bluuebunny/crossref_metadata_2025_split huggingface dataset:
3-D Geomechanical Modeling and Wellbore Stability Analysis in Abu Butabul Field
Authors: Qiuguo Li , Zhang Xing , Al-Ghammari Khalid , Mohsin Labib , Jiroudi Fadi , Al Rawahi Ahmed 
Published: November 2012

Abstract
Abu Butabul Field is located within onshore Oman Block 60 in the Western region of the Central Oman Desert (Figure 1). Gas-condensate was discovered in the field in 1998. The main reservoir is the Cambro-Ordovician clastic Bank formation, which is buried over 4200 m below sea level with very low porosity and permeability. Wellbore instability related drilling problems were encountered while drilling most of the appraisal wells in the field. The problems were mainly in the shallower Natih and Nahr Umr formations, Gharif formation and deeper Safiq, Ghudun and Mabrouk formations. A geomechanical modeling study was conducted in the field to understand the causes of the wellbore instability problems and to provide recommendations for drilling new wells.
Data from nine wells were analyzed and used for the construction of 1-D mechanical earth models. Rock mechanical testing data on core samples and pressure and stress memasurement were integrated in the models. Wellbore stability analysis of those wells provided insight into the causes of the wellbore instability problems. To predict wellbore stability at any location in the field more efficiently and capturing the lateral formation property variation as indicated by the seismic data, a 3-D geomechanical model was constructed and subsequently used for predicting wellbore stability for new wells to be drilled in the field and hydraulic fracturing pressures for fracturing stimulation of horizontal wells.
This paper describes the process of constructing the 1-D mechanical earth models, performing wellbore stability analysis for the appraisal wells, Integeration of 3D seismic Inversion, constructing the 3-D geomechanical model, predicting wellbore stability for new wells using data contained in the 3-D model and post-drill wellbore stability analysis of the planned wells.
Maximising the Life of Corroding Tubing by Combining Accurate MultiFinger Caliper Data with Corrosion Modelling
Authors: Billingham M A , King B , Murray A 
Published: November 2012

Abstract
The purpose of this paper is to discuss the relationship and value brought by empirical field data measurement, extensive interpretation and analysis of that measured field data and powerful predictive modelling with the input of multiple production parameters, for the prediction of rate of corrosion in downhole completions.
This paper involves studies conducted upon Tullow Oil's Bangora Field in Block 9, Bangladesh. Compositional analysis of the gas produced from discovery well Bangora 1 identified CO2 as being present at a concentration of around 0.6 mol%. Initial corrosion modelling highlighted that carbon steel completions were not suitable for long term production in this environment, however carbon steel completions were installed for logistical reasons and a corrosion monitoring programme utilising multi-finger caliper surveys was put in place. These surveys identified extensive corrosion of production tubing within a short period of production.
Accurately calibrated multi-finger sensor measurement was performed and repeated four times within a 2 year timeframe by Read Well Services. Intetech Ltd was engaged to carry out detailed corrosion modelling and prediction with input parameters including fluid production rates, well head and bottom hole pressures and temperatures and produced fluids composition. This modelling and direct measurement of the corrosion rates showed a good level of agreement and have given confidence to the life of the completion in relation to the rate of corrosion before expected failure.
The technical benefit of this work has been that it has reduced the risk that a tubing leak arises, which would require the well to be shut-in resulting in significant deffered production and associated loss of revenue while waiting mobilization of workover equipment. Cost savings have arisen by being able to safely defer the time to workover of the wells in a location where workover equipment is not readily available and to reduce the frequency of caliper surveys. Tubing replacement is planned at as late a date as possible consistent with the modelling predictions, thus maximising the useful life of the string.
Managing One of the Biggest Turnarounds/Shutdowns - Approach and Lessons Learnt
Authors: Dowd Darrell , Daher Elie 
Published: November 2012

Abstract
A major IOC planned its biggest turnaround in its history in a heavy oil up-grader / Refinery in North America.
The major challenge was to ensure that safety aspects on the project are properly managed with over 3500 workers on site. To break this challenge down into manageable chunks such as ramping up to get over 300 safety personnel in a short time, ensuring training and permitting for over 3500 workers, deploying effective and adequate Gas Detection systems and monitoring, ensuring adequate supply and with the right amounts of breathing air to manage escapes or working under air in critical places during the shutdown and Confined Space Works where it is required with proper permitting, safety watch and effective rescue plans.
To execute this massive task, a proactive approach has to be utilized with a very early planning cycle to ensure adequate sourcing, surveying, centralized dispatching, mitigating potential risks and communicating effectively with all stakeholders and contractors. This approach has produced some tangible benefits to the project, namely an improved tracking of equipment and manpower, streamlined delivery process, enabled accurate and timely reporting to contracts and to client reps.
This paper shares some key statistics on this project like number of safety personnel deployed ( over 300), number of specialized safety equipment used (over 1200), number of jobs dispatched (over 3000), number of asset shrinkage ( No downtime), no LTI, and a total estimated savings on total safety spent of over 1 Million Dollars.
In addition, this paper aims at sharing some of the lessons learnt around project management, planning and communication.
An Improved Approach for Generating Saturation Functions for Simulation Models Using Dynamic Rock Types
Authors: G. Ghedan Shawket , Huang Qingfeng , Wu Yahong 
Published: November 2012

Abstract
Rock typing is a key factor in reservoir characterization studies. It is often assumed that Static Reservoir Rock Types (SRRTs) are capable of assigning multi-phase flow characteristics, such as capillary pressure and relative permeability curves to the cells of dynamic simulation models. However, SRRTs fail to capture the actual reservoir variability, due to lack of representation of wettability difference at different elevations above Free Water Level (FWL), especially in highly heterogeneous thick carbonate reservoirs. These shortcomings of SRRTs can be resolved through Dynamic Reservoir Rock Types (DRRTs), in which wettability effect is imposed on SRRTs to generate saturation functions for simulation models.
This research proposes a modified DRRT approach by integrating the data from geological models and SCAL tests. First, the defined static rock types are sub-divided into sub-static rock types using either porosity or permeability frequency distribution. Second, a modified correlation equation is proposed and applied to more accurately estimate the initial water saturation versus height above FWL from well logs. Third, each sub-static rock type is further divided into a number of DRRTs by determining the capillary pressure and relative permeability curves in the oil zone from the Gas-Oil Contact (GOC) to the Dry-Oil Limit (DOL). The DRRTs are extended to the zone from DOL to the FWL by including wettability effect which would affect the curvature of the relative permeability curves but not its saturation end points, through changing the Corey exponents in the modified Brooks-Corey model.
This modified DRRT approach is applied in terms of the dynamic rock typing plug-ins to generate sub-rock types from static rock types, and build a comprehensive and automatic approach to generate saturation tables for dynamic rock types that can be prospectively loaded into commercial simulators for reliable reservoir initialization, history match and prediction processes.
Case Study: Predicting to Refine Mitigation Plans to Ensure Well Integrity for Supercritical CO2 Injection for EOR Projects
Authors: Obeidi Adel , Al Aryani Fatema 
Published: November 2012

Abstract
Maintaining wellbore integrity throughout the life of a well has become a major concern for production optimization. Corrosion logs are mainly run to investigate and inspect the casing integrity and corrosion severity. In this paper, we will discuss a case study for well integrity monitoring for a specific case, where the focus of monitoring integrity was on a miscible CO2-EOR pilot to evaluate and understand the effect of miscible supercritical CO2 flood on the down-hole well equipment, the effect of CO2 on various designed materials, the Impacts of corrosion inhibitor on well metallurgy in a CO2 environment, Integration of differently data sourced in forecasting and therefore designing mitigation plans of zones that could be potentially negatively impacted, perforation design and optimizing for well performance, and down-hole completion accessories and logging portfolio selection.
The case study comprises three wells drilled vertically; a number of mechanical and electromagnetic wire-line logging tools were deployed to investigate the integrity of the wells.
Cement bond integrity was evaluated prior to injection of supercritical CO2 into the reservoir in order to ensure correct cement placement and protection was in place for adequate mechanical support for the casing, to safeguard against fluid corrosion, and to isolate permeable zones at different pressures to avoid hydraulic communication.
Another approach was targeted to better understand the area presumed to be affected early by the flood by assessing the open hole data conventional logging technologies to determine the permeability contrast of the reservoir in order to predict the CO2 flow path and entry points.
The paper will expound some important lessons learnt were derived from this case study and the critical data needed to provide understanding of the EOR flood behavior that can be used as indicators for mitigation plans and robust design of CO2 impacted wells.
The Application of Streamline Reservoir Simulation Calculations to the Management of Oilfield Scale
Authors: Hassane Tharwat , Mackay Eric 
Published: November 2012

Abstract
Inorganic scales precipitate in oilfield systems - downhole in the reservoir, in the production flow tubing, and in surface facilities - as a consequence of thermodynamic changes that affect the flowing brines. These changes may be induced by temperature or pressure changes, or by mixing of incompatible brines. While much work has been performed to study the effect of thermodynamic changes such as pressure decrease or temperature increase on scale precipitation, it is only recently that a body of work has been developed on the impact that the dynamics of brine mixing in the reservoir has on scale precipitation in situ. Much of this work has been conducted using finite difference simulators, which are handicapped with regard to these calculations in that numerical dispersion effects can be orders of magnitude greater than physical dispersion.
The introduction of chemical reaction calculations into streamline simulation models presents a very significant opportunity for improving the accuracy of such calculations. While numerical dispersion effects for immiscible calculations (eg water displacing oil) can be countered by pseudoisation of the relative permeability functions, in finite difference models it is difficult to control numerical dispersion for miscible displacements - eg seawater (with a SO4 concentration) displacing formation water (with a Ba concentration), which may lead to scaling in the reservoir (BaSO4 precipitation). Streamline simulation reduces the numerical errors for both miscible and immiscible displacement - so making the scaling calculations much more accurate.
The objective of this paper is to study the application of a streamline simulator that has the appropriate chemistry modelling capabilities to simulate realistic reservoir scenarios. The workflow will consist of two stages:
Study of synthetic systems to identify the impact of brine mixing in simple scenarios (eg single layer and multi layer quarter five spot patterns) Application of the technique to full field reservoir systems where produced brine chemistry data are available.
The calculations performed will demonstrate where, and under what conditions, scale precipitation takes place in situ in the reservoir, and what the resulting impact on the chemical composition of the produced brine will be. This information is key in the planning of management of oilfield scale, especially in deepwater developments where options for scale mitigation may be limited. As a result of this work, it is expected that guidelines will be drawn up for the use of streamline simulation, particularly during the FEED stage of new projects, and when considering infill well drilling in mature projects. These guidelines will be illustrated by reference to field examples.
Saudi Arabia's Two World Records for Aided Coiled Tubing Reach and Real Time Logging in Extended Reach Well
Authors: O. Arukhe James , A. Dhufairi Mubarak , A. Ghamdi Saleh , Duthie Laurie , Yatem Karam , Elsherif Tamer , Ahmed Danish 
Published: November 2012

Abstract
Two new records exist in one of current world's largest oil increment field development projects in Saudi Arabia. The records set while achieving a well's intervention objectives include; 1. Attaining the deepest coiled tubing (CT) reach for rigless well intervention at 29,897 ft (9.11 km) measured depth in an extended reach open hole horizontal power injector well using a CT tractor and; 2. The first application of real time logging enabled through a wired motor head assembly via the tractor. The intervention objectives were to acid stimulate an open hole completed relatively deep in the reservoir with total depth of 29,897 feet and open hole length of 6,697 feet utilizing 2′ CT with open hole tractor, to perform injectivity / falloff test, and to conduct real time logging for evaluating the reservoir's injectivity profile.
The paper examines several challenges that engineers and operators encountered during intervention in this well. A partially sealing high viscosity tar layer exists between the overlaying oil column and underlying aquifer. Operationally, the challenge was to overcome obstructions arising from tar accumulation during the well intervention. This challenge was overcome by the use of a solvent and the well was successfully acidized with the aid of the CT-tractor. The other concern was the tractor integrity while large amount of acid is pumped and the extended exposure time of tractor to acid. The tractor successfully handled huge amounts of corrosive fluids in a sour environment while providing the required pulling force to reach the total depth of the well to set the intervention record for tractor reach without adverse effects on the integrity of its O-rings, seals, and mechanical parts. In addition to organic deposits, azimuth changes in the well added to well entry challenges as a result of changes in hole inclination, doglegs, and azimuth. The application of real time informed decisions was critical in overcoming all the challenges, optimizing stimulation design, and yielding a notable and consistent injectivity increase with evidence of extended life and a true reflection of deep penetration into the damage zone. The successful re-entry will benefit industry operators confronting similar intervention challenges.
Behavioral Based Approaches in Preventing Incidents Using Incident Root Causes & Trend Analysis
Authors: Tayab Muhammad R 
Published: November 2012

Abstract
Preventing the ‘next accident’ is a key issue and a challenge in high risk businesses such as oil & gas industry and ADCO is no exception to this rule. Over the last five years, ADCO has exercised significant efforts and resources to achieve a high safety standard at its work sites, but the trends of reoccurrence of incidents have been observed. Concerns have been raised whether any lessons have been learnt from previous accidents.
In 2010, extra efforts were put-in place in incident investigation processes by introducing extended root cause analysis training and use of HSE Electronic Action, Reporting and Tracking System (HEARTS) to accomplish trend analysis. The data indicated that the majority of root causes (72%) can be linked to human behavior, resulting in unsafe behavior and/or creating unsafe conditions. Consequences of not addressing behavioral issues and the recommendations for influencing the positive behaviors are discussed here at length.
Key Words: Root Causes, Behavioural Based Audits, Incident Prevention, Critical Behaviour, Work Planning, Effective Leadership
Wellbore Strengthening and Continuous Mud Circulation Allow to Save an Expandable Liner: Field Application Offshore Italy
Authors: De Grandis Giuseppe , Maliardi Alberto , Ligrone Angelo , Arpini Franco 
Published: November 2012

Abstract
Wellbore strengthening techniques have been used in recent years to increase the capability of wellbores to maintain higher pressures. By increasing the fracture resistance of formations, operators can save rig-time and large volumes of drilling fluids.
The Luna-41 well, offshore Italy, intersects a critical interval comprising high pressurized formations overlaying a lower pressure depleted zone. The initial plan for the well was to divide this interval into two separate hole sections using two different mud systems. A casing string would have been set to isolate the shallower high pressure region followed by an expandable liner to isolate the over pressured shales laying above the depleted reservoir level.
An alternative design was proposed that required only one fluid system and a single casing string, thus saving an expandable liner. Thanks to the wellbore strengthening application and the proprietary continuous mud circulation device, the accomplished well program allowed an 8-day rig-time reduction and a 3-MMUSD cost saving.
A specific modelling tool developed for wellbore strengthening applications was used to assist with fluid design. The tool calculates the width of microfractures induced by differential pressure and the Particle Size Distribution (PSD) of carbonate materials required to plug such microfractures and ultimately strengthen the wellbore.
The mud formulation for Luna-41 was tested in the laboratory using a Pore Plugging Apparatus (PPA) and aloxite discs with pore sizes corresponding to the calculated microfracture width. The fluid used to drill the critical interval was a salt saturated system based on polyglycerol complex and supplemented with a polyamine inhibitor.
The field application was a success. The depleted zone was drilled without incurring lost circulation. This paper describes the results of the field application as well as the fluid engineering process and laboratory testing to highlight the benefits - such as accessing depleted reservoirs and saving casing strings - that wellbore strengthening combined with a continuous mud circulation system can bring to the industry.
Novel Method of Production Back-Allocation Using Geochemical Fingerprinting
Authors: Nouvelle Xavier , Rojas Katherine , Stankiewicz Artur 
Published: November 2012

Abstract
Geochemical fingerprinting using gas chromatography techniques is a proven alternative or additional tool to traditional approaches for the production back-allocation such as metering or production logging tools. It can be applied in various scenarios, from commingled reservoirs in a single well to allocation of multiple wells or entire fields produced via the same evacuation system. The approach is fast, cost-effective and does not require interruption of production, thus enabling frequent monitoring of production. The method is based on detailed comparison of fluid compositions obtained from gas chromatography of representative samples acquired from the point of interest (single reservoir, well, etc.), called further the ‘end-member’ and the ‘commingled fluid’ to be allocated. Production allocation using a geochemical fingerprinting approach has been successfully used across the globe with specific traction in North America, the North Sea region and the Middle East.
Our method is based on analysis of ratios of heights of neighboring chromatographic peaks (compounds) rather than the single peak heights or areas that all the chromatograms have in common. Such approach reduces inconsistencies between light and heavy hydrocarbons due to some problems of reproducibility during the sampling or during the analysis. It also allows us to tackle issues related to the changes in compositions of end-members during production. In addition, the resolution manages the non-linearity of the equations derived from the physics of the mixtures. The non-Gaussian distribution of the errors is taken into account to comply with the maximum likelihood. Thus, a solid theoretical framework is established to avoid current issues encountered when peak ratios are utilized. Benefits of this method include firstly, a complete management of the uncertainties on the proportions of end-members and on each individual peak ratio employed. In addition to minimization of ‘calibration’ lab mixtures, elimination of manual peak selection (sometimes subjective). Finally, with this methodology employed heir in there is theoretically, no limitation on the number of end-members.
In this paper we demonstrate our approach applied successfully on a series of case studies including biodegraded oils and ‘annoyingly’ similar fluids. We demonstrate that our approach can be successfully and cost-effectively applied to allow for more reliable reservoir/field management.
Tight Gas Reservoirs; Challenges for Appraisal and Development, Case History from Abu Dhabi Oil Company for Onshore Operations (ADCO) Fields
Authors: Al-Shaarawy Osama A. , Al-Ameri Fatima , Abdulla Duaa , Al Baloushi Abdulla , De Castro Alex , Sulaiman Tarek , Masoud Rashad , Al-Ammari Khalid 
Published: November 2012

Abstract
ADCO operates the oil and gas reservoirs/fields in onshore Abu Dhabi. Tight gas reservoirs are thin bedded, laminated and heterogonous carbonate reservoirs. Testing of the tight gas reservoirs in vertical wells was not justifying the completion, hence the production, mostly for economic reasons due to low and non-sustainable rate.
Recently, ADCO commenced a campaign to appraise the tight gas reservoirs in the onshore operating fields. The first trial was commenced in Jan 2010. In which, the Lower Thamama; with five (5) sub-layers, thin-bedded, laminated and heterogeneous gas reservoirs were appraised. The drilling within a six (6) feet thick interval of sub-layer for almost 1000’ was really an operational challenge prior to dive the well across the dense (stylolitic) interval to drill the second thin sub-layer. The well trajectory was adapted to appraise as much sub-layers as possible aiming benefiting maximizing the reservoir contact per drainhole.
The production results from the first appraisal well encouraged the team to set a development plan. The well-planning by targeting different sub-layers minimized the well interference and improved the draining areas per well.
The 3D seismic interpretation, core data, log analysis and formation evaluation in addition to test data from vertical wells were the basis for the 3D reservoir modeling in order to understand the lateral heterogeneity of the reservoir hence planning the well geometry to geosteering within the developed reservoir areas. Imaging While Drilling is a real-time tool that afforded excellent well-placement practices.
ADCO is enthusiastic to aggressively tackle the tight reservoir issues to produce bypassed hydrocarbons. The challenges are huge however the expectations are immense.