bluuebunny/crossref_metadata_2025_split huggingface dataset:
Value of PSDM Processing on Low Relief Structure in East Onshore Abu Dhabi
Authors: Ghafri Thuraya Al , Seo Youngtak , Liu Jinhui , Kim Dong-Oh , Aijing Ren , Belaid Kamel , Mingqiu Zhao , Wenrui Jia 
Published: November 2018

Abstract
The Arabian Gulf is prolific of low relief geological structures, however, their definition and imaging present in general a genuine challenge. It is also commonly understood that low relief structures won't benefit from Pre-Stack Depth Migration (PSDM) whereas, Pre-Stack Time Migration (PSTM) is the ultimate required process. Thus, PSTM is frequently applied for the imaging of these low relief structures.
Nonetheless, our recent 3D PSDM processing work has demonstrated that this perception is not all the time correct and has proved that PSDM can indeed add significant value to low relief structures.
An Anisotropic PSDM (APSDM) workflow was carefully designed and meticulously applied on a very low relief structure located onshore Abu Dhabi –UAE.
The main objectives of this 3D Anisotropic PSDM processing were established as follows: Achieve an accurate & clearer depth structure image with higher resolution.Mitigate & address the observed depth uncertainties at the existing wells.Enhance the faults architecture & imaging.Analyze anisotropic velocity & build a reliable velocity model for depth imaging.Interpret azimuth volumes in depth & time domains.
The designed processing workflow consisted of the following main five stages: Gathers pre-conditioning and residual noise attenuation adopting the principle of amplitude preservation.Velocity building & updating using available well data, interpreted horizons and applying VTI full azimuth and multi azimuth velocity tomography processes.Depth imaging using Kirchhoff PSDM in OVT (Offset Vector Tile) domain.Post migration processing for residual inter-bed multiples & noise attenuation in addition to azimuthal anisotropy analysis and final depth-tie examination.Post stack processing for acquisition foot print removal and signal to noise ratio (S/N) enhancement.
It should be noted that the selection of the optimum processing parameters at all the processing steps was done after the implementation of an intensive testing & rigorous QC/QA procedures.
The main results and findings revealed by the 3D Anisotropic PSDM processing and the subsequent 3D seismic data interpretation are summarized as follows: PSDM shows less depth uncertainty compared to PSTM at existing wells. However, based on the results of recent drilling activities which have been conducted after PSDM, depth uncertainty at new well locations still exists.Reliable velocity model was built for depth imaging. This was established after 12 tomography iterations carried out for the isotropic velocity model and four iterations of anisotropy updates and VTI azimuthal velocity tomography.Some low relief structures are better defined in PSDM than PSTM.Seismic continuity of some target levels has been improved.Seismic resolution is degraded due to the limited frequency content.Fault imaging has been improved at some locations.
Selected Results from Big Carbonate Pore System Database: A Case Study from Saudi Aramco
Authors: Serag El Din Samy , Clerke Edward , Badawi Ahmad 
Published: November 2018

Abstract
Carbonate reservoir complexities are both described and hidden by the use of the common and generic term, "heterogeneous", with usually little serious effort then expended to define and quantify the meaning and dimensions of the term. Saudi Aramco, the custodian of the world’s largest petroleum reserves in carbonate reservoirs, is making long-term efforts to bring light to the carbonate "heterogeneity" darkness. We are constructing the industry’s largest integrated petrophysical and geological databases for our major carbonate reservoirs.
Our large databases contain porosity, permeability, grain density and pore system information from core plugs carefully integrated with a full suite of well log data and core descriptions. These cores have been described in detail using the most current carbonate sequence stratigraphic techniques and all these data have been captured digitally and integrated consistently and carefully. Our database for one field contains 1695 limestone pore systems (a pore system is defined by a single Thomeer hyperbola), obtained from 931 plug samples by Thomeer analysis of core plug mercury capillary pressure data (MICP) with plans to expand the measurements to 1500 plug samples for just this one major reservoir by the year 2020. The current core plugs for the database now include samples from 30 cored wells (up from the 10 cored wells of the previous Rosetta Stone project) to obtain statistically robust reservoir petrophysical data at the facies level. Pore system data are now also being acquired in vertical wells for constrained reservoir layering and vertical reservoir model tie points using nuclear magnetic resonance (NMR) well log data and the CIPHER software for the Thomeer parameter MICP-consistent spectral porosity analysis.
At Saudi Aramco, our extensive facies – petrophysical properties database process delivers the reference reservoir property database for our major carbonate reservoir models. The reference database improves our understanding and modelling of the variation and covariation of the facies and petrophysical rock types (PRTs) for reservoir modeling. It also provides sound statistical support for the population of the reservoir with petrophysical pore system properties within the sequence stratigraphic facies framework. For the reservoir dynamics, the database allows detailed investigations into the statistical linkages of pore system properties which control permeability and relative permeability developed by Clerke and coworkers to the sequence stratigraphic reservoir facies.
We report here selected results from a very large quantity of relationships and statistical attributes that can be derived from this database. At the general carbonates level, these reference databases demonstrate that the reservoir complexity hidden in the shadow of "heterogeneity" is actually the prevalence and statistical distribution of these multimodal pore systems and their attributes.
A Method to Obtain a Permeability - Constrained and Consistent Saturation Height Model
Authors: Hulea Iulian N. 
Published: November 2018

Abstract
The process of differentiating between rock volumes based on petrophysical properties and geological indicators is commonly referred to as rock typing. A rock type can be identified by a given porosity – permeability (k-Phi) transform and Saturation Height Model (SHM) in petrophysical space. Rock typing is a useful method by which geological interpretations are combined with petrophysical measurements and translated into physical space for use in subsurface modelling. Efforts here involve utilizing k-Phi transforms as an input to SHM, thereby streamlining the rock typing process and allowing for compatibility with existing rock typing workflows.
A fundamental part of building realistic subsurface models includes populating a geologic framework with petrophysical properties. From a petrophysical point of view, critical properties with significant impact on the modelling outcome (hydrocarbon volumes recoverable and producibility) are hydrocarbon saturation, permeability and relative permeability. Hydrocarbon saturation is an expression of the rock capillarity translated into a mathematical expression from capillary pressure measurements or well log saturations. Permeability is commonly predicted from porosity, via transform equations used to differentiate reservoir rocks of different quality.
Previous work has shown that permeability and SHM used for subsurface modelling are generally consistent. This implies that the number of input parameters to the SHM can be reduced, which can be done by integrating permeability and saturation data (from logs and core measurements). The number of parameters used in the predictive SHM is reduced from six to four. Here, we propose to constrain the entry pressure (responsible for hydrocarbon entry height) by using routine core analysis data. This approach aiming to look at the plug and log scale has significant benefits when a SHM is derived from well log saturation data or when a limited range in properties is sampled by capillary pressure measurements. The workflow allows the use of other permeability sources (like Drill Stem Test if representative of matrix) as starting point in the process of building a SHM via a simplified Brooks-Corey function. The function can be looked at as a hybrid between the Leverett's J and Brooks-Corey function with entry pressure dependency on the permeability to porosity ratio higher than for Leverett's J (0.7 vs 0.5). The result of linking k-Phi transforms to saturation height modelling allows for compatibility with multiple rock typing approaches that utilize different sorts of parameters to define k-Phi, including Lucia's classic rock fabric numbers, a useful benchmark.
Producing Heavy Oil – The Subsea Brownfield Challenge
Authors: Conde Joao , Banks Mark 
Published: November 2018

Abstract

Objectives
The key challenges concerning heavy oil are not associated with finding reserves, but in extracting, producing and transporting heavy crudes. This is even more challenging given the new normal lower oil price. In this presentation, a case study will be presented showing the successful implementation of highly technical modelling techniques in brownfield heavy oil field developments (UKCS).
Infinity's flow assurance and process engineers have been involved in almost all of the heavy oil developments in the UK continental shelf. - Mariner (12-14°API) and Bressay (11°API), Kraken (14°API), Bentley (10-12°API) and Corona (16°API) are some of the examples worth noting.

Methods and Procedures
In the last couple of years the Production Assurance team at infinity have been responsible for the pre-FEED and FEED stages of one of the most important heavy oil fields in the UKCS. Infinity have provided engineering support to several major E&P companies for their heavy oil developments. This paper focusses on the unusual rheological properties, variable Flow Assurance characteristics during production and the most recent modelling approaches to study the behaviour of these challenging fluids. These projects are particularly interesting as they combine the challenge of both heavy oil and brownfield developments.

Results/Novel Information
Key issues for design of heavy oil fields and development of a safe/optimum operating philosophy are addressed and will be shared in this presentation such as:Modelling non-Newtonian fluids with very high viscosities (impact on line sizing);Oil/water dispersion and formation of a stable emulsion;Selection of an artificial lift option and their respective impacts on the behaviour of the system (focus on HSP technology);Operational issues including relatively high restart pressures following an unplanned shutdown (gel formation).
The key challenges with modelling heavy oil were developed and a novel approach to simulation and data benchmarking was developed in order to solve the classic heavy oil modelling issues. As an example, the relationship between shear rate and shear stress in difficult fluids that deviate from the classic Newtonian behaviour demands a very close relationship between the flow assurance engineers modelling the system and the fluid lab experiments required to benchmark the models.
Comprehensive Workflow of Matrix Acidizing Design and Analysis in Multi-Layer / Multi-Zone Reservoir - Offshore Case History
Authors: Zareiforoush Ali , Safari Alireza , Momeni Ali 
Published: November 2018

Abstract
In this paper we present details of the approach utilized to optimize the well stimulation campaign in the continued development of a huge carbonate gas condensate field in the Offshore Iran. This study discusses what have been done differently, best practices, and learning. What is different in this campaign from previous ones?
Detailed design ✓ Detailed well-by-well review ✓ Fundamental data collection for parameters analysis - operational, subsurface, treating fluid data ✓ Data management system allowing for quick access ✓ Design tool for detailed damage diagnosis, fluid system selection, pumping schedule design, and pressure matches. ✓ QA/QC and compatibility tests aiming to obtain high success rate. Challenges ✓ High contrasts in porosity, permeability and initial pressure ✓ Complex mineralogical & lithology composition ✓ Fissures and Vuggy porosity ✓ Long perforated intervals and well inclination effects ✓ Pre-acid nearwellbore reservoir initial condition ✓ High rate and ΔT effects on completion & cement integrity Objectives ✓ Optimum zonal coverage ✓ Keep completion integrity while high rate injection ✓ Use minimum volume of chemicals ✓ Reduce operation risks & costs
Optimum acid placement in bullheading treatment in commingled mode is still the challenging issue in in Iran well stimulation jobs. We propose a comprehensive step-by-step workflow to get the best results using Nodal Analysis & Stimulation Software in a logical way described later in the text. Diversion techniques history in this field is: Mechanical diversion, Ball sealers, Selective perforation with polymer based diverter, Selective perforation with high injection rate and VDA technique. Our new diversion method that deployed along with a revised placement model, field calibrated to more accurately predict treatment pressure responses, to optimize acidizing design and to maximize diversion in this layered reservoir, studied in this paper.
Results presented include stimulation treatment plots alongside model post treatment pressure matches, pre and post stimulation production logs, clean up data and well test interpretations to validate the models. We describe high/low permeability, multi zone treatments with a bullheaded matrix acidizing technique. We observed in one well through tubing treatment pressures response and oscillate between 2000 and 3500 psi, far above what is typically observed in this field in which the pressure reduction happened quickly from 3000 to 1000-500 psi.
We conclude that due to enhanced diversion results in uniform zonal depletion which is due to uniform zonal acid coverage. We have also found operational benefits in deploying the system in that commingled zones, normally perforated and stimulated in several stages can now be easily and effectively stimulated using a one-stage technique.
Project Specific AUT Automatic Ultrasonic Testing Validation to Determine Height Sizing Accuracy for Pipeline Girth Weld ECA Acceptance Criteria.
Authors: Putsherry Dinesh , Misra Durgamadhaba 
Published: November 2018

Abstract
Objective of project specific AUT (Automated Ultrasonic Testing using Zonal Discrimination) Procedure validation is to verify that the implementation of pre-qualified AUT system performance for the inspection of project specific Pipeline girth welds without changing any essential parameter of system qualification processes.
As per the requirement of DNV-OS-F101, the purpose of the project specific AUT validation is not to perform any new PoD (Probability of detection) analysis. However, to verify the reliability aspects of the system in terms of HSA (height sizing accuracy) to meet the AUT system qualification requirement is to ascertain the project specific AUT procedure adequately capable of detecting and sizing of the smallest critical defects. This is achieved through a detailed validation programme using the project specific welding procedure and pipe material representing actual pipelay scenario.
Modern Approach for Determination of Natural Gas Composition and Heating Value at Custody Transfer
Authors: Veerakumar Ukkirapandian , Lallan Sanjay Singh , Bahumaish Zeyad , Abbas Ahmad 
Published: November 2018

Abstract

Objective and scope
Determination of composition of natural gas and its gross heating value (GHV) at the custody transfer is important for the seller and buyer to calculate the energy content transferred in million BTU (MMBTU). The objective is to develop right analytical technique and equipment to ensure collecting representative sample at high pressure and accurate determination of its composition and gross heating value.

Method and procedure
The low pressure gases at different pressure are compressed and dehydrated to remove moisture. The liquid condensate is dehydrated in a stripper and its pressure is boosted to 150 bar and mixed with dry gas. A special flow and temperature controlled vaporizer is used and spot samples are collected in high pressure cylinders for gas and piston cylinders for liquid. GC with thermal conductivity detector (TCD) and flame ionization detector (FID) with automated gas conditioning unit are used for determination of gas composition. TCD detects the permanent gases and hydrocarbons from C1 to C5 and the FID detects C6 and break down compounds up to C14 including heavier aromatics. Their concentration is derived based on their response factors and bridge calculation using i-pentane in FID. As the gas is sour containing high H2S, special safety precautions are taken with appropriate personal protection.

Results, discussion and conclusions
The gas composition analysis was performed as per GPA 2286 using a gas chromatograph. The low pressure gas contained 35 - 45 mol % of methane while the high pressure gas had 80 – 85 mol % methane. Ethane, propane, butanes and hydrocarbons up to C14 were present. H2S and CO2 were present up to 6.0 mol%. The GHV was calculated from the gas composition and the energy content of the gas was derived from the flow rate and GHV. The laboratory data was compared with online analyzer and corrective actions were taken in case of any abnormality. The designing a special vaporizer and a customized gas chromatograph helped us to determine the export gas composition and its energy content accurately. The trend and variation of gas quality are correlated with feed gas supply and helped for adjusting process conditions to achieve operational excellence.

Novel/Additive Information
The measurement of gas composition and its energy is important for the seller and buyer. Any difference in the gas quality will have direct cost implications in the sale and it is important to standardize the sampling and analysis techniques to be best accuracy possible.
ASP Journey, from Pilot to Full Field Implementation in South of the Sultanate of Oman
Authors: Alkindi Abdullah , Mahrouqi Dawoud , Baqlani Safa , Llaguno Inaki , Mjeni Rifaat , Mahrooqi Majid , Nadeem Muhammed 
Published: November 2018

Abstract
The Marmul inverted five-spot pilot was successfully completed in 2016, demonstrating the effectiveness of Alkaline Surfactant Polymer (ASP) flooding in improving oil recovery from Al khalata reservoir. Earlier studies including core flood experiments, single well chemical tracer tests and small scale models indicated a potential of &gt;10% of ASP incremental recovery over polymer flood and &gt;20% over water flood. The pilot included a custom-built ASP facility, a first of its kind of scale squeeze treatment for high pH, state-of-the-art nuclear magnetic resonance (NMR) technology for vertical saturation estimates and very extensive sampling and surveillance programme. Overall, the pilot operation was very smooth and stable, achieving high facility uptime, good injectivity, accurate chemical dosing and met the surveillance target.
The estimated ASP incremental recovery from the pilot was over 30%, which increased the interest in a field-wide ASP injection. The acquired pilot results and operation experience were used to scale up the facilities design and assess the impact of key uncertainties observed in the field and the lab. Major factors influencing the recovery factor and project efficiency were analysed including chemicals formulation, facilities design and water treatment technologies. A mind-shift on the formulation cocktail and facilities design was proposed to improve the economic attractiveness of the process on large scale implementations. A phased development is proposed to de-risk subsurface and surface concepts which are different from those in the pilot.
This paper discusses in brief the pilot operation & performance, scaling up the results to full field implementation and key design considerations for a cost effective ASP project.
Management of Change: A Journey towards Simplifying the MOC Process in ADNOC Onshore
Authors: Al Harbi Mosleh , Viswanathan Rajesh , Al Shamsi Marwan 
Published: November 2018

Abstract
Management of Change is a standardized process to manage change and ensure that risks to the integrity of assets are within an acceptable level. This is applicable for all temporary and permanent changes, technology, facilities, equipment, operations and organizational arrangements. This will ensure that risks are As Low As reasonably Practical (ALARP). During the Operation phase of the facilities, a robust management of change process could prevent Major industrial accidents. (Lessons learnt from incidents like Flixborough).
This paper will detail the journey over a decade in ADNOC Onshore where the MOC process has evolved from a paper based system to an auditable electronic application.
The MOC process in ADNOC Onshore has evolved as a mature electronic application meeting all the minimum requirements as per the standard and ensuring that the risks arising out of the changes are managed within ALARP.
Management of change is governed by corporate integrity standard (CIS-17) and the process was rolled out as an electronic application in 2012.Till 2015 the number of backlogs in the MOC application grew to 800+. The major reasons for the bottlenecks were identified as complex approval cycle, business process, deliverables were not clear, controls were not enforced by the system and performance monitoring was poor. The application had multiple modules and the records were getting stuck leading to delay in approvals. Some of the key stakeholders were missing in the workflow.(e.g. MOC Forum, Technical authority)
MOC Enhancement program was developed to focus on four main pillars. (Developing new business Process, Reducing Backlogs, Develop new application and Roll out of the new process). The new business process was approved by all stakeholders and issued for implementation by the CEO. Backlogs were reduced after screening workshops with all stakeholders from 800+ to 121 cases. New Application was developed as per the revised business process embedding controls and ensuring the deliverables at each stage are met. The new application was rolled out successfully in July 2017 and this was followed up with series of awareness workshops and training all facilities.