Field Application of Software Model and Wellbore Strengthening Materials for Drilling Depleted Reservoirs and Mechanically Weak Formations in Gulf of Suez

2021 ◽  
Author(s):  
Youssry Abd El-Aziz Mohamed ◽  
Ragab Saber Ahmed ◽  
Ayman Abd El-ghany Al-Zahry ◽  
Amr Ismail Moustafa ◽  
Radi Ahmed Elnashar ◽  
...  
Keyword(s):  
Field Application ◽  
Rock Properties ◽  
Software Model ◽  
Software Models ◽  
Well Design ◽  
Wellbore Pressure ◽  
Drilling Operations ◽  
Wellbore Strengthening ◽  
Fracture Gradient ◽  
Selection Of

Abstract Drilling operations might require increasing mud weight beyond formation's fracture gradient margin which may lead to downhole losses into formation and other potential problems resulting in Non-Productive Time (NPT). This paper describes successful application of wellbore strengthening software (WSS) to simulate formations’ strengthening process by increasing Hoop Stress while drilling depleted reservoir sand or mechanically weak formations. The software model takes into consideration well design, basic rock properties and in-situ earth stresses. The paper also defines design of mud formula and lab procedures verifying the designed wellbore strengthening materials (WSM) blend and successful application in field. Design and selection of mud formula are main pillars of successful formation strengthening procedure to match with induced fractures width. Unlike other software models that use generic particle size distribution (PSD) data, software in this study takes into consideration PSD of specific batches of WSM to simulate wellbore strengthening process and recommend the optimum WSM blend, concentrations. Based on mud formula design from WSS, lab tests were conducted to verify concentrations and selection of WSM and accordingly formulas were applied successfully for complicated drilling operations. Static and dynamic formation strengthening techniques were applied successfully in multiple wells. Based on software results and recommendations, Techniques’ application managed to strengthen weak formations up to 121% of original fracture gradient, decreased section drilling time by 20% which resulted in drilling costs reduction by up to 24.2 %. As a result of this successful application in many critical wells, WSS results are now integral to operator's well plan to enhance wellbore pressure integrity of weak intervals, in following drilling operations. The presented study is based on an innovative approach to strengthen weak and depleted formations in critical drilling operations using exact PSD data of WSM batches, formation properties and customized software model, an optimum concentrations blend can be selected to strengthen wellbore and hence it can be customized for every application where optimum formation strengthening is required.

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.

MPD Well-Design Process Optimizes Design, Delivery of Deepwater Well

2021 ◽  
Vol 73 (02) ◽  
pp. 49-50
Author(s):  
Judy Feder
Keyword(s):  
Pore Pressure ◽  
Design Process ◽  
Pressure Profile ◽  
Base Case ◽  
Well Design ◽  
Managed Pressure Drilling ◽  
Drilling Operations ◽  
Integrity Tests ◽  
Fracture Gradient ◽  
Exploration Well

This article, written by JPT Technology Editor Judy Feder, contains highlights of paper SPE 200504, “Using MPD Well-Design Process To Optimize Design and Delivery of a Deepwater Exploration Well,” by Sharief Moghazy, SPE, Wilmer Gaviria, SPE, and Roger Van Noort, SPE, Shell, et al., prepared for the 2020 SPE/IADC Managed Pressure Drilling and Underbalanced Operations Conference and Exhibition, originally scheduled to be held in Denver, Colorado, 21-22 April. The paper has not been peer reviewed. The complete paper presents a case for using managed pressure drilling (MPD), and the full capabilities of its associated well-design process, to optimize all aspects of the well-delivery process in deep water, including design, safety, and subsurface data acquisition. The process was used to design and drill a deepwater exploration well with an expected pressure ramp and narrow drilling margins while acquiring valuable subsurface data. Introduction The operator’s only offset well in the area faced many challenges including a pressure ramp, resulting in narrow drilling margins. The team experienced several margin-related issues, such as kicks and losses, that resulted in permanent abandonment of the well without reaching the objectives. Given those results, and the subsurface uncertainty, the operator determined that the use of MPD would have mitigated many of the risks and non-productive-time events experienced in that well. The drilling contractor procured a rig fitted with an MPD system to drill a new exploratory well. MPD and the MPD well-design process were employed to increase the likelihood of drilling the well to total depth (TD) safely and successfully by providing the capability to accomplish the following: Account for pore pressure/fracture gradient (PPFG) uncertainty and navigate the expected pressure ramp and narrow margin sections safely by holding a constant bottomhole pressure and adjusting as needed during drilling operations Optimize the location of the casing/liner shoes by identifying the pressure profile based on real-time pore pressure data to potentially eliminate casing/liners, streamline the well design, and retain contingency strings in the event of a more-aggressive pore-pressure ramp Enable early kick and loss-detection capabilities and dynamic influx management to identify, react, and address downhole issues more quickly Use dynamic formation integrity tests (DFIT), dynamic leakoff tests, and dynamic pore-pressure tests (DPPT) to identify the extremes of the drilling margin, derisk subsurface uncertainty, and make decisions while drilling The process used hydraulics modeling to assess the feasibility of several potential scenarios and to understand the deepest possible casing points for a particular PPFG case, mud weight (MW), and well-design scheme. After a base-case well design was created, the maximum allowable kick tolerance was determined using an influx management envelope (IME) analysis, which was used as an input for an MPD operations matrix to be used during the operational phase. During the drilling of the well, the use of the MPD system and the calibration of the hydraulics model to the actual subsurface information allowed the team to continue drilling through more-benign conditions and optimize the well-design configuration.

Developing a Managed Pressure Drilling Strategy for Casing Drilling Operations

2009 ◽  
Vol 62-64 ◽  
pp. 456-465
Author(s):  
Babs Mufutau Oyeneyin ◽  
V.C. Kelessidis ◽  
G. Bandelis ◽  
P. Dalamarinis
Keyword(s):  
Real Time ◽  
Drilling Fluid ◽  
Fluid Flows ◽  
Well Design ◽  
Managed Pressure Drilling ◽  
Wellbore Pressure ◽  
Theoretical Predictions ◽  
Drilling Operations ◽  
Horizontal Annuli ◽  
Casing Drilling

Casing drilling can be an effective method of reducing drilling costs and minimising drilling problems but its uptake around the world has been slow with only a few wells drilled so far with casing. Complex geological features like the high overburden on top of shallow unconsolidated reservoirs characteristic of offshore West Africa can benefit from casing drilling when effectively combined with Managed Pressure Drilling technique. For the industry to develop a managed pressure drilling capability that will allow today’s generation of complex wells to be drilled safely with casing, it is necessary to develop models that include the effect of eccentricity , rotation and fluid rheology at bottom hole conditions on flow and pressure regimes, and to embed these models within an easy to use, intuitive well design package for pre planning and as a real time tool to monitor and provide forward simulations based on real time rig and downhole data. The paper presents new results of the theoretical predictions of the wellbore pressure regimes incurred when different types of drilling fluid flows in concentric and eccentric horizontal annuli. The concentric and eccentric casing drilling results are compared with parallel predictions from conventional drillstring results from developed analytical solutions integrated into the VisWELL(DeskTop Simulator) , which is used in simulating well operations.

Suitability of Natural Geomedia for Radwaste Storage

1982 ◽  
Vol 15 ◽  
Author(s):  
W. S. Fyfe
Keyword(s):  
Rock Properties ◽  
Fracture Flow ◽  
Time Prediction ◽  
Sedimentary Sequences ◽  
Rock Types ◽  
Direct Observations ◽  
Long Time ◽  
Mining Disturbance ◽  
Selection Of

ABSTRACTSelection of the best rock types for radwaste disposal will depend on their having minimal permeability, maximal flow dispersion, minimal chance of forming new wide aperture fractures, maximal ion retention, and minimal thermal and mining disturbance. While no rock is perfect, thinly bedded complex sedimentary sequences may have good properties, either as repository rocks, or as cover to a repository.Long time prediction of such favorable properties of a rock at a given site may be best modelled from studies of in situ rock properties. Fracture flow, dispersion history, and geological stability can be derived from direct observations of rocks themselves, and can provide the parameters needed for convincing demonstration of repository security for appropriate times.

Managing Wellbore Stability Window and Well Integrity by Adjusting the Tight Margin to Successfully Drill through Naturally Fractured Zone Onshore Niger Delta

2021 ◽  
Author(s):  
Bassey Akong ◽  
Samuel Orimoloye ◽  
Friday Otutu ◽  
Akinwale Ojo ◽  
Goodluck Mfonnom ◽  
...  
Keyword(s):  
Niger Delta ◽  
Wellbore Stability ◽  
Rock Properties ◽  
Failure Behavior ◽  
Natural Fractures ◽  
Gas Well ◽  
Well Integrity ◽  
Trajectory Formation ◽  
Naturally Fractured ◽  
Drilling Operations

Abstract The analysis of wellbore stability in gas wells is vital for effective drilling operations, especially in Brown fields and for modern drilling technologies. Tensile failure mode of Wellbore stability problems usually occur when drilling through hydrocarbon formations such as shale, unconsolidated sandstone, sand units, natural fractured formations and HPHT formations with narrow safety mud window. These problems can significantly affect drilling time, costs and the whole drilling operations. In the case of the candidate onshore gas well Niger Delta, there was severe lost circulation events and gas cut mud while drilling. However, there was need for a consistent adjustment of the tight drilling margin, flow, and mud rheology to allow for effective filter-cake formation around the penetrated natural fractures and traversed depleted intervals without jeopardizing the well integrity. Several assumptions were validly made for formations with voids or natural fractures, because the presence of these geological features influenced rock anisotropic properties, wellbore stress concentration and failure behavior with end point of partial – to-total loss circulation events. This was a complicated phenomenon, because the pre-drilled stress distribution simulation around the candidate wellbore was investigated to be affected by factors such as rock properties, far-field principal stresses, wellbore trajectory, formation pore pressure, reservoir and drilling fluids properties and time without much interest on traversing through voids or naturally fractured layers. This study reviews the major causes of the severe losses encountered, the adopted fractured permeability mid-line mudweight window mitigation process, stress caging strategies and other operational decisions adopted to further salvage and drill through the naturally fractured and depleted intervals, hence regaining the well integrity by reducing NPT and promoting well-early-time-production for the onshore gas well Niger Delta.

A Generalized Model for the Field Assessment of Drilling Fluid Viscoelasticity

2021 ◽  
Author(s):  
Chen Hongbo ◽  
Okesanya Temi ◽  
Kuru Ergun ◽  
Heath Garett ◽  
Hadley Dylan
Keyword(s):  
Drilling Fluid ◽  
Field Testing ◽  
Field Application ◽  
Testing Equipment ◽  
Drilling Fluids ◽  
Rotational Viscometer ◽  
Generalized Model ◽  
Fluid Elasticity ◽  
Field Samples ◽  
Drilling Operations

Abstract Recent studies highlight the significant role of drilling fluid elasticity in particle suspension and hole cleaning during drilling operations. Traditional methods to quantify fluid elasticity require the use of advanced rheometers not suitable for field application. The main objectives of the study were to develop a generalized model for determining viscoelasticity of a drilling fluid using standard field-testing equipment, investigate the factors influencing drilling fluid viscoelasticity in the field, and provide an understanding of the viscoelasticity concept. Over 80 fluid formulations used in this study included field samples of oil-based drilling fluids as well as laboratory samples formulated with bentonite and other polymers such as partially-hydrolyzed polyacrylamide, synthesized xanthan gum, and polyacrylic acid. Detailed rheological characterizations of these fluids used a funnel viscometer and a rotational viscometer. Elastic properties of the drilling fluids (quantified in terms of the energy required to cause an irreversible deformation in the fluid's structure) were obtained from oscillatory tests conducted using a cone-and-plate type rheometer. Using an empirical approach, a non-iterative model for quantifying elasticity correlated test results from a funnel viscometer and a rotational viscometer. The generalized model was able to predict the elasticity of drilling fluids with a mean absolute error of 5.75%. In addition, the model offers practical versatility by requiring only standard drilling fluid testing equipment to predict viscoelasticity. Experimental results showed that non-aqueous fluid (NAF) viscoelasticity is inversely proportional to the oil-water ratio and the presence of clay greatly debilitates the elasticity of the samples while enhancing their viscosity. The work efforts present a model for estimating drilling fluid elasticity using standard drilling fluid field-testing equipment. Furthermore, a revised approach helps to describe the viscoelastic property of a fluid that involves quantifying the amount of energy required to irreversibly deform a unit volume of viscoelastic fluid. The methodology, combined with the explanation of the viscoelasticity concept, provides a practical tool for optimizing drilling operations based on the viscoelasticity of drilling fluids.

Wellbore Strengthening Design Criteria and Enhanced Fracture Gradient for Widening Stable Mud Weight Window and Enabling Safe and Efficient Drilling in Depleted Reservoirs

2021 ◽  
Author(s):  
Chee Phuat Tan ◽  
Wan Nur Safawati Wan Mohd Zainudin ◽  
M Solehuddin Razak ◽  
Siti Shahara Zakaria ◽  
Thanavathy Patma Nesan ◽  
...  
Keyword(s):  
Particle Size ◽  
Ct Scan ◽  
Design Criteria ◽  
Drilling Mud ◽  
Fracture Width ◽  
Wellbore Strengthening ◽  
Fracture Gradient ◽  
Mud Loss ◽  
Gradient Enhancement ◽  
Compound Particle

Abstract Drilling in permeable formations, especially depleted reservoirs, can particularly benefit from simultaneous wellbore shielding and strengthening functionalities of drilling mud compounds. The ability to generate simultaneous wellbore shielding and strengthening in reservoirs has potential to widen stable mud weight windows to drill such reservoirs without the need to switch from wellbore strengthening compound to wellbore shielding compound, and vice-versa. Wellbore shielding and strengthening experiments were conducted on three outcrop sandstones with three mud compounds. The wellbore shielding stage was conducted by increasing the confining and borehole pressures in 4-5 steps until both reached target pressures. CT scan images demonstrate consistency of the filtration rates with observed CT scanned mud cakes which are dependent on the sandstone pore size and mud compound particle size distributions. In wellbore strengthening stage, the borehole pressure was increased until fracture was initiated, which was detected via borehole pressure trend and CT scan imaging. The fractures generated were observed to be plugged by mud filter solids which are visible in the CT scan images. The extent of observed fracture solid plugging varies with rock elastic properties, fracture width and mud compound particle size distribution. Based on the laboratory test data, fracture gradient enhancement concept was developed for the mud compounds. In addition, the data obtained and observations from the tests were used to develop optimal empirical design criteria and guidelines to achieve dual wellbore strengthening and shielding performance of the mud compounds. The design criteria were validated on a well which was treated with one of the mud compounds based on its mud loss events during drilling and running casing.

scholarly journals Dependability Modeling and Assessment in UML-Based Software Development

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Simona Bernardi ◽  
José Merseguer ◽  
Dorina C. Petriu
Keyword(s):  
Software Development ◽  
Formal Model ◽  
General Purpose ◽  
Software Modeling ◽  
Model Driven ◽  
Domain Specific ◽  
Software Model ◽  
Software Models ◽  
Assessment Approach ◽  
System Properties

Assessment of software nonfunctional properties (NFP) is an important problem in software development. In the context of model-driven development, an emerging approach for the analysis of different NFPs consists of the following steps: (a) to extend the software models with annotations describing the NFP of interest; (b) to transform automatically the annotated software model to the formalism chosen for NFP analysis; (c) to analyze the formal model using existing solvers; (d) to assess the software based on the results and give feedback to designers. Such a modeling→analysis→assessment approach can be applied to any software modeling language, be it general purpose or domain specific. In this paper, we focus on UML-based development and on the dependability NFP, which encompasses reliability, availability, safety, integrity, and maintainability. The paper presents the profile used to extend UML with dependability information, the model transformation to generate a DSPN formal model, and the assessment of the system properties based on the DSPN results.

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