Re-saturation targets identified from 4D seismic softening responses in the Forties Field

2017 ◽  
Vol 8 (1) ◽  
pp. 473-483 ◽  
Author(s):  
Lyndsay Singer ◽  
Grant Byerley ◽  
Phil Rose

AbstractA novel 4D methodology by targeting softening responses, a decrease in impedance over time, is described from the Forties Field. It is demonstrated that these anomalies identified areas where oil had re-saturated previously swept rock. When first observed in some of the older vintages of 4D data, softening responses were dismissed as side lobes of underlying water-swept reservoirs. With improved 4D data quality, softening responses were seen to be clearly responding to an acoustic softening effect isolated in the reservoir. Pressure measurements ruled out hypotheses of gas exsolution or geomechanically induced dilatation of the overlying shale.At the time of writing 22 re-saturation targets had been drilled at Forties with an average water saturation (Sw) of 28%, close to virgin conditions. These results indicated that a previously swept sand can be re-saturated to near initial oil conditions.The driving mechanism behind the re-saturation is understood to be related to changes in both production offtake and water injection. The resulting complex hydrodynamic interactions appeared to be moving banks of oil around the field. From 2011 to year-end of 2015 re-saturation targets produced 14.6 MMBO and were a key target type at the Forties Field.

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Junting Guo ◽  
Teng Teng ◽  
Xiaoyan Zhu ◽  
Yuming Wang ◽  
Zhaolong Li ◽  
...  

Water injection-induced rock softening and the associated water seepage characteristics are the common and basic problems in underground reservoir construction and the prevention of mine water disaster. In this paper, a series of experimental studies was carried out to investigate these characteristics with the weakly cemented sandy mudstone collected from Shendong Buertai coal mine, China. The characteristics of water softening and the stress-seepage interactions in water-saturated weakly cemented sandy mudstone were directly obtained. Then, a modification method of the constitutive model for rock mass considering the softening effect and a stress-damage-driven model for permeability evolution were established. Research results show that water saturation reduces the tensile strength, compressive strength, and cohesion by 56% and reduces the elastic modulus by 28%. The hydraulic effects on Poisson’s ratio and internal friction angle are negligible. The relationship between the permeability of weakly cemented sandy mudstone with complete compaction deformation is to be divided into three stages of seepage shielding, seepage surge, and seepage recovery. Rock permeability in each stage has a negative exponential relationship with the effective stress. This research provides a theoretical basis for the researches of hydromechanical couplings on weakly cemented sandy mudstone, which is insightful for rock engineering practice.


2021 ◽  
Author(s):  
Junting Guo ◽  
Teng Teng ◽  
Xiaoyan Zhu ◽  
Yuming Wang ◽  
Zhaolong Li

Abstract Water injection induced rock softening and the associated water seepage characteristics are the common and basic problems in hard roof pressure relief, underground reservoir construction and the prevention of mine water disaster. In this paper, a series of laboratory studies was carried out to investigate these characteristics with the weakly cemented sandy mudstone collected from Shendong Buertai coal mine, China. The characteristics of water softening and the stress-seepage interactions in saturated weekly cemented sandy mudstone were directly obtained. Then a modification method of the constitutive model for rock mass considering the softening effect and a stress-damage-driven model for permeability evolution were established. Research results show that water saturation reduces the tensile strength, compressive strength and cohesion by 56%, and reduces the elastic modulus by 28%. The hydraulic effect on Poisson’s ratio and internal friction angle is negligible. The relationship between the permeability of weakly cemented sandy mudstone with complete compaction deformation is to be divided into three stages of seepage shielding, seepage surge and seepage recovery. Rock permeability in each stage has a negative exponential relationship with the effective stress. This research provides a theoretical basis for the researches of hydro-mechanical couplings on weakly cemented sandy mudstone, which is insightful for rock engineering practice.


Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1010
Author(s):  
Przemysław Snopiński ◽  
Tibor Donič ◽  
Tomasz Tański ◽  
Krzysztof Matus ◽  
Branislav Hadzima ◽  
...  

To date, numerous investigations have shown the beneficial effect of ultrasonic vibration-assisted forming technology due to its influence on the forming load, flow stress, friction condition reduction and the increase of the metal forming limit. Although the immediate occurring force and mean stress reduction are known phenomena, the underlying effects of ultrasonic-based material softening remain an object of current research. Therefore, in this article, we investigate the effect of upsetting with and without the ultrasonic vibrations (USV) on the evolution of the microstructure, stress relaxation and hardness of the AlMg3 aluminum alloy. To understand the process physics, after the UAC (ultrasonic assisted compression), the microstructures of the samples were analyzed by light and electron microscopy, including the orientation imaging via electron backscatter diffraction. According to the test result, it is found that ultrasonic vibration can reduce flow stress during the ultrasonic-assisted compression (UAC) process for the investigated aluminum–magnesium alloy due to the acoustic softening effect. By comparing the microstructures of samples compressed with and without simultaneous application of ultrasonic vibrations, the enhanced shear banding and grain rotation were found to be responsible for grain refinement enhancement. The coupled action of the ultrasonic vibrations and plastic deformation decreased the grains of AlMg3 alloy from ~270 μm to ~1.52 μm, which has resulted in a hardness enhancement of UAC processed sample to about 117 HV.


Author(s):  
A. A. Kushlaf ◽  
A. E. El Mezweghy

This paper is to study the structural framework, stratigraphy, and the petro-physical characteristics of Facha reservoir of Gir Formation in Aswad oil field, which is located in Block NC74B at the Zella Trough, south-west of Sirt basin, Libya. The data used have been got from well-logging records of nine exploratory wells distributed in Aswad oil field. These data have been analyzed and interpreted through using analytical cross-plots in order to calculate the petro-physical parameters. The results revealed that the lithological facies consists mainly of dolomite. Moreover, they revealed that the lateral distribution of the petro-physical parameters of Facha reservoir indicates that average porosity is 10-23%, average water saturation is 52- 93%, and net pay is of 62.44 ft. This shows that Facha member is a good reservoir rock. The variations in values between wells have been affected by the trend of faults; this indicates that the area is structurally controlled.


2014 ◽  
Vol 1020 ◽  
pp. 472-477 ◽  
Author(s):  
Vruyr Sargsyan ◽  
Emil Saratikyan

Abstract. Geo-technological extraction methods recently are widely used in the mining industry. Removing the metals from underground ore deposits is carried out by injecting chemicals (solvents, oxidants, reducing agents) into wells drilled in them, and the subsequent extraction of metals from saturated solutions. Particularly, this method utilized for the extraction of uranium from flooded sediments and copper from poor (substandard) ores, as well as some non-ferrous and rare metals from waste dumps and tailings of substandard ore mines and processing enterprises. The paper discusses methods developed for prediction of moisture content (water saturation) in rocks under filtration of liquid with incomplete saturation of pores while changing the concentration of the metal in the liquid phase (in an ore body), as well as problems of dissolution and desorption of metal salts on the surface cracks or pores on ore body based on molecular diffusion equation of metal salts. The present work conducted for developing the methods for calculating the liquid filtration through underground deposits of minerals and forecasting of dissolving and washing out metals. It is shown that the processes which take place with the use of chemical reagents are different comparing to the similar processes with water injection. These data allow to predict the changes in the concentration of salts and metals in the liquid and solid phases depending on time.


Author(s):  
Rishika Rishika ◽  
Sven Feurer ◽  
Kelly L Haws

Abstract Licensing is a well-documented form of justifying individual indulgent choices, but less is known about how licensing affects food decision-making patterns over time. Accordingly, we examine whether consumers incorporate licensing strategically and deliberately in their long-term consumption patterns and identify reward programs as a context in which strategic licensing is likely to occur. We propose that members with lower-calorie consumption patterns strategically indulge more on reward purchase occasions, and that forethought is required for such an effect to occur. A longitudinal study analyzing 272,677 real food purchases made by 7,828 consumers over a 14-month period provides striking evidence of our key proposition. An exploration of the inter-purchase time-related aspect of purchase acceleration suggests that forethought on behalf of consumers is necessary for strategic licensing to occur. A subsequent experimental study (N = 605) comprising five consecutive choice occasions provides additional evidence of forethought by demonstrating that strategic licensing occurs only when expected (but not windfall reward) occasions are involved, and by showing that anticipated negative affect for not indulging is the driving mechanism. We conclude with a discussion of the implications of our results for consumers, managers, and public policy makers.


2021 ◽  
Author(s):  
Bashar Alramahi ◽  
Qaed Jaafar ◽  
Hisham Al-Qassab

Abstract Classifying rock facies and estimating permeability is particularly challenging in Microporous dominated carbonate rocks. Reservoir rock types with a very small porosity range could have up to two orders of magnitude permeability difference resulting in high uncertainty in facies and permeability assignment in static and dynamic models. While seismic and conventional porosity logs can guide the mapping of large scale features to define resource density, estimating permeability requires the integration of advanced logs, core measurements, production data and a general understanding of the geologic depositional setting. Core based primary drainage capillary pressure measurements, including porous plate and mercury injection, offer a valuable insight into the relation between rock quality (i.e., permeability, pore throat size) and water saturation at various capillary pressure levels. Capillary pressure data was incorporated into a petrophysical workflow that compares current (Archie) water saturation at a particular height above free water level (i.e., capillary pressure) to the expected water saturation from core based capillary pressure measurements of various rock facies. This was then used to assign rock facies, and ultimately, estimate permeability along the entire wellbore, differentiating low quality microporous rocks from high quality grainstones with similar porosity values. The workflow first requires normalizing log based water saturations relative to structural position and proximity to the free water level to ensure that the only variable impacting current day water saturation is reservoir quality. This paper presents a case study where this workflow was used to detect the presence of grainstone facies in a giant Middle Eastern Carbonate Field. Log based algorithms were used to compare Archie water saturation with primary drainage core based saturation height functions of different rock facies to detect the presence of grainstones and estimate their permeability. Grainstones were then mapped spatially over the field and overlaid with field wide oil production and water injection data to confirm a positive correlation between predicted reservoir quality and productivity/injectivity of the reservoir facies. Core based permeability measurements were also used to confirm predicted permeability trends along wellbores where core was acquired. This workflow presents a novel approach in integrating core, log and dynamic production data to map high quality reservoir facies guiding future field development strategy, workover decisions, and selection of future well locations.


Circulation ◽  
2020 ◽  
Vol 141 (Suppl_1) ◽  
Author(s):  
Kathryn Foti ◽  
Lawrence J Appel ◽  
Kunihiro Matsushita ◽  
Josef Coresh ◽  
G Caleb Alexander ◽  
...  

Introduction: Clinical practice guidelines emphasize the importance of accurate blood pressure measurement and recording to diagnose and treat hypertension. Trends in terminal digit preference (typically manifest by a terminal digit of ‘0’) have not been examined nationally. The growing use of automated blood pressure devices may have reduced terminal digit preference and improved accuracy over time. Objective: To evaluate trends in terminal digit preference in office blood pressure measurements among adults with hypertension by patient and provider characteristics. Methods: We used IQVIA National Disease and Therapeutic Index (NDTI) data from January 2014 through June 2019. The NDTI is designed to be nationally-representative of all patient visits to office-based physicians and uses a two-stage stratified sampling design to sample ~4,000 physicians per quarter who report information on all patient visits on 2 random workdays. We included all hypertension treatment visits (~60M/year) among adults aged ≥18. We examined trends in the proportion of hypertension treatment visits with recorded systolic (SBP) and diastolic (DBP) blood pressure measurements with a terminal digit ‘0’. The expected percent of blood pressures with ‘0’ is 10% for automated and 20% for manual readings. Results: There was a decrease in the percent of visits with SBP (43.0% to 37.4%) or DBP (44.3% to 38.1%) recordings ending in zero ( Table ). The decrease in percent of SBPs with a terminal zero was similar by patient and provider characteristics, though the percentage of SBPs with a terminal ‘0’ was consistently higher among patients aged ≥60, when SBP ≥140 mmHg, and among cardiologists. Conclusions: Terminal digit preference is common indicating systematic error in blood pressure measurement and recording, despite some improvement over time. This may lead to under- and overtreatment of patients with hypertension. Improving the quality of blood pressure measurement is central to improving hypertension diagnosis and control in clinical practice.


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