Concept of Well Design: NPT on Drillers Table - An Eco-Geomechanical Model for Borehole Stability Management

2012 ◽  
Author(s):  
Akong Bassey ◽  
Adewale Dosunmu ◽  
Tunde Alabi ◽  
Otutu Friday ◽  
Grace Nnorom
Keyword(s):  
Geomechanical Model ◽  
Borehole Stability ◽  
Well Design

Development of a new approach for hydraulic fracturing in tight sand with pre-existing natural fractures

2016 ◽  
Vol 56 (1) ◽  
pp. 225 ◽  
Author(s):  
Kunakorn Pokalai ◽  
David Kulikowski ◽  
Raymond L. Johnson ◽  
Manouchehr Haghighi ◽  
Dennis Cooke
Keyword(s):  
Hydraulic Fracturing ◽  
Hydraulic Fracture ◽  
High Stress ◽  
Gas Production ◽  
Natural Fracture ◽  
Rock Properties ◽  
Fracture Plane ◽  
Natural Fractures ◽  
Geomechanical Model ◽  
Well Design

Hydraulic fracturing in tight gas reservoirs has been performed in the Cooper Basin for decades in reservoirs containing high stress and pre-existing natural fractures, especially near faults. The hydraulic fracture is affected by factors such as tortuosity, high entry pressures, and the rock fabric including natural fractures. These factors cause fracture plane rotation and complexities, leading to fracture disconnection or reduced proppant placement during the treatment. In this paper, rock properties are estimated for a targeted formation using well logs to create a geomechanical model. Natural fracture and stress azimuths within the interval were interpreted from borehole image logs. The image log interpretations inferred that fissures are oriented 30–60° relative to the maximum horizontal stress. Next, diagnostic fracture injection test (DFIT) data was used with the poro-elastic stress equations to predict tectonic strains. Finally, the geomechanical model was history-matched with a planar 3D hydraulic fracturing simulator, and gave more insight into fracture propagation in an environment of pre-existing natural fractures. The natural fracture azimuths and calibrated geomechanical model are input into a framework to evaluate varying scenarios that might result based on a vertical or inclined well design. A well design is proposed based on the natural fracture orientation relative to the hydraulic fracture that minimises complexity to optimise proppant placement. In addition, further models and diagnostics are proposed to aid predicting the hydraulically induced fracture geometry, its impact on gas production, and optimising wellbore trajectory to positively interact with pre-existing natural fractures.

Integrated wellbore-quality and risk-assessment study guides successful drilling in Amazon jungle

Geophysics ◽  
2006 ◽  
Vol 71 (6) ◽  
pp. E99-E105 ◽  
Author(s):  
Azra N. Tutuncu ◽  
Mikhail Geilikman ◽  
Brent Couzens ◽  
Floris van Duyvenboode
Keyword(s):  
Risk Assessment ◽  
Trajectory Optimization ◽  
Horizontal Stress ◽  
Rock Properties ◽  
Borehole Stability ◽  
Hole Cleaning ◽  
Lost Circulation ◽  
Assessment Study ◽  
Well Design ◽  
Fracture Gradient

Significant lost-circulation and wellbore-instability problems in the form of bit balling, stuck pipe, and adverse mud-shale interactions have been experienced in wells drilled prior to the study at three prospects in the Amazon jungle. An integrated borehole-stability and risk-assessment study has been carried out to enable successful drilling by optimizing borehole fluid pressures and predicting safe openhole times in various troublesome zones. The guidelines for hole-cleaning parameters and well-trajectory optimization have been obtained using improved fracture gradient and horizontal stress-anisotropy proprietary models based on special drill-cuttings data. Monopole and dipole sonic and imaging logs along with drilling data from the prospect wellshave been used to determine in-situ stresses, rock properties, andformation strength. These parameters have been utilized in borehole stability, hole cleaning, and open-hole time analyses for a comprehensive risk assessment and for selection of the optimum wellpath and drilling design. The wellbore pressures required for borehole stability turned out to be the highest for vertical wells and lowest for the horizontal ones, making drilling of highly deviated and horizontal wells attractive for the prospects. As a result, a wellpath with high deviation in the direction of maximum horizontal stress has been recommended as the most stable choice. The recommendations have been incorporated in the well design and implemented in the field with real-time borehole stability monitoring to result in successful drilling and efficient project economics.

Drilling and 4D seismic calibrated geomechanical model: Enabling extended-reach drilling well design in complex subsalt GOM play

2016 ◽  
Author(s):  
Farid Mohamed ◽  
Goke Akinniranye ◽  
Zhao Chad Kong ◽  
Samarjit Chakraborty ◽  
Christopher Walker ◽  
...  
Keyword(s):  
Geomechanical Model ◽  
Well Design ◽  
Extended Reach Drilling ◽  
4D Seismic

scholarly journals The Research on Borehole Stability in Depleted Reservoir and Caprock: Using the Geophysics Logging Data

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Junliang Yuan ◽  
Jingen Deng ◽  
Yong Luo ◽  
Shisheng Guo ◽  
Haishan Zhang ◽  
...  
Keyword(s):  
Pore Pressure ◽  
Oil And Gas ◽  
Geomechanical Model ◽  
Borehole Stability ◽  
In Situ Stresses ◽  
Pressure Depletion

Long-term oil and gas exploitation in reservoir will lead to pore pressure depletion. The pore pressure depletion will result in changes of horizontal in-situ stresses both in reservoirs and caprock formations. Using the geophysics logging data, the magnitude and orientation changes of horizontal stresses in caprock and reservoir are studied. Furthermore, the borehole stability can be affected by in-situ stresses changes. To address this issue, the dehydration from caprock to reservoir and roof effect of caprock are performed. Based on that, the influence scope and magnitude of horizontal stresses reduction in caprock above the depleted reservoirs are estimated. The effects of development on borehole stability in both reservoir and caprock are studied step by step with the above geomechanical model.

scholarly journals Determination of Safe Mud Weight Window in Rumaila Oilfield, Southern Iraq

2021 ◽  
Vol 54 (2F) ◽  
pp. 48-61
Author(s):  
Walaa Khyrie ◽  
Ayad Alrazzaq
Keyword(s):  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Failure Criteria ◽  
Well Test ◽  
Geomechanical Model ◽  
Gas Industry ◽  
Wellbore Instability ◽  
North West ◽  
Well Design ◽  
Open Hole

The oil and gas industry, wellbore instability plays an important role in financial losses and stops the operations while the drilling which leads to extra time known as non-productive time. In this work, a comprehensive study was carried out to realize the nature of the instability problems of the wellbore in Rumaila oilfield to improve the well design. The study goal is to develop a geomechanical model in one dimension by utilizing Schlumberger Techlog (Version 2015) software. Open hole wireline measurements were needed to develop the model. The model calibrating and validating with core laboratory tests (triaxial test), well test (Mini-frac test), repeated formation test. Mohr-Coulomb, Mogi-Coulomb, and Modified Lade are the three failure criteria which utilized to analyze the borehole breakouts and to determine the minimum mud weight needed for a stable wellbore wall. For more accuracy of the geomechanical model, the predicted profile of the borehole instability is compared with the actual failure of the borehole that is recorded by caliper log. The results of the analysis showed that the Mogi-Coulomb criteria are closer to the true well failure compared with the other two criteria and considered as the better criteria in predicting the rock failure in the Rumaila oilfield. The wellbore instability analysis revealed that the vertical and low deviated wells (less than 40º) is safer and more stable. While, the horizontal and directional wells should be drilled longitudinally to the direction of the minimum horizontal stresses at a range between 140º–150º North West-South East and the mud weight recommended is increased to 10.5 ppg to avoid most of instabilities problems. The results contribute in development plan of the wells nearby the studied area and decreasing NPT and cost.

scholarly journals Analysis of the deep drilling technology in unstable formations at the Semyrenky gas condensate field

2021 ◽  
pp. 52-64
Author(s):  
A. K. Raptanov ◽  
◽  
V. V. Ruzhenskyi ◽  
B. I. Kostiv ◽  
M. A. Myslyuk ◽  
...  
Keyword(s):  
High Speed ◽  
Gas Condensate ◽  
Drilling Mud ◽  
Deep Drilling ◽  
Borehole Stability ◽  
Well Drilling ◽  
Rock Stability ◽  
Well Design ◽  
Drilling Technology ◽  
Drilling Conditions

The paper presents a general overview of deep drilling in unstable formations at the Semyrenky gas condensate field of the Dnipro-Donetsk Trough, including well design, bottom hole assemblies (BHA), drilling conditions, and drilling muds. Problems encountered during drilling for production casing of Wells 72- and 75-Semyrenky using high-speed drilling methods are analyzed. The relationships between the rate of penetration and disturbed rock stability, volume excess and depth, as well as consistent empirical patterns in changes in mud properties and depth are established. With these technical and economic performance indicators for well drilling are given, elements of a borehole stability management strategy were defined, the principles of mud selection for drilling through problem zones are validated. The paper discusses the requirements to a mud hydraulics program to reduce the erosion of borehole walls, specific borehole preparation techniques, such as reaming and gauging, for drilling in problem zones, and alternative options to ensure borehole stability. Keywords: borehole stability; statistical models; hole gauging; hole geometry; drilling mud; BHA.

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