Wellbore pressure management of offshore wells during casing running in narrow safety pressure window formations

2021 ◽  
Vol 199 ◽  
pp. 108284
Author(s):  
Yuhong Xie ◽  
Min Ouyang ◽  
Hu Zhao ◽  
Lie Li ◽  
Yingtao Feng
Keyword(s):  
Pressure Management ◽  
Wellbore Pressure

scholarly journals Study on the Surge-Swab Pressure considering the Effect of the Cutting Plug in Shale Drilling

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Tianyi Tan ◽  
Hui Zhang ◽  
Xusheng Ma ◽  
Yufei Chen
Keyword(s):  
Horizontal Wells ◽  
Wellbore Stability ◽  
Pressure Management ◽  
Accurate Calculation ◽  
Wellbore Instability ◽  
Wellbore Pressure ◽  
The Difference ◽  
Open Pipe ◽  
Frequent Problem

Wellbore instability is a frequent problem of shale drilling. Accurate calculation of surge-swab pressures in tripping processes is essential for wellbore pressure management to maintain wellbore stability. However, cutting plugs formed in shale horizontal wells have not been considered in previous surge-swab pressure models. In this paper, a surge-swab pressure model considering the effect of cutting plugs is established for both open pipe string and closed pipe string conditions; In this model, the osmotic pressure of a cutting plug is analyzed. The reduction of cutting plug porosity due to shale hydration expansion and dispersion is considered, ultimately resulting in an impermeable cutting plug. A case study is conducted to analyze swab pressures in a tripping out process. The results show that, in a closed pipe condition, the cutting plug significantly increases the swab pressures below it, which increase with the decrease of cutting plug porosity and the increase of cutting plug length. Under the give condition, the swab pressure at the bottom of the well increases from 3.60 MPa to 8.82 MPa due to the cutting plug, increasing by 244.9%. In an open pipe string condition, the cutting plug affects the flow rate in the pipes and the annulus, resulting in a higher swab pressure above the cutting plug compared to a no-cutting plug annulus. The difference increases with the decrease of the porosity and the increase of the length and the measured depth of the cutting plug. Consequently, the extra surge-swab pressures caused by cutting plugs could result in wellbore pressures out of safety mud density window, whereas are ignored by previous models. The model proposes a more accurate wellbore pressure prediction and guarantees the wellbore stability in shale drilling.

Anti-Flushing Design for Continuous Circulation System

2010 ◽  
Vol 160-162 ◽  
pp. 768-772
Author(s):  
Ding Feng ◽  
Liu Li ◽  
Hai Xiong Tang
Keyword(s):  
Drill String ◽  
Wellbore Stability ◽  
Small Hole ◽  
Pressure Increase ◽  
Circulation System ◽  
Pressure Management ◽  
Well Drilling ◽  
Critical Part ◽  
Wellbore Pressure

Proper wellbore pressure management is a critical part of the drilling practice, where static and dynamic fluid pressures are used to contain formation pressures and assure wellbore stability, to solve the problem; the anti-flushing device is has been developed. The anti-flushing device is designed to counter downhole pressure increase due to safety of narrow mud window and the key to fast drilling. Reasonable control anti-flushing device is the best way to solve the safety of narrow mud window and the key to fast drilling. This paper describes the anti-flushing device, which is run as an integral part of the drill string. The anti-flushing device has been built to operate the 8-1/2 "section of well drilling, keeping continuous loop, To avoiding annular cutting is sank into accumulation when the drill string were connected and the pump stopped, cleaning the small hole by maximum.

Study of dynamic pressure on the packer for deep-water perforation

Open Physics ◽  
2021 ◽  
Vol 19 (1) ◽  
pp. 215-223
Author(s):  
Hao Huang ◽  
Qiao Deng ◽  
Hui Zhang
Keyword(s):  
Deep Water ◽  
Peak Pressure ◽  
Orthogonal Design ◽  
Dynamic Pressure ◽  
Three Dimensional ◽  
Calculation Model ◽  
Well Testing ◽  
Technical Problems ◽  
Wellbore Pressure ◽  
Three Dimensional Finite Element

Abstract The packer is one of the most important tools in deep-water perforation combined well testing, and its safety directly determines the success of perforation test operations. The study of dynamic perforating pressure on the packer is one of the key technical problems in the production of deep-water wells. However, there are few studies on the safety of packers with shock loads. In this article, the three-dimensional finite element models of downhole perforation have been established, and a series of numerical simulations are carried out by using orthogonal design. The relationship between the perforating peak pressure on the packer with the factors such as perforating charge quantity, wellbore pressure, perforating explosion volume, formation pressure, and elastic modulus is established. Meanwhile, the database is established based on the results of numerical simulation, and the calculation model of peak pressure on the packer during perforating is obtained by considering the reflection and transmission of shock waves on the packer. The results of this study have been applied in the field case of deep-water well, and the safety optimization program for deep-water downhole perforation safety has been put forward. This study provides important theoretical guidance for the safety of the packer during deep-water perforating.

scholarly journals Sex-Specific Associations between Blood Pressure and Risk of Atrial Fibrillation Subtypes in the Tromsø Study

2021 ◽  
Vol 10 (7) ◽  
pp. 1514
Author(s):  
Hilde Espnes ◽  
Jocasta Ball ◽  
Maja-Lisa Løchen ◽  
Tom Wilsgaard ◽  
Inger Njølstad ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Blood Pressure ◽  
Proportional Hazards ◽  
Cox Proportional Hazards ◽  
Pressure Management ◽  
Reference Models ◽  
Proportional Hazards Regression ◽  
Hazard Ratios ◽  
Increased Risk

The aim of this study was to explore sex-specific associations between systolic blood pressure (SBP), hypertension, and the risk of incident atrial fibrillation (AF) subtypes, including paroxysmal, persistent, and permanent AF, in a general population. A total of 13,137 women and 11,667 men who participated in the fourth survey of the Tromsø Study (1994–1995) were followed up for incident AF until the end of 2016. Cox proportional hazards regression analysis was conducted using fractional polynomials for SBP to provide sex- and AF-subtype-specific hazard ratios (HRs) for SBP. An SBP of 120 mmHg was used as the reference. Models were adjusted for other cardiovascular risk factors. Over a mean follow-up of 17.6 ± 6.6 years, incident AF occurred in 914 (7.0%) women (501 with paroxysmal/persistent AF and 413 with permanent AF) and 1104 (9.5%) men (606 with paroxysmal/persistent AF and 498 with permanent AF). In women, an SBP of 180 mmHg was associated with an HR of 2.10 (95% confidence interval [CI] 1.60–2.76) for paroxysmal/persistent AF and an HR of 1.80 (95% CI 1.33–2.44) for permanent AF. In men, an SBP of 180 mmHg was associated with an HR of 1.90 (95% CI 1.46–2.46) for paroxysmal/persistent AF, while there was no association with the risk of permanent AF. In conclusion, increasing SBP was associated with an increased risk of both paroxysmal/persistent AF and permanent AF in women, but only paroxysmal/persistent AF in men. Our findings highlight the importance of sex-specific risk stratification and optimizing blood pressure management for the prevention of AF subtypes in clinical practice.

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