Real-Time Wellbore Stability Evaluation for Deepwater Drilling During Tripping

Zhang, Feifei; Kang, Yongfeng; Wang, Zhaoyang; Miska, Stefan; Yu, Mengjiao; Zamanipour, Zahra

doi:10.2118/180307-ms

Cited by 9 publications

(3 citation statements)

References 42 publications

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“…Excessive pressure variation in the wellbore can create instability and other drilling problems. Accurate prediction of pressure variation is vital for estimating the maximum tripping or reaming speeds to keep the pressure in the wellbore within specified limits of the safe operational window [34] [35].…”

Section: Preventive Measures For Wellbore Stability Problemsmentioning

confidence: 99%

Wellbore Stability Problems in Deepwater Gas Wells

Aregbe¹

2017

WJET

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The analysis of wellbore stability in deepwater gas wells is vital for effective drilling operations, especially in deepwater remote areas and for modern drilling technologies. Wellbore stability problems usually occur when drilling through hydrocarbon formations such as shale, unconsolidated sandstone, fractured carbonate formations and HPHT formations with narrow safety mud window. These problems can significantly affect drilling time, costs and the whole drilling operations. In deepwater gas wells, there is also the possible of gas hydrate problems because of the low temperature and high pressure conditions of the environment as well as the coexistence of gas and water inside the wellbore. These hydrates can block the mud line, surface choke line and even the BOP stack if no hydrate preventive measures are considered. In addition, the dissociation of these hydrates in the wellbore may gasify the drilling fluid and reduce drilling mud density, hydrostatic pressure, change mud rheology and cause wellbore instabilities. Traditional wellbore stability analysis considered the formation to be isotropic and assumed that the rock mechanical properties are independent of in-situ stress direction. This assumption is invalid for formations with layers or natural fractures because the presence of these geological features will influence rock anisotropic properties, wellbore stress concentration and failure behavior. This is a complicated phenomenon because the stress distribution around a wellbore is affected by factors such as rock properties, far-field principal stresses, wellbore trajectory, formation pore pressure, reservoir and drilling fluids properties and time. This research work reviews the major causes of wellbore stability problems in deepwater gas wells and outlines different preventive measures for effective drilling operation, because real-time monitoring of drilling process can provide necessary information for solving any wellbore stability problems in a short time.

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Section: Preventive Measures For Wellbore Stability Problemsmentioning

confidence: 99%

Wellbore Stability Problems in Deepwater Gas Wells

Aregbe¹

2017

WJET

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“…The variation of maximum surge pressure and swabbing pressure at each depth within the wellbore with time were predicted proposed solving the transient surge pressure of each passage using the mixing implicit feature line method, which obtained the numerical solutions of transient surge pressure under various conditions [27]. To acquire the wellbore pressure and ground stress field in the near-wellbore section of deepwater drilling, some scholars proposed a method for analyzing wellbore stability based on the oscillation coupling of transient surge pressure [28]. Considering the liquid-solid twophase medium, researchers studied the transient surge pressure during tripping operations with the use of the numerical simulation method [29].…”

Section: Introductionmentioning

confidence: 99%

Research on Managed-Pressure Running Casing in Oil and Gas Wells with the Negative Pressure Window

Mei

Yang

Zhang³

et al. 2023

Processes

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The failure of managed-pressure running casing in oil and gas wells may lead to complex accidents such as overflow or leakage. The technique of using multi-density gradient drilling fluids in wellbores with negative pressure windows (NPWs) is often used to deal with this situation. Therefore, it is vital to analyze the dynamic slurry column structure and calculate the wellbore pressure during casing running. For this issue, the model of transient surge pressure is established during casing running. The calculation equation of the model is proposed, and the calculations of the wellbore pressure are carried out with the exploration of Well LT-X1, located in the Xinjiang oil field. A circulation scheme is designed as follows: Circulate 125 m3 of drilling fluid with a density of 2.45 g/cm3 and 155 m3 of drilling fluid with a density of 2.35 g/cm3 at a depth of 3560 m. From there, circulate 164 m3 of drilling fluid with a density of 2.35 g/cm3 at a depth of 5900 m. Finally, at a depth of 7050 m, circulate 250 m3 of drilling fluid with a density of 2.30 g/cm3. The casing running speeds and back-pressure values were designed as follows for the respective well sections: 0–1523 m: 0.160 m/s casing speed, 0 MPa back pressure; 1523–3560 m: 0.160 m/s casing speed, 1.641 MPa back pressure; 3560–5900 m: 0.145 m/s casing speed, 2.427 MPa back pressure; 5900–6674 m: 0.137 m/s casing speed, 4.041 MPa back pressure; 6674–7050 m: 0.124 m/s casing speed, 4.457 MPa back pressure. The results show that optimizing structure of the multi-density gradient drilling fluid with different densities and applying annular back pressure in stages, with the accurate calculation of wellbore pressure, can achieve the goals of leak-proofing and pressure-stabilization. It is concluded that this result may serve as the foundation for managed-pressure running casing technology.

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“…The conventional methods used to assess the wellbore stability analysis generally assume that the loads acting on the wellbore are in steady-state [1][2][3]. Nonetheless, recent researches have revealed that the magnitudes of the loads affecting the wellbore stability are more likely to change over time; therefore, the wellbore pressure is prone to fluctuations [4,5]. The drill string vibration cyclic load is one of the most common sources of wellbore pressure fluctuations and numerous researches have demonstrated its impact on wellbore stability: ref.…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation of the Influence of the Drill String Vibration Cyclic Loads on the Development of the Wellbore Natural Fracture

et al. 2021

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Wellbore instability is one of the most serious issues faced in the drilling process. During drilling operations, the cyclic loads applied on the fractured formation progressively modify the initial parameters (i.e., length and width) of the fractured formation, thus resulting into undesirable wellbore instability. In this paper, using a nonlinear finite element software (ABAQUS) as the numerical simulator, a poro-elasto-plastic model has been established which aimed at analyzing the influence of drill string vibration cyclic loads on the development of the wellbore natural fracture. The numerical results showed that the fracture width as a function of time profiles followed a sinusoidal behavior similar to the drill string vibration cyclic load profiles. For different cyclic load magnitudes with constant number of cyclic loads, the highest percentage increase of the fracture width after integration of cyclic loads was 64.77%. Interestingly, the fracture width increased with the fracture length in the near wellbore region while it globally decreased in the region far away from the wellbore. But for constant cyclic load magnitude with different number of cyclic loads, the biggest percentage increase of the fracture width after integration of cyclic loads was slightly lower representing 63.12% while the oscillating period of the fracture width increased with the number of cyclic loads. The parametric study revealed that the drill string vibration cyclic loads were relatively independent of the fracture length and the bottom hole pressure. However, the fracture width and the loss circulation rates were considerably impacted by the drill string vibration and the highest percentage increase of the loss circulation rate after integration of cyclic loads was 14.3%. This study provides an insight into the coupling of the fracture rock development and the continuous cyclic loads generated by drill string vibrations which is an aspect that has been rarely discussed in the literature.

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Real-Time Wellbore Stability Evaluation for Deepwater Drilling During Tripping

Cited by 9 publications

References 42 publications

Wellbore Stability Problems in Deepwater Gas Wells

Wellbore Stability Problems in Deepwater Gas Wells

Research on Managed-Pressure Running Casing in Oil and Gas Wells with the Negative Pressure Window

Numerical Investigation of the Influence of the Drill String Vibration Cyclic Loads on the Development of the Wellbore Natural Fracture

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