeability variation of low-rank coal includes three stages: rapid loss stage (0–3 MPa), slow loss stage (3–9 MPa), and stable loss stage (>9 MPa). In the process of effective stress reduction, the irreversible damage rate linearly increases. Fracture permeability is easier to recover than pore permeability during pressure relief. Coal macerals have an important influence on the initial permeability and stress sensitivity of low-rank coal. The ratio of vitrinite to inertinite of low-rank coal is positively correlated with initial permeability, but negatively correlated with the permeability loss rate and the fracture compression coefficient (Cf). Cf shows a decreasing trend of the negative index with an increase in effective stress and is highly positively correlated with the average permeability loss rate. The porosity–permeability index model and the permeability–effective stress-sensitive model of low-rank coal under effective stress are established. Research shows that inertinite is helpful to improve the stress sensitivity of low-rank coal. Accordingly, to reduce the damage of coal reservoir permeability, the pressure should steadily change either in the process of fracturing or drainage.

The Vestiges of Childhood Interparental Conflict: Adolescent Sensitization to Recent Interparental Conflict.

This study examined whether childhood interparental conflict moderated the mediational pathway involving adolescent exposure to interparental conflict, their negative emotional reactivity to family conflict, and their psychological problems in a sample of 235 children (Mage =6years). Significant moderated-mediation findings indicated that the mediational path among Wave 4 interparental conflict during adolescence, change in youth negative reactivity (Waves 4-5), and their psychological problems (Waves 4-6) was significant for teens who experienced low, rather than high, levels of childhood interparental conflict (Waves 1-3). Supporting the stress sensitization model, analyses showed that adolescents exposed to high interparental conflict during childhood evidenced greater increases in negative reactivity than their peers when recent parental conflicts were mild.

Permeability experiments with overburden pressure of coal measure reservoirs and numerical analysis of its stress sensitivity: A case study of Qinshui Basin, China

The commingled exploitation of coal measure reservoirs has become the main trend in the development of coalbed methane (CBM) in the central and southern Qinshui Basin. In fact, the porosity and permeability (P&amp;P) of coal measure reservoirs and the evolution of their stress sensitivity are a focus of the basic theory of commingling exploitation. In this study, the coal measure reservoirs in this area are taken as the research object, and the P&amp;P characteristics and stress sensitivity of coal measure reservoirs under different overburden pressure conditions were investigated by P&amp;P experiments on coal, sandstone, and mudstone. The results show that the P&amp;P decreases as a negative exponential function with the increase in effective stress, and the initial porosity and initial permeability of coal are both significantly higher than those of mudstone and sandstone. Besides, the permeability stress sensitivity coefficients of coal, mudstone, and sandstone all decline with a wavy trend with the increase in effective stress. Coal is more sensitive to stress than mudstone and sandstone in the medium and low pressure stages (Pc&lt;5 MPa), while their stress sensitivities tend to become equal in the medium and high pressure stages (Pc&gt;5 MPa). Since the type of coal rich in organic matter is soft rock, it is more susceptible to damage and deformation in the medium and low pressure state (Pc&lt;5 MPa). In contrast, sandstone and mudstone contain more brittle minerals such as cuttings, quartz, and clay minerals, which are, in general, more resistant to deformation, and are less sensitive than coal at the medium and low pressure stages. Finally, a stress sensitivity model based on the Langmuir equation was proposed in this study. With the aid of the model, the stress sensitivities of porosity and permeability of coal, sandstone, and mudstone were analyzed accurately.

A Novel Model for Well Production Performance Estimate in Low-Permeability and Tight Reservoirs Considering Stress Sensitivity

Abstract Stress sensitivity phenomenon is an important property in low-permeability and tight reservoirs and has a large impact on the productivity of production wells, which is defined as the effect of effective stress on the reservoir parameters such as permeability, threshold pressure gradient, and rock compressibility change accordingly. Most of the previous works are focused on the effect of effective stress on permeability and threshold pressure gradient, while rock compressibility is critical of stress sensitivity but rarely noticed. A series of rock compressibility measurement experiments have been conducted, and the quantitative relationship between effective stress and rock compressibility is accurately described in this paper. In the experiment, the defects in previous experiments were eliminated by using a new-type core holder. The results show that as the effective stress increases, the rock compressibility becomes lower. Then, a stress sensitivity model that considers the effect of effective stress on rock compressibility is established due to the experimental results. The well performance of a vertical well estimated by this model shows when considering the effect of effective stress on the rock compressibility, the production rate and recovery factor are larger than those without considering it. Moreover, the effect of porosity and confining pressure on the productivity of a vertical well is also studied and discussed in this paper. The results show that the productivity of a vertical well decreases with the increase in overburden pressure, and increases with the increase in the porosity.