scholarly journals Analytical and Experimental Investigation of the Critical Length in Casing–Liner Overlap

2019 ◽  
Vol 11 (23) ◽  
pp. 6861 ◽  
Author(s):  
Mustafa Al Ramadan ◽  
Saeed Salehi ◽  
Chinedum Ezeakacha ◽  
Catalin Teodoriu
Keyword(s):  
Critical Length ◽  
Fluid Migration ◽  
Test Duration ◽  
Gas Migration ◽  
Gas Leakage ◽  
Pressure Test ◽  
Seal Assembly ◽  
Casing Pressure ◽  
The Cost ◽  
Selection Of

Offshore drilling operations exhibit various difficulties attributed to shallow flows worldwide. One of the most common practices for drilling offshore wells is to use liners and liner hangers rather than using full casing strings. This reduces the cost of drilling operation. Liners and liner hangers are required to pass certain standards prior to their deployment in the field. This ensures their ability to withstand harsh downhole conditions and maintain the integrity of the well. A liner hanger contains an integrated seal assembly that acts as a barrier to prevent fluid migration. The cement that is placed within the casing–liner overlap is also considered a barrier, and it is critical that it maintains the integrity of the well by mitigating fluid migration to other formations and to the surface. The failure of this dual barrier (cement and seal assembly) system to seal the annular space can result in serious problems that might jeopardize a well’s integrity. Typically, in field applications, the length of a casing–liner overlap is chosen arbitrarily. In some cases, shorter overlaps (50 to 200 ft) are chosen because of the lower cost and easy identification of leaks during pressure tests. However, some loss of well control incidents (particularly the incident that motivated this study) have been linked to fluid leakages along the casing–liner overlap. This paper investigates the critical length of the casing–liner overlap by modeling gas leakage through the cement placed within the overlap using analytical and experimental approaches. Leakage scenarios were developed to mimic gas migration within the cement in the casing–liner overlap. The results showed that the longer the casing–liner overlap, the higher the leakage time. The results also showed that the current casing pressure test duration of 30 min may not be adequate to verify the integrity of the cement within the overlap. Based on the results and analyses, it is recommended to increase the pressure test duration to 90 min. In addition, the results suggest that the length of the casing–liner overlap should not be less than 300 ft to maintain the integrity of the well in the case of gas influx. Further details are highlighted in the results section. In practice, the current rationale behind the selection of a casing–liner overlap length is not sustainable. Thus, the major advantage of this study is that with field data, it provides both scientific and research-based evidence that can be used to inform the decision behind the selection of the casing–liner overlap length, especially in gas migration-prone zones.

Pilot-Scale Experimental Study and Mathematical Modeling of Buoyant Settling of Immiscible Heavy Fluid in Mud To Stop Annular-Gas Migration Above Leaking Cement

SPE Journal ◽  
2017 ◽  
Vol 23 (01) ◽  
pp. 186-204
Author(s):  
Efecan Demirci ◽  
Andrew K. Wojtanowicz
Keyword(s):  
Pressure Change ◽  
Pilot Scale ◽  
Injection Rate ◽  
Gas Migration ◽  
Heavy Fluid ◽  
Process Measures ◽  
Gas Leakage ◽  
Two Fluids ◽  
High Dependency ◽  
Casing Pressure

Summary Annular casing pressure (ACP) is defined as the accumulated pressure on the casing head. If pressure returns after bleed-down, then the casing annulus is said to be showing sustained casing pressure (SCP). SCP is caused by late gas migration in the annular-fluid column above the top of leaking cement and may result in atmospheric emissions or underground blowouts. Removal of SCP is required in places where SCP is regulated, particularly before the well-plugging and abandonment operations. Annular-intervention methods for SCP removal, which are less expensive than the conventional downhole-intervention methods, typically involve injecting heavy fluid into the affected annulus that would displace the annular fluid (AF), balance the pressure at the top of cement, and stop the gas leakage. Previous studies stated that the use of immiscible combinations of two fluids is more effective for the purpose; however, inattentive applications may result in excessive use of heavy fluid. In this study, a 20-ft carbon-steel pilot-well annulus was manufactured and used for displacement experiments with various water-based drilling muds and heavy fluids with different properties. Pressure-change data were collected from four different levels of the annulus, and volumes of fluids going in and out of the annulus were measured. Experiments indicated the formation of a mixture zone that would build bottoms up and expand during ongoing displacement. The proposed pressure-buildup model suggests an exponential distribution of density of this zone, and shows its high dependency on fluids’ properties and injection rate. The mathematical models were also converted into dimensionless process measures and proposed for use in real-well applications. The study demonstrates the viability and recommends the correct application of the method.

scholarly journals A Prediction Model for Sustained Casing Pressure under the Effect of Gas Migration Variety

2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Fuping Feng ◽  
Ziyuan Cong ◽  
Wuyi Shan ◽  
Chaoyang Hu ◽  
Maosen Yan ◽  
...  
Keyword(s):  
Reynolds Number ◽  
Prediction Model ◽  
Recovery Time ◽  
Oil And Gas ◽  
Pressure Recovery ◽  
Flow State ◽  
Gas Migration ◽  
Gas Leakage ◽  
Sustained Casing Pressure ◽  
Casing Pressure

Sustained casing pressure (SCP) is a challenge in the well integrity management in oil and gas fields around the world. The flow state of leaked gas will change when migrated up annulus protective fluid. To show the influence of gas migration on casing pressure recovery, a prediction model of SCP based on Reynolds number of bubbles was established. The casing pressure prediction of typical wells and the sensitivity analysis of casing pressure are performed. The results show that the casing pressure recovery time decreases with the increase of cement permeability. However, larger cement permeability has little effect on the casing pressure after stabilization. Increasing the height of annulus protective fluid reduces the stable casing pressure value and shortens the casing pressure recovery time. Compared with the existing models, the results show that the time of casing pressure recovery will be shortened by the change of gas migration, and the effect of bubbles Re < 1 on SCP will be greater. The new model can be used to detect and treat the SCP problem caused by small Reynolds number gas leakage.

Determination of the minimum number of technological bases of a part

2020 ◽  
pp. 73-75
Author(s):  
B.M. Bazrov ◽  
T.M. Gaynutdinov
Keyword(s):  
Cost Price ◽  
Labor Input ◽  
Part Surface ◽  
Technological Base ◽  
Size Accuracy ◽  
Minimum Number ◽  
The Cost ◽  
Input Cost ◽  
Selection Of

The selection of technological bases is considered before the choice of the type of billet and the development of the route of the technological process. A technique is proposed for selecting the minimum number of sets of technological bases according to the criterion of equality in the cost price of manufacturing the part according to the principle of unity and combination of bases at this stage. Keywords: part, surface, coordinating size, accuracy, design and technological base, labor input, cost price. [email protected]

scholarly journals The Recent Progress of Natural Sources and Manufacturing Process of Biodiesel: A Review

2021 ◽  
Vol 13 (10) ◽  
pp. 5599
Author(s):  
Eko Supriyanto ◽  
Jayan Sentanuhady ◽  
Ariyana Dwiputra ◽  
Ari Permana ◽  
Muhammad Akhsin Muflikhun
Keyword(s):  
Recent Progress ◽  
Review Paper ◽  
Ghg Emissions ◽  
Production Method ◽  
Biodiesel Production ◽  
Natural Sources ◽  
Harmful Emissions ◽  
Daily Energy ◽  
The Cost ◽  
Selection Of

Biodiesel has caught the attention of many researchers because it has great potential to be a sustainable fossil fuel substitute. Biodiesel has a non-toxic and renewable nature and has been proven to emit less environmentally harmful emissions such as hydrocarbons (HC), and carbon monoxide (CO) as smoke particles during combustion. Problems related to global warming caused by greenhouse gas (GHG) emissions could also be solved by utilizing biodiesel as a daily energy source. However, the expensive cost of biodiesel production, mainly because of the cost of natural feedstock, hinders the potential of biodiesel commercialization. The selection of natural sources of biodiesel should be made with observations from economic, agricultural, and technical perspectives to obtain one feasible biodiesel with superior characteristics. This review paper presents a detailed overview of various natural sources, their physicochemical properties, the performance, emission, and combustion characteristics of biodiesel when used in a diesel engine. The recent progress in studies about natural feedstocks and manufacturing methods used in biodiesel production were evaluated in detail. Finally, the findings of the present work reveal that transesterification is currently the most superior and commonly used biodiesel production method compared to other methods available.

Recruitment and selection of couples for intervention research: Achieving developmental homogeneity at the cost of demographic diversity.

2006 ◽  
Vol 74 (4) ◽  
pp. 777-784 ◽  
Author(s):  
Ronald D. Rogge ◽  
Rebecca J. Cobb ◽  
Lisa B. Story ◽  
Matthew D. Johnson ◽  
Erika E. Lawrence ◽  
...  
Keyword(s):  
Intervention Research ◽  
Demographic Diversity ◽  
Recruitment And Selection ◽  
The Cost ◽  
Selection Of

Construction of Temporary Accommodation Camp and Selection of Optimal Type of Building

2015 ◽  
Vol 725-726 ◽  
pp. 105-110
Author(s):  
Aleksandr Birjukov ◽  
Sergey Bolotin
Keyword(s):  
Type Systems ◽  
Structural Systems ◽  
Basic Criterion ◽  
Economic Indexes ◽  
The Cost ◽  
Container Type ◽  
Selection Of ◽  
Optimal Type ◽  
Temporary Accommodation

Surveys performed nationwide show that mobile temporary accommodation camps are being manufactured by more than 200 specialized enterprises (without considering the minor manufacturers) acting under different ministries and agencies. According to the analysis performed, today 26 basic mobile structural systems consisting of 18 conveyor-type and 8 demountable-type systems are being used on a national basis. Today national manufacturers are producing more than 250 types of container-type buildings and facilities which differ in functionality, capacity, climatic category, price and other technical-and-economic indexes. Use of mobile accommodation complexes is characterized by certain advantages. Basic criterion for mobile accommodation camp construction consists in its timely commissioning. Basic predicted indexes affecting the cost of temporary accommodation camp could serve as an endorsement of the forwarded standpoint.

The Use of SGLT2i and GLP-1 RA in Patients with Type 2 Diabetes in Thailand: Evidence Review and Recommendations

2021 ◽  
Vol 104 (11) ◽  
pp. 1850-1865
Keyword(s):  
Type 2 Diabetes ◽  
Glucose Lowering ◽  
Sodium Glucose Cotransporter ◽  
Evidence Review ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1 ◽  
Glucose Lowering Therapy ◽  
The Cost ◽  
Selection Of

Background: Cardiovascular (CV) and renal comorbidities are common among type 2 diabetes (T2D) patients, and significantly increase the cost and burden of care. Both sodium-glucose cotransporter-2 inhibitors (SGLT2i) and glucagon-like peptide-1 receptor agonists (GLP-1 RA) improve key outcomes including major CV events, hospitalization for heart failure, and renal outcomes, albeit to varying degrees in different T2D populations. Materials and Methods: The authors reviewed evidence from GLP-1 RA and SGLT2i CV outcomes trials and real-world studies in Thailand and elsewhere. Results: The authors formulated recommendations to guide selection of anti-diabetes medication based on patients’ clinical characteristics and CV or renal risk profile. Conclusion: These recommendations could help guide management of CV/renal comorbidities and risk alongside glucose-lowering therapy for individual patients. Keywords: Type 2 diabetes mellitus; Cardiovascular diseases; Chronic kidney disease; Clinical outcomes; SGLT2i; GLP-1 RA

Influence of the cost of technological equipment of body production on indicators of efficiency of working processes

2021 ◽  
pp. 28-32
Author(s):  
Keyword(s):  
Quality Index ◽  
Production Efficiency ◽  
Statistical Data ◽  
The Body ◽  
Technological Equipment ◽  
Production Body ◽  
Body Production ◽  
The Cost ◽  
Efficiency Indicators ◽  
Selection Of

The possibilities for the development of bodywork in the context of the growing level of competition are analyzed in the article. The technological processes of bodywork are considered and the problem of choosing technological equipment is indicated. The statistical data about the efficiency indicators of company body divisions, operating in the body repair market in Krasnoyarsk, are presented. A composite quality index for the equipment of the bodywork department (using the example of body stocks) is proposed and calculated, and on its basis, some recommendations are given for companies which plan to enter the market of body repair services. Keywords: body production, body repair, body equipment, body production efficiency, selection of technological equipment

Prescreening in large populations as a tool for identifying elevated CO2-responsive genotypes in plants

2019 ◽  
Vol 46 (1) ◽  
pp. 1 ◽  
Author(s):  
Hiroyuki Shimono ◽  
Graham Farquhar ◽  
Matthew Brookhouse ◽  
Florian A. Busch ◽  
Anthony O'Grady ◽  
...  
Keyword(s):  
Genetic Selection ◽  
Co2 Concentration ◽  
Elevated Atmospheric Co2 ◽  
High Performing ◽  
Active Selection ◽  
Wide Range ◽  
Large Populations ◽  
Increase Productivity ◽  
The Cost ◽  
Selection Of

Elevated atmospheric CO2 concentration (e[CO2]) can stimulate the photosynthesis and productivity of C3 species including food and forest crops. Intraspecific variation in responsiveness to e[CO2] can be exploited to increase productivity under e[CO2]. However, active selection of genotypes to increase productivity under e[CO2] is rarely performed across a wide range of germplasm, because of constraints of space and the cost of CO2 fumigation facilities. If we are to capitalise on recent advances in whole genome sequencing, approaches are required to help overcome these issues of space and cost. Here, we discuss the advantage of applying prescreening as a tool in large genome×e[CO2] experiments, where a surrogate for e[CO2] was used to select cultivars for more detailed analysis under e[CO2] conditions. We discuss why phenotypic prescreening in population-wide screening for e[CO2] responsiveness is necessary, what approaches could be used for prescreening for e[CO2] responsiveness, and how the data can be used to improve genetic selection of high-performing cultivars. We do this within the framework of understanding the strengths and limitations of genotype–phenotype mapping.

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