bluuebunny/crossref_metadata_2025 huggingface dataset:
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

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

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

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

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

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

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

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

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

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

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.
Near Sea Bed Characterization Study Using Scholte Wave Data Offshore Abu Dhabi -UAE
Authors: Matarid Tarek , Belaid Kamel , Ishiyama Tomohide , Lehman Christoph , Al Riyami Ahmed , Seddik Sameh , Bhowmick Arunava , Al-Jarwan Ali R. , Strobbia Claudio , Laake Andreas , Anastasia M , Morrison Dave
Published: November 2012

In conventional seismic data processing Scholte and Guided Wave data are commonly considered as noise and therefore, are removed at an early stage of any seismic data processing sequence. This paper describes an innovative approach in characterizing near sea bed via surface wave inversion using Scholte wave data.

2-D & 3-D OBC seismic data sets were selected and reprocessed as a test focusing on shallow near surface data. The ultimate objective of this work was to attempt to locate the closest area to borrow the necessary volume of sediments / sand for the construction of artificial Islands (2) which are required for the development of an offshore oil field. In addition to the primary geotechnical objective, the test aimed to validate the potential of surface wave inversion using OBC data in shallow water.

The near surface characterization revealed a complex geology with velocity inversions and the results were incorporated to optimize the geothechnical survey program since it was able to differentiate a relatively low velocity anomaly area which could be related to soft sediments from hard rocky surface having a higher shear velocity.
Vital Role of Nanomaterials in Drilling Fluid and Reservoir Protection Applications
Authors: Long Li , Xianguang Xu , Jinsheng Sun , Xubo Yuan , Yingmin Li
Published: November 2012

Nanotechnology has already contributed significantly to technological advances in the energy industries. Nanotechnology has the potential to introduce revolutionary change in drilling industry. Nanotechnology produces nanomaterials with many attractive properties, which can play an important role in intensifying mud cake quality, reducing friction, eliminating differential pipe sticking, maintaining borehole stability, protecting reservoir, and enhancing oil and gas recovery.

Recent research has indicated that nanomaterials have special characteristics for a broad range of applications in the fields of drilling fluids and reservoir protection, where fluid loss control, borehole stability, hole cleaning, torque and drag reduction, lost circulation control, and reservoir protection are of interest.

This paper presents an extensive literature review of assessing the applications of nanomaterials in drilling fluids and reservoir protection, and evaluates the potential technical benefits that these nanomaterials might provide to petroleum development and production.
3D OBC Seismic Data Acquisition Productivity Enhancement
Authors: Nakayama Shotaro , Belaid Kamel , Ishiyama Tomohide
Published: November 2012

Ocean Bottom Cable (OBC) seismic survey has several technical advantages over conventional towed streamer technique. However, its usage is still limited as requirement of relatively large operational efforts likely results in more survey cost and duration. Moreover, OBC seismic operations could affect other field activities and multi-vessel operations required for OBC survey and longer survey duration potentially increase HSE risks in fields.

Consequently, enhancement and optimization of OBC survey productivity is essential particularly in specific situations such as shallow water, congested producing oil/ gas fields (e.g. Offshore Abu Dhabi) and in environmentally restricted areas.

Although several studies have been carried out to establish key parameters, designs and geometries for high OBC survey productivity, the current developments in the seismic industry technology and equipment are enabling to establish a variety of survey designs and geometries which were not feasible previously. Therefore, our study was conducted with the aim to analyze the impact of OBC Survey Designs / Geometries on productivity considering the current available equipment and technology and meeting the established geophysical survey objectives.

Applications of dual source operations were also discussed by using two cases: (1) Distanced Separated Simultaneous Shooting (DS3); and (2) Dual Source Vessel Flip-Flop Shooting (DSVFFS). Dual source operations for both marine streamer and land cases have been well described whereas few examples of its applicability to OBC survey have been presented. In this paper, we described the impact of dual source operations on OBC survey efficiency and technical challenges determined from the relationship between OBC Survey Geometries/Designs and interference noise wave fields which have to be considered as more complex scenario than other types of surveys.

We believe that the established new approach will assist to acquire future OBC survey with high productivity and in a very cost effective manner.
Tengiz Field Surveillance: Planning Strategy and Implementation
Authors: Tursinbayeva Damira , Lindsell Karl , Zalan Tom , Dunger Darrin , Kassenov Baurzhan , Howery Randy
Published: November 2012

Over the field life, surveillance in Tengiz oil field has provided historical and baseline data for simulation history matching, static and dynamic reservoir characterization and modeling, and the foundation for efficient well management. Hence, it continues to be an important part of everyday field operations. At the surveillance planning stage, the comprehensive opportunity list of well candidates is developed based on input provided by members of multiple teams: geologists and petrophysists, production and reservoir engineers, drilling and field operations specialists. SCADA system, permanent downhole gauges (PDHGs) and multiphase flow meters (MPFMs) are widely implemented for production data acquisition and analysis. However, the majority of surveillance activities still need well intervention into the high pressure, high H2S concentration wellbores, often during harsh weather conditions. Each job execution plan is therefore focused on the safest procedure to obtain the necessary data. Each planned survey in the surveillance plan is ranked according to the value of information to be obtained, in order to help schedule the timing of surveillance based on plant production needs.

The ultimate goal is to safely execute planned surveillance to support production optimization and field development work. This paper will highlight TCO success in addressing the different reservoir and well production uncertainties through a properly designed surveillance plan with both short and long-term objectives.
Experiments and Simulation of the Near-Wellbore Dynamics and Displacement Efficiencies of Polymer Injection, Matzen Field, Austria
Authors: Gumpenberger Thomas , Deckers Marie , Kornberger Martin , Clemens Torsten
Published: November 2012

High molecular weight partially hydrolyzed polyacrylamides (HPAM), have been shown to effectively increase oil recovery of medium viscous and heavy oil.

Using a rheometer, these polymers show shear thinning behavior. However, determining the apparent viscosity from coreflood tests for different frontal velocities, an increase in the apparent viscosity is observed. This apparent increase is attributed to the visco-elastic properties of the polymers.

In this paper, a set of laboratory experiments has been performed for cores similar to the rock in the 8th Torton Horizon (8 TH) of the Matzen Field in Austria. The results show that for the conditions in the near-wellbore region of the reservoir, an increase in apparent viscosity is expected. In addition, the relationship of velocity versus apparent viscosity for pre-sheared polymers was investigated. Dependent on the amount of pre-shearing, the apparent viscosity was significantly decreased. For different polymer concentrations, the apparent viscosity versus velocity of the pre-sheared polymers was almost identical.

A polymer injection pilot performed in the 8 TH in the Matzen Field in Austria confirmed that shearing of the polymer solution in the near-wellbore occurs for injection below the fracturing pressure. Above the fracturing pressure, the flow velocities are significantly decreased owing to the large surface area of the fracture. Hence, polymer injection should be performed above the fracturing pressure to improve sweep efficiency.
Major Accident Prevention and Lessons Learned in Oil & Gas: Four Guidelines and Thirteen Best Practices for Governing Safe Supply Chains
Authors: Jacoby David S.
Published: November 2012

Poor supply chain management can set the conditions for failures of catastrophic proportions, both economically and in terms of safety. It has been the root cause of several of the largest disasters in oil and gas history. Many professionals fail to recognize important gaps due to the complexity of the web of supply relationships and the number of critical interfaces that can be misaligned. Professionals from executive offices, HSE, procurement, logistics, operations, and risk management need to take four major steps to ensure a safe supply chain: 1) Establish governance & organization to ensure organizational accountability for governance and management of supply chain risk, by appointing a supply chain czar and engaging crossfunctional stakeholders; 2) Adopt an internationally accepted top-level supply chain risk management framework and articulate first-level principles, including a policy on single sourcing; 3) Universally adopt formal "reinforcing" metrics and measurement systems, including measurement of supply chain risk, Total Cost methodologies, and quantification of the cost of supplier non-compliance; and 4) Extend supply chain strategy and policies to suppliers by scanning for suppliers that excel in HSE, setting supplier expectations and targets, training suppliers, and establishing mechanisms to hold them accountable including periodic audits.
Reservoir Characterization and Modeling of a Carbonate Reservoir - Case Study
Authors: Tariq Mohamed , Bizarro Paulo , Sousa Ana de , Ribeiro Maria T.
Published: November 2012

This paper describes the work undertaken to build a 3D static model of a Lower Cretaceous Carbonate Reservoir located in Kazakhstan called X-Field. This reservoir has been pervasively dolomitized, and presents several challenges for development optimization. This model will be used to support further appraisal and development activities, in order to tackle key uncertainties, such as reservoir quality distribution.

All of the available data were quality controlled, analyzed and interpreted (including data from logs and cores), to produce porosity, permeability and RRT (reservoir rock type) models. These are believed to be representative of the reservoir's behavior and connectivity.

In order to identify the main flow zones and understand the reservoir's complexity, Reservoir Rock Typing (RRT) was performed on two cored wells by analyzing CCAL and SCAL data, including thin sections, MICP measurements, porosity and permeability. A comprehensive RRT methodology using Winland R35 method and poro-perm plot was followed, which resulted in defining five rock types. The outcome from the RRT study was confirmed by poro-perm plot, which showed the presence of five flow units.

The 3D model was built by using corner point grids (CPG), and contains a total of 2,380,050 cells. Several models of porosity and RRT were generated, representing "low", "mid", and "high" case scenarios of reservoir quality distribution. Finally, permeability models were created for each scenario, conditioned to their respective Winland R35 porosity-permeability relationships per RRT.

Comparison between the different porosity (Φ), permeability (k), and RRT models and scenarios, will allow a better management of the reservoir uncertainties during the appraisal and development stages for this reservoir.
Multistage Transverse Fracturing of Horizontal Well: A New Integrated Model to Develop Tight Gas Sands
Authors: Yu Haiqing , Rahman M. M.
Published: November 2012

As the demand for gas increases worldwide, tight and deep unconventional gas sands are becoming the target for development. Continuous progress in hydraulic fracturing technology has resulted in multistage transverse fracturing of horizontal well in tight gas sands. However, for such reservoirs the conventional approach of simply fracturing the formation to stimulate the horizontal well is inadequate. This is because most currently available commercial software lack proper optimization tools in them and they do not take into consideration several key parameters and realistic constraints. Even the systematic design methods for fracture treatment parameters with constraints are not well presented in the literature. Although larger the number of transverse fractures higher the productivity, there are optimal number of fractures and optimum treatment parameters when real field constraints and economic aspects are considered. A new integrated but constrained model to optimize multistage transverse fractures has been developed to maximize gas production and net present value with minimum treatment cost. Model couples both the industry experience and unified fracturing design parameters based on hydraulic fracture mechanics. Unified fracturing design defines the optimal compromise between the fracture width and fracture length for a given mass of proppant. Model integrates unified fracture geometry, reservoir in-situ parameters, treatment parameters controllable at every stage, realistic design constraints, and production and economic modules. The integrated model has been successfully applied to a hypothetical deeper and tight gas sands to demonstrate its merits. A simple and accurate analytical approach has been used for evaluating and optimizing the productivity. This model could also be used to study the potential of the deep UAE offshore tight gas sands, which is yet to be developed.
ADCO's Assets Integrity Requirements during Projects Execution
Authors: Daoud Mohamed , Mohamed Alaa , Drahib Saleh , Badyab Ahmed
Published: November 2012

ADCO integrity policy calls for ensuring that the new assets are designed to fit the intended services, engineered and constructed in accordance with approved company specifications.

The execution strategy of the Asset Integrity Management System (AIMS) requirements is based on progressive implementation starting as early as initiation phase of the project.

ADCO integrity requirements are in line with the requirements of Shell DEP standards that taken as the technical basis for Front end Engineering Design (FEED) and Engineering Procurement and Construction (EPC).

The main integrity services within EPC scope include assignment of asset coding, assessment / identification of the asset HSE & Business criticality, development and implementation of supply Quality Assurance/ Quality Control (QA/QC) philosophy document, establish and implement a project specific Management of change procedure.

Several AIMS reviews are in place and shall be conducted at definite mile stones of the project life cycle that guarantee the quality of the set specific Integrity deliverables.

The purpose of this paper is to share ADCO's experience during project execution, both in terms of technical and project quality/ integrity management issues.

The projects integrity practices implemented throughout the lifecycle of the project, starting with conceptual and preliminary engineering, through detailed engineering, procurement and construction are highlighted in the paper.
Stress Testing with a Wireline Tool using a Drilled Hole Sealed with a Compression Pad
Authors: Edwards John , Rodriguez Adrian , Judd Tobias , Kristensen Morten , Tevis Chris , Harrigan Edward , Al Rashdi Yaqoob , Hindriks Cornelius
Published: November 2012

A new method of stress testing with a wireline tool uses a drilled hole sealed with a compression pad to apply hydraulic pressure to the reservoir. Geomechanics modeling shows why this reduces the fracture initiation pressure and avoids intersecting the borehole with the induced fracture. The superposition of two induced stresses, mechanical and hydraulic, causes the tensile failure to initiate towards the end of the drilled hole as the hydraulic pressure is increased. The 9-mm-diameter hole is drilled from the center of the sealing compression pad to a depth of up to 15 cm. A fracture initiating some distance from the wellbore will be located part way through the near-wellbore perturbed stress field and will propagate away from the wellbore to the far field in the direction of reduced minimum stress. Reservoir simulation shows that the leakage rate of injected fluid around the compression pad is insignificant.

The first jobs using this technique are described, including procedures for passive tool orientation so that the drilled hole is aligned with the maximum horizontal stress. Information revealed about breakdown pressures in tight dolomite explained why drilling-induced fractures were affecting resistivity logs and well test interpretation. The current procedure for stress testing is the pumping of drilling mud between inflated packers. The new technique described here solves two problems associated with the inflated packer method. The pumped fluid volumes are much smaller, so clean fracture fluid from a sample chamber can be used instead of mud. And the system compressibility is reduced, so the pressure transients are more responsive to the formation.

The ability to induce a fracture in the formation with a pad tool using dedicated fluid with a low dead volume creates a new way of connecting to the reservoir, an alternative to connecting via the borehole wall surface. This large, undamaged contact area due to the induced fracture beyond the drilling-damaged zone will facilitate sampling low-permeability formations or high-viscosity oils.
Experimental Investigation of Oil Recovery by Different Injection Scenarios under Low Oil/Gas IFT and Mixed-Wet Condition: Water-Flood, Gas Injection, WAG and SWAG Injection
Authors: Sohrabi Mehran , Fatemi S. Mobeen
Published: November 2012

Water flooding and gas injection are two widely used improved oil recovery techniques that can be applied individually or combined as water alternating gas (WAG) or simultaneous gas and water (SWAG) injection. To do reservoir development planning, for possible implementation of these oil recovery schemes, reliable reservoir performance prediction is needed. Most of the existing reservoir simulators are unable to adequately account for all the complex multi-phase and multi-physics processes involved in these oil recovery techniques. That is particularly the case under mixed-wet and low gas-oil IFT (near-miscible) conditions. Performing reliable laboratory experiments is the key to evaluating the performance of these oil recovery techniques under reservoir conditions.

We present the results of a comprehensive series of well-controlled coreflood experiments carried out under mixed-wet condition using a very low IFT gas-oil system. The experiments include oil recovery by water flood (WF), continues gas injection (CGI), two series of WAG, and two series of SWAG injection tests. The difference between the two WAG experiments is the order in which gas and water injections are carried out. The first WAG test started with water injection whereas the second WAG experiment started with gas injection. The difference between the two SWAG experiments is the gas/water (SWAG) ratio, which was 0.25 for the first one and 1.0 for the second SWAG test.

The results show that in both mixed-wet cores, WAG injection has a superior performance over WF, CGI and SWAG injection. Oil recovery by the WAG test which had started with water injection was higher than the WAG test started with gas injection. SWAG performed better compare to CGI. However, surprisingly, SWAG resulted in lower oil recovery compared to primary waterflood in these mixed-wet systems. It was observed that increasing the gas/water ratio in SWAG leads to faster gas breakthrough, higher produced gas/oil ratio and further reduction in the recovery performance of SWAG. Compared to the other injection strategies, a very high pressure drop across the core was observed during SWAG injection indicating injectivity problems with the application of the process in mixed-wet rocks. The results show that for mixed-wet rocks, amongst the studied injection strategies, SWAG is the worst and alternating injection of water and gas (WAG), starting with a water flood period, is the best injection strategy.
Evaluation and Comparison of Innovative Environmental Monitoring Methods for the Offshore Oil and Gas Industry
Authors: Galgani François , Kampala Benjamin , Canovas Sophie , Cazes Laurent , Michel Cédric , Alboussière Marie-Charlotte
Published: November 2012

Monitoring data contributes to environmental risk and impact assessments, baseline studies and operational monitoring and is important to the environmental management of offshore Exploration & Production (E&P) activities. The quality of such studies may, in principle, be limited to the quality of data. In recent years, there have been several new methods in development which aim to supplement and/or replace conventionally used monitored data sources. These new methods have become available in a time of many key changes which affect the marine monitoring, such as increased regulatory and stakeholder expectations and activities occurring in more sensitive and remote areas.

In this study, an analysis of the concurrent application of five monitoring methods is presented on an E&P site where historical environmental data are available. Foraminiferal assessment, biomarkers, passive samplers and ecotoxicology were all compared to conventional benthos analysis. The objective was to evaluate the added value of new monitoring methods in advance of future validation in extreme environments such as arctic and deep seas.

Evaluation of the various methods was performed and presented with the advantages and limiting factors. Results show that non-conventional methods may provide advantages in terms of analytical abilities, cost effectiveness, spatial and temporal coverage and geographic applicability. Specifically, passive samplers report hydrocarbon concentrations at very low limits of detection and foraminiferal diversity was shown to provide historical information when baseline data is unavailable. These new monitoring methods offer improvements over conventional methods which have been in use for decades and may offer environmental managers rigorous and useful alternatives to conventional analysis.
Project Management Consultants Performance Enhancement Program
Authors: Al-Ghuraiba Muhammad M. , Al-Qahtani Mohammad
Published: November 2012

Over the years KOC has been working to enhance the Health, Safety, Quality and Project Management of their projects through initiatives in order the meet the company's strategic goals of 2030. The company has recognized that the Project Management Consultants (PMC's) are key players in the execution of KOC's strategic projects. Therefore an initiative was put in place to develop an incentive/disincentive program which included the PMC's. The PMC's performance is based on how well the contractor is being managed for KOC.

The primary objectives of the PMC Performance Enhancement Program are:

➢ Achieve improved PMC Performance ➢ Effectively manage the performance of the EPC Contractors for assigned projects within the approve schedule and budgets ➢ Encourage and reward the PMC's to achieve the set goals for the projects.

This has been successfully implemented on several projects where all aspects of the program were proven to be successful. This program has been embraced by all of the PMC's on contract with KOC. The program has been in place for over a year and is proving to be successful in helping KOC reach its strategic goals by the year 2030.
Asphaltene Precipitation Behavior during Gas Injection in a UAE Carbonate Reservoir and a Faster Experimental Strategy to Predict Asphaltene Onset Pressure
Authors: Zhou Yu , Sarma Hemanta K.
Published: November 2012

Asphaltene deposition is a major production constraint in several carbonate reservoirs in United Arab Emirates (UAE). The negative effects of asphaltene include plugging of reservoir formation, wellbore, tubing and surface production facilities and causing shutdown of certain wells. Many of these carbonate reservoirs are likely to be parts of a strategic EOR program through gas injection in the near term. However, as gas injection may further exacerbate the asphaltene problem, it is essential to investigate, as a priori, the effects of gas injection on asphaltene precipitation and deposition and this is the motivation for this study.

A critical analysis of the asphaltene problems to be faced in this particular field was carried out with both HC and CO2 gases as likely injectants under reservoir conditions. In doing so, different gas injection scenarios were studied. The results from experimental studies have been interpreted. The effects of gas injection ratio and depressurization speed on asphaltene onset pressure (AOP) have also been carefully studied. The strategy to adopt an equal-time-stepwise depressurization approach in this study yielded a more reliable result than conventional AOP detection method and also helped reduce the experimental time. In addition, asphaltene precipitation growth history and its nature as solids were studied with the aid of a high pressure microscope (HPM).

The asphaltene onset pressure is found to be affected by the way of system depressurization (frequency and time step magnitude) since it has a direct bearing on the stabilization time. Based on this study, a faster and more reliable method of AOP determination by using light scattering technique with near infrared range (NIR) light was proposed. The AOP of oil depends on the volume of injection for both HC and CO2 gases. It is noted that asphaltene deposition envelope enlargs with the increasing volume of injected gas.