Elasto-Plastic Analysis on Wellbore Stability under the Condition of Permeation

2010 ◽  
Vol 156-157 ◽  
pp. 1292-1296
Author(s):  
Jian Bing Sang ◽  
Su Fang Xing ◽  
Chen Hua Lu ◽  
Wen Jia Wang ◽  
Bo Liu
Keyword(s):  
Porous Medium ◽  
Failure Criterion ◽  
Oil And Gas ◽  
Pressure Effect ◽  
Wellbore Stability ◽  
Gas Drilling ◽  
Plastic Analysis ◽  
Key Factor ◽  
Drilling Operations ◽  
Distribution Of Stress

Maintaining the wellbore stability is a key factor for oil and gas drilling operations. In this paper, sock is regarded porous medium. Crevice pressure, effect of permeation and SD effect are considered. The elastic and plastic stresses around the wellbore sock were analysed according to MVM failure criterion. Distribution of stress and displacement was obtained, which can provide theory reference for the wellbore stability.

Assessing Wellbore Stability With a Modified Lade Failure Criterion

2020 ◽  
Vol 142 (8) ◽  
Author(s):  
Babak Bahrami ◽  
Ali Sadatshojaie ◽  
David A Wood
Keyword(s):  
Neural Network ◽  
Rock Mass ◽  
Failure Criterion ◽  
Oil And Gas ◽  
Poisson Ratio ◽  
Failure Criteria ◽  
Wellbore Stability ◽  
Depth Interval ◽  
Gas Reservoirs ◽  
Operational Processes

Abstract The importance of evaluating wellbore stability in analyzing and estimating the efficiency of drilling directionally into oil and gas reservoirs is well known. Geomechanical data and failure criterion can be used to model and control rock mass behavior in response to the stresses imposed upon it. Understanding and managing the risks of rock mass deformation significantly improve operational processes such as wellbore stability, sand production, and hydraulic fracturing. The modified Lade failure criterion is established as the most precise failure criterion based on previous studies. By combining it with tensions around the wellbore, a novel relationship is derived for determining the stable mud window. To investigate the accuracy of the new relationship, two geomechanical models (neural network and empirical correlations) for a one-directional wellbore are developed and their performance compared with two other failure criteria (Hoek–Brown and Mogi–Coulomb). The geomechanical parameters (Young’s modulus, Poisson ratio, uniaxial compressive strength, and internal friction coefficient) obtained from the models show that neural network configurations perform better than those built with the empirical equation. The horizontal minimum and maximum stress values across the depth interval of interest (2347–2500 m) are established for a case study reservoir. The model provides an accurate prediction of wellbore instability when applying the modified Lade criterion; the stable mud weight is derived with improved precision compared to the other failure criteria evaluated. A key advantage of the developed method is that it does not require input knowledge of the reservoir’s structural boundaries (e.g., the fault regime) or core test data.

Research on HSE Risk Assessment and Control in Oil-Gas Drilling Operations

2014 ◽  
Vol 919-921 ◽  
pp. 500-506
Author(s):  
Fei Li ◽  
Guang Zhang
Keyword(s):  
Risk Assessment ◽  
Evaluation Method ◽  
Oil And Gas ◽  
Assessment System ◽  
Control Measures ◽  
Fuzzy Evaluation ◽  
Oil And Gas Exploration ◽  
Gas Drilling ◽  
Drilling Operations ◽  
Oil Gas

As the leading of oil and gas exploration and development, oil-gas drilling operations with high investment, high technology, and other industries interchange and perennial wild characteristics, there are various HSE risks during operation. Constructing HSE risk assessment system of oil-gas drilling operations, using AHP to construct indicators were analyzed and compared, and calculate the index weight. Then build fuzzy evaluation matrix based on expert evaluation method, get fuzzy evaluation result is "high risk". Finally, from four aspects (people, object, environment, and management) proposed HSE control measures.

scholarly journals CFD Method for Predicting Annular Pressure Losses and Cuttings Concentration in Eccentric Horizontal Wells

2014 ◽  
Vol 2014 ◽  
pp. 1-16 ◽  
Author(s):  
Titus N. Ofei ◽  
Sonny Irawan ◽  
William Pao
Keyword(s):  
Experimental Data ◽  
Oil And Gas ◽  
Current Model ◽  
Fluid Velocity ◽  
Pipe Diameter ◽  
Pressure Losses ◽  
Gas Drilling ◽  
Drilling Parameters ◽  
Drilling Operations ◽  
Oil And Gas Drilling

In oil and gas drilling operations, predictions of pressure losses and cuttings concentration in the annulus are very complex due to the combination of interacting drilling parameters. Past studies have proposed many empirical correlations to estimate pressure losses and cuttings concentration. However, these developed correlations are limited to their experimental data range and setup, and hence, they cannot be applicable to all cases. CFD methods have the advantages of handling complex multiphase flow problems, as well as, an unlimited number of physical and operational conditions. The present study employs the inhomogeneous (Eulerian-Eulerian) model to simulate a two-phase solid-fluid flow and predict pressure losses and cuttings concentration in eccentric horizontal annuli as a function of varying drilling parameters: fluid velocity, diameter ratio (ratio of inner pipe diameter to outer pipe diameter), inner pipe rotation speed, and fluid type. Experimental data for pressure losses and cuttings concentration from previous literature compared very well with simulation data, confirming the validity of the current model. The study shows how reliable CFD methods can replicate the actual, yet complex oil and gas drilling operations.

scholarly journals Improving the Iraqi Oil Well Cement Properties Using Barolift: an Experimental Investigation

2021 ◽  
pp. 147-156
Author(s):  
Ali M. Hadi ◽  
Ayad A. Al-Haleem
Keyword(s):  
Compressive Strength ◽  
Oil And Gas ◽  
Free Water ◽  
American Petroleum Institute ◽  
Oil Well ◽  
Cement Slurry ◽  
X Ray ◽  
Gas Drilling ◽  
Drilling Operations ◽  
Well Cement

Cement is a major component in oil and gas drilling operations that is used to maintain the integrity of boreholes by preventing the movement of formation fluids through the annular space and outside the casing. In 2019, Iraq National Oil Company ordered all international oil and gas companies which are working in Iraq to use Iraqi cement (made in Iraq) in all Iraqi oil fields; however, the X-ray fluorescence (XRF) and compressive strength results in this study show that this cement is not matching with American Petroleum Institute (API) standards. During this study, barolift was used to improve the properties of Iraqi cement used in oil wells at high pressure and high temperature (HPHT). Barolift (1 g) was added to cement admixture to evaluate its influence on improving the performance of cement, mainly related to the property of toughness.  Primarily, the quality and quantity of cement contents were determined using X-ray fluorescence. Experiments were conducted to examine the characteristics of the base cement and the cement system containing 1g of barolift, such as thickening time, free water, compressive strength, and porosity. X-ray diffraction (XRD), scanning electron microscope (SEM), and energy dispersive X-ray spectroscopy (EDS) were conducted for analyzing the microstructure of cement powder. The experimental results showed that barolift acted as a retarder and improved the thickening time, slightly increased the free water, enhanced the mechanical properties, reduced the porosity, and aided in scheming new cement slurry to withstand the HPHT conditions. Microstructure analysis showed that barolift particles blocked the capillaries by filling cement spaces and, thus, a denser and stricter cement network was achieved.

scholarly journals Experimental Investigation of the Effects of Drilling Fluid Activity on the Hydration Behavior of Shale Reservoirs in Northwestern Hunan, China

Energies ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 3151 ◽  
Author(s):  
Han Cao ◽  
Zheng Zhang ◽  
Ting Bao ◽  
Pinghe Sun ◽  
Tianyi Wang ◽  
...  
Keyword(s):  
Oil And Gas ◽  
Drilling Fluid ◽  
Contact Angles ◽  
Wellbore Stability ◽  
Adsorption Rate ◽  
Drilling Fluids ◽  
Swelling Ratio ◽  
Gas Drilling ◽  
Surface Hydration ◽  
The Relationship

The interaction between drilling fluid and shale has a significant impact on wellbore stability during shale oil and gas drilling operations. This paper investigates the effects of the drilling fluid activity on the surface and osmotic hydration characteristics of shale. Experiments were conducted to measure the influence of drilling fluid activity on surface wettability by monitoring the evolution of fluid-shale contact angles. The relationship between drilling fluid activity and shale swelling ratio was determined to investigate the osmotic hydration behavior. The results indicate that, with increasing drilling fluid activity, the fluid–shale contact angles gradually increase—the higher the activity, the faster the adsorption rate; and the stronger the inhibition ability, the weaker the surface hydration action. The surface adsorption rate of the shale with a KCl drilling fluid was found to be the highest. Regarding the osmotic hydration action on the shale, the negative extreme swelling ratio (b) of the shale was found to be: bKCl < bCTAB < bSDBS. Moreover, based on the relationship between the shale swelling ratio and drilling fluid activity, shale hydration can be divided into complete dehydration, weak dehydration, surface hydration, and osmotic hydration, which contributes to the choice of drilling fluids to improve wellbore stability.

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