scholarly journals A New Model for Real-Time Prediction of Wellbore Stability Considering Elastic and Strength Anisotropy of Bedding Formation

Energies ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 251
Author(s):  
Liqin Ding ◽  
Zhiqiao Wang ◽  
Jianguo Lv ◽  
Yu Wang ◽  
Baolin Liu
Keyword(s):  
Theoretical Model ◽  
Real Time ◽  
Field Data ◽  
In Situ Stress ◽  
Wellbore Stability ◽  
Real Field ◽  
Strength Anisotropy ◽  
Safety Control ◽  
Time Prediction

Severe wellbore stability issues were reported while drilling in laminated formation with weak planes such as beddings. To accurately determine the safe mud weight according to the changing environment is of primary importance for safety control of drilling. Considering both the elastic and strength anisotropy of bedding formation, a novel theoretical model is established and the stress and failure around wellbores are analyzed. The accuracy and applicability of the theoretical model is verified by in situ field data. For the purpose of fulfilling real-time prediction, the method flowchart of programming is also provided. The results show that the model built can be conveniently used to predict the stress distribution, failure area, and collapse and fracture pressure while drilling, and rather good predictions can be made compared to real field data. In addition, the inhomogeneity of in situ stress and elastic parameters affect the upper limit of the safe mud weight window (SMWW) greater than the lower limit. Negative SMWW may appear with the direction change of the wellbore or weak plane, especially when the azimuths of them change. As to the magnitude of SMWW, the anisotropic effects of Young’s modulus are greater than the Poisson’s ratio. The method established in this paper can greatly help with the precise prediction of wellbore stability as drilling proceeds in bedding formation.

A Novel Method to Determine the Drilling Fluid Density for Gypsum-Salt Layer

2021 ◽  
Author(s):  
Jitong Liu ◽  
Wanjun Li ◽  
Haiqiu Zhou ◽  
Yixin Gu ◽  
Fuhua Jiang ◽  
...  
Keyword(s):  
Drilling Fluid ◽  
In Situ Stress ◽  
Wellbore Stability ◽  
Shrinkage Rate ◽  
Fluid Density ◽  
Salt Layer ◽  
Rock Creep ◽  
Key Factor ◽  
Well Abandonment

Abstract The reservoir underneath the salt bed usually has high formation pressure and large production rate. However, downhole complexities such as wellbore shrinkage, stuck pipe, casing deformation and brine crystallization prone to occur in the drilling and completion of the salt bed. The drilling safety is affected and may lead to the failure of drilling to the target reservoir. The drilling fluid density is the key factor to maintain the salt bed’s wellbore stability. The in-situ stress of the composite salt bed (gypsum-salt -gypsum-salt-gypsum) is usually uneven distributed. Creep deformation and wellbore shrinkage affect each other within layers. The wellbore stability is difficult to maintain. Limited theorical reference existed for drilling fluid density selection to mitigate the borehole shrinkage in the composite gypsum-salt layers. This paper established a composite gypsum-salt model based on the rock mechanism and experiments, and a safe-drilling density selection layout is formed to solve the borehole shrinkage problem. This study provides fundamental basis for drilling fluid density selection for gypsum-salt layers. The experiment results show that, with the same drilling fluid density, the borehole shrinkage rate of the minimum horizontal in-situ stress azimuth is higher than that of the maximum horizontal in-situ stress azimuth. However, the borehole shrinkage rate of the gypsum layer is higher than salt layer. The hydration expansion of the gypsum is the dominant reason for the shrinkage of the composite salt-gypsum layer. In order to mitigate the borehole diameter reduction, the drilling fluid density is determined that can lower the creep rate less than 0.001, as a result, the borehole shrinkage of salt-gypsum layer is slowed. At the same time, it is necessary to improve the salinity, filter loss and plugging ability of the drilling fluid to inhibit the creep of the soft shale formation. The research results provide technical support for the safe drilling of composite salt-gypsum layers. This achievement has been applied to 135 wells in the Amu Darya, which completely solved the of wellbore shrinkage problem caused by salt rock creep. Complexities such as stuck string and well abandonment due to high-pressure brine crystallization are eliminated. The drilling cycle is shortened by 21% and the drilling costs is reduced by 15%.

Integrity Assurance of an Oil Transportation Pipeline in a Transformed Design Environment

2015 ◽  
Author(s):  
Amitabh Kumar ◽  
Brian McShane ◽  
Mark McQueen
Keyword(s):  
Field Data ◽  
Oil And Gas ◽  
High Reliability ◽  
Complex Loading ◽  
Calibration Method ◽  
Real Field ◽  
Design Environment ◽  
Data Feedback ◽  
Integrity Management

A large Oil and Gas pipeline gathering system is commonly used to transport processed oil and gas from an offshore platform to an onshore receiving facility. High reliability and integrity for continuous operation of these systems is crucial to ensure constant supply of hydrocarbon to the onshore processing facility and eventually to market. When such a system is exposed to a series of complex environmental loadings, it is often difficult to predict the response path, in-situ condition and therefore the system’s ability to withstand subsequent future loading scenarios. In order to continue to operate the pipeline after a significant environmental event, an overall approach needs to be developed to — (a) Understand the system loading and the associated integrity, (b) Develop a series of criteria staging the sequence of actions following an event that will verify the pipeline integrity and (c) Ensure that the integrity management solution is simple and easy to understand so that it can be implemented consistently. For a complex loading scenario, one of the main challenges is the ability to predict the controlling parameter(s) that drives the global integrity of these systems. In such scenarios, the presence of numerous parameters makes the technical modeling and prediction tasks arduous. To address such scenarios, first and foremost, it is crucial to understand the baseline environment data and other associated critical design input elements. If the “design environmental baseline” has transformed (due to large events e.g. storms etc.) from its original condition; it modifies the dynamics of the system. To address this problem, a thorough modeling and assessment of the in-situ condition is essential. Further, a robust calibration method is required to predict the future response path and therefore expected pipeline condition. The study further compares the planned integrity management solutions to the field data to validate the efficiency of the predicted scenarios. By the inclusion of real field-data feedback to the modeling method, balanced integrity solutions can be achieved and the ability to quantify the risks is made more practical and actionable.

Real-Time Prediction Method for Performance Degradation Trend Based on Reliability Experimental Data

2013 ◽  
Vol 321-324 ◽  
pp. 757-761 ◽  
Author(s):  
Chen Liang Song ◽  
Zhen Liu ◽  
Bin Long ◽  
Cheng Lin Yang
Keyword(s):  
Experimental Data ◽  
Real Time ◽  
Field Data ◽  
Prediction Method ◽  
Field Method ◽  
Performance Degradation ◽  
New Method ◽  
Time Prediction ◽  
Prediction Result ◽  
The Relationship

According to the real-time prediction for performance degradation trend, the commonly used method is just based on field data. But this methods prediction result will not be so much ideal when the fitting of degradation trend of field data is not good. To solve the problem, the paper introduces a new method which is not only based on field method but also based on reliability experimental data coming from the history experiment. We use the relationship between the field data and reliability experimental data to get the result of the two kinds of data respectively and then get the weights according to the two prediction results. Finally, the final real-time prediction result for performance degradation tendency can obtain by allocating the weights to the two prediction results.

APPLICATION OF GUIDELINE CHARTS IN DECISIONMAKING ON WELL TRAJECTORY AND MUD WEIGHT PROGRAM

2001 ◽  
Vol 41 (1) ◽  
pp. 609
Author(s):  
X. Chen ◽  
C.P. Tan ◽  
C.M. Haberfield
Keyword(s):  
Stability Analysis ◽  
Case Studies ◽  
In Situ Stress ◽  
Wellbore Stability ◽  
Material Strength ◽  
Stress Regime ◽  
Wellbore Instability ◽  
Well Trajectory

To prevent or minimise wellbore instability problems, it is critical to determine the optimum wellbore profile and to design an appropriate mud weight program based on wellbore stability analysis. It is a complex and iterative decisionmaking procedure since various factors, such as in-situ stress regime, material strength and poroelastic properties, strength and poroelastic anisotropies, initial and induced pore pressures, must be considered in the assessment and determination.This paper describes the methodology and procedure for determination of optimum wellbore profile and mud weight program based on rock mechanics consideration. The methodology is presented in the form of guideline charts and the procedure of applying the methodology is described. The application of the methodology and procedure is demonstrated through two field case studies with different in-situ stress regimes in Australia and Indonesia.

The in-situ stress state of the Rhine-Ruhr region and its implications for the geothermal energy utilization

2020 ◽  
Author(s):  
Michal Kruszewski ◽  
Giordano Montegrossi ◽  
Tobias Backers ◽  
Erik Saenger
Keyword(s):  
Stress State ◽  
Geothermal Energy ◽  
In Situ Stress ◽  
Wellbore Stability ◽  
Energy Utilization ◽  
Natural Fracture ◽  
Electricity Production ◽  
The Future ◽  
Ruhr Region

<p>The Rhine-Ruhr region is one of the largest metropolitan areas in Europe, with more than 10 million inhabitants, located in western Germany. The region is defined by the rich coal-bearing layers from the upper Carboniferous period, extracted as early as the 13<sup>th</sup> century and belonging to the sub-Variscan Trough. In 2018, after more than 700 years of exploration, the last black coal mine was closed in the area. One of the most promising re-uses of the abandoned coal mines is the exploitation of geothermal energy sources. Additionally, to the geothermal energy extracted from existing mines, potential deep geothermal reservoirs within the Rhine-Ruhr, may exist at depths between 4.5 and 6 km, where Devonian limestones were found. Based on the available temperature profiles from deep exploration wells in the area, geothermal gradient amounts to 36.8<sup>o</sup>C/km and results in reservoir temperatures between 170<sup>o</sup>C and 220<sup>o</sup>C, which will enable not only heat but even electricity production. This study provides a comprehensive investigation of the full in-situ stress state tensor with its anisotropy and presents crucial physical formation and natural fracture properties. The data for this investigation was acquired from the extensive borehole logging and geomechanical campaigns carried out in deep coal exploration wells throughout the 1980s as well as from the recent shallow geothermal research wells. Acquired data allowed assessing critically-stressed, i.e. hydraulically active, fractures undergoing shear displacement, being primarily responsible for the future geothermal reservoir permeability. Extensive sets of microseismic, subsidence and drilling data were used to confirm the results of the analysis. Additionally, wellbore stability analysis and potential drill paths for the future medium-to-deep geothermal wells in the region were assessed. This study is a part of the 3D-RuhrMarie project, which aims to assess the intrinsic seismic risk within the Rhine-Ruhr region to promote safer and economically more efficient exploration and exploitation of the future geothermal resources.</p>

The Influence of Anchor Inclination on Pull-out Resistance of Clays

1973 ◽  
Vol 10 (4) ◽  
pp. 664-669 ◽  
Author(s):  
T. H. Hanna
Keyword(s):  
Shear Stress ◽  
Theoretical Model ◽  
Stress State ◽  
In Situ Stress ◽  
Stiff Clays ◽  
Pile Shaft ◽  
Pull Out

A theoretical model is described that was used to examine the influence of anchor inclination on pull-out capacity. Use was made of previous general findings for pile shaft adhesion prediction in stiff clays. It is shown that the adhesion available at the anchor shaft – clay interface depends on: (1) the in situ stress state in the ground; (2) anchor inclination; and (3) the initial shear stress existing in the ground in the direction of the anchor shaft. The possible importance of the reported trends is considered.

In-Situ Stress And Wellbore Stability In A Brazilian Basin

2001 ◽  
Author(s):  
Aline Theophilo Silva ◽  
Claudio Lima ◽  
Luis Antonio Canelas Palermo
Keyword(s):  
In Situ Stress ◽  
Wellbore Stability
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