bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimization of Tripping Speed to Minimize Surge & Swab Pressure
Authors: Al-Abduljabbar A. M. , Hossain M. Enamul , Gharbi S. Al , Al-Rubaii M. 
Published: January 2018

Abstract
Pressure changes due to surge and swab has been a concern in the drilling industry for many years. The fast and sudden movement of the drill string while pulling out of hole causes the wellbore pressure to decrease. This is due to the frictional forces between the pipe moving upward and the drilling mud that is stationary, which is known as the swab pressure. The opposite is also true, moving quickly inside wellbore will cause the pressure to increase, and this is known as the surge pressure. If these pressure changes become very high, the formation might get fractured which introduces influx leading to a kick. In severe cases, this kick might lead to a blowout which endangers human lives and environment.
This article focuses on the fundamental theory of surge and swab in addition to the maximum pipe running speed that avoids surging and swabbing the well. Further, calculations are carried out to optimizing the maximum pipe tripping speed by employing different parameters as input values. Both laminar and turbulent flows are considered in addition to closed ended pipes since it is the most critical one. The objective of this study is to optimize the drilling parameters that specify the maximum pipe tripping speed with different hole's sizes and pipe dimensions. Moreover, this research offers the optimized values to identify the factors that heavily affect surge and swab pressures. The results show that annular space and bottom-hole assembly (BHA) length have significant effects on surge and swab pressure values. Sensitivity analysis shows that pipe size and mud rheology impacts surge and swab values, but not significant. In fact, it is the annular velocity which is heavily affected by BHA length and size. When it comes to casing, the size was not an issue because the annular space is larger compared to smaller casing sizes. In addition, study shows that depth plays vital roles that can be seen with smaller casing sized. This study will enhance the understanding of drilling problems while drilling due to surge or swab pressures.
Use of Managed Pressure Drilling Paved the Way to a Massive Gas Field Discovery in Egypt Western Desert: Case History
Authors: Emam S. S. , Brand P. R. , Gabaldon O. R. , Vityk M. , Leithy A. El , Shanab M. Abou , Hamdy B. , Abdel-Moniem M. , El-Desouky W. , El-Azm H. Abo 
Published: January 2018

Abstract
The BTE – 2 was planned as a land based deep vertical exploration well in Egypt (the deepest ever drilled by Bapetco), designed to evaluate the Abu Roash, Bahariya and Kharita formations, testing the Kharita gas reservoirs and leading into the development of the entire BTE prospect. The complexities included HT classification, formation pressures uncertainties, deep total depth, and introducing a new technology, Managed Pressure Drilling (MPD), to the rig.
MPD played a pivotal role in the major discovery of the exploratory "BTE – 2" well, which led to initial estimated in place volumes of 0.8 TCF for the BTE prospect. MPD allowed the operator to reach the reservoir section by successfully navigating the 0.45 ppg operating window in the upper section. MPD also created a wide range of benefits throughout drilling the 1080 meters section, including managing the BHP through the narrow drilling window, real time prognosis of the pore pressure and fracture gradients incorporating the use of Pressure While Drilling technology, efficiently managing drilling through severe conditions, optimizing logging operations and MPD running and cementing of the 7 inches liner.
A high Intensity kick was detected by the MPD system in Abu Roash "G" formation. Implementing the MPD assisted shut in method helped minimizing influx size. The kick was initially circulated conventionally and the MPD system was engaged during the second circulation while slightly increasing the Mud Weight.
Using the MPD system helped to control the annular pressure profile during multiple rig pump problems and motor stalling events. Due to the small operating window, running the 7 inches liner was a major challenge, even while using the MPD system. Non homogeneous drilling fluid, high loss rates and high PP added complexity to the process. Establishing a closed loop system created a safer and better monitoring and controlling system for the 7 inches liner running operations.
Managed Pressure Cementing was the only valid and reliable method to cement the 7 inches liner in place. The MPD system was used to manage the slim drilling window, and the Coriolis flow meter helped to identify the required pressure values to minimize associated losses.
Employing the MPD Constant Bottom Hole Pressure (CBHP) technique resulted in numerous learnings, especially when the MPD technique is a first use for the drilling rig crews. This paper highlights and emphasizes the distinguished learnings (not specific to a particular project) that could help in planning and implementation of future MPD wells.
Pioneering the First Hydraulic Fracturing in Iraq's Complex Reservoir
Authors: Syed I. Hussein , Ahmed A. Raheem , Abd Hatem R. , Alabdali S. Adnan , Yandong C. , Wenxin C. , Xinmin Z. , Zhaowei L. , Jin O. , Mingyue C. , Ding Y. , Zhu D. , Liang C. , Theseira K. , Mohd Faiz M. , Ab Murad M. 
Published: January 2018

Abstract
X reservoir in one of Iraq's field, is a medium pore, low permeability and small pore throat limestone oil reservoir with poor petrophysical characteristics. This reservoir group in which X reservoir is in constitutes to about 20% of the total resource in place. Conventional development allows only about 0.3% of reserves to be developed and this needed to be improved further. The mixed results of various stimulation campaigns (for example matrix acidising and acid fracturing) carried out earlier for this reservoir has prompted the Operator to evaluate the hydraulic fracturing stimulation, first of its kind in Iraq to further gauge its effectiveness and feasibility for field implementation.
This paper will discuss the steps undertaken before, during and after the hydraulic fracturing execution. In planning for this campaign, steps were taken to analyse the rock properties and mechanics of the formation to understand the challenges for the hydraulic fracturing and to enable optimisation of the fracturing parameters. Fracture fluid design, proppant optimisation and treatment design were proposed to systematically optimise the process of the hydraulic fracturing. As a deduction, the principles and recommendations of design optimisation for hydraulic fracturing in carbonate reservoirs will be presented in this paper.
The preliminary production gain from this pilot hydraulic fracturing exceeded the pre-job stimulation more than 10 times, showing promise of a new way of developing this challenging reservoir in the future. Comprehensive analysis of the reservoir characteristics and suitable fracturing design are key to this achievement. This approach will be the benchmark for future hydraulic fracturing jobs planned in the field. The optimisation study in this paper could serve as a reference to improve hydraulic fracturing efficiency and success in other similar carbonate reservoirs.
Being the first ever hydraulic fracturing campaign ever performed in Iraq, this paper will focus on the challenges, execution and preliminary results.
Understanding Cement Quality in Intermediate Casing Against Aquifers Using Cement Bond Logs: A Case Study of Cementing Against Aquifers in UAE
Authors: Hanif R. , Ashour S. H. , Yee S. , Hay M. Abdel 
Published: January 2018

Abstract
Cement and Casing integrity across the surface aquifers is as imperative as against the reservoir section, to avoid ground water communication. Zonal isolation among aquifers is obligatory as per local regulations. Understanding the expected cement quality in the intermediate casing across aquifers is desirable. It is essential to understand why there are wells with good cement across aquifers while some wells exhibit poor cementing, keeping the procedures and parameters identical.
A study was conducted to understand the aquifer pressures and overburden geologic features in the entire field and understand how they impact cement quality. Aquifer pressures are incorporated with seismic features to anticipate the aquifer behavior. Representative Wells were selected in different field areas encountering either different aquifer pressures or geological features. The cement bond logs (CBL) were interpreted in these wells, along with the information from drilling, and established the link between cement quality and aquifer behavior in the specific area.
It is observed that poor cement is present where either aquifer pressure is low or there are aquifers channels, sinkholes or other geological features derived from seismic interpretation.
To perform better cementation across the aquifers it is essential to understand the aquifer behavior in specific area of the field, address the issues in the well prognosis to the cement team, plan and perform cementing operations accordingly.
Design and Implementation of the Well Delivery Project Gate System
Authors: Al-Salem Mohammad , Al-Shehab Nawaf , Decena Jose 
Published: January 2018

Abstract
Kuwait Oil Company (KOC) launched a Project Gate System (PGS) program in 2010, which resulted in the development of the KOC PGS Process. The PGS Process was implemented in 2012, and has been applied to surface facility capital projects only. However, subsurface projects were excluded from the PGS, at that time.
In order to also improve the drilling of wells and facilitate the attainment of forecasted production targets efficiently and on time, a study of the development and implementation of a similar PGS Process for the delivery of wells was requested, in 2013. The study concluded that a parallel Well Delivery PGS (WD PGS) Process should be developed based on IOCs’ and NOCs’ best practices for well delivery, KOC's experience with the PGS Process, and the fit-for-purpose requirements of the concerned KOC stakeholders in all business Directorates.
Enhancing Jack-Up Performance Using Spudcan Extensions
Authors: van der List Remco H. , Akkermans Richard A. , Blaauw Floris W. , Baan Rutger C. 
Published: January 2018

Abstract
Jack-ups are designed to withstand specific environmental conditions at a defined water depth in combination with certain types of soil conditions. A balanced design results in an almost full utilization of the design elements under such conditions. Typical design elements used are the holding system (either the leg fixation system if present, or the jacking system), leg chord elements or the preload capacity. This means that if an owner wants to use the jack-up beyond the original design conditions, for example to operate in deeper water or in harsher conditions or with bearing pressure limitations, some of these elements would have to be upgraded. However, these elements are fully integrated into the overall design of the jack-up and thus an upgrade is always a very costly and often also a time-consuming affair.
A simpler way of upgrading the overall capacity of a jack-up is through the use of spudcan extensions. Spudcan extensions can be designed to replace the existing spudcan in the form of a new spudcan below the existing one at the bottom of the leg, a so-called add-on spudcan, or as a temporary or permanent extension of the original spudcan. In these cases, the impact of the spudcan extensions on the total jack-up are very limited, where in the best case the jack-up remains as-is and in the worst case only the lower ends of the legs are affected. The purpose of spudcan extensions is generally twofold:
Limit the leg penetration into the seabed, effectively reducing the free leg length below the hull; Move part of the overall leg bending moment from the hull towards the spudcan, effectively reducing the loads acting at hull level;
The first purpose is relatively simple and usually results in just an enlargement of the total horizontal projected area of the spudcan. In this case, the spudcan extension can be a welded permanent structure, or if the owner wants to be able to go back to the original design it will be designed to connect temporarily to the chords of the lower end of the legs or the top plate of the spudcan, fitting around the existing spudcan.
The second purpose is a bit more complicated, as the extension must now be able to attract overall leg bending moments. This usually means that the extension must either be significantly bigger than the original spudcan or equipped with skirts, or a combination of both. The size and type of spudcan required depends heavily on the soil conditions of the intended area of operation. The end result is mostly in the shape of an add-on spudcan, but can also be executed as a permanent extension.
GustoMSC shall present the design considerations of typical spudcan extensions, apply spudcan extension to three well known types of GustoMSC jack-ups and show the influence of spudcan extensions to the capacity of the jack-ups.
Microbial Assessment and Control in Drilling Operations
Authors: Sindi Mohammed E. , Ezzat Abdalla M , Ba Hamdan Abdulaziz A , Subhi Mohammed A , Al-Humaid Ghassan A. , Al-Humam Abdulmohsen A. , Zhu Xiangyang 
Published: January 2018

Abstract
Microbial contamination and extensive growth of bacteria in the drilling mud impact drilling operation and reservoir integrity. To reduce the damaging effect of microbial growth, drilling mud is generally treated with biocides for microbial control and preventing loss of rheological properties from biodegradation. Make-up water and drilling mud samples from reserve tank and mixing tank were collected from three drilling rigs in Saudi Aramco oilfields. The baseline number of general aerobic bacteria (GAB) and sulfate-reducing bacteria (SRB) in make-up water and drilling mud samples were determined using the Most Probable Number (MPN) method. Microbial growth in the drilling mud and microbial control using glutaraldehyde-based biocide were evaluated under the conditions simulating short-term (&lt;24 hours) and long-term (up to 7 days) downtime of drilling operations. In short operational downtime, the current practice in Saudi Aramco with no biocide addition resulted in high number of GAB (105-107/ml) in the mud samples. In long operational downtime, addition of 1500 ppm of biocide (1/3 of normal dosage) at Day 3 was effective in controlling GAB and SRB growth in drilling mud. Biocide performance was significantly affected by sulfide content in the mud; higher dosage and more frequent treatment may be required to control the microbial growth in the drilling mud. The study indicated that biocide treatment is essential for microbial control in drilling operation, especially in the period of operational downtime. Finally, drilling mud operation and field best practice for microbial control were recommended to be implemented in all Saudi Aramco drilling rigs.
Mechanical Specific Energy and Statistical Techniques to Maximizing the Drilling Rates for Production Section of Mishrif Wells in Southern Iraq Fields
Authors: Alsubaih Ahmed , Albadran Firas , Alkanaani Nuhad 
Published: January 2018

Abstract
The Mechanical Specific Energy (MSE) and Statistical Analysis Approach (SAA) have been widely implemented in oil and/or gas well drilling industry to enhance the Rate of Penetration (ROP) and reduce the operation cost. This work focuses on predicting and optimizing the drilling efficiency and performance in the production section of Mishrif reservoir in southern Iraq fields. The drilling data from twenty-five wells has analyzed and examined to improve the drilling productivity relied upon MSE and statistical approaches. By using MSE technique, the minimum required energy to drill unit volume of each formation has determined to improve the drilling speed and avoid unnecessary energy consumption that may come out in the form of bit wearing / balling or vibration. The optimum energy is achieved when the MSE value comes close to the unconfined compressive strength (UCS) value that obtained from the empirical formula for limestone and shale rocks. The flounder and threshold points have recognized to optimize drilling data in the offset wells to enhance ROP in the future wells. In the statistical approach, the regression coefficients have obtained from the screened and filtered fields drilling data then the empirical equations to estimate ROP have constructed by using linear regression analysis through a commercial software. The optimization techniques lead to an impressive increase in the rate of penetration in the production section of the Mishrif reservoir. The MSE surveillance provides a reliable tool to maximize the ROP and reduce some drilling problems by using sufficient energy to drill each formation below the flounder point. An excessive energy consumption throughout drilling can be observed in the majority of wells been investigated. Thus, the non-productive time has mitigated considerably by utilizing drilling variables that have induced MSE equal to the unconfined compressive strength of the rocks. On another hand, the statistical analysis of real-time data for twenty-seven wells revealed a remarkable improvement in drilling performance by suggesting an empirical equation that predicts ROP through changing some key parameters such as Flow Rate (FL), Weight On Bit (WOB), Torque (TQ), Revolution Per Minute (RPM), Mud Weight (MWT) and Total Flow Area (TFA). The recommended drilling parameters resulted from this work can be used to reduce the drilling cost and prevent/mitigate the time-dependent failure in the production section.
Successful Acidizing of an HF Acid Sensitive Formation Using a Protective Ion-Complexing Agent
Authors: Salmi Ahmed Al , Al-Yaaribi Ahmed , Al-Ruzeiqi Saleh 
Published: January 2018

Abstract
Sandstone matrix acidizing is a challenge in most cases. The conventional mud acid system involving hydrochloric acid and hydrofluoric acid (HCl:HF) is widely used in stimulating sandstone formations. The disadvantage of using HCl:HF is in its rapid reaction rate, resulting in insoluble by-products from secondary and tertiary reactions that limit the treatment effectiveness. The system can also limit the acid's performance capability when deep formation stimulation is targeted.
Enhancing HCL:HF acid system has been developed by utilizing of a protective ion-complexing agent. The agent forms a temporary protective film on clay surfaces allowing the acid to react with the remaining parts of the formation. The stimulation treatment fluids can be placed within the open hole reservoir section using two methods. The first utilizes 2-in. by 1-in. concentric coil tubing (CCT) with side-jetting nozzles to achieve uniform placement across the horizontal section and deep penetration inside the matrix. The second method uses a conventional bull heading treatment.
Laboratory testing was performed to qualify the treatment. Different minerals were used to evaluate and understand the retardation of different acid systems. The solubility of clays was lower comparing to normal HF acid systems, indicating the slow reaction of the acid on clays and a sign that improved retardation was achieved. Further testing confirmed the formation of a protective layer on clays, enabling the acid to react more efficiently with the remaining minerals. After successful laboratory testing, field trials were conducted on four oil-producing wells in southern Oman that experienced fines migration issues. The main acid system was squeezed into the matrix, followed by brine post flush, and then flowed back. Treatments with the protective acid systems in the treated wells showed a net oil gain of 30% to 80% sustained for longer than six months.
This paper outlines the technical challenges in the design and application of the proposed acid system and presents the successful lab results indicating the formation of the protective film on the clays minerals and the deep penetration phenomenon.
Reduction of Subsurface Losses and Non-Productive Time During Deepwater Drilling by Application of Wellbore Strengthening Mechanism – A Strategic Approach
Authors: Alimuddin Sultan , Sharma Sunil , Mahadeshwar Sachin , Marinescu Pavel , Raman Chakrapani Venkat , Kumar Yogesh , Velavaraj Nirmaladevi K , Panicker Santosh , Rahim Syed Abdul 
Published: January 2018

Abstract
To maximize oil and gas production, it is paramount to reach the whole reservoir and extract hydrocarbon resources efficiently. Moreover, to reduce the costs in today's market, the well should be drilled in minimum operating time with no operational failures. This paper presents a detailed study and outline of a neoteric practice of using a wellbore strengthening while drilling, to drill a depleted deepwater reservoir and eliminate nonproductive time related to downhole losses. This novel solution has the potential to be used while drilling depleted reservoir sections in all Middle East areas.
In a deepwater block situated on India's east coast, synthetic-based reservoir drilling fluids are used to drill the reservoir section. While drilling depleted reservoir sands, dynamic losses amounting to 300 bbl/hr were encountered that led to nonproductive time and even abandonment of well. To continue the drilling campaign and lessen the downhole losses, fracture sizes of depleted reservoir sands were simulated using proprietary software. Considering the measurement-while-drilling (MWD) tool's limitations and other reservoir behavior, a reservoir drilling fluid with wellbore strengthening material was formulated. Extensive laboratory tests were conducted to confirm the bridge and sealing capability of the solution. Subsequent to laboratory testing, the same reservoir drilling fluid formulation was field trialed. The well was drilled successfully with no hindrance, except minor losses encountered at the top of the sand. Implementing this customized solution, combined with precise running strategy, led to effective results in more than four wells to date.
This paper presents a comprehensive study of drilling depleted zones using wellbore strengthening while drilling, identifying ideal products, studying reservoir compatibility, calculating cost effectiveness, evaluating overall performance based results, and overcoming challenges while implementing the strategy in deepwater wells. A detailed comparison of all the challenges that occurred while drilling and the proper troubleshooting steps are also discussed. Finally, the paper aims to compare the existing results with previous drilling techniques, which may help operators with the future development of respective fields. In this application, new technology of reservoir-friendly, loss prevention materials of ultra large size were used successfully.