bluuebunny/crossref_metadata_2025 huggingface dataset:
Interpreting CO2 Pilot Floods in Heterogeneous Carbonate Reservoirs
Authors: Al-Hammadi K. , Al-Yafei A. , Rawahi A. , Hafez H. H. , Ghori S. G. , Putney K. L. , Matthews T. R. , Stadler M. P.
Published: November 2012

A poorly designed and executed pilot may lead to incorrectly rejecting an appropriate EOR process or conversely implementing an unsuitable EOR process. This paper illustrates a systematic approach to selecting a suitable design concept for a miscible CO2 injection pilot for a large onshore oil reservoir in Abu Dhabi, UAE.

Selection of the design concept was based on evaluation criteria determined by the objectives of the pilot. The process incorporated pilot-specific and field-development-level considerations into the development of evaluation criteria, which were subsequently used to assess multiple pilot concept alternatives. An extensive simulation study evaluated dozens of potential well options, focusing specifically on the impact of multiple well types and orientations of wells (production and injection) on oil recovery. The process resulted in a pilot concept that is optimal in terms of net present oil recovery and minimization of CO2 migration that could result in misinterpretation of pilot results.
Protecting the Digital Oil Field from Emerging Cyber Threats
Authors: AL-Issa Ayman
Published: November 2012

Whilst best-in-class automation has been put place in industrial plants during the past few years, brought about by the developments in Industrial Control Systems (ICS), the industry has become vulnerable to new types of industrial risks. The Distributed Control Systems (DCS), Safety Instrumented Systems (SIS), Fire and Gas Systems (F&G), SCADA Systems, etc that were put in place are essentially computer systems and became the source of concern as these have become intentional targets to hackers, espionage and blackmailers. The cyber security threat to process control networks and systems was also increasing with successful industrial attacks taking place.

Integrated operations in exploration, drilling, processing, refining and almost all oil and gas process operations are using such systems. The Digital Oil Field (DOF) vision materialized as a result of the advances in the application of automation, remote control, real-time data acquisition, and the enablement of collaborative work environments. This vision essentially raised the need to integrate the process control systems with corporate business networks. This has led to the vital need to put in place a robust industrial cyber security infrastructure. This paper will discuss:

A first of its kind cyber defense infrastructure design for protecting the Digital Oil Fields and Critical Infrastructures from Cyber attacks. The importance of developing the integrated systems design concepts incorporating at its core the ICS Security by design. The value of engaging digital security specialists at the Front End Engineering Development (FEED) stage in Digital Oil Field projects.
Process Management Strategies for Performance Improvement of Intelligent Field Commissioning: South Ghawar Case Study
Authors: Ruvalcaba Velarde S. A. , Oubiña A.
Published: November 2012

The Intelligent Field in Saudi Aramco is gaining widespread applicability after successful implementation in its oil fields for real-time data acquisition. The historical field data collected on equipment status and project development enables to build a case study on process management strategies to improve the performance of Intelligent Fields surface facilities project execution and deployment.

The application of this study focuses on the analysis of the project commissioning stage of Intelligent Fields surface facilities and how business strategies can increase the efficiency of the process through the involved organizations. Project commissioning requires an integrative process and operational effort across internal organizations: facilities, projects, production and operations, as well as the involvement of external organizations such as equipment manufacturers, contractors and service providers.

The results present an integrative approach on process workflow optimization and performance measurement for project execution as well as gap analysis and root cause analysis for continuous improvement. Here, the asset team involvement is recognized as a central entity that brings together stakeholders to pursue improvement and measure implementation through strategic alignment with business goals.

The case study contribution resides in how to foster efficiency in the project execution of Intelligent Fields surface facilities through performance improvement strategies. Efficiency is driven by cross-organizational teams who mitigate the challenges throughout the commissioning and start-up stages.
Improving Sub Salt Wellbore Stability Predictions Using 3D Geomechanical Simulations
Authors: van der Zee Wouter , Taylor Jack , Brudy Martin
Published: November 2012

Some of the most active and high profile hydrocarbon plays currently being explored and developed around the world lie below a salt canopy. Drilling through a thick salt canopy has the potential to provide a faster route to reach a sub-salt objective rather than drilling through the overpressured sedimentary section in a supra-salt mini-basin. Unfortunately, numerous geological factors can complicate the drilling leading to expensive sidetracking or casing operations. Wellbore stability problems, such as unexpected low fracture gradient, are relatively common while drilling close and out of salt structures. Significant savings on drilling costs can be made if potential wellbore stability problems could be identified and avoided in the well planning process. In this paper we present a workflow to improve wellbore stability predictions for drilling through and near salt structures.

Common assumptions in wellbore stability studies on stress magnitude and orientation are not valid while drilling close to a salt body as salt structures create, due to their shape and rheological behavior, a perturbation of the stress field with strong spatial variation of the principal stress magnitudes and orientations. To provide realistic stress input data for wellbore stability predictions, the stress fields around salt structures are simulated using non-linear materials and realistic 3D geometries. The workflow presented in this paper provides an efficient way to create realistic 3D finite-element based geomechanical simulations from these complicated structural data.

The workflow allows for a detailed simulation of the stress field around salt bodies that is new to the hydrocarbon industry and helps to significantly reduce the risk for wellbore failures of increasingly costly wells drilled to exploit, e.g., sub-salt plays in the Gulf of Mexico and offshore Brazil.
Optimize Early Oil Production Facilities for a H2S Environment
Authors: Scharner Manfred
Published: November 2012

Optimize early oil production facilities for a H2S environment

Companies active in Exploration & Prodution (E&P) are entering blocks with the target to explore and find new Hydorcarbons (HCs).

Probably most of those E&P companies are chasing "early roduction", once they have discovery promising a feasible commercial discovery. Moreover, this early productionshould be done in an optimized way. This paper outlines the approach that OMV has taken in order to "optimize the early oil production in an H2S environment" for a block in Kurdistan, Region of Iraq.

Looking at the project environment, the first question we needed to answer ourselves was: Optimized in which respect?

Highest safety / HSSE standards? High H2S (> 10% in the associated gas) content encountered in the DST! Shortest time for oil to produce, deliver and commercialize? Earliest possible production with standard equipment from the shelf Maximize initial oil production? Just produce to the limit with no proper knowledge (no appraisal done yet) of the reservoir and the reservoir drive.

The answer to the above questions was not an easy one, however, with HSSE being OMV's priority in all operations "SAFETY First!" has been clear from the very beginning. Independent from all other technical and business issues, OMV started a "Pre development Study" with the target to have a plan forward, if we would encounteroil in commercial quantities. Actually, that study was started prior (!) to the spud of the first Exploration well.

this created certain costs, but the study provided valuable input for the definition of our "optimized" solution under the given project environment.

The following steps in the project definition and developmentwill be introduced in detail at the SPE conference:

Conduct Pre-Development Study: Identify country specific basics Opportunity Framing with definition of scenarios "Do we look wide enough?" Define the "optimized - preferred scenario" Minimum economic field size: Prove the Scenario (OPEX+CAPEX) against the MEF Prepare contracting / procurement strategy Prepare and float the invitation to tender for the early production facilities
Can Simulation Models Validated with Waterflooding Data Reliably Predict Three Phase Flow Processes of Gas and WAG Flooding?
Authors: Al Harbi Amal , Ghedan Shawket G. , Brantferger Kenneth , Kompanik Gary Steven
Published: November 2012

Several giant carbonate reservoirs have undergone decades of waterflooding, and are now transitioning to EOR recovery processes. Simulation models that were calibrated via history matching while undergoing a waterflood (i.e.two phase flow performance) are utilized now to predict three phase flow performance encountered with EOR processes. How reliable are these predictions? Are they accurate enough to be used for business decisions?

In this work, validity and reliability of simulation models, that has been history matched by two-phase flow processes of water flooding, to predict the performance of three-phase flow of WAG processes was assessed.

To accomplish study objective, fine grid of two 5-spot sectors model was built and then upscaled. Upscaled model was then history matched to the results obtained from the fine model using water flooding data and utilizing pseudo functions data. The resulted cases as well as the fine model were then taken to prediction to estimate the performance of three-phase flow of gas and WAG processes. Results of fine and coarse models were then analyzed and compared to draw conclusions on the reliability of the coarse models to match the predicted results of the reference model of the fine simulation model.
Simulation Modeling for Optimized LWD Fluid Sampling Under Different Invasion Profiles
Authors: Agrawal Samarth , Coskun Sefer B. , Hunnur Anup
Published: November 2012

Understanding the properties of formation fluid is a critical step in reservoir characterization. The use of Logging While Drilling (LWD) based fluid sampling becomes increasingly important in high risk scenarios. The LWD environment is significantly different from that of Wireline (WL) for sampling operations as the dynamic filtrate invasion is still in effect. LWD sampling is a relatively new technology and its sampling efficiency compared to WL sampling is not well known. This study aims to understand the effects of dynamic invasion processes on LWD fluid sampling and compare its performance with WL based fluid sampling. The results of the simulation study performed revealed that when the wait time after the drilling is optimized, LWD can provide cleaner samples in shorter cleanup time than WL sampling. It also revealed that the reservoir fluid breakthrough time would be shorter in LWD sampling compared to that of WL. This study indicates that with proper modeling, an optimized sampling program can be executed to meet the objectives of the LWD sampling operations in the most economic manner.
Rig less Innovative Practice to Restore In-Active Well Productivity Off Shore Field Abu Dhabi.
Authors: Ladmia Abdelhak , Al-Marri Faisal M. , Hassane Mohamed Abdelsalam , Al-Neaimi Ahmed Khalifa , Khalil Hassan Ibrahim , Ibrahim Mohamed El-Sayed , Santhanam Kalakad , Abu Chaker Hicham , Al-Sheikh Hosny Mustafa , Moslem Samaawi , Al Marasy Hatem , Salsman Alan
Published: November 2012

Several wells in Offshore field Abu Dhabi are unable to flow due to Low Well Head Flowing Pressure LWHFP and also other wells are unable to flow due to Asphaltenes deposit causing a restriction under certain conditions of pressure and temperature even after a remedial job using a mixture of Xylene-Diesel (20% / 80%). However the well in this case, Well-1, has a combined problem being unable to flow with both LWHFP & asphaltenes deposit.

In some applications the field layout and operation conditions also cause restrictions in production from the producing wells. The use of the technique of re-perforation using a 2’’ Premium Deep Penetrating Gun plus additional acid stimulation with a coiled tubing unit CTU to remove formation damage through double casing is a cost effective way to lower the skin and boost the flowing pressure of LWHFP wells.

Remediation of LWHFP often requires a complex and time consuming intervention (Acid Fracturation, Side Track etc.) with relatively low success rate, which is perhaps why thousands of wells globally currently exhibit LWHFP and cannot be produced due to high line pressure (HPP) in the gathering pipelines.

The objective of this paper is to highlight the challenging yet successful techniques implemented to remediate restricted tubing due to asphaltenes precipitation and restore productivity in the off-shore Field, Abu Dhabi. These jobs are done rigless to aid efficiency and keep cost down and have been successful at getting the wells back on line.
Value of Well Test in the Determination and Characterization of Natural Fractured Reservoir Properties in Large Onshore Abu Dhabi Carbonate Field
Authors: Abdul Rehman Abdul Samad , Kumar Arun , Bejaoui Riadh , Nazarbayev Nurbek , Shuaib Mohamed , Sirat Manhal , Singh Maniesh , Al-Dayyani Taha , Ancuta Cristian , Farcasanu Angelo , Gholipour Ali , Belayneh Mandefro
Published: November 2012

Identifying natural fractures and assessing their impact on flow behavior in hydrocarbon reservoirs have been one of the key challenges in defining the field development strategy. Failure to correctly represent the natural fractures when working on a reservoir development plan can lead to poor performance and failure to analyze reservoir response. Pressure transient testing is widely recognized as a core competency in the oil industry as it provides subsurface specialists with valuable information regarding the reservoir properties, well connectivity to the reservoir and extent of reach into the reservoir.

When borehole image (BHI) data triggers a signal that fractures are seen in wells but flow rates do not show production dominated by fractures, the engineers working on the reservoir need to pay attention to pressure transient tests. Depending on the contrast between fracture permeability and matrix permeability, pressure transient analysis in a fractured reservoir can show clear dual porosity behavior, or the effect can be masked by the wellbore storage. The latter happens when the contrast between the matrix permeability and the fracture permeability is small.

The two parameters which characterize a dual porosity model are the storativity ratio, ω, and the inter-porosity flow coefficient, λ. The average value of λ for the vertical wells studied is 25*10−4, confirming a low contrast between fissure and matrix permeability. For the storativity ratio, a typical value is between 0.001% and 0.1%. An average of 0.03% has been calculated from the well tests.

With the results from pressure transient tests, BHI and core description, fractures have been defined as mild with relative low-intensity. Numerical modeling on a field sector was employed to test the impact of the fractures on production.
Hydrocarbon Habitat of the Early Permian Unayzah Formation in Abu Dhabi
Authors: Taher Ahmed , Al Shateri Abdulla , Al Mehsin Khalil , Witte Johan , Al Zaabi Mohammed
Published: November 2012

The pre-Khuff principal hydrocarbon reservoir, Unayzah Formation, consists mainly of distal braid plain sandstones characterized by aeolian and sabkha facies with minor fluvial units. It extends between the pre-Khuff and the Hercynian unconformities. In Abu Dhabi, the Unayzah-A is further subdivided into three members, Members 1 and 2 are comprised of sandstone reservoirs and Member 3 consists of siltstone and shale sediments.

Facies controls on reservoir quality are weak. The main controls on porosity reduction of the reservoir are mechanical compaction and silica cementation. Quartz cementation tends to be the most severe in the cleanest, coarsest sandstones and near certain fractures. The presence of clay mineral grain coatings, although reducing the permeability, but locally protects the rock from secondary quartz overgrowth and preserve the porosity to great depths of burial. Without the grain coating, porosity will decrease with depth until the reservoir rock is completely tight.

Unayzah reservoir seals are provided by the Basal Khuff Clastics, tight Basal Khuff Carbonate and Middle Khuff Anhydrite. The Basal Khuff Carbonate seal does not appear to be regionally extensive but localized and potentially prospect specific. However, there are insufficient data to accurately define the seal for the Unayzah hydrocarbon accumulations.

Due to lack of deep penetrations in Abu Dhabi, basin modeling for Silurian hot shale source rock is challenging. Therefore, much of the unknown source and tectonic information were derived from the surrounding countries. This comes from understanding the regional tectonics and depositional trends of the southeastern Arabian plate, which helped to extrapolate the source trends into the Abu Dhabi area. The basin model shows that oil from Silurian source rock was generated early in the basin history and was widespread by the Late Triassic (220 Ma). Significant gas generation occurred during Lower Cretaceous (140 Ma) and dominated the hydrocarbon system by Middle Cretaceous (110 Ma). During the Early Tertiary (50 Ma), the source rock was highly mature for gas generation and at present-day, the charge is still active in the north offshore of Abu Dhabi.

The pre-Khuff charge history showed that the southern offshore and onshore structures are underfilled. The filling of these structures ranges between 50% and 80%, but in some onshore structures the filling is less than 50%. The middle and northern offshore structures are expected to be filled to spill point.
An Innovative Approach to Image Fracture Dimensions by Injecting Ferrofluids
Authors: Sengupta Soumyadipta
Published: November 2012

Hydraulic fracturing is a common method used to increase productivity of oil and gas reservoirs. Microseismic technologies have been used to image the dimensions of fractures. Background noise is a serious drawback of this method. This paper proposes a more direct method of measuring fracture dimensions. It shall discuss the magnetic theory, ferrofluids and their magnetic properties, setup of this method and interpretation techniques. Fracturing fluids shall have nano-sized metal particles. These particles will make the fracture a very large conductor and magnetic material in the earth. A variable magnetic field shall be generated by using coils wrapped around the casing string. This variable magnetic field shall generate eddy currents in the fracture. These eddy currents will produce a magnetic field of their own with a distinctive phase shift. An array of receivers shall be placed on the ground which will detect magnetic field signals with a distinctive phase shift. This phase shift is characteristic of the nano metal particles present in the fracturing fluid. The receivers on the ground shall help in determining the fracture length and width. Another array of receivers shall be kept on an offset well to determine the height of the fractures.

Fracture dimensions cannot be studied properly in laboratory because the anisotropy of the formation is very difficult to create. But this method will offer a method of comparison between planned and actual fracture dimensions. This will help in refinement of hydraulic fracturing simulators. Effects of in-situ stress conditions on fracture dimensions shall be better understood.

Manganese or zinc doped ferrite of concentration 160g/bbl and sizes between 10nm to 1μm shall have a magnetic permeability of 50μ0. Silver nanoparticles can also be used since it will provide a distinct phase shift which shall be easily identifiable. This paper shall also discuss the method of interpreting fracture dimensions from magnetic signals.

Shale gas formations are a prime target for hydraulic fracturing. These formations can modelled better with use of this method. Effectiveness of hydraulic fracturing operation can be gauged and improved using this method.
Application of Streamline Simulation to Reservoir Management: Management of WAG Injection Optimization
Authors: Bouaouaja Mohamed , Bassiouni Mahmoud , Nasiri Amir , Shaker Ashraf , Al Basry Ali H. , Masdour Rabah , Takahashi Masahiro , El Mahdi Ahmad
Published: November 2012

Reservoir management practices are classically based on analytical models and standard Reservoir Engineering tools. In the waterfood or water alternating gas recovery process, the analysis is made traditionally with the hypothesis of constant predefined patterns. The producer – injector pair's interaction is quantified based on predefined geometrical analysis of the percentages of contribution of each injector to a producer. In the absence of certain degree of reservoir homogeneity, and also possible injection/production technical issues this method presents a lot of limitation and may lead to erroneous results. Fields in the Middle East are dominantly carbonates and the flow paths are guided by heterogeneous distribution of reservoir characteristics mainly permeability.

This paper outlines a case study for the usage of streamline simulation in predefining the optimized rates of each producer and injector in order to optimize the recovery from individual pattern. The study quantified the interaction between producers and injectors pairs and defined the dynamic pattern distribution through the history. A number of attributes can be derived for each producer injector and pattern. Attributes such as the instantaneous and cumulative voidage replacement ratio, sweep efficiency and injection leakage can be analyzed in order to give more weight in the optimization stage to certain producer and certain injectors. It was concluded that the geometrical lay out of the patterns is not necessary respected and the injectors may support producers outside their geometrical patterns. There was as well a certain amount of the injection that is not contributing to any production and it is not targeting or supporting any specific well.

A number of forecast scenarios were conducted and through ranking different realizations based on total patterns sweep efficiency, the best scenario was selected to determine the allowable volumes to be injected and produced. The scenario showed better control of the patterns as there was a reduction of any redundant injection and the leakage was cut down.
Smart Nano-EOR Process for Abu Dhabi Carbonate Reservoirs
Authors: Haroun Mohamed , Al Hassan Saeed , Ansari Arsalan , Al Kindy Nabeela , Abou Sayed Nada , Ali Basma , Sarma Hemanta
Published: November 2012

EOR technologies such as CO2 flooding, chemical floods and WAG have been on the forefront of oil and gas R&D for the past 4 decades. While most of them are demonstrating very promising results in both lab scale and field pilots, the thrive for exploring additional EOR technologies while achieving full field application has yet to be achieved. Nano EOR is among the new frontiers that demand more improvements, therefore, new concepts and extensive innovative experimental procedures are required to identify and address key associated uncertainties.

The procedure proposed in this report includes an understanding of the Nano-EOR physical processes on lab-scale models of carbonate reservoir retrieved core plugs. (Ogolo et al., 2010). The main objectives include reducing the HSE concerns of handling and transporting the nano particles as well as targeting the unswept oil.

Carbonate core-plugs from Abu Dhabi producing oilfields with porosity ranging from 10 to 24% and permeability ranging from 77 to 149 mD were tested. Several nano particles including Fe (III) O, CuO and NiO of 50 nm range were tested after the waterflooding stage and compared for ultimate recovery factors. The nano EOR was also compared on the same cores subjected to the same conditions against chemical EOR and Electrically Enhanced Oil Recovery (EEOR). A Smart Nano-EOR process is proposed in this study that allows shifting from simultaneous to sequential Nano-EOR alongside EK.

The results obtained on our tested cores reveal that the waterflooding recovery factor ranged from 48 to 63% based on the rock properties, whereas Smart Nano-EOR revealed an ultimate recovery factor of 57 to 85% respectively. The Smart Nano-EOR process is fine tuned to reach the ultimate recovery factor when the specific mechanism is optimized based on both rock and fluid properties. Uncovering physical process enablers will be discussed in this paper to further understand the mechanisms involved in Smart-Nano-EOR.
Azimuthal Seismic Analysis Yields New Insights for a Giant Onshore Oil Field, U.A.E.
Authors: Mahmoud Sabry L. , Othman Adel A. , El Kadi Hassan H. , Berteussen Karl
Published: November 2012

An azimuthal seismic study for fault and fracture identification was carried out on a giant onshore carbonate oil reservoir in the U.A.E., Middle East. The seismic reflectivity analysis was performed using advanced independently processed azimuthal sectors from compressional waves. The seismic attributes demonstrated superior capability of defining accurately the detailed reservoir faults and the fracture networks. Although the full azimuthal study achieved excellent results, the azimuthal stacks were observed to sharpen the reservoir subtle structural features. Beside the traditional land seismic data processing, additional challenges were to properly process the seismic data due to the surface topography and the lateral variations in subsurface rock properties. Azimuthal processing successfully demonstrated:

Improved fault imaging relative to the available conventionally processed seismic data. Additional information about the seismic anisotropy in the reservoir zones.

The analysis showed encouraging results and a relatively good match to known fault/fracture locations. The successful results of the study suggest that high quality 3D wide azimuthal seismic data with relative true amplitude preservation can be used to identify the fracture permeability pathways in carbonate reservoirs. The azimuthal sectors study and results facilitated the quantification of the presence of faults, and suggest that fractured zones can be identified. Another important procedure in this study is the use of the integrated approach during processing and interpretation. Overall, the results of this Azimuthal Study for fractured carbonate reservoir characterization revealed encouraging outputs and valuable guidelines for similar studies in the future.
An Integrated History Matching Approach of a Fractured Basement Reservoir - Block S2, Yemen
Authors: Zabalza Isabelle , Legrand Nicolas , Neff Pascale
Published: November 2012

This work addresses the challenging task of history matching a fractured basement reservoir.

Habban field, south-western part of Yemen, produces from two different horizons: the Kuhlan sandstone overlaying the fractured basement.

The fractured basement reservoir is characterized by two types of fracturing: background fractures with very low effective permeability of less than 0.001mD and fracture corridors with an effective permeability ranging from 0.01 up to 10 mD, and a total porosity of 1.3% only. Two sets of fracture corridors, with N-S and NW-SE mean orientation, contribute to production whereas background fractures act as storage feeding in those corridors.

The large contrast in properties between Kuhlan and Basement adds-on further challenges: Kuhlan possesses good reservoir properties but moderate storage (~10m thick), whereas fractured basement has extremely poor reservoir properties but significant storage (~700m thick).

Habban field has produced since end 2006 by depletion through 30 slanted wells. To optimally assess different production strategies, a simulation model was built. Dynamic data (MDT, PLT, BHP, production rates) were used to constrain the dynamic model on well by well basis.

Due to this extremely challenging setting, a very high focus was put on a history matching process that integrates geology and reservoir simulation work to result into an enhanced understanding of field mechanisms.

One main conclusion of this integrated history matching approach is that water comes to wells from neighborhood formations through main faults, explaining then the erratic water production (no crest to flank correlation). Second highlight concerns the major contribution of N-S main fractures. Finally understanding of the communication mechanism between basement and Kuhlan was enhanced, showing that despite basement poor properties, basement oil feeds in Kuhlan, as Kuhlan is produced. This synergized understanding of Habban mechanisms is a clear milestone for further well location planning and oil recovery optimization under uncertainty.
Design of an Inline Power Generating System for Remote Oil and Gas Production Installation
Authors: Idachaba Francis E
Published: November 2012

A major challenge faced by oil and gas production companies is the supply of a reliable, cost effective, low maintenance and renewable source of power supply to the remote wellheads especially in areas prone to vandalization. Strategies deployed to provide power supply at these remote locations range from the installation of diesel generator sets, solar panels, inverters and battery banks among others. These solutions have been found to require constant monitoring and fueling in the case of the diesel generators, been prone to vandalization as in the case of solar panels and batteries. The inline power supply system comprises of a turbine system installed in a branch pipe. The system is inserted on a flow line from the wellhead so that it utilizes the fluid flow to provide the required kinetic energy to turn the turbine which is direct coupled to a gear and a DC generator. The output of the generator is fed to an electronic board which comprises of a regulator and a DC/DC converter. The DC/DC converter is responsible for providing the required DC level for wellhead instruments and communication devices. The system comprises of two identical installations in branched pipes providing 100% redundancy. The main application for this technology is in the provision of safe and vandalization proof power supply to remote oil and gas production installations especially at the wellheads. No oil or gas preprocessing is required as the turbine requires only the kinetic energy in the fluid. The use of an active flow line also guarantees the system protection against vandalization. The 100% redundancy guarantees that the system has negligible impact on the production process once deployed. The system provides a safe and cost effective safe power supply system for wellhead locations and reduces the OPEX required to keep the production facility powered
Practical Down Hole Dielectric and Diffusion-based Magnetic Resonance Workflow for Saturations and Viscosity of Heavy Oil Reservoirs Using a Laboratory Viscosity Calibration
Authors: Bachman H. N. , Rampurawala M. , Valori A. , Ali F. , Nicot B. , Sangani P. , Denny T. , Newton S.
Published: November 2012

Unconventional resources merit strong attention in the oilfield today. Great value is placed on understanding the amount and viscosity of the oil which in turn guides the production strategy. We demonstrate a workflow employed in Middle East carbonate reservoirs containing intermediate to heavy oil. The workflow combines dielectric and nuclear magnetic resonance (NMR) log data, and it is complemented by laboratory measurements. The applicable range of viscosities is tens to thousands of centipoises.

Integrating dielectric and NMR log data provides a more accurate determination of saturation and viscosity. The workflow does not require any change to the processing of the raw data and is simple to implement. We demonstrate the workflow using log data along with correlations from lab measurements on core and bulk fluids. The workflow solves three key challenges for heavy oil analysis.

The first challenge is the overlap of heavy oil and bound water NMR signals, compounded by a radial variation of saturations near the wellbore. Conveniently, the physics of dielectric and NMR measurement results in depths of investigation of 1 to 4 inches. Dielectric-based analysis provides the total water-filled porosity, which improves the NMR-based saturation and fluid characterization. The second challenge comes from the effect of restricted diffusion of water molecules in pores. We show that a restricted diffusion model is required to obtain accurate saturations and viscosity. The third challenge is the reduced NMR sensitivity to viscosity for heavy oil. Lab measurements on core and bulk oil samples provide the parameters required to link NMR to viscosity.

We describe a workflow based on dielectric and NMR log data for a more accurate determination of fluid saturations and oil viscosity. The workflow takes into account a) the combined dielectric and NMR data; b) the carbonate restricted diffusion effect inherent in the NMR response for carbonates; and c) laboratory validation and interpretation support using core plugs in wells where the dielectric data was not available. We use log data covering a range of heavy oil viscosities to demonstrate the workflow in four wells.
Optimization of Inflow Control Device Placement and Mechanical Conformance Decisions Using a New Coupled Well-Intervention Simulator
Authors: Thornton Kim , Jorquera Ricardo , Soliman M. Y.
Published: November 2012

To optimize production from long horizontal wells, the completion design engineer must consider reservoir heterogeneity so that water breakthrough can be avoided. Reservoir heterogeneity is even more critical when combined with the presence of a strong aquifer; one of the methods commonly used to control this condition has been to have uniform water movement towards the horizontal well. Traditionally, inflow control devices (ICDs) have been used in horizontal wells to achieve this goal. However, design of the ICDs and now autonomous inflow control devices (AICDs) to achieve optimum productivity from the horizontal well can only be achieved by properly linking the ICD and AICD design to reservoir characteristics. Unfortunately, operators and service companies have often applied ICDs without adequate methods to verify completion efficiency over time, since available tools to quantify reservoir complexities and their effects over time have not been readily available.

In this paper, a methodology and a numerical simulation approach that are designed to improve the success ratio of mechanical conformance treatments is presented. This approach combines a comprehensive solution for determining ICD and AICD effects on the wellbore behavior with a reservoir numerical simulator. The methodology considers the following: Placement techniquesAnnular flow controlICD flow size, rate, and number of ICDsReservoir fluid propertiesReservoir permeability distribution effectsFluid-property changes including prediction of water and gas breakthrough over time.

A numerical simulator that couples the wellbore and reservoir characteristics has been developed that can provide an efficient means for optimizing ICD/AICD design and initialization. Simulated examples are given for basic conformance phenomena such as coning and channeling. Field cases will be presented that demonstrate the application of this method and how it designed an optimum ICD/AICD completion solution.

This method reduced risks associated with ICD design and optimized the system designs through more accurately predicting water and hydrocarbon production.
Improving the Production Potential of Shale Gas Wells by Optimizing Multi-Stage Completions Cost Using High-Resolution LWD Images
Authors: Janwadkar Sandeep , Thomas Mark , Denney Steve
Published: November 2012

Developing unconventional shale gas plays in the Middle East is starting to gain momentum in activity based on the success of unconventional shale gas in North America. A closer look at the statistics reveal that although initial well productivity in North America has increased with the adoption of new drilling and completion technologies, it is still difficult to forecast the success of a single well, as results may be quite inconsistent within the same section or across the play. This paper reviews the factors affecting well productivity and focuses on optimized completions design based on a better understanding of the stress fields in the sub-surface as well as the fracture network. Based on experience from the Barnett Shale, one of the most mature and prolific natural gas fields in North America, the paper will highlight the importance of natural fractures, offset induced fractures, faults, and internal stresses, which are increasingly important to characterize and map as infield drilling increases. A high-resolution logging while drilling (LWD) electrical imaging tool was used to acquire images on a well drilled between two wells drilled between two offset wells 600ft apart within the same section. Fracture systems, faults, and stresses in the field were interpreted and mapped to further develop completions, fracture treatments and well placements. The paper shows how LWD images were used to determine which stages had previously been fractured and to explain how production from offset wells was reduced by as much as 40%. Operators have increased well productivity by up to 20% in more than 300 wells drilled to date. Lessons learned can be applied to most conventional and unconventional plays around the world.
Extended Reach Drilling (ERD) Optimization in Layer a Shale through Geomechanical Characterization
Authors: Grini Morten , Ottesen Steinar , Al Junaibi Hamad Saleh , Jorden John , Crawford Brian , Boyd Douglas Alexander , Martin Wallace W. , Alramahi Bashar , Gosavi Shekhar
Published: November 2012

Significant rock strength anisotropy associated with weak bedding laminations in shale can lead to wellbore instability challenges especially when drilling Extended Reach Drilling (ERD) wells that require low angles of attack relative to the formation bedding planes. Past drilling experience with water-based muds in offshore Abu Dhabi showed a high frequency of hole-cleaning and stuck-pipe events for wells deviated above approximately 40° from vertical. This was attributed to shale instability due to the invasion of the drilling fluids into micro-fractures along bedding planes as longer exposure lengths and times increased with the angle of deviation.

Recently the decision to further develop a giant field with wells drilled from artificial islands has created the need for large numbers of ERD wells that will cross the shale formations at angles in the range of 40° to 85°. Pilot holes have been successfully drilled across shales at angles up to 80° by using non-aqueous drilling fluid (NADF) with mud weights predicted with an ExxonMobil proprietary model that uses previous experience and limited log data. Nevertheless, it was considered advantageous, if not essential, to better understand the mechanisms for shale instability as a function of both the angle of inclination and azimuth of the section, since it is critical to reliable prediction of the mud weight and chemistry required to avoid well-bore instability.

An extensive program of tri-axial compression testing of orientated preserved core plugs was conducted in order to quantify the degree of strength anisotropy associated with both a reservoir cap, Layer A shale and intra-reservoir shales encountered while drilling offshore Abu Dhabi. This work showed that Layer A shale's compressive strength can be reduced by approximately 70 to 75% and the intra-reservoir shares by approximately 45 to 50%, when the shear plane of failure aligns with the weak laminations, compared to loading parallel, or perpendicular to the bedding planes.

The inclusion of the measured strength anisotropy functions into a wellbore stability model is shown to accurately predict the observed mud weights associated with induced wellbore breakout. The non-aqueous (NADF) mud weight required for wellbore stability was incorporated in an Integrated Hole Quality and Quantitative Risk Assessment (IHQ/QRA) study to evaluate the drillability of various ERD well designs. Actual field drilling performance with NADF has also been used to validate the model. Increased understanding of this wellbore failure mechanism has the potential to reduce drilling risk and significantly increase current extended reach drilling limits for ZADCO's long term field development plan offshore Abu Dhabi.
Electrification and Energy Efficiency in Oil and Gas Upstream
Authors: Devold Håvard
Published: November 2012

Oil and Gas electrification projects are being planned in countries as diverse as Norway, Qatar, Saudi Arabia, Malaysia, Russia, Canada and Australia. Climate policies and emissions reductions are important also for these countries, but the project decisions are primarily based on economic considerations. The environmental and economic results of electrification are documented in numerous studies.

Reduced operating costs, improved energy efficiency, uptime, stability and HSE factors such as reduced noise, vibration and fewer ignition sources means that more and more oil companies are now focusing on electrification.

This paper looks at the overall CAPEX and OPEX elements and discusses the operational and economic scenarios and their impact on the life cycle cost of a set of cases; LNG and Offshore Facilities. We believe these models support economic benefits in the longer term, and that the environmental footprint is significantly reduced due to 50-70% improved energy efficiency.
Turnaround / Shutdown Best Practice of Centralized Dispatch, Distribution and Qa/Qc of Safety Services
Authors: Dowd Darrell , Daher Elie
Published: November 2012

In shutdowns and turnarounds there are three groups interacting together during the event. The operation team (owners who get the equipment ready to work on), the mechanical maintenance team (typically made up of various contractors who perform the work) and the shared services team that support both of the above in getting their tasks completed, one of which is Safety Services.

Items such as, Breathing air delivery, gas detection/testing, confined space entry monitoring, high angle rescue and other constitute the main bulk of the shared safety services typically used on site during the shutdowns and turnarounds.

In most places, these services are thought of as extra requirement and as a cost center, although necessary and supported, safety isn't viewed as one of the productivity tools in a turnaround. They are typically left to the contractors to manage independently or in isolation creating redundancy in the amount of equipment available, incompatibility in the variety of brands and systems and duplication of efforts resulting in delays in tasks and a general poor perception of safety.

This paper demonstrates the effective use of a system of a a QA/QC process and a centralized distribution and dispatch for on site safety services such as Q-Cycle™, Resource Track™ and Site Courier™ of United Safety, in achieving safety goals as well as schedule productivity gains. This system and process can benefit both the owner/ operating companies as well as the general contractors as either or both can use it. It reviews an electronic method of tracking, reporting and data capture of the distribution and management of site safety services. Centralized distribution and dispatch system can manage daily needs as well as provide data for future planning. In addition, the paper covers the case study and results of this system used in a large, major IOC turnaround; how the data benefited the operator and the mechanical contracting group as well as saved time and money through service quality and inventory management.
Novel Drilling Technology Improves Verticality in Top Hole Sections While Reducing Drilling Time and Costs
Authors: Barton Steve , Herrington David , Prill Jonathan , Neil Paul
Published: November 2012

The challenges involved in maintaining straight and truly vertical bores in the vertical section of the well continue to plague the drilling industry. These challenges result in massive losses in drilling efficiency, and subsequently excessive costs associated with complications caused by "corkscrew" wells. Increasingly complex drilling programs are being designed, often involving extended lateral and horizontal sections to be drilled to optimize production through multiple payzones. As the reach of these wells is extended further each year, the importance of maintaining a truly straight and vertical top section becomes more and more critical. The deeper the well and the deviated reach extends, the more difficult it becomes to move the drill string through the well bore and continue drilling ahead to target. The vertical section of the well has a particularly high impact in these wells as the weight that is transferred though this section must be efficiently transferred down the well bore in order to effectively provide weight on the bit to penetrate the formation and continue to drill ahead.

As the drill string drills ahead vertically, natural variations in the earth or tendencies in the formation caused by formation layers that are deposited at an angle to the surface or random deposits of hard rock can push the bit off of its true vertical trajectory. When this occurs, a correction must be made to steer the bit and drill string back on course for true vertical. The more curves or kinks created by correcting the drift of the bit, the more points of contact exist through the vertical section.

The number of deviations and corrections in a well is often referred to as its tortuosity. These points of contact each have a frictional impact on the drill string and ultimately result in increased levels of torque and drag. These forces ultimately hinder the drilling process by interfering with the transfer of weight through the vertical section to the drill string below as well as causing a resistance to the rotation of the drill string.