bluuebunny/crossref_metadata_2025 huggingface dataset:
Deepwater MPD Operation and Design Method
Authors: Kuroda Y. , Kudo H. , Toyoda K.
Published: November 2017

INPEX Offshore North West Sabah, LTD. has committed to drill two deepwater exploration wells in water depth upto greater than 1,000m offshore Sabah in East Malaysia. The typical deepwater wells, due to narrow drilling window between pore pressure and fracture gradient, require multiple CSG strings to reach total depth. Because of the uncertainty in pore pressure and fracture gradient prediction, which causes pressure-related well control problems, the initial CSG design with conventional method was conservative and highly costly design.

Managed Pressure Drilling (MPD) with Constant Bottom Hole Pressure (CBHP) mode enables the development of an adaptive well design and safe operation by providing the following key points: Improved Kick ToleranceEarly Kick Detection by Coriolis Meter can reduce influx volume. Once MPD system detects the influx in "auto mode", the system automatically increases back-pressure to stop the flow while drilling. Typical influx in MPD mode is less than 3 bbls.Improved Safety and Well ControlIt mitigates the risk of exceeding MAASP with MPD because of smaller influx. Also it can enhance ability to safely circulate out gas in the riser.ECD ManagementIt enables to maintain the constant bottom hole pressure during drilling and connection. Adjusting MPD choke can manage the drilling safety margin.

MPD application with the adaptive CSG design will most likely eliminate at least one CSG, and has potential saving of two CSG strings, which represents significant cost saving.

The method introduced here is applicable to any deepwater well which has narrow drilling window. MPD application with Below Tension Ring RCD (Rotating Control Device) on 6th generation dynamic positioning rig can develop real time CSG setting depth optimization with the management of bottom hole pressure in each hole section.
Engineered Fit-For-Purpose Cement System to Withstand Life-Of-The-Well Pressure and Temperature Cycling
Authors: Al-Yami Abdullah S. , Wagle Vikrant B. , Abdurrahman Riefky , Taoutaou Salim
Published: November 2017

Due to pressure and temperature changes during the life of the well (from drilling to production); globally many Casing-Casing Annular (CCA) leaks are observed in the annuli between surface and intermediate casings. A new approach to well cementing had to be developed, and advanced cement technologies considered, taking into account both short and long term design parameters.

To assess the effect of pressure and temperature cycling on the long-term well integrity, finite element modeling of sections of interest was performed to analyze the stresses applied on the cement sheath throughout the life of the well. Such modeling requires detailed knowledge of the pressure and temperature cycles, as well as the mechanical properties of the formations, casings and cement.

The output is a failure analysis of the cement sheath in terms of compression, tension and micro annulus development. Once the failure mechanisms are well understood, further sensitivity analyses permit to select the most adequate cement system for the application, based on target windows of compressive and tensile strengths, Young's modulus, Poisson's Ratio, and expansion capacity.

The paper will discuss a case study where a fit-for-purpose durable cement system was designed to meet the required mechanical properties as suggested by the stress modeling performed on a candidate well. It was placed as a Tail slurry on the 9 5/8" Tieback casing to provide 1000 ft. of long-term hydraulic isolation in the cased annulus should the liner top packer fail to seal the high-pressure water formation below. A post-job analysis using job data and cement evaluation logs showed that placement was executed as per design and that the durable cement system provided excellent bonding and annular coverage. The well was later drilled to total depth, completed, fractured and delivered to production without CCA pressure at the wellhead.

The new approach consists of performing finite elements stress modeling during the well planning phase to custom design cement systems that will withstand the anticipated loads.
The Development and Field Testing of Novel Online Salt-in-Crude Oil Measurement Method and Analyzer - A Systematic Approach to Technology Qualification
Authors: Duval Sebastien , Less Simone , Szczebiot Ryszard , Prada Iran Charry , White Ramsey , Al-Khabaz Sajjad , Vilagines Regis
Published: November 2017

This paper describes a new approach to online monitoring salt content in crude oil. An extensive experimental study was conducted in the laboratory on different crude oil types, to evaluate accuracy and repeatability of the new method in comparison with the existing standard, the ASTM D3230. Following the successful laboratory study, an industrial prototype based on this new method was designed, installed in a production facility, and tested for 6 months.

Maintaining crude oil production rate and quality are the primary targets of any oil producer. Salt (defined here summarily as a mixture of Na, Mg, and Ca chlorides) is one of the undesirable crude oil contaminants that affects crude oil quality. Salt is mostly entrapped in the micron-sized water droplets carried out from the last separation vessel of oil production facilities. While measuring salt content per the existing ASTM D3230 standard offers no difficulty in laboratories, implementation of online measurements remains very challenging.

Commercial analyzers based on the ASTM D3230 mix crude oil with three different solvents (Xylene, Methanol, and Butanol) and measure the mixture conductivity. Due to their numerous moving parts, commercial online analyzers’ reliability is low and maintenance is difficult and costly. Additionally, procurement, storage, and handling of these highly flammable, toxic, and low boiling point chemicals are not practical in remote areas or offshore production sites.

Saudi Aramco Research & Development Center and Saudi Aramco Oil Operation worked jointly to simplify the measurement protocol by replacing the three hazardous solvents with a relatively harmless single solvent. This solvent is very stable and has a high boiling point; consequently, it can be stored in large quantities, which significantly reduces the frequency of replenishments and limits the operator’s exposure to chemicals. The application of the new single solvent method has multiple advantages: ∘It reduces moving parts and complexity, and hence the fabrication and maintenance costs of industrial online analyzers.∘It reduces solvent consumption, as the solvent/crude oil mixture ratio is 50/50, in comparison with ASTM D3230 ratio of 90/10, thus further reducing the operating costs.∘It increases salt content in the measurement cell because of higher crude oil to solvent ratio, thus improving accuracy.∘It can be implemented by simple modifications to existing commercial analyzers.
Drilling while Casing Extended-Reach Wells?What is the Limit?
Authors: Li He , Gao Deli , Li Xin , Sun Fengrui , Liu Yongsheng
Published: November 2017

As an innovative drilling method, Casing-while-Drilling (CwD) was first proposed to reduce the non-productive-time (NPT) required to trip the drill pipe and run the casing. However, several case studies have confirmed the plastering effect it produces during the implementation of this drilling method. The plastering effect, which refers to "plastering" drilled cuttings and lost circulation materials (LCMs) on the wellbore wall to form an impermeable mud cake and simultaneously plug the induced fractures, can strengthen the wellbore wall and provide a wider safe mud weight window (SMWW) during the drilling process. Thus, the models published before to predict the maximum allowable measured depth (MAMD) of extended-reach-wells (ERWs) drilled with conventional drilling method should be amended for CwD with consideration of the plastering effect it produces.

In this work, a prediction model of the MAMD of ERWs drilled with CwD considering the plastering effect is presented. Two kinds of strengthening mechanisms (i.e., the fracture based and non-fracture-based wellbore strengthening mechanisms) are properly combined to quantify the resultant improvement of the fracture pressure gradient by the plastering effect. Meanwhile, the factors that affect the MAMD with CwD are also investigated.

The results show that, for non-fracture-based wellbore strengthening mechanism, the impermeable mud cake formed by plastering effect significantly improves the fracture pressure gradient. Whereas, the thermal effect caused by continuously contact of the casing string with wellbore wall is not obvious for the resultant improvement. Besides, the wellbore will be strengthened a lot by plugging the induced fractures with the drilled cuttings and LCMs during the drilling process. Although forming mud-cake with low porosity and permeability can contribute to a higher fracture initiation pressure (FIP), it will inversely decrease the fracture re-initiation pressure (FRIP). Thus, the factors that play a positive role in non-fracture based wellbore strengthening mechanism may impair the effect of fracture based wellbore strengthening mechanism. Therefore, these influencing factors should be properly combined, in order to attain a greater MAMD with CwD method.
The Evaluation of the First Biodegradable Diverter in Acid Fracturing in Kuwait: Case Study
Authors: Al-Othman M. R. , Elmofti M. , Bu Hamad A. , Alhouti N. B. , Al-Haddad M. N. , Al Hamad A. M. , Allam A. , Eid W.
Published: November 2017

Numerous methods have been applied in matrix acidizing over the previous decades to successfully stimulate multiple zones. These methods have also been implemented in fracture acidizing with varying degrees of success. This paper discusses the application of a new biodegradable material used for diversion in multiple zones or long formation intervals and presents improved results obtained using a new biodegradable diverter.

Acid-fracturing diversion can be more challenging than diversion for matrix acidizing. To effectively stimulate multiple or large zones, the diversion treatment should be able to bridge not only the perforations themselves, but often inside the fracture system as well. This can be difficult because acid reacts with the rock, forming an etched/enlarged path, thus the diversion also requires bridging inside this conductive path. This differs from matrix acidizing techniques, in which the diversion depends mostly on the perforations in an interval(s) and the stimulated reservoir permeability. Historically, several methods have been implemented for acid-fracturing diversion, such as ball sealers, viscous fluids, packers, etc., resulting in limited success or cost-ineffective results. The new biodegradable material helps improve acid fracturing diversion success in multiple zones or long formation intervals.

The development of this biodegradable material is discussed along with a case study. Also, details are provided of the biodegradable material evaluation that consists of 1) pre and post-temperature logs, 2) pre and post-injection logging profiles, 3) pre and post-production history, and 4) further recommendations. The results of the evaluation methods show that the biodegradable material can be used as an effective alternative diversion method to seal existing perforations and effectively stimulate all perforated intervals. Production increased more than threefold, and the targeted fracture height was achieved based on the temperature log data.
Design of Safe Well on the Top of Atharamura Anticline, Tripura, India, on the Basis of Predicted Pore Pressure from Seismic Velocity Data
Authors: Brahma Jwngsar , Sircar Anirbid
Published: November 2017

Pore pressure prediction is essential part of wildcat well planning. In India, Tripura sub – basin is characterised by huge anticlines, normal faults and abnormally pressured formations. These factors push the wildcat well planning in this area into wide margin of uncertainty. Pore pressures were predicted from seismic velocities by using modified Eaton’s method over the synclinal and flank part of Atharamura to understand the pressure succession towards the anticline. These predicted pore pressure on the flank part lead to a reasonable match when plotted with offset well measured pore pressures. To reduce the uncertainty fracture pressure were established by various methods such as Hubbert & Willis method and Matthews & Kelly method from predicted pore pressures. But the fracture pressures were predicted with available horizontal stress correlations due to lack of Poisson’s ratio curve for the study area. The mud pressure required to drill the well is calculated using median line principle and hence drilling mud window is established by assuming virtual tight conditions. The plot of Equivalent Circulation Density (ECD) versus depth suggest that well can be drilled with two casing policy. But it is found that adding one more casing pipe will ensure the safety of well. Casing pipes were designed on the basis of collapse pressure, burst pressure and tensile load. Finally a well plan which includes pore pressure, fracture pressure, drilling mud policy, casing policy, kick tolerance graph were proposed to give clear picture on well planning on the top of the anticline in pore pressure point of view.
Normalized Depths as Key Input and Detailed QC Steps for Improved Permeability Predictions Using Existing Machine Learning Techniques
Authors: Voleti Deepak Kumar , Kundu Ashish , Singh Maniesh
Published: November 2017

Because of advance computing technologies, machine learning today is widely used for many types of prediction. The performance of existing prediction techniques has been quite acceptable but still it needs improvement. In oil industry, this type of machine learning is being used for Permeability prediction. In case of homogeneous reservoir, conventional permeability prediction techniques are very well documented in the available published literature and are easy to be implemented however, it is a real challenge in case of complex carbonate reservoir which are highly affected by diagenetic overprint. The machine learning algorithms exactly does according to what user had trained for it. It get confused either if it receives a new unseen input for which it was not trained or it has multiple answer to the same input. This study shows that by using selective intelligent inputs (quantitative factors influencing permeability) and with proper segregated and intuitive training to machine it is possible to gain better correlation between different inputs and a reliable permeability prediction can be achieved.

The studied Early Cretaceous reservoir has a large areal extent with 20% average porosity and large range of permeability, from 0.1 to 1000 md due to preferential diagenetic processes over large variety of lithofacies. Capturing high permeability streaks/zone simultaneously with low K intervals was quiet important to understand the fluid flow dynamics and hence was a real challenge in this project. This paper describe the workflow developed to analyze data in different dimensions away from the conventional ways, detailed QC steps and preparing the intelligent input data sets (Normalized depths, Rock types, zonal and sectorial flags, synthetic permeability guide curve, etc.) which facilitate the machine to make a best decision and output optimum results. This paper shows two- point normalization method to bring reservoir depth interval between 0 to100 and pick up consistent permeability profile in each sector which correlates better to stratigraphic framework.

In this study, the models were built with 3081 CCA data from 30 spatially distributed cored wells and blind tested on 10 other cored wells; later these models were used to predict permeability in 210 uncored wells. Comparison of the predicted permeability with the well test permeability shows Ktest/Klog in the range of 1.05 to1.6 suggesting fair to very good reconciliation. The normalized depth vs. predicted permeability and an independent cumulative permeability QC plots are introduced to qualify the prediction model.

The workflow shown in this paper is logically built and gives the interpreter flexibility to choose inputs based on the observed permeability variance. The QC flags and the predictive models are easy to implement and update permeability model as the new data comes.
Mapping Completion Design Trends in a Compartmentalized Tight Oil Reservoir for Rapid Evaluation Using Artificial Neural Networks
Authors: Bansal Y. , Ertekin T. , Karpyn Z. T.
Published: November 2017

Lower oil prices pose a threat to developing tight oil reservoirs economically. Typically, completion cost varies between 50-70% of the total capital costs of drilling unconventional wells (EIA, 2016). Major challenges in justification of drilling these new wells lie with the uncertainty in production, and thus, with the efficiency of drilling and completion design of these wells. Identifying a suitable completion design can be a complex problem as tight oil systems are discontinuous hydrocarbon sources. These resources often present challenges in building good geological models. However, abundant data for production, well logs, seismic, drilling and completions are available through recent developments in these formations. This information can be utilized to characterize these reservoirs and identify case-specific and cost-effective completion strategies. This paper discusses the utilization of the data to map completion trends in tight oil systems to optimally complete these wells. The available data is used to generate trends for completion parameters with the application of artificial neural networks. It is shown that the complex relationship among geological properties, well logs, production history, and completions methodology can be established with this methodology. The suggested completion design may enable to lower the effective cost of production from these wells. In addition, the proposed ANN based proxy takes only a few seconds to suggest completion design for a new well. It is also shown that the proxy model developed with this application can easily be utilized with available optimization algorithms to optimize the completion parameters in a time efficient manner.
Engineering and Constructability Challenges of Site Preparation at Zirku Island for the Satah Al-Razboot New Oil Field Development in the Arabian Gulf
Authors: Ahmed Iqbal , Seddik Sameh , Al-Hajaj Mohamed Eissa , Chasiotis Ioannis , Vandolas Vasilis
Published: November 2017

Abu Dhabi Marine Operating Company (ADMA-OPCO) is developing the Satah Al Razboot (SARB) Oil Field, located in the Arabian Gulf in the United Arab Emirates (UAE). Two new artificial islands have been constructed for oil extraction, while the processing, storage and offloading facilities for SARB are located on Zirku Island. Construction of the Zirku Island facilities was conceived and planned for implementation on a modularized basis because of the relatively remote offshore location, which required the incorporation of a permanent jetty and harbor for the transportation of these modules. The Zirku Island topography consists of mountainous terrain composed of a special set of geological conditions characteristic of salt domes. A major requirement of the project was the design and construction of cut and fill slopes as high as 75 meters. The site works have required substantial excavation and backfilling work to create level platforms for the proposed facilities. Surplus excavated material has been used onshore and nearshore to create new land. A robust material management plan was devised to efficiently move the huge excavated material volumes to the designated fill areas and stockpile locations directly due to space constraints. Close collaboration between the project teams and contractors of the different packages of the SARB Project has resulted in the successful delivery of the Site Preparation Project's goals. The main challenges and lessons learned are shared as part of the paper.
Successful Completion of the First Ten Multistage Acid Fracturing of an Oil Producer in Saudi Arabia
Authors: AlOtaibi F. M. , Al-Dahlan M. N. , Rafie M. , Otaibi S. G. , Said Rifat , Aljulaih H. A.
Published: November 2017

Challenges have arisen when developing a relatively tight oil reservoir in Saudi Arabia using conventional matrix stimulation techniques to improve well productivity. The oil producer wells responsiveness to matrix stimulation was not adequate to supply the estimated oil production capacity due to the tightness carbonate reservoir formation. In order to get better well productivity in this low permeability environment, open hole with multistage frac completion using swellable isolation packers was chosen to develop this reservoir.

This paper discusses the challenge journey of first ten multistage job from the well drilling and completion stage, design and lab optimization of the fracturing fluids, modeling of the optimized fracture geometry, onsite well QA/QC of each stage fracturing fluids. In addition, step rates test regression approach prior each stage for fracturing gradient calculation, pre and post fracturing injectivity test, and finally analyzing the flowback samples for four days.

A ten multistage acid fracturing was performed on an oil producer well that was drilled as a single lateral into the oil tight carbonate reservoir. The well was completed with a ten sleeve multistage fracturing and eleven oil swellable packers. These packers showed excellent zonal isolation with no communication observed during the fracturing operation. The job resulted in a well producing 9 folds of production, with a water cut range less than 10 %. The four days flowback samples analysis revealed the need for longer cleaning up time.

A successful approach was achieved using multistage acid fracturing technique. Lessons learned from this job planning and execution shed the importance of previously steps for future acid fracturing jobs in similar oil fields.
Myanmar Online Bowtie to Prevent Major Accident Events MAEs
Authors: Rujipattanapong Sontirat , Apornsuvan Akaradech
Published: November 2017

Objective / Scope

With the PTTEPI goal of Safety "Everybody returns home safely and nobody gets hurt". PTTEPI has developed "Myanmar Online Bowtie to Prevent Major Accident Events" to provide "Line-of-sight to Safety Case barriers status" contributing to Process Safety Management and Asset Reliability and Integrity Management process of "Ensuring asset can perform its required function efficiently and effectively whilst safeguarding life and the environment" for managing workplace safety.

The Myanmar Online Bowtie can illustrate the status of safety barriers by color-coded graphics e.g. Red, Amber or Green for each Major Accident Event and barrier groups at any given time. It is a traceable and transparent system to measure compliance with the management system for Asset Integrity. In addition, it is a bottom-up monitoring tool from site personnel, Technical Authority (TA), to decision makers or management team in order to prioritize operational tasks and resources for barrier repairs, modifications and temporary measures based on barrier conditions and recording. MAE can provide a safety alert for the management support on the operation when necessary.

The Myanmar Online Bowtie can provide an integrated system to monitor key Safety Critical Elements (SCE), a mix of plant (equipment function, or deviation), process (documents) and people (personal certificate/training records), in the following areas:
Achieving Cost Reduction In Mature Gas Fields Through Material Optimization
Authors: Terras Y. , Mansur D. , Saithala J. R. , Flores P. R. , Gonuguntla M. S.
Published: November 2017

After standardizing a well design and drilling multiple wells in a mature field, it is often difficult to find new ways to reduce the cost of the wells. The traditional approaches to reduce the well cost during the planning and design phase of the well is to look at opportunities to reduce the number of casings required (for instance by changing casing show depth, changing mud systems to combine drilling sections, etc.), to reduce the size of casings required (slimming down the well design) and to look for new technologies allowing faster delivery of the well (for instance through ROP enhancement, faster casing running, etc.). After going through this well design optimization phase and improving the drilling performance thanks to the implementation of operational learnings, it becomes increasingly difficult to reduce further the well cost as the well delivery reaches a plateau.

Following a challenge of the functional requirements of the wells, an initiative was raised to review the different materials used across the Petroleum Development Oman (PDO) gas wells portfolio and assess if they were fit for purpose or if there was any possibility to change these materials for more cost effective ones while remaining compliant with the minimum functional requirements of the wells and retaining a high level of standardization in the materials used. Due to the high corrosion tendency of the produced fluids and the required service life of the wells (>20 years), this review focused mainly on the tubing, wellhead and Christmas trees as expensive Corrosion Resistant Alloys (CRA’s) are selected for well completion materials.

A structured approach was put in place to gather actual production field data and compare them to the design functional requirements while in parallel conducting in-house detailed laboratory tests on a specific more cost effective CRA material to improve the operating envelop of such material and extend its use to a wider range of application. This resulted in a set of new material recommendations that were reviewed from a casing design perspective to assess the potential implementation.

Ultimately, several changes were made to the materials selected for the Christmas trees and the tubings on specific fields that resulted in an estimated 3 mln USD cost savings per year for the entire gas portfolio.
A Robust Surveillance and Optimization Workflow for Offshore Gas Lifted Wells
Authors: Xiao Feng , Dani Neeraj R. , Long Ted A. , Gantt Justin A. , Borden Zachary H. , El-Bakry Amr
Published: November 2017

In this paper we present an automated surveillance and optimization system for gas lifted wells. The system integrates flow instability diagnostics, steady-state flow models, and transient multiphase flow models to provide engineers and operators with a complete solution for well flow surveillance and optimization. This system is a significant enhancement to the Gas Lift Optimization Workflow (GLOW™) that was developed and deployed to multiple assets including a platform in the Gulf of Mexico. The system calibrates the models to match flowrates and pressures from multiple well tests. The calibrated models are then used to produce operational maps that provide accurate and robust flow instability recovery recommendations and stability constraints for optimization routines.

We will show an example implementation of the system for a gas lifted well from an offshore platform. In most cases, the calibrated transient flow models accurately replicated the amplitude and frequency of pressure and flowrate oscillations for two types of flow instability: casing heading and hydrodynamic slugging. We also compare transient flow and steady-state models, and discuss the use of both to maximize computing efficiency.

The developed system uses multiphase flow transient models, in an automated way, to produce operational maps that can aid either asset staff or the GLOW™ system to optimize production while steering away from unstable flow. In summary, the system provides a comprehensive, robust, and integrated set of tools for the surveillance and optimization needs of asset staff.
Optimization of Offshore Pipeline Routing Using DTM & FEA Tools
Authors: Singh Devinder , Selvam Rajendran , Qambar Najem A. , Shebli Adnan Al , Bufalah Salah Jebara , Ismail Jawed , Panambur Sandeep
Published: November 2017

Pipeline routing being one of the crucial activities of pipeline design, significantly affects almost every other aspect of the design process. Seabed terrain at many locations in Arabian Peninsula and other parts of the world is revealed to be rough & undulating which sometimes presents a significant challenge in routing the pipeline. The common challenges for pipeline routing on the rough seabed terrain can be identified and evaluated using the advanced tools at early stage of the design to select an optimized route.

Figure 1 depicts the examples of pipeline routing on the rough seabed.

Figure 1 Examples of Digital Terrain Models showing a Typical Pipeline Route over a Rough Seabed

Intent of presenting this paper is to showcase the design process followed to identify the key challenges involved in the routing of offshore pipeline on a rough & undulating seabed terrain and the methodology adopted to successfully overcome / mitigate them while achieving an optimized result in terms of most techno-economically feasible route. In addition, new technique based on least geocost path is briefly touched upon for its future application.
ESP Data Analytics: Predicting Failures for Improved Production Performance
Authors: Abdelaziz Mohannad , Lastra Rafael , Xiao J. J.
Published: November 2017

Failures of Electric Submersible Pumps (ESPs) are common occurrences in the oil industry. The random nature of these failures results in production disruption that amounts to hundreds of millions of barrels of lost or deferred oil production annually. Although important improvements have been made in the last fifteen years on ESP sensors, data collection and communications systems, the industry still lacks a system that can provide ESP health condition monitoring with the capability to accurately predict impending ESP failures. The intent of this study was to evaluate the value of Principal Component Analysis (PCA) as a tool to detect developing ESP failures and predict remaining operating time before failure.

Complete historical data of five ESP installations was used. For each installation, a stable region was selected to construct a PCA-based model, which was later used to find projections for the whole data set on the principal component axes. Different techniques were used to correlate projected data with the original data and to draw the conclusions of the study.

The analysis showed that PCA data scattered away from the origin before the occurrence of each of the failures. But a more powerful observation was that PCA projections showed distinctive data clusters representing subtle changes in the system that are not apparent by directly examining the actual measured parameters.

This study concluded that PCA has potential to be used as a tool to identify dynamic changes in the ESP system and therefore to detect developing ESP problems. PCA can also be used as unsupervised Machine Learning (ML) technique to identify hidden patterns and as an essential pre-processing technique for other ML algorithms. PCA can be used as the foundation for the development of better tools for detection of developing ESP failures and prediction remaining ESP run time.
A Novel Efficient Solution to Isolate Cross Communicating Reservoirs and Delay Water Advance without Impacting Well's Workover/Drilling Duration: Case Studies from Giant Offshore Field in Abu Dhabi
Authors: Elfeky Mohamed Helmy , Al-Neaimi Ahmed , Yousef Omar , Al-Hosani Ibrahim , Iwama Hiroki , Farhan Salman , Seoud Abouel , Channa Zohaib , Khemissa Hocine , Khan Muhammad Navaid
Published: November 2017

Facing a well control issue while drilling multi reservoirs with different reservoir pressure is very common in oil field worldwide, each and every engineer who is involved in the operations is dealing with this issue on daily basis. However, if the unexpected high pressure is observed while drilling a matured reservoir with known pressure, it is always a challenge to identify the source of the problem and to define the efficient remedial action plan, without compromising the well deliverables.

The case study presented in this paper is related to a workover of a well in a giant offshore field in Abu Dhabi, where abnormally high pressure encountered while drilling the reservoir section with little amount of flow into the wellbore. Identifying the source of discrepancy and to establish the mitigate plan without impacting Well's Workover/Drilling duration was a serious challenge. What made the situation more complicated was the high risk of water in the heel section of 6" horizontal drain, which was prone to shorten the well life significantly.

This paper will introduce an efficient novel solution to use 4 ½" casing liner in a certain configuration, consisting of the mechanical and the Swellable packers to cure the cross communicating reservoirs (source of abnormal high pressure); and isolate the risky heel section of the well, to extend well life without impacting the planned well duration.

This work will also describe the process of identifying the source of pressure, selecting the most suitable well completion strategy to meet the well objectives successfully. Moreover, it will also shed some light on the need of using reservoir simulation technique to assess different well completion options. Finally, the paper will be concluded with methodology on how to save time and cost whilst changing plans to cope with the unforeseen issues.
Innovative Approach to Save Plant and People
Authors: Subramaniam K. , Sharma A. M. , Awadhi I. Al , Mashjari K. Al
Published: November 2017

Hydrocarbons and Acid gases flares are common in Oil and gas processing plants. Main flame extinguishment is encountered as major concern in these flares due to the inability to re-ignite the main flame through pilots. This can result in serious HSE concern by release of toxic (H2S) and hazardous hydrocarbon into environment, causing harm to people and surrounding. This paper presents the approach followed in flare system design which will enhance reliability of flare system for safe plant operation.

Main issues in flares such as main flame extinguishment, failure of pilot, damage and burn of pilot, failure of thermocouples and blockage of pilot gas lines / fire ball lines were studied. All past inspection reports were reviewed to identify failure mechanism. Further aerial survey report were also reviewed. As flare pilots are exposed to severe operating temperature and service conditions, detail metallurgical study was performed to understand high temperature sulphidation corrosion. As existing flare were with old design, new technologies were explored and gap in current flare design were identified.

Material review concluded that existing Inconel material will prematurely fail in high temperature acidic environment. Hence new pilot assembly and flare tip of SS310S material were installed. To further enhance service life, Pilots were ceramic coated and thickness of pilot /FFG pipe were increased. Wind proof pilot design with weather hood and integral thermowell in single cast assembly were used to minimize welding. This approach avoided weld failures in the Pilot which have been observed earlier. Flare tip are provided with wind shields to minimize impact due to flame impingement which damages the Pilot Assembly. Instead of existing single ignition and monitoring system, Dual Ignition through High Energy ignition and FFG & dual monitoring System using ionization rod and thermocouple are provided to ensure availability in the event of a primary system failure.

Above new design improvements were successfully implemented in two of the existing flares. Continuous monitoring of the improvements confirmed reliable performance with no flare system failure in past 1.5 years. This will reduce cost by almost 50% due to decreased maintenance and increased life span. Further, it will optimize shutdowns and increase major maintenance cycles from 2 to 5 years.

Conventional approach of like to like replacement of flare system in case of failure do not address the issue and can affect people, plant and environment. However, implementation of the design improvements based on above approach will not only ensure reliable and safe plant operation but also reduce maintenance cost.
Journey of Developing the Transition Zone for a Giant Carbonate Reservoir from Subsurface Modeling to Execution – Case Study
Authors: Gazar Ashraf Lotfy , Alklih Mohamad Yousef , Al-Shabibi Tariq Ali , Latief Agus Izudin , Fauzi Tengku Mohd , Syofyan Syofvas , Hashimura Tadashi
Published: November 2017

This work presents a case study of developing the transition zone for a giant oil reservoir with significant gas cap and water aquifer, in Abu Dhabi-UAE, addressing geological and dynamic aspects, field development approach and present status. The reservoir lies within a relatively low relief heterogeneous carbonate structural trap and characterized by lateral and vertical variations in reservoir rock and fluid properties. Given the relatively low permeability of the mentioned reservoir, the transition zone contains a significant STOIIP; which called for this challenging development.

A number of parameters were addressed and optimized as part of the transition zone development plan. The dynamic modeling suggests that a full field ultimate recovery of 70% can be achieved by developing the transition zone. However, considering the complexity of the reservoir, thickness of the transition zone and current market conditions, the field development would be economically viable for a period of 50 years under miscible hydrocarbon WAG, provided the most effective development strategy in terms of the definition of transition zone, optimization of the number, location, orientation and horizontal reach of the proposed wells. Various development strategies for the transition zone were investigated during the study considering all possible uncertainties and economic drivers, all of which are discussed in details in this paper.

12 years of early production scheme (EPS, 1993 to 2005) and 12 years of phase-I development helped better understand the reservoir and characterize the transition zone. Total of +150 wells penetrated the reservoir with good data gathering (ROS, Core, SCAL, PVT, MDTs…etc.). PVT studies indicate a wide range of compositional variation areal and vertical, which further complicates the development plan considering the surrounding sensitive environment.

The transition zone is defined by rock types and the corresponding critical saturation. The amount of recoverable oil in the transition zone is depending on the distribution of oil saturation as a function of depth and the relationship between initial and residual oil saturation in the transition zone.

The reservoir is under EOR (Miscible HC GI at crest and WAG at flank) since commissioning of phase-I in 2005 and tracers were injected in 2012; adding challenges to the history matching and tracking of the flood front. Given the limitation on surface handling capacity of the current facilities, the transition zone development called for well placement in the upper part of the transition zone using 6 months WAG cycles. The first well of the transition zone development has been drilled; which has positively validated the definition of the transition zone, built confidence on the subsurface modeling approach and commended the planning strategy.
Comparison of Erosion Resistance of Iron Carbonate Protective Layer with Calcium Carbonate Particles Versus Sand
Authors: Nassef Anass S. , Banazadeh-Neishabouri Nafiseh , Keller Michael W. , Roberts Kenneth P. , Rybicki Edmund F. , Iski Erin V. , Shirazi Siamack A.
Published: November 2017

In oil and gas production, solid particles can be entrained in the produced fluid. While sand is widely considered as the most common source of solid particles, calcium carbonate particles can also be entrained in the flow, especially in carbonate formations. These entrained solid particlescan erode steel pipe surfaces and protective corrosion products, such as iron carbonate (FeCO3) scale that forms on the steel surface as a result ofthe CO2 corrosion process. The removal of protective layers can lead to high corrosion rates. Extensive research has previously been conducted to study the effect of sand erosion on removing protective iron carbonate scales. However, little is known about the erosion resistance of iron carbonate scale for calcium carbonate particles. The goal of the research presented in this paper is to study the erosion resistance of iron carbonate scale when eroded by calcium carbonate particles, and compare this erosion behavior with scale eroded by sand. Additionally, this research reports data and modeling that describe under what conditions removal of iron carbonate scale and the resulting erosion-corrosion are anticipated by solid particles such as sand or calcium carbonate.

Results, for the conditions considered in this study, show that CaCO3 particles can cause considerable damage to iron carbonate scale leading to severe corrosion. For these conditions, sand was found to be more erosive than CaCO3 particles. Results from the erosion model developed in this study showed good agreement with current and previous experimental data.
First Successful Application of Ceramic Sand Screen in Maturing Oil Field, Offshore East Malaysia
Authors: Sidek Sulaiman , Hui Lian Kellen Goh , Ching Yap Bee , Trjangganung Kukuh , Madon Bahrom , Yusop Zainuddin , Gundemoni Bhargava Ram , Jackson Richard , Barth Peter
Published: November 2017

This paper will present the first successful application of ceramic sand screen in Malaysia. Oil production from the field has a long history beginning with the first production in 1972. A great number of sand control methods have been tested and applied in the field. Production history has showed instances of sand production contributed by factors such as in-situ stress changes, increase in water production and cascading effect from production operation activities.

A few wells completed with primary sand control equipment have failed and remedial action by metallic through tubing sand screen experiencing rapid wear, forcing the operator to control sand production by beaning down the wells and closely monitoring sand production at surface overtime. Worse still, some of the wells had to be closed-in. Hence ceramic sand screen was considered as remedial sand control due to its superior durability and resistance compared to metallic sand screen.

This paper incorporates sand retention tests conducted using actual core samples to customize the slot opening/size, impact test conducted using actual ceramic sand screen assemblies in a training well to look closely at the installation mode and tool assemblies, newly-developedinstallationand well unloading procedure as guidance for offshore personnel and actual field result of the wells installed with the ceramic sand screen.

Through tubing remedial sand control using ceramic sand screen has successfully revived the idle wells back to production at a lower total cost, oil gain beyond the initial target and higher Return OfInvestment (ROI). It has proven to be a great new technique which enables the effective sand control in highly erosive environment and would openup bigger opportunities to unleash locked-in potential of wells with sand production problem throughout PETRONAS’ operation.
Value of LEAN Mentality with Trailer Mounted Well Test Unit in the Sultanate of Oman
Authors: Castiblanco Rafael
Published: November 2017

LEAN originated with Toyota in Japan as a means of driving efficiency across the value chain by making often small-scale changes and has since been further refined into a system used by businesses across the world aiming to do more for less. PDO first piloted the LEAN approach in 2009 and has since rolled it out across all aspects of the business, streamlining work procedures, reducing bureaucracy, eradicating inefficiency, avoiding duplication of activities and eliminating waste.

To facilitate the adoption of the LEAN culture, PDO developed a training program for the workforce. Relevant training courses such as LEAN Basics, LEAN Manager and LEAN Practitioner were launched. Most of the company received LEAN Basics training. Managers attended the LEAN Manager course, while selected candidates that had an identified high value LEAN project that could be implemented, attended the LEAN Practitioner course.

The training courses reached all levels of the company facilitating implementation of the LEAN projects, but most importantly, the upskill of the workforce empowered them to actively look for ideas on how to work in a LEAN way. In addition to the main LEAN projects that required a certified LEAN practitioner for implementation, PDO encouraged people to come forward with LEAN ideas through a Continuous Improvement platform. Some of the Continuous Improvement ideas could be very easily implemented by the same people that came up with the idea while others would require involvement from higher management for implementation.

The Continuous Improvement ideas are tracked by department. The cost saving and/or time liberation of each idea is recorded and monitored monthly, which has helped make it visible to all levels of the organization how everyone can contribute in a very critical time of the Oil and Gas industry.

This paper describes the step change in operating costs for Well Testing Operations by adoption of the LEAN way of thinking in the Well Engineering department of PDO in the Sultanate of Oman.