bluuebunny/crossref_metadata_2025_split huggingface dataset:
Using Integrated Geomechanical Study To Resolve Expensive Wellbore Instability Problems While Drilling Through Zubair Shale/Sand Sequence of Kuwait: A Case Study.
Authors: Azim Shaikh Abdul , Mukherjee Pritish , Al-Anezi Salah Ali , Al-Otaibi Basel , Al-Saad Badr , Perumalla Satya , Araujo Ewerton , Babbington Jeremy F 
Published: October 2011

Abstract
The Lower Cretaceous Zubair formation in Kuwait comprises oil-bearing sands intercalated with shale sequences. Historically, drilling into this formation presented major wellbore instability issues that include hole pack -off, stuck pipe and logging tools, high over-pull, tight zones while tripping, and severe hole washouts. These well problems have a significant impact on well costs and timeline.
Wells drilled in every orientation have experienced instability problems in this formation. Vertical wells have encountered major washouts and difficulties with wireline logging operations. Deviated wells have been even more unstable and often required sidetracks - greatly increasing well costs.
This paper analyzes these wellbore instability problems, including the failure mechanisms, and presents the actions taken to resolve them. A solution to these instability issues is presented, which was derived by building geomechanical models using well data, drilling problem analysis, core inspection, and core -based rock mechanical test results.
We used chemoporoelastic and anisotropic geomechanical models to simulate the behavior of the Zubair formation while drilling in vertical and deviated holes to understand the wellbore instability experiences.
Based on the analysis, changes in mud weight, reformulation of the mud system, and modified drilling practices were incorporated in the well plan of new high-angle wells. Success was achieved in drilling the wells and running the casing in this formation with deviations as high as 80°. The study helped to achieve a large reduction in indirect NPT due to wellbore instability. This experience is also a key learning and input for designing future complex trajectories. It is expected that a major measurable impact in the form of smoother operations and optimized well cost will occur during the drilling campaign based on recommendations from this analysis.
Integrating Petrophysics, Geomodeling and Advanced Well Placement Technology for Efficient Field Development
Authors: Barbosa Jose E. , Ali Arfan , Hern Caroline 
Published: October 2011

Abstract
This paper describes how petrophysics and geomodeling, integrated with advanced well placement technology, can be used to optimize well trajectory in horizontal well drilling operations. We have simulated a 3D facies model of the Mulichinco Formation within a hydrocarbon field located in the Neuquen Basin (Argentina) by taking into account petrophysical, geological and geophysical data. The integrated approach allows to analysis of possible drilling scenarios and to prepare contingency plans in time for maximizing hydrocarbon production. We have also compared our simulated 3D models with the LWD data of an existing horizontal well in order to optimize well placement in real time and to reduce risks associated with drilling in non-pay zones. The results presented in this paper are complementary to the prior information available in the studied field from other conventional techniques.
Initially we tested the new approach on four existing horizontal wells, targeting shallow marine sandstones within the upper Mulichinco Formation (Valanginian), where an excellent match was observed between the predicted and actual facies encountered. We subsequently applied the technique by taking into account the data from 31 wells in the field. This new approach can be used to optimize well placement in any depositional environment (both onshore and offshore) by highlighting the geosteering hazards and ensuring that the wellbore is drilled inside the "sweet spot" and away from non-productive layers. The new approach and the associated horizontal well data also improve understanding of the distribution of facies and their geometrical configuration.
Characterization a Self-destructing Filter cake by Using Computer Tomography
Authors: Elkatatny S. M. , Rostami Ameneh , Nasr-El-Din H. A. 
Published: October 2011

Abstract
Drilling long horizontal and multilateral wells with very low drawdown makes efficient cleaning and stimulation treatments very challenging. None of the conventional chemical cleaning methods can overcome problems for filter-cake removal in long horizontal and maximum reservoir contact wells because of limitations such as the complex geometry of wells, nonuniform chemical distribution, low contact between cleaning fluids/filter cake, and high chemical reaction rate, especially at high temperatures.
All of these challenges lead us to develop a new system of filter cake removal method that addresses several key problems inherent in the removal of drilling fluid filter cake, cleaning, and stimulation treatments of horizontal and multilateral wells. This system is a water-based drilling fluid that is weighted with calcium carbonate and has a mixture of solid-acid precursor and particulate solid-acid reactive material. This fluid has both functions of drilling and completion and can reach total depth of MRC wells. It has the ability to effectively stimulate the whole horizontal sections after drilling.
Previous work by the authors on this self-destructing drilling fluid system resulted in obtaining the best formula based on the original water-based mud (SPE 136400). High temperature high pressure filter press results (SPE 139087) showed high filter cake efficiency in cleaning the filter cake. Unlike the conventional reactive acids such as HCl, the slow reaction kinetics ensured good distribution of the generated acid across the filter cake.
The objective of this study is to determine the homogeneity of the self-destructive filter cake. Image J software and Grabit software combined with CT scan results were used to determine the filter cake properties such as porosity, permeability and thickness of the self-destructing filter cake system.
An Energy Based Comparison of Alternative Drilling Methods
Authors: Elahifar Behzad , Esmaeili Abdolali , Prohaska Michael , Thonhauser Gerhard 
Published: October 2011

Abstract
During the last decades, non-conventional solutions for more economical well bore drilling have been investigated. Big research efforts and budgets have been spent on alternative drilling methods; such as laser drilling or jet assisted drilling. Simplified assumptions predicted a big future for such technologies. However, to get a better and more realistic picture of the feasibility of such unconventional ways to drill rock, the ability to apply them in field scale applications needs to be questioned. In this paper a holistic energy approach to evaluate drilling alternatives is proposed.
To evaluate the energy balance of the drilling system the amount of energy generated, e.g by the rig at surface, needs to be put in comparison with all system energy consumption to lead to an effective energy available to destroy rock at the bottom of the hole. To test this concept a small scale laboratory setup is used to compare different drilling methods under similar conditions.
This paper presents a systematic approach using an energy concept to compare alternative drilling methods on a laboratory scale. In this first approach laser assisted spallation and conventional drilling were compared. As a by-product, also the optimum mode for spallation drilling, continuous versus pulse wave, will be presented.
Positive Displacement Motor Innovation Drives Increased Performance with PDC Bits in Unconventional Plays
Authors: Azizov Azar , Davila Wilfredo , Nnanna Obi , Rizen Andrej 
Published: October 2011

Abstract
The introduction of new, wear-resistant polycrystalline diamond compact (PDC) bit cutter technology in recent years has dramatically increased the demand for increased torque output from the positive displacement motor (PDM). The commercial introduction of pre-contoured (i.e., equidistant rubber thickness) stators in 2000 solved the theoretical technical challenge of developing very high torque output in a PDM. Yet, in cost-sensitive, land-based drilling markets where conventional power sections are still a major factor, the requirement for traditional motor power section construction restricted the rate of penetration improvements.
Recent developments in the chemistry of the standard stator elastomer have enabled a step-change improvement in the performance and durability of the power sections in PDMs. This premium elastomer, manufactured in conventional stator cans, can generate higher differential pressure and subsequently more torque, while achieving increased durability, even in some of today's oil-based drilling environments. This higher level of torque and increased downhole durability is ideally suited for the increasing toughness and aggressiveness of today's premium PDC bit. This paper will review in detail this innovative motor technology, describe how it enables reaching higher performance levels, and present several case histories illustrating this performance enhancement.
Development and Optimization of PDC bits for Rotary Steerable Systems through Unstable Formations
Authors: Portillo Oscar , Bahlany Salah , Agudelo Gloria , Alvarez Octavio , Al- Marzooqi Ali 
Published: October 2011

Abstract
Directional drilling in the build up section at North Oman Field in the Sultanate of Oman is challenging because of highly intercalated and unstable formations. The formation consists primarily of soft to medium hard limestones, dolomites inter- bedded with anhydrite, and a thick layer of unstable shale that forms the cap-rock of the targeted reservoir. The field development plan (FDP) specifies drilling long horizontal wells with two casing strings and a liner, and requires the reservoir section to be placed within the top meter of reservoir rock. Consequently, it is critical to land inside the top meter of the reservoir. The lack of directional control throughout the soft intervals, high dip angles in some of the formations, and the short vertical section from surface to landing point requiring BUR of 5 to 6 degrees/30mts created complications in drilling the build section. With these elements, optimum directional tools steerability is necessary to achieve the well objectives.
To overcome these challenges, the operator and drill Bit Company developed an optimization process to design a polycrystalline diamond compact (PDC) bit to use with point-the-bit rotary steerable systems (RSS). The optimization process included increasing the bit steerability and stability to increase the rate of penetration (ROP). This challenge required the development of a new PDC technology with optimized drilling practices and a reliable drive system. Specific bit design algorithms were incorporated with a new bit gage configuration, and drilling simulation software was used to optimize bit cutting structure design in the directional drilling environment. Significant bit design improvements were achieved. Going through field testing, drilling parameter evaluation and optimization, an 8½-in PDC bit design was created that established benchmark performances in the North Oman Field field.
The successful development of the PDC bit with the RSS system enabled record bit runs in the build sections, which were drilled in accordance with the FDP with significant ROP improvements compared to conventional motor. This paper reviews the bit design and optimization process that helped to improve the drilling performance and hole geometry, reduce rig days, and enable early delivery of the wells in the challenging Sultanate of Oman drilling environment.
Progression of Offshore Drilling Safety Culture through Smart System, Experience in South Pars Gas Field, Phase 12
Authors: Rahimi R. 
Published: October 2011

Abstract
The PETROPARS Drilling department has developed a safety culture via SMART system in its drilling operations that employs a high level of behavior-based observations to help instill a broad based understanding of safety and hazard recognition. Senior management developed safety principles, but the day-to-day incorporation of the safety principles are coordinated by the workers themselves. This has led to a progressive improvement in safety results as the program and culture has matured.
The majority of the subsurface work is conducted on offshore jack-up drilling rigs by contract drilling personnel and service companies. In order to establish the desired safety culture, core safety principles were established and communicated by management. Then safety leadership training was provided to all key workers to gain understanding and commitment. Finally a behavior-based safety observation program was adopted and modified to fit this work environment. This behavior-based program has implemented through SMART system or (See Monitor Act Reinforce Track) that covered all aspects of the offshore drilling operation. The evolution of worker participation has been far greater than originally envisioned.
This paper demonstrates that safety can be improved with direct participation of the workforce in a behavior-based observation program according to PETROPARS achievement.
Feasibility Study of Casing Drilling Application in HPHT Environments; A Review of Challenges, Benefits, and Limitations
Authors: Radwan Amr , Karimi Moji 
Published: October 2011

Abstract
HPHT wells present many economic, technical, operational and HSE challenges. Casing Drilling is introduced as a potential alternative method for drilling HPHT wells. The benefits and limitations of Casing Drilling are investigated in this study in correlation with the current HPHT challenges.
The operational mud weight window can be widened beyond the traditional trip margin through the well-known Plastering/Smear Effect of Casing Drilling. Moreover, many mud challenges in HPHT wells can be eliminated including static and dynamic barite sag, drilling mud deterioration under static conditions, heavy solids content and wellbore cleaning inefficiency. The wells drilled with casing are more gauged and the quality of the cement sheath is better. Casing drilling can provide better protection for logging tools and allow many conventional tools to be used without any modification.
Casing Drilling can significantly reduce the cost of drilling through harsh environments. Additionally, drilling hazards of HPHT wells will be minimized because Casing Drilling can eliminate drilling problems such as stuck pipes, well control incidents, surge and swab effects, wellbore instability, and lost circulation. However, to ensure that this technology can present the previously argued benefits, there are some challenges that need more studies. Most of these issues are related to the manufacturing features of the materials (e.g., dope channels and substantial thermal expansion) and excessive loads (e.g., wear, torque and drag). The recommendations suggested in the study can help in limiting and overcoming these challenges.
The proposed methodology can potentially take drilling HPHT wells to a new level and also pave the way for xHPHT environment. Casing Drilling opens a new window to the current technologies and tools in HPHT wells without significant modification. Also it is a potential option to eliminate economic, operational and HSE challenges in drilling HPHT wells.
Understanding and Eliminating Drill String Twist-Offs by the Collection of High Frequency Dynamics Data
Authors: Raap Constantijn , Craig Andrew , Perez Daniel 
Published: October 2011

Abstract
Drill string twist-offs are an expensive problem to the oil and gas drilling industry. With ever increasing rig and operating costs, there is an increased focus to avoid twist-off related expenses, such as: costs associated with time required to trip out of hole and replace the failed components, the cost of repair or replacement of failed equipment, fishing operations and possibly the cost of side-tracking. Oil and gas operators attempt to prevent drill string failures by optimizing the drill string and trajectory designs. Drill string manufacturers aim to engineer drill pipe and tools with ever increasing strength properties and maximum fatigue resistance. In addition to this, drilling contractors and service companies have extensive inspection programs to avoid failure. Despite these efforts, twist-offs remain an important problem for a large number of drilling applications. Recent research and analyses suggest that the majority of drill string failures are caused by fatigue. Since the root cause of a fatigue failure cannot always be identified from surface drilling parameters or laboratory analysis, the evaluation of drilling dynamics data is essential for understanding the cause of a twist-off.
This paper will present several case studies from the North Africa region to illustrate the important contribution of drill string vibration on fatigue-related failures. In all cases, high resolution dynamics recorders were incorporated into the BHA, or drill string, close to the location of the twist-off. Analysis of the dynamics data revealed that the drill string was exposed to severe lateral vibration prior to the twist-off events. Furthermore, the observed vibration was the major contributor to the sustained fatigue due to the resulting severe shock loading and increased bending stresses generated during vibration. The paper will also present mitigation practices or changes that were implemented based on the drilling dynamic analyses as well as potential solutions for the remaining case studies. Generally, these solutions are significantly more cost effective than the traditional approaches of reducing twist-offs such as: increased frequency of inspection programs or enhanced mechanical properties on connections and drill strings.
Successful Auto Gaslift using Intelligent Completion Boosted Oil Production – A Case History from Petroleum Development Oman
Authors: Peringod Chandran , Al-Ruheili Sharifa , Kerecin Zeljko , Sonti Kartik , Sukkestad Tor 
Published: October 2011

Abstract
Field B is undergoing implementation of an accelerated development plan and around 40 wells have been drilled so far. Due to the volatile nature of the crude and high GOR, gas recycling was identified as the reservoir pressure maintenance strategy. There are 4 gas injectors in the field injecting into two reservoirs. As per the original development plan, no artificial lift was envisaged and model results showed sustained natural flow from the well. However, after drilling and completing the wells, it was found that sand connectivity and continuity were far more complicated than expected. This resulted in depleting the reservoirs in certain compartments thus requiring some form of artificial lift. Further, this field will be undergoing a gas blow down project from 2015 onwards, and the challenge to the Well & Reservoir Management Team was to maximize recovery before gas blow down.
A series of options were considered and gaslift was selected as the most viable artificial lift mode. Lead time for the conventional gaslift and the cost associated with special piping materials were adversely impacting the plans and an innovative idea of auto gaslift was proposed as an alternate to conventional gaslift. Accordingly, Well #XX was selected for application of this technology. Auto gaslift uses high pressure gas from a gas reservoir admitted into the tubing using an intelligent completion & special ICV with gas trim and straddle packers. A down hole pressure gauge installed on top of the packer will assist in tuning the choke settings during auto gas lifting. Based on the success of this well, 5 more wells were re-completed with Auto gaslift technology resulting in increasing the production by 50% from the field. Currently, this technology is being evaluated for other fields in the company's assets.
This paper explains the technology of Auto gaslift, details of intelligent completion used in the wells, results obtained, gaslift optimization, lessons learned and way forward for artificial lift in other fields with similar reservoir conditions.
Drilling Efficiency Optimization (DEO) in Casing while Drilling Operations in the Sultanate of Oman
Authors: Sanchez F. , Smith M. , Al Kindy M , Gray D. , Aderele S. 
Published: October 2011

Abstract
The industry acknowledges that well engineers in the Sultanate of Oman identified long ago a number of technical challenges when drilling through the Fiqa formation. The most daunting is wellbore instability which results in hundreds of unproductive rig-hours when drilling wells for both exploration/appraisal and development campaigns. But more recently, Casing while Drilling (CwD) was recognized as the most cost-effective mitigation system against the risk of stuck-pipe, continuous back- reaming and unplanned casing setting depths in such highly reactive, time-dependent shale. In consequence, current portfolio of deep and ultra-deep wells in Northern Oman (Figure 1) mandates CwD as the new conventional approach for drilling large- diameter surface sections, instead of the drill-pipe method.
Figure 1 Operator's Fields located at the Northern of Oman (red arrow)
During the trial-phase of CwD (2009–2010), the Drilling Efficiency Optimization (DEO) concept and a few related tools/techniques were rarely utilized. The reason responds to the fact that operator's major objective was to prove the CwD- concept in deep surface sections with minimum well-design integrity risk; in which the critical challenge was the delivery of a wide range of drilling performance optimization ideas. Nonetheless, a more systematic DEO approach during the phases of well planning, execution, and post-drill analysis was utilized in the subsequent ‘CwD Implementation Campaign’ to improve overall performance through the most-top formations in four different fields across the North.
The operator identified a few critical areas of opportunity that led to successful operations, such as specialized rig-crew training sessions, real-time management of drilling parameters, optimum mud properties and hydraulic energy, wellbore strengthening quality, bottom-hole-assembly (BHA) design, and mechanic energy surveillance. All enabling technologies and resources dedicated to these areas combined aided to accelerate well delivery time by up to 58% and reduce cost per meter drilled-and- cased by over 25%. A main conclusion is that CwD technology deployment with DEO approach is the best-in-class, value creative solution through troublesome, most top formations in Northern Oman.