bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimizing Unconventional Completions - An Integrated Approach
Authors: Fulks Robert , Hughes Simon , Geldmacher Ingo
Published: November 2016

North American unconventional well completion design has evolved dramatically since 2013 in an effort to keep pace with the productivity gains realized in horizontal drilling. Several trends have emerged during the current industry downturn. Among these trends are a focus on core acreage with higher yield potential, the use of longer laterals, a movement towards higher proppant loading (pounds per linear foot), an increased reliance on plug and perf techniques, and decreased stage length and perforation cluster spacing (increased perf density). As a result associated improvements in well initial production (IP) rates and estimated ultimate recoveries (EUR's) have been highlighted in oil & gas operator's quarterly shareholder's reports during 2015 and early 2016.

Unconventional multi-stage completion designs have also quickly evolved along a path paralleling these trends. Horizontal well IP rates and EUR's have also been enhanced through the adoption of integrated completion designs. Recently introduced geo-engineered completions rely on cross-functional expertise and software to integrate petrophysical, geomechanical, drilling, and production data into a completion design. In cases where geo-engineered designs were used, wells showed improvements in EUR's over those associated with increased lateral lengths, proppant loading and stage counts. In one recent case using a geo-engineered design it was demonstrated that fewer stages and clusters achieved higher production than offset wells while injecting less proppant and fluid; thus achieving lower completion cost.

The use of engineered workflows in tight or unconventional reservoirs is not new. Multiple case histories have been published in recent literature illustrating the use of stress variability/contrast or mechanical specific energy (MSE) to generate brittleness or other fraccability indices to group stages with similar rock characteristics. In contrast to engineered designs, newer geo-engineered designs integrate multiple inputs (attributes) to determine basin and formation-specific weighted algorithms that correlate to stage and cluster production contribution improvement. The geo-engineered approach has proven repeatable and can be accomplished even when key wireline or LWD data is not available.

This paper will document how geo-engineered completion designs evolved from engineered workflows. Multiple inputs (e.g. production, wireline/LWD/mud logs, core analyses, and big data from national and state data bases) can be combined to determine stage length and perforation cluster positioning. Case studies will demonstrate that geo-engineered horizontal completion designs deliver superior well production results when compared to geometric, high-intensity plug & perf designs.
Khurais Central Processing Facility Journey toward Excellence in Energy Efficiency
Authors: Al-Abbasi Amro K. , Al-Babtain Bader S.
Published: November 2016

This paper shares Khurais Central Processing Facility success journey in carrying out various energy optimizations as part of the Saudi Aramco operational excellence initiatives that have resulted in significant value creation to the company. It has achieved five years in a row annual reduction in energy intensity index (EII) performance and this is achieved through various energy initiatives that spanned throughout those years following its startup in 2009, and resulted in winning two international awards. The team adopted a systematic approach that unleashed creativity and pragmatic solutions to all identified opportunities. The process started by developing the internal guidelines for the facility Energy management system that is aligned with the corporate targets, and set the baseline for the journey.

Identifying opportunities for optimization cannot be done without a monitoring tool, and the team created its in-house performance monitoring tool and deploying it in its day-to-day operations. Generally, the basic frame work of the tool is the comparison of performance between actual and target performance indicators (KPIs). Any deviation of performance from the intended target will be alerted and called for attention. The bigger the gap, then the bigger the opportunity for the engineers to clear this performance gap and realize the benefits. What is unique about Khurais performance monitoring tool lies in the advisory features that guide the improvement efforts effectively. The advisory element provides the plant personnel with the required actions for carrying out the improvement work. In addition, the monitoring tool incorporates features of prioritizing improvement efforts to help them focus on key efforts. And only recently, Khurais is awarded a US patent for its unique performance tool.

The monitoring tool and close follow up resulted in generating major initiatives that leverage internal facility capabilities, by clearly exploiting low hanging fruit initiatives that require in many cases low capital investment. Such initiatives include; maximizing the oil train capacity so that any lower train load is shut down and hence minimizing power consumption; maximizing heat recovery steam generation utilization to minimize dependence on auxiliary boilers; and focusing on major equipment (compressors) efficiency enhancement by reducing the recycling while maintaining a reasonable safety margin. After implementing such initiatives, sustaining the benefits prove to be the greatest challenge, and again Khurais utilized its monitoring tool to do so. These initiatives and monitoring led to encouraging results, where from 2010 to 2015, the facility has improved its energy efficiency by 15%.

As part of the continuous improvement journey, KhPD is exploring opportunities for deploying proven energy efficiency technologies, such as LED lightings and absorption chillers that will exploit any waste heat available in our facility.
An Improved Approach for Estimation of Flow and Hysteresis Parameters Applicable to WAG Experiments
Authors: Mahzari Pedram , Sohrabi Mehran
Published: November 2016

Water-alternating-gas (WAG) injection has demonstrated encouraging results for improving oil recovery. However, numerical simulation of three-phase flow and the associated hysteresis effects are not well-understood. Currently, modelling of hysteresis phenomena occurring in WAG cycles is based on updating two-phase relative permeabilities (krs) to account for three-phase characteristics, which is not a trivial task. In this work, a new assessment on the WAG-hysteresis model, which was originally developed for water-wet conditions, was carried out by automatic history-matching of two coreflood experiments in water-wet and mixed-wet conditions. Here in this work, it was attempted to estimate a set of more reliable two-phase krs within active saturation ranges of coreflood experiments performed under water-wet and mixed-wet conditions. Using the first cycle of the WAG experiments (first waterflood and the subsequent gas flood), the two-phase krs (oil/water and gas/oil) were estimated assuming minimal hysteresis occurs in the first cycle. For subsequent cycles, pertinent parameters of the WAG-hysteresis model are included in automatic history-matching process. The outcome of these history-matching exercises would indicate how the WAG-hysteresis model would perform under different wettability conditions using a more representative set of two-phase krs. Also, using these experiments, the ability of the WAG-hysteresis model in simulating the full cycles of WAG injections would be assessed. In other words, auto-history-matching of whole WAG coreflood experiments would enable integrated simulation of two and three-phase flow regions co-existing in cyclic WAG injection.

The results indicate that history-matching the whole WAG experiment would lead to significantly improved simulation outcome. Values of the tuned Land trapping coefficient and the reduction factor for residual oil saturation were close to experimentally extracted information, which highlights the importance of two elements in evaluating WAG experiments; (i) including full-WAG experiments in history-matching and (ii) using a more representative set of two-phase krs. Therefore, employing our new methodology to estimate two-phase krs from first cycle of a WAG experiment could make the estimated unsteady-state krs more reliable for simulating hysteresis effects. Furthermore, the results show that the WAG-hysteresis model failed to reasonably predict the coreflood experiment performed at mixed-wet conditions. The failure can be attributed to two sources; 1) non-wet behaviour of water in mixed-wet systems, which should be reflected in three-phase water relative permeability curves and 2) over-simplifications assumptions embedded in the WAG-hysteresis model such as the linear Som reduction models. Hence, a series of modifications should be applied to change the formulations of the WAG-hysteresis model to develop a versatile model for mixed-wet conditions.
Improving Control of Torsional Vibrations of Motor-Driven Reciprocating Compressors
Authors: Holopainen Timo P. , Arkkio Antero
Published: November 2016

Torsional vibrations establish a remarkable risk for decreased reliability and availability of motor-driven reciprocating compressors in oil and gas industry. This risk can be significantly reduced by careful analysis and design of torsional drive trains. A drive train is composed of separate parts, as motor, coupling, flywheel and compressor. These components are usually produced by separate manufacturers. Thus, the control of torsional vibrations requires seamless cooperation between the system integrator and component suppliers.

Torsional analysis is based on the inertia, stiffness and damping properties of the train components. Usually, the chosen motor manufacturer provides this data to the system integrator. In addition to the mechanical properties, electric motors are characterized by the magnetic stiffness and damping induced by the magnetic fields in the air-gap between the rotor and stator.

The main aim of this paper is to describe the modelling of magnetic effects in general terms as part of the drive train torsional analysis. The second aim is to show the significance of the magnetic stiffness and damping particularly in motor-driven reciprocating compressors with a soft coupling.

This paper describes a recently introduced approach for the modelling of magnetic effects. This approach combines the accuracy of Finite Element Method (FEM) with the portability of parametric space-vector models. This is enabled by the linearization of the electromagnetic behavior in the operation point of the motor. The significance of portability follows from the typical procedure of torsional analysis and design carried out usually by the system integrator.

The calculation example is a motor-driven reciprocating compressor with a soft coupling. It is well-known that in these motor-compressors the effect of magnetic stiffness is significant due to several natural frequencies and excitation orders below the motor supply frequency. In general, the magnetic stiffness increases the natural frequencies, and the magnetic damping decreases the oscillation amplitudes of the lowest torsional modes.

The calculation example shows that the accuracy of the analytic formulae can be clearly increased by the presented new method. In addition, the calculation results demonstrate the significance of magnetic stiffness and damping in motor-driven compressors with a soft coupling. Thus, the reliability and availability of these compressor trains can be improved by including the magnetic effects into the analysis.
The Disruptive Concept of 3D Cutters and Hybrid Bits in Polycrystalline Diamond Compact Drill- Bit Design
Authors: Negm Sara , Aguib Karim , Karuppiah Venki , ElOufy Mamdouh , Remah Mostafa , Zayyan Mohammad , Sheikh Omar El
Published: November 2016

The innovation used in polycrystalline diamond compact (PDC) bit design has historically focused on two main elements—cutting structure (CS) stability, whether statically or dynamically, and the grade and quality of the PDC cutting element, which mainly involves the diamond microstructure and interface design. Since the onset of PDC bit development, there existed a limitation on PDC cutter element construction, and that is they had to be cylindrical diamond tables. This geometric PDC constraint derived everything else relating to PDC bit design. This constraint has finally been overcome. With the advent of new manufacturing techniques, PDC geometry flexibility has now been unlocked. Three-dimensional (3D) cutters add two new degrees of freedom to PDC bit design—cutter geometry and cutter placement on the bit face.

The first wave of 3D cutters included a conical diamond element (CDE), ridged diamond element (RDE), and rolling PDC cutter (RPC). This paper will present the fundamentals of such technology and their effect on field performance. The process by which these elements are applied to a PDC bit is by thorough review of bit-face anatomy versus the drilled application challenge. With such in-depth analysis, these new cutters are separately or concurrently utilized in a "hybrid" bit design, which eliminates traditional PDC bit failures, such as ringout, cored dulls, and impact in extreme applications, including fully drilling conglomerates.

The hybrid bit solution is a disruptive concept that is application-specific and significantly increases drilling efficiency through the selection of the proper technology mix. Moreover, embedded in the development of 3D cutters are the latest diamond microstructures that were traditionally the focus of PDC manufacturers. This paper highlights field deployment results to prove the concept of the technology mix per application in addition to some of the perceived risks.

Chronic deficiencies affecting PDC bit life have been resolved with new, innovative cutter geometries and their placement on the bit face depending on failure modes and load distribution. In addition, the proper selection of the applications suitable for each technology deployment is a key factor in the success of the trials and preserving the bits' cutting structure throughout the bit run. Consequently, the new method improved the bits' lifetime, drilled footage, and rate of penetration compared with the PDC bits using conventional cutters. The effectiveness of the newly introduced 3D cutter technologies and hybrid bits on lowering the cost per foot shows the success of such an approach in harsh economic climates and that the development of new technology is more important than ever in times of pricing pressure.
Innovative Approach to Treat Produced Water for Re-Use in Saudi Aramco Reservoirs Pressure Maintenance
Authors: Soliman Mohamed Ahmed , Al-Zahrani Talal , Al-Qallaf Mohammed , Salu Samusideen , Ansari Nisar
Published: November 2016

As part of Saudi Aramco's continuous commitment to conserve the ground water, this initiative will conserve more than 744 MBD of ground water. This can be achieved by reusing the abundant disposal water available onsite as power water injection for reservoir pressure maintenance. The target is to conserve the Kingdom's precious ground water while maintaining crude production.

The produced or disposal water at Qatif is untapped resource with great potential as an alternative source to replace the valuable Wasia ground water to maintain pressure in C, D and F reservoirs of Qatif field. However, this formation water separated from LPPT, HPPT, LPDT, dehydrators, desalters and other separation units in the Qatif plant contains variable amounts of oil contaminant and suspended solids.

To maintain good/long-term injectivity of disposal wells in Qatif field, water quality this formation water to be treated to meet the oil reservoir injection specifications. The Injected disposal water should be clean to avoid the adverse impact on well injectivity.

Maximum oil-in-water content to be less than 20 ppm (wt). Maximum total oil and suspended solids (TSS) to be less than 50 ppm. Mean particle size of suspended solid shall not exceed 5 micron.

In this study, disposal water samples collected from Qatif water-oil separation plant (WOSEP) were characterized for TSS, oil content and key ions composition. Coreflood tests were carried out on reservoir core plugs at reservoir conditions (temperature of 220 °F and a pressure of 3,000 psi) to assess the effect of this disposal water on core permeability and required filtration to improve its injectivity. Also, several water treatment proposals were identified to meet the reservoir injection specifications. The expected OPEX and CAPEX benefits of implementing the best option are:

Ground water conservation of up to 744 MBWD. Power cost saving of up to 36 MW. Minimize capital cost by avoiding the installation of two additional WOSEP vessels, six new large pumps, new water injection network and the drilling of 10 additional disposal wells.
Challenges in the Selection of a Reliable Ultrasonic Flow Metering System for Custody Transfer Gas Application
Authors: Ganesan Sankara Subramanian , Malik Asadullah , Rajendran Arivazhagan
Published: November 2016

The intent of this paper is to highlight the challenges and improvements to be carried out during the selection of a reliable Ultrasonic Flow metering system (UFM) in Custody Transfer Gas Applications. All gas measurement technologies having limitations including UFM. The main challenges in the UFM measurements are profile distortion, noise and ingress of foreign particles.

In addition to above, the paper also highlights the improvements such as dedicated H2S and HC dew point measurements alongwith GC in custody transfer metering system for the quality of the delivered gas. The design of Zconfiguration has been emphasized which ensures the online proving as well as availability. Moreover the redundant meters are provided with dedicated flow computers, which further ensures the reliability and availability of the metering measurments in-line with international standards.
Energy Saving Through Enhanced NGL Production
Authors: Al Mashjari Khoula , Al Awadhi Ibrahim , Sharma Ashok
Published: November 2016

Replacement of ageing and damage equipment is necessary when repair is not feasible. However, the task becomes challenging when OEM no more exists, it is special equipment and has limited manufacturer. This paper presents the approach followed in design and engineering for replacement of specialized exchanger in cryogenic service which resulted in energy saving through increased NGL Production.

Hybrid type fully welded Cryogenic plate heat exchanger was installed during early nineties. During 2013 inspection, it was reported to be internally leaking. Due to complex geometry of the heat exchanger, it was not feasible to detect and repair, which resulted in NGL production loss of 30 Tons/Day. Instead of like to like replacement, different options were reviewed considering actual gas composition & process parameters and identified the manufacturer for this specialized heat exchanger. The best option which can not only meet performance requirement but also minimize plant modifications, was selected.

The replacement was implemented on a fast-track basis. Close coordination between different stakeholders ensured accelerated technical evaluation and purchase order placement (one month compared to normal 3-month period). Improved latest design of plate embossing was used which increased heat transfer area from existing 1275m2 to 1687.9m2 and resulted in increased heat duty from 5665 KW to 6465 kW. In order to avoid any increase in weight of new exchanger and at the same time ensure integrity, exchanger design was performed as per AD2000 Code, plate pack was designed for differential pressure, high strength stainless steel was used and finite element analysis was performed. Integration with brownfield facilities including nozzles and support locations were appropriately addressed to eliminate site modifications. Design, manufacturing and testing was closely monitored with resulted in flawless manufacturing within eight (8) months. Unique Airfreight of heavy exchanger (40T) was successfully carried out with careful planning which resulted in reduction of transportation time of usual 8 weeks to 1 week. Successful installation and commissioning of heat exchanger resulted in increase in NGL production of about 60 Ton/Day (Energy = 893 BBTU/Annum).

Instead of conventional approach of like to like equipment replacement, innovative approach of enhancing design and performance of the heat exchanger, and close coordination during manufacturing, transportation and installation phases resulted in energy saving through enhanced NGL production, while maintaining safety and integrity in brownfield conditions. This initiative was appreciated by COMPANY management by awarding it a special recognition as part of 2014 GASCO Energy Award.
Optimize, Sustain and Transform: Drilling Performance Improvements Through 12-1/4" Intermediate Section
Authors: Alawi Mohamed Al , Najwani Mohamed , Walker Hamish , Wingate John
Published: November 2016

The Operator is developing a large onshore field in the Sultanate of Oman. Its full field development requires the construction of over 300 wells. Critical to the success of the project is the sustained reduction in drilling time per well. This paper outlines the strategy and performance improvements achieved through the 12-1/4" intermediate hole section in the pursuit of this goal.

The vertical 12-1/4″ section measures 2,650 m and consists primarily of hard carbonate sequences. There is a 350 m clastic base, of which the final 170m comprises very hard and abrasive sandstone. Multiple bit runs with sub-optimal ROP characterize drilling performance through this section. The ideal section TD is 20 m below the hard basal section.

Several drilling optimization initiatives were developed into a Continuous Improvement strategy to address performance opportunities. Work streams included, offset well analysis, KPI delineation, standardized drilling practices and procedures, BHA and drill bit design, parameter optimization, real-time monitoring, and rig site bit run supervision. The removal of unnecessary downhole tools and the transition from matrix to steel body PDC bits has also helped reduce costs. The Operator fostered collaborative working relationships with its bit vendors to develop applicable bit technology whilst encouraging competition to drive incremental performance.

A novel initiative specifically developed for this application has been real-time monitoring using an ROP console. The advisor console is located both in the office and on the drill floor. The key functionalities of the system include, engineered optimum parameter fairways, real-time performance benchmarking, look-ahead lithology/rock strength/stringer identification, drilling related risk alerts, and current/upcoming formation information. The system is tailored to each rig type, BHA and bit type, and ensures latest performance expectations and parameter advice can be disseminated across rig lines.

The strategy has meant the section can now be drilled twice as fast, using half the number of bits. Section Total Depth (TD) is also frequently reached to the optimized depth (in one bit run) enabling continued optimization for the start of the next section (8-3/8").
Coal Bed Methane - Unconventional Gas Becomes an Optimised Solution
Authors: Amott Nick , Garlick Paul , Andrews Paul , Wagensveld Steven van
Published: November 2016

Tight gas resources as exemplified by the dramatic increase in production in the USA and being aggressively developed worldwide, have analogues with Coal Bed Methane (CBM). CBM (sometimes known as Coal Seam Gas) is an unconventional resource where gas is adsorbed within the solid matrix of a coal seam. CBM projects are characterised by large, complex and repetitive gathering system infrastructure which are similar to the general traits of tight gas production systems, especially those associated with fracturing well stimulation techniques.

CBM has been utilised as a source of natural gas for decades, predominantly in the USA, Canada and Australia. However, the majority of the worlds’ 143 trillion cubic metres of Coal Bed Methane remain untapped. To date, the more favourable economics of conventional gas reserves extraction and the recent burgeoning shale gas resource in the USA has limited CBM exploitation. However, increasing demand for gas in eastern markets has led to renewed interest and investment in CBM development. This paper presents a "primer" for CBM covering the resources, extraction methods, gas characterisation and environmental considerations; including co-production of water and land management issues due to the thousands of wells required for a development. The collected gas is usually compressed, dehydrated and exported as sales gas, and provides an excellent feedstock for LNG production.

Unlike conventional gas production, the gas and water production rates from an individual CBM well cannot be known until the well is completed (and in the case of tight gas, fractured), so CBM/tight gas projects present design engineers with technical challenges in terms of optimisation, equipment sizing and modularisation. The geographically distributed, capital intensive nature of CBM projects also places great focus on cost and scope optimisation by operating companies and design contractors.

An introduction to CBM production and facilities design is presented in this paper, together with discussion of an innovative, patent pending method of modelling gas and water gathering system networks, using Monte Carlo analysis and a genetic algorithm for cost optimisation.
New Concentric Dual Diameter Fixed Cutter Technology Bit Drills 56 Faster and Saves Operator Drilling Time in Directional Application Through Challenging Abrasive Sandstone in One of the Largest Reservoirs in the Middle East
Authors: Al-Mayyan Haitham , Malik Abdullah , Sumait Bader , Fayed Moustafa , Khalil Karim , Khalil Ahmed
Published: November 2016

This paper will discuss the deployment of the concentric dual diameter fixed cutter bit technology which was introduced in January 2015. The bit was deployed and tested several times in a tangent, directional application and J-shap wells in Burgan Field, South of Kuwait and achieved the fastest penetration rate in the application.

The concentric dual diameter bit is composed of a smaller pilot and a larger reamer section, where the reamer section dictates the final drill size. Conventional fixed cutter bits take very little advantage of stress relieving the rock, as it only affects the borehole wall. Concentric dual diameter technology bits are able to initially drill with a leading smaller pilot section efficiently to relieve the stress of the rocks. Subsequently, the reamer section removes the stress-relieved rock with lower mechanical specific energy compared to regular fixed cutter bits, giving it the advantage to generate higher penetration rates. Another advantage of the concentric dual diameter technology bits is the stability of the bit, since two gauge sections are available to be in constant contact with the borehole while drilling.

The first 12 ¼ in. concentric dual diameter technology bit in conjunction with directional 8¼ in. PDM (0.16 R/G, 7/8 lobes, 4 stages, 1.5 BH) BHA was tested in a directional application J-Shape well in Burgan Field, South of Kuwait. The bit was able to deliver improved performance by drilling the tangent section from 4345 ft to 6019 ft from Ahmadi to Burgan formation, total 1674 ft in 17 hrs with 98.4 ft/hr. The bit showed excellent steerability, building from 39 deg to 43 deg with 3 deg/100 ft max DLG severity. The section lithology consists mainly of Shale, Limestone & Sandstone.

The performance capability was confirmed when the second bit run in conjunction with directional 8¼ in. PDM (0.16 R/G, 7/8 lobes, 4 stages, 1.5 BH) BHA was tested in a directional application S-Shape well in Burgan Field, South of Kuwait. The bit was able to deliver improved performance by drilling the dropping section total 940 ft from Ahmadi to Burgan formation. The bit showed excellent steerability, dropping from 15 deg to 0 deg with 3 deg/100 ft max DLG severity. The section lithology consists mainly of Shale, Limestone & Sandstone.

The 12 ¼ in. concentric dual diameter was able to surpass the average rate of penetration for the same application in the Burgan Field by 56% saving the operator drilling time and making the concentric dual diameter bit design the top performing drill bit in the field.
Integrated Off-Bottom Cemented Inflow Control Device System Design Toward Well Delivery Optimization
Authors: Al Madan Mohammed A. , Khamseen Mazen Bu , Suherdiana Hedy , Abdulmohsen Ahmad Al
Published: November 2016

Off-bottom cementing (OBC) operations are unique to Saudi Arabia and also represents one of the most challenging types of drilling and workover operations, when deployed in combination with inflow control devices (ICDs) across horizontal sections. In a conventional ICD system, an inner string with packer setting tools is required for setting open hole packers, and to have 100% circulation at the bottom of the completion, to wash down any tight spots. As a consequence, this introduces additional issues such as health, safety and environment, logistics and additional rig time. The inner string also increases the ICD completion string weight, while deploying the system in the horizontal section, creating more drag and increasing the risk of getting stuck.

The multitasking valve (MTV) feature in the upgraded ICDs offers safe, simple and cost-effective deployment operations. The MTV allows the system to be deployed without the need for an inner string. This will positively impact the deployment by simplifying the complexity in the rig operation while achieving 100% circulation at the shoe. Besides, all the hydraulically activated equipment, such as the liner hanger packer, open hole mechanical packers, etc., can be pressurized and set simultaneously. Furthermore, the ICD completion will weigh less in the horizontal section, resulting in less friction and drag to reach total depth (TD). The MTV feature provides an opportunity to deploy the ICD system and the OBC liner system together in one trip. This paper will discuss the first deployment of a combined ICD system with an OBC system for a workover operation, in a historical oil well producer in the Kingdom of Saudi Arabia. The merged system was successfully deployed to depth, then cemented off-bottom, saving approximately 40 hours of rig operation time.
Paradigm Shift in Development Strategy for a Giant Clastic Reservoir in North Kuwait: Vertical Conformance Initiative in North Kuwait
Authors: Jamal Mariam , Gonzalez Ron Angel , Slimani Karim , Abdulbasset Mohamed
Published: November 2016

Sabiriyah Upper Burgan is a multilayer clastic reservoir in North Kuwait under active water flood since 2000, which has been rated as one of the most heterogenous reservoirs as per analogous studies in the past. With five major flow units, poor sweep efficiency often results from spatial variation and/or heterogeneity in the permeability of the reservoir rock, usually resulting in an irregular displacement front of the injected fluid. The initial completion design did not address the injection profile control. Also, conventional techniques to improve vertical conformance did not give desired results. The objective of using Water Flooding Regulator (WFR) is flooding all the units so as to improve the overall sweep efficiency.

To optimize vertical & areal sweep efficiency and enhance production from the uncontacted portions of this reservoir, a paradigm shift in water flood strategy was adopted for selective injection strings using WFR. These devices[RAJ1] enable to control injection rates in specific layers irrespective of the reservoir pressure, permeability, skin damage or any other factors that would normally affect flow, focusing where the oil needs to be swept. The new completion design with WFR was installed in one of the water injector wells, thereby recompleting the well, switching from the conventional to the straddled packer completion, grouping five flowunits into three zones with WFR, rationalizing the splits as per needs per layer vis-a-vis to the perforations in nearby producers.

Prior to the installation of the WFR, surveillance actions such as re-perforation, ILT and injectivity test, were conducted. Workover rig was deployed with an integrated plan for running the completion. Since three units have been grouped in one zone, allocating the water in each unit during the design stage itself was done as per the best reservoir management practice involving all stakeholder teams.

The first implementation of WFR in Kuwait, has proved the concept of improving vertical injection profile by enabling higher injection rates into layers that never received water before and regulating the distibution into all layers. As most of the water injected into the well (more than 90%) was traversing through one zone only before the job, the vertical distribution of injected water due to WFR approach resulted in choking the flow through this layer to about 60% and improve the flow through the remaining uncontacted layers. In the long term, this approach is likely to to add to production, reserves and ultimate recovery factor.

Based on comprehensive evaluation, a campaign of completing nine more vertical injector wells with this selective-string design is planned by Kuwait Oil Company (KOC)[RAJ2][JMAR3]. The re-engineering of injection profile has paved the way for application of this technique in other similar reservoirs of Kuwait.
Casing Wear and Stiff String Modeling Sensitivity Analysis – The Contribution of DP Pipe-Body and Tool-Joint on Casing Contact
Authors: Vavasseur D. , Mackenzie N. , Nobbs B. , Brillaud L. , Aichinger F. , Dao N.
Published: November 2016

Casing wear due to pipe body and tool-joint of Range 2 and Range 3 DP is compared using a stiff-string torque & drag & buckling model coupled to a 3D meshed casing wear calculation. Results are compared for multiple well profiles, either smooth or tortuous, in addition to differing pipe-body and tool-joint wear factors.

The driving force behind the study was to investigate if the benefits Range 3 DP over Range 2 DP, such as reducing the ECD during drilling as well increasing the lifespan of rotating BOPs, outweigh the potential casing wear. To accurately determine casing wear, all rotating operations must be taken into account and therefore a complete BHA run program must be detailed. The casing wear was found by determining the evolution of tool-joint and pipe body contact points along the drillstring and during all the operations using a stiff-string Torque and Drag model. Then, based on the contact force history, a linear Hall model was applied to a detailed 3D casing mesh which takes into account the differing OD's of tool-joint and pipe body. A sensitivity analysis was performed by varying the wear factors attributed to either the pipe body or tool-joint along with the tortuosity and shape of the wells.

The results of the study show that, for smooth well trajectories, a Range 3 pipe will cause reduced overall casing wear even if an increased wear factor for the additional pipe body contacts is taken into account. If a realistic tortuosity is added to the well trajectory, the contact forces are much higher. For Range 3 drill pipe, the number of pipe body contact points increases significantly. For equal tool joint and pipe body wear factor, casing wear becomes preliminary dependent on the well shape and tortuosity. If an increased wear factor for the pipe body contacts is taken into account, Range 3 pipes will cause significantly more wear than Range 2 pipes depending on the well shape.

This paper will show the benefits of using a stiff string model, taking into account a 3D oriented casing contact, while performing casing wear calculations and which conditions the use of range 3 pipes may result in significantly increased casing wear.
A First In-Line Remove Geochemstuiry Pilot for an Offshore Field
Authors: Al-Amrie Omar , Blondeau Christophe , Berthier Maxime , Ruau Olivier , Baylaucq Antoine , Massoue Didier , Lescoute Laurent
Published: November 2016

Total has been operating oil and gas production from a series of heterogeneous reservoirs offshore Abu Dhabi since 1974. Today's world class recovery factor obtained on some of the fields is due to early application of new technologies such as enhanced artificial lift multi-lateral wells, field-wide tracer and state-of-the-art reservoir monitoring and well management. High-complexity in such a field required very fine reservoir monitoring to update production allocation from multi-drain wells, to extend field production.

Developing reliable and cost effective monitoring tools is primordial to reduce operating cost, especially for mature fields in a low oil price environment. Since the middle of the 1990's, allocation by geochemistry has been regularly used to allocate production between reservoirs with significant oil signature differences. It has been mainly used to reduce the number of production logging acquisition runs and to provide a production allocation in wells for which the production logging is not possible.

This technique has proved to be a reliable technique but has had a major drawback associated with the time and logistics required to collect and send well head samples to laboratories for batch analysis. Delays of up to 6 months from sample collection to results availability have had inevitable consequences on the implementation of the required actions.

The first in-line GeoChemistry remote Tool (GCT) has been developed by Total and successfully field tested on oil wells in 2015. This tool allows for automated sequential sampling operations, oil separation and oil signature analysis, enables within a few hours, an individual reservoir oil production allocation to be estimated. This tool connects directly to well heads while sampling produced fluids. Fluids are sent in the dual-skid system through a sampler where oil, gas and water are separated and from here then to an analyzer which is a coupling between gel permeation chromatography with ultra violet detector. Finally, results can be obtained in real time after processing and correlation of analytical data through statistical software (oil composition & production split between producing layers).

This paper describes challenges encountered to implement and test the tool in the field. Indeed, after validation of this first pilot, the offshore environment combined with a large typology of wells tested (high water cut, high GOR, H2S, gas activations, slugging behaviour) led to an upgrade of the prototype which will provide greater accuracy and wider range of application in the campaign planned for 2016.
Challenges of Commissioning Grass Root Ruwais Refinery West
Authors: Mukherjee Somen
Published: November 2016

Abu Dhabi Oil Refining Company, Takreer has recently commissioned the Ruwais Refinery Expansion Project. The Grass Root refinery having capacity to process 417,000 BPSD (Barrels per Stream Day) of Murban crude. Commissioning & Startup is one of the most critical milestones and phase of projects in refinery. It is the last visible step of a project execution process. It moves the project from the "end of construction" to the "commercial operation" status. This paper focus the challenges associated with new refinery commissioning and start-up situations, an understanding of the tools and techniques that can be used to facilitate the effective planning, execution, control and management of these situations. The work process on a Refinery project involves basic engineering, detail engineering, procurement, construction & erection, precommissioning and startup. While each of these activities has its own importance but construction and adoption of successful precommissioning Strategy are the two crucial activities that determine a safe flawless startup. This paper address some the critical commissioing issue encountered while strating a grass root refinery and petrochemical complex.
New Economical Process to Monetize High-CO2 Natural Gas
Authors: Ayasse Conrad , M. Shahin Ahmed , Ayasse Alan , Ayasse Rob
Published: November 2016

Objectives/Scope:

Presently, high capital and operating costs are preventing monetization of high-pressure natural gas containing substantial quantities of CO2. The objective of the paper is to highlight an advancement in the removal of CO2 from high-pressure natural gas, such as the Natuna and Llaird fields. In particular, the paper will show how the Verdis Process dramatically reduces the operating costs and energy demand of CO2 removal, and how the Process integrates with pipelining or deep well disposal of the CO2 while producing market-ready natural gas.

Methods, Procedures, Process:

The presentation will be structured in 3 parts. The first part will briefly outline the current state of the art in CO2 removal from high-pressure natural gas, the second part will explain the Verdis CO2 Process, which uses a solid-state absorbent, and the economic and environmental benefits it can bring, and the third part will explain the applicability over a wide range of gas compositions, including the presence of hydrogen sulfide.

Results, observations, Conclusions:

High-pressure gas (over 1100 psi) containing elevated levels of CO2 is difficult to monetize because of the high cost of CO2 removal. Although un-economical, cryogenic processes have been the leading technologies for treating this difficult gas because a liquid CO2 product facilitates deep well disposal of the CO2 without compression. However, the process is very energy-intensive. Verdis has now developed an energy-efficient solid state CO2 absorbent that can be stripped with dry gas at 90-130 ºC and at pressures higher than those of the feed gas. By using warm CO2 at over 1100 psi as the stripping gas, the stripped CO2 can be returned to the liquid state just by cooling to below 30 ºC ready for disposal downhole or pipelining. No compressors are needed. Even for lower-pressure natural gas, while a liquid CO2 is not produced directly, the CO2 compression costs for liquifying are substantially reduced.

Novel/Additive Information:

The Process is entirely novel. The Presentation will enhance the understanding of the audience members of CO2 recovery in general and the Verdis Process in particular, and provide a new alternative for treating high-pressure natural gas and other difficult gases containing CO2.
Pore Scale Characterisation of Coal: An Unconventional Challenge
Authors: Mostaghimi Peyman , Armstrong Ryan T. , Gerami Alireza , Hu Yibing , Jing Yu , Kamali Fetemeh , Liu Min , Liu Zhishang , Lu Xiao , Ramandi Hamed L. , Zamani Ali , Zhang Yulai
Published: November 2016

Coal seam gas is an unconventional resource for natural gas that is becoming popular due to its environmental benefit and abundance. This paper reviews recent developments on the pore-scale characterisation of coal from coal seam gas reserviors. The development of micro-computed tomography (micro-CT) imaging has enabled for the 3D characterization of the fracture system in coals. This provides detailed insights into understanding flow in these unconventional reservoirs. A novel image calibration method in which the skeleton of the fracture system is obtained from micro-CT imaging while the fracture apertures are measured from scanning electron microscopy (SEM) is described. We also show the application of micro-CT imaging for studying diffusion processes in ultralow permeability matrices and discuss the incorporation of the data into calculations of gas production from unconventional reservoirs. The extraction of statistical information from micro-CT images to reconstruct coal cleat system are also demonstrated. This technique allows for preserving the key attributes of the cleat system while the generated fracture network is not limited in terms of size nor resolution. The developments of microfluidic methods for understanding the complex displacement mechanisms in coal seams are also described. These low-cost experimental methods can provide unique information about the displacement mechanisms occurring during gas production from coal seam reservoirs. Variation of coal contact angle with pressure is analysed and results demonstrate important wettability processes that occur in coal seams. We describe numerical methods for prediction of petrophysical properties from micro-CT images of coal and discuss the associated limitations when dealing with coal samples. The paper concludes by addressing the challenges faced when characterising coal at the micro-scale and approaches for population of coal data into reservoir simulators for relaible prediction of reservoir behaviour during gas production as well as CO2 sequestration in coalbeds.
Development of Next Generation High Torque OCTG Premium Connection for Extended Reach Wells
Authors: Buster Jerry , Perkins Justin , Azeredo Leonardo
Published: November 2016

The development and installation of production casing for the mid-range laterals (2000’ to 5000’) has typically not presented substantial problems during installation and this technology has been mastered by most operators drilling these wells. However the longer laterals (>6000’) is generating industry challenges that are not an issue with shorter lateral wells. The installation of the casing string in the longer laterals is exposed to dynamic loading on both the casing and connections which may exceed the capability of commercially available connections on the market today.

This progression from the mid-range length laterals has required for connection technology to follow. Therefore these wells require an Extreme High Torque OCTG threaded and coupled Premium Connection to aid the operator to reach their target location during the installation of long lateral casing and liner sections.

These longer lateral wells that require the connection to be exposed to extreme torques, bending, and rotational loads, may render some commercially available connections ineffective to get the string to location and could leave the sealability performance to be compromised also. Depending on the well bore conditions in these wells, based on the trajectory, may impose additional loads on the connections which may not have been validated through the connection design.

Therefore connections used for these wells require to be validated for combined loading conditions with temperature, while maintaining high torque requirement in order to install the production casing. The loads are experienced during the installation process, and once the string is installed the connections will still have to provide an effective seal to support the fracturing and production life cycle of the well.

This paper demonstrates how the latest generation of those connections have been tested and validated to the extreme loads prior to being installed in the well bore. This connection has been installed in several wells and experienced the above loading conditions through the installation and production phase and has maintained sealability performance. This paper will also cover a case study from the initial well design discussion, to installation and then production phase utilized for these wells.