Modeling and analysis of sustained annular pressure and gas accumulation caused by tubing integrity failure in the production process of deep natural gas wells

2021 ◽  
pp. 1-10
Author(s):  
Bo Zhang ◽  
Nu Lu ◽  
Yujie Guo ◽  
Qing Wang ◽  
Mengzhe Cai ◽  
...  
Keyword(s):  
Gas Well ◽  
Modeling And Analysis ◽  
Safe Production ◽  
Bottom Hole ◽  
Reduce Risk ◽  
Cement Integrity ◽  
Potential Methods ◽  
Gas Volume ◽  
The Impact ◽  
Energy Conservation Law

Abstract Sustained annular pressure caused by tubing leakage seriously threatens the safe production of deep gas well. Therefore, it is necessary to fully understand the characteristics of sustained annular pressure and find potential methods to reduce risk. However, most models are about annular pressure caused by thermal expansion and cement integrity failure. Therefore, this paper establishes a model based on the energy conservation law, gas PVT properties and volume consistence law, to study sustained annular pressure caused by tubing leakage. The results indicate that the pressure and gas volume in tubing-casing annulus increase simultaneously and gradually slow down after tubing leakage happens. The decrease of bottom-hole pressure can reduce the risk of annular pressure, which can be realized by downhole choke. Other measures can also control the rising speed of annular pressure, including enhancement of production rate, increase of initial length of gas column and annular liquid with high compressibility, but the the impact of formation energy and annular gas volume should be considered. Sustained annular pressure caused by shallow leaking point has faster rising speed, longer rising period and higher pressure value. Large leaking point leads to remarkable increase of leaking rate and pressure rising speed. The integrity of upper tubing string should be strengthened.

scholarly journals Kinematics and dynamics analysis of new rotary-percussive PDM drilling tool

2021 ◽  
pp. 146134842198915
Author(s):  
Jialin Tian ◽  
Xuehua Hu ◽  
Liming Dai ◽  
Lin Yang ◽  
Yi Yang ◽  
...  
Keyword(s):  
Drill String ◽  
Structure Design ◽  
Drilling Process ◽  
Analysis Model ◽  
Drilling Tool ◽  
Stick Slip ◽  
Rate Of Penetration ◽  
Bottom Hole ◽  
Bottom Hole Assembly ◽  
The Impact

This paper presents a new drilling tool with multidirectional and controllable vibrations for enhancing the drilling rate of penetration and reducing the wellbore friction in complex well structure. Based on the structure design, the working mechanism is analyzed in downhole conditions. Then, combined with the impact theory and the drilling process, the theoretical models including the various impact forces are established. Also, to study the downhole performance, the bottom hole assembly dynamics characteristics in new condition are discussed. Moreover, to study the influence of key parameters on the impact force, the parabolic effect of the tool and the rebound of the drill string were considered, and the kinematics and mechanical properties of the new tool under working conditions were calculated. For the importance of the roller as a vibration generator, the displacement trajectory of the roller under different rotating speed and weight on bit was compared and analyzed. The reliable and accuracy of the theoretical model were verified by comparing the calculation results and experimental test results. The results show that the new design can produce a continuous and stable periodic impact. By adjusting the design parameter matching to the working condition, the bottom hole assembly with the new tool can improve the rate of penetration and reduce the wellbore friction or drilling stick-slip with benign vibration. The analysis model can also be used for a similar method or design just by changing the relative parameters. The research and results can provide references for enhancing drilling efficiency and safe production.

Openhole Multistage Completion Evaluation Incorporating Deployment of Downhole Shut-in Tool Application in Sour Carbonate Gas Wells, Field Application

2021 ◽  
Author(s):  
Mauricio Espinosa ◽  
Jairo Leal ◽  
Ron Zbitowsky ◽  
Eduardo Pacheco
Keyword(s):  
Gas Flow ◽  
Operational Risk ◽  
Tool Design ◽  
Lessons Learned ◽  
Differential Pressure ◽  
Gas Wells ◽  
Flow Area ◽  
Gas Well ◽  
Heterogeneous Rocks ◽  
The Impact

Abstract This paper highlights the first successful application of a field deployment of a high-temperature (HT) downhole shut-in tool (DHSIT) in multistage fracturing completions (MSF) producing retrograde gas condensate and from sour carbonate reservoirs. Many gas operators and service providers have made various attempts in the past to evaluate the long-term benefit of MSF completions while deploying DHSIT devices but have achieved only limited success (Ref. 1 and 2). During such deployments, many challenges and difficulties were faced in the attempt to deploy and retrieve those tools as well as to complete sound data interpretation to successfully identify both reservoir, stimulation, and downhole productivity parameters, and especially when having a combination of both heterogeneous rocks having retrograde gas pressure-volume-temperature (PVT) complexities. Therefore, a robust design of a DHSIT was needed to accurately shut-in the well, hold differential pressure, capture downhole pressure transient data, and thereby identify acid fracture design/conductivity, evaluate total KH, reduce wellbore storage effects, properly evaluate transient pressure effects, and then obtain a better understanding of frac geometry, reservoir parameters, and geologic uncertainties. Several aspects were taken into consideration for overcoming those challenges when preparing the DHSIT tool design including but not limited to proper metallurgy selection, enough gas flow area, impact on well drawdown, tool differential pressure, proper elastomer selection, shut-in time programming, internal completion diameter, and battery operation life and temperature. This paper is based on the first successful deployment and retrieval of the DHSIT in a 4-½" MSF sour carbonate gas well. The trial proved that all design considerations were important and took into consideration all well parameters. This project confirmed that DHSIT devices can successfully withstand the challenges of operating in sour carbonate MSF gas wells as well as minimize operational risk. This successful trial demonstrates the value of utilizing the DHSIT, and confirms more tangible values for wellbore conductivity post stimulation. All this was achieved by the proper metallurgy selection, maximizing gas flow area, minimizing the impact on well drawdown, and reducing well shut-in time and deferred gas production. Proper battery selection and elastomer design also enabled the tool to be operated at temperatures as high as 350 °F. The case study includes the detailed analysis of deployment and retrieval lessons learned, and includes equalization procedures, which added to the complexity of the operation. The paper captures all engineering concepts, tool design, setting packer mechanism, deployment procedures, and tool equalization and retrieval along with data evaluation and interpretation. In addition to lessons learned based on the field trial, various recommendations will be presented to minimize operational risk, optimize shut-in time and maximize data quality and interpretation. Utilizing the lessons learned and the developed procedures presented in this paper will allow for the expansion of this technology to different gas well types and formations as well as standardize use to proper evaluate the value of future MSF completions and stimulation designs.

Numerical modeling and analysis of the noncontacting impulse gas face seals

2018 ◽  
Vol 233 (8) ◽  
pp. 1139-1153
Author(s):  
Slawomir Blasiak
Keyword(s):  
Computer Software ◽  
Surface Modifications ◽  
Mechanical Seals ◽  
Face Surface ◽  
Modeling And Analysis ◽  
C Language ◽  
Model Studies ◽  
Face Seals ◽  
Radial Gap ◽  
The Impact

Noncontacting mechanical seals with various kinds of face surface modifications have established their position in the sealing technique. Over the last few years, a lot of works dedicated to the impact of various surface modifications on the dynamics of working rings have been created. This paper presents model studies regarding relatively unknown noncontacting impulse gas face seals. Here, a mathematical model of impulse gas face seals is developed including the nonlinear Reynolds equation and stator dynamics equations, which were solved simultaneously using numerical methods. An original computer software written in C + + language was developed. A number of numerical tests were conducted and the phenomena occurring in the radial gap during seal operation were analyzed. Final conclusions were drawn and several features were indicated characterizing impulse face seals. It should be emphasized that numerical research on this type of seals has not been published yet. The literature usually presents simplified models for the noncompressible medium, which can be solved with the use of analytical methods.

scholarly journals Changes in the Portfolio Management and Construction under the Pandemic Era

2021 ◽  
Vol 275 ◽  
pp. 01005
Author(s):  
Ruipeng Tan
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Stock Returns ◽  
Financial Market ◽  
Portfolio Management ◽  
Portfolio Construction ◽  
Sample Data ◽  
Before And After ◽  
Reduce Risk ◽  
The Impact

This paper focuses on comparing portfolio management and construction before and after the coronavirus. First, this paper presents the importance of building up portfolios for investors to diversify their risks. Theories on portfolio management are discussed in this section to show how they have been developed to help on investing and reduce risk. Then, the paper moves on to show the impact of the pandemic on the financial market and portfolio management. Sample data on tech stock returns are collected to perform a Monte Carlo simulation on portfolio construction to find out the efficient portfolio before and after the COVID-19 outbreak. The efficient portfolio is build based on the Markowitz theory to find the combination. Comparisons between these portfolio constructions are made to find out the changes in portfolio management and construction under the pandemic era. In conclusion, this paper presents how pandemic has changed and impacted the investments and lists recommendations on future portfolio management and construction.

scholarly journals DEVELOPMENT OF AN ASPHALT-RESIN-PARAFFIN DEPOSITS INHIBITOR AND SUBSTANTIATION OF THE TECHNOLOGICAL PARAMETERS OF ITS INJECTION INTO THE BOTTOM-HOLE FORMATION ZONE

2020 ◽  
Vol 17 (34) ◽  
pp. 769-781 ◽  
Author(s):  
Karina Shamilevna KHAIBULLINA ◽  
Grigory Yurievich KOROBOV ◽  
Aleksandr Viktorovich LEKOMTSEV
Keyword(s):  
Core Material ◽  
Hole Formation ◽  
Technological Parameters ◽  
Oil Saturation ◽  
Bottom Hole ◽  
Formation Zone ◽  
Production Wells ◽  
Bulk Model ◽  
Corrosive Activity ◽  
The Impact

The problem of the formation of asphalt-resin-paraffin deposits (ARPD) in oil fields within the “well – bottom-hole formation zone” system is still relevant. To prevent the formation of ARPD in the “bottom-hole formation zone – well” system, the ARPD inhibitors must have high adsorption and low desorption properties concerning the rock. The composition of inhibitors often includes surfactants. Nonionic surfactants, namely, polyesters, are widely used to prevent the formation of ARPD. However, currently, little is known about inhibitors with a combined effect, for example, possessing depressor-dispersing properties for ARPD. This work aimed to develop a combined inhibitor possessing not only depressor-dispersing properties but also having good adsorption and desorption properties to the rock to prevent the formation of ARPD. The paper presents the research results on the development of an ARPD inhibitor, as well as the effects of determination of its depressor dispersing, inhibiting, and corrosive properties; the temperature of oil saturation with paraffin is determined as well. The studies of the ARPD inhibitor adsorption were carried out by the static and dynamic methods. In contrast, the process of the inhibitor desorption was studied by oil filtering through a saturated sample of the rock using a bulk model and core material. The impact of the fluid flow rate on the inhibitor desorption rate was studied. The technological parameters of the ARPD inhibitor solution injection into the bottom-hole formation zone of production wells were calculated. The developed composition has high inhibiting properties concerning the ARPD, depressor dispersing properties, low corrosive activity for a metal surface, and is capable of lowering the temperature of oil saturation with paraffin.

Modeling and analysis of soft robotic fingers using the fin ray effect

2020 ◽  
Vol 39 (14) ◽  
pp. 1686-1705
Author(s):  
Xiaowei Shan ◽  
Lionel Birglen
Keyword(s):  
Contact Forces ◽  
Accurate Estimation ◽  
Modeling And Analysis ◽  
Physical Experiments ◽  
Fin Ray ◽  
And Performance ◽  
Difficult Challenge ◽  
Kinetostatic Model ◽  
Individual Contact ◽  
The Impact

Soft grasping of random objects in unstructured environments has been a research topic of predilection both in academia and in industry because of its complexity but great practical relevance. However, accurate modeling of soft hands and fingers has proven a difficult challenge to tackle. Focusing on this issue, this article presents a detailed mathematical modeling and performance analysis of parallel grippers equipped with soft fingers taking advantage of the fin ray effect (FRE). The FRE, based on biomimetic principles, is most commonly found in the design of grasping soft fingers, but despite their popularity, finding a convenient model to assess the grasp capabilities of these fingers is challenging. This article aims at solving this issue by providing an analytic tool to better understand and ultimately design this type of soft fingers. First, a kinetostatic model of a general multi-crossbeam finger is established. This model will allow for a fast yet accurate estimation of the contact forces generated when the fingers grasp an arbitrarily shaped object. The obtained mathematical model will be subsequently validated by numerically to ensure the estimations of the overall grasp strength and individual contact forces are indeed accurate. Physical experiments conducted with 3D-printed fingers of the most common architecture of FRE fingers will also be presented and shown to support the proposed model. Finally, the impact of the relative stiffness between different areas of the fingers will be evaluated to provide insight into further refinement and optimization of these fingers.

scholarly journals Respiratory patient experience of measures to reduce risk of COVID-19: findings from a descriptive cross-sectional UK wide survey

BMJ Open ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. e040951 ◽  
Author(s):  
Keir Philip ◽  
Andrew Cumella ◽  
Joe Farrington-Douglas ◽  
Michael Laffan ◽  
Nicholas Hopkinson
Keyword(s):  
Healthcare Services ◽  
Social Consequences ◽  
Chronic Obstructive ◽  
Cross Sectional ◽  
Social Distancing ◽  
Pulmonary Endometriosis ◽  
Reduce Risk ◽  
The Impact ◽  
Respiratory Conditions

ObjectivesTo assess the experience of people with long-term respiratory conditions regarding the impact of measures to reduce risk of COVID-19.DesignAnalysis of data (n=9515) from the Asthma UK and British Lung Foundation partnership COVID-19 survey collected online between 1 and 8 April 2020.SettingCommunity.Participants9515 people with self-reported long-term respiratory conditions. 81% female, age ranges from ≤17 years to 80 years and above, from all nations of the UK. Long-term respiratory conditions reported included asthma (83%), chronic obstructive pulmonary disease (10%), bronchiectasis (4%), interstitial lung disease (2%) and ‘other’ (<1%) (eg, lung cancer and pulmonary endometriosis).Outcome measuresStudy responses related to impacts on key elements of healthcare, as well as practical, psychological and social consequences related to the COVID-19 pandemic and social distancing measures.Results45% reported disruptions to care, including cancellations of appointments, investigations, pulmonary rehabilitation, treatment and monitoring. Other practical impacts such as difficulty accessing healthcare services for other issues and getting basic necessities such as food were also common. 36% did not use online prescriptions, and 54% had not accessed online inhaler technique videos. Psychosocial impacts including anxiety, loneliness and concerns about personal health and family were prevalent. 81% reported engaging in physical activity. Among the 11% who were smokers, 48% reported they were planning to quit smoking because of COVID-19.ConclusionsCOVID-19 and related social distancing measures are having profound impacts on people with chronic respiratory conditions. Urgent adaptation and signposting of services is required to mitigate the negative health consequences of the COVID-19 response for this group.

Modeling and Analysis of Single Hydraulic Props in Coal Mines

2016 ◽  
Vol 693 ◽  
pp. 364-372
Author(s):  
Tao He ◽  
Cao Feng Yu ◽  
Xiao Lei Wu ◽  
Hai Shun Deng
Keyword(s):  
Support System ◽  
Safety Valve ◽  
Impact Load ◽  
Dynamic Performance ◽  
Core Stability ◽  
Mine Safety ◽  
Dead Volume ◽  
Modeling And Analysis ◽  
Hydraulic Prop ◽  
The Impact

This research is focused on dynamic performance of water hydraulic single hydraulic prop, the mathematical and AMESim model of single hydraulic prop are established. And the drop hammer is introduced to simulate the impact load of the surrounding rock acting on the prop. The performance parameters of prop retract displacement and cavity pressure are used as the research objects. The working process of single hydraulic prop is reproduced by the simulation. And the influence of safety valve parameters on the support system is analyzed. The results show that: increasing maximal valve core stroke and dead volume or reducing valve damping hole diameter can improve the support performance of the single hydraulic prop. But the influence of equivalent damping has two sides. For support system, decrease damping can improve the support performance, but for the safety valve, reduce the damping make the valve core stability decline. In addition, the pressure overshoot of the optimized system is 18.3%, adjusting time is 0.5s and the retract displacement is 10mm. The dynamic performances meet the technology requirements of the coal mine safety production of China.

Ambiguity Aversion Decreases the Impact of Partial Insurance: Evidence from African Farmers

2019 ◽  
Vol 17 (5) ◽  
pp. 1428-1469 ◽  
Author(s):  
Gharad Bryan
Keyword(s):  
New Technologies ◽  
Ambiguity Aversion ◽  
Smallholder Farmers ◽  
Limited Liability ◽  
Comparative Statics ◽  
Reduce Risk ◽  
Using Data ◽  
Credit Contracts ◽  
The Impact ◽  
Partial Insurance

Abstract Indemnifying smallholder farmers against crop loss is thought to play an important role in encouraging the adoption of new technologies and facilitating productivity growth, but to be infeasible due to information problems. Consequently there is interest in developing alternative, partial, insurance products. Examples include rainfall insurance and the limited liability inherent in credit contracts. I argue that although these products may reduce information asymmetry, ambiguity averse farmers struggle to assess whether the contracts reduce risk. This problem is most pronounced when the production technology is ambiguous, as is likely the case for new technologies. I formalize this argument and test the theory using data from two RCTs, conducted in Malawi and Kenya. Comparative statics from the theory are consistent with both sets of data, and I argue that income losses from ambiguity aversion may be substantial.

Modeling and Analysis of a Ball and Beam System Including Impacts and Dry Friction

2014 ◽  
Author(s):  
Diego Colón ◽  
Átila Madureira Bueno ◽  
Ivando S. Diniz ◽  
Jose M. Balthazar
Keyword(s):  
Differential Inclusion ◽  
Dry Friction ◽  
Viscous Friction ◽  
Mathematical Object ◽  
Contact Forces ◽  
Modeling And Analysis ◽  
Typical Situation ◽  
Beam System ◽  
The Impact ◽  
Ball And Beam System

The Ball and Beam system is a common didactical plant that presents a complex nonlinear dynamics. This comes from the fact that the ball rolls over the beam, which rotates around its barycenter. In order to deduce the system’s equations, composition of movement must be applied, using a non-inertial reference frame attached to the beam. In the Literature, a common hypothesis is to suppose that the ball rolls without slipping. If a viscous friction is supposed to be present, a simpler situation is obtained, where Lagrangean mechanics can be applied, and no contact force is known. Even then, the dynamics is very nonlinear. However, this model does not include all the relevant phenomena, such as ball’s slipping at higher beam’s inclination angles, dry friction between the ball and the beam, and impacts between: 1) the ball and the ends of the beam, and 2) the beam and the base (ground). These additions to the model impose the necessity to calculate, in a simulation setting, the contact forces, and the Newton’s approach to determine the system’s equations becomes more convenient. Also, discontinuities in the model are introduced, and the simpler mathematical object for model such systems are the differential inclusion systems. In this work, we deduce the Ball and Beam differential inclusion system, including dry friction and the impact between the ball and beam. We also present simulation results for the corresponding differential inclusion system in a typical situation.

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