bluuebunny/crossref_metadata_2025 huggingface dataset:
Expandable Liner Deployment Remedies Premature Casing Point in an Offshore Gas Well
Authors: AlMusa Abdulaziz S. , Obi Ikenna I. , Garcia Joaquin S.
Published: November 2017

Offshore deep gas wells in Saudi Arabia present diverse challenges for drilling that must be overcome to reduce non-productive time. The nature of deep well design dictates multiple casing strings that require long drilling sections through problematic zones. The objective of arriving to the designated casing point is crucial to avoid jeopardizing the well requirements. Expandable liners have proven to be a viable solution that was implemented in offshore field X in Saudi Arabia.

Field X is a challenging field in which numerous geological formations are troublesome. In order to meet completion size requirements, long drilling sections are required that combine different problematic zones. Even though the casing design takes into consideration these problems, the risks are still present. Lost circulation is one of the most prominent issues that have been tackled through different methods. Depending on the scenario, there may be cases where a section is terminated due to the severity of lost circulation and the casing is installed at a premature depth. Expandable liners provided a solution to this scenario.

The case that will be discussed is an implementation of expandable liners in well X-1. Lost circulation was the main reason for terminating the casing point shallower than what was required. Even though significant efforts were made to cure the losses, the situation necessitated to conclude the section. The expandable liner implementation salvaged the remainder of the section whilst preserving the casing size rather than resorting to slim down the well design. Consequentially, this prevented further complications in subsequent sections avoiding further expense and NPT.

The value of this method lies in its robust solution to premature casing points where it resumes the well to its original plan.
Post-Stack Seismic Merge: A Case History, a Pathway for a Desirable Survey Overlap
Authors: Mahgoub Mohamed , Hagiwara Hiroshi , Hammadi Yousif Al , Matarid Tarek , Hindi Hani Bu
Published: November 2017

Merging 3D seismic surveys into a seamless single 3D volume, either post-stack stage or pre-stack stage, is a challenging task on seismic data processing. This study describes some tips from coastline Abu Dhabi where we successfully managed merging two partially overlapping surveys during post-stack stage, one from transition zone (land and shallow marine) while the other one from offshore 3D OBC seismic survey, in order to understand subtle geological structure relationship among two areas. Since spatial sampling between two surveys are greatly diverse due to different orientations and grid sizes, a conjugate grid which is identical to a main cube had been applied over the subordinate one that enable the whole dataset to interpolate and process as a same grid. Then we deployed pre-conditioning steps over the subordinate dataset to minimize their quality differences where we particularly focused on residual noise, multiples, frequency contents and event timings. Lastly, a matching filter was designed and applied to the subordinate side to compensate residual amplitude, frequency and phase and produce a final dataset for structure interpretation.

A single consolidated seamlessly merged volume was produced throughout the steps as described above along with well-to-seismic calibrations. Seismic interpretation was conducted over the main reservoir between two datasets/fields with a good degree of confidence. The present day structure separation and structure growth history were analyzed as a part of the structure interpretation. Moreover, this case study illustrates the add values of the seismic 3D merge from the aspect of regional structure restoration, and revealing structure relationship between the overlapping surveys. The final merging result outcome of this case study has an amenable structure continuity and seamless horizon mapping of the common reservoir target level between the two surveys. Additionally, the merged seismic cube did showcase a lateral zero phase wavelet stability of the existing wells that verified the reliability of the conducted post-stack seismic merging processing workflow. This case study has successfully demonstrated and summarized key technical tips that are recommended for merging datasets on post-stack domain in the future. However, pre-stack merge is also and still strongly recommended since static corrections, velocity pickings and imaging processing can be applied throughout the two surveys in one go while these cannot be fixed on post-stack merge. From data acquisition perspectives; enough overlap to reaching the full-fold rim of the overlapping surveys is highly recommended.
Inhouse Design and Implementation of Well Integrity Database Management System
Authors: Elrefai M. A. , Al Mutairi A. M. , Al Saadi M. , Nasser F. , Abdi R. M. , ALQamzi A. , AlNaqbi M. A. , Ashgar Ali
Published: November 2017

The Utilization of well integrity management and monitoring system consider a key success for establishing reliable strategic decision impacting the production targets for any organization. ADMAOPCO is a pioneer in constructing and developing Well Integrity Database Management System (WIDMS) purely in-house through integration of well integrity team and digital oil field team. The new software application provides well integrity team with full implementation for the key well integrity elements in order to achieve the objective of the company.Incorporate the current well Integrity data to the organization repository.Full integration of all related application and database, to eliminate fragmented solution to business needs.Elimination of redundant data and processes; thereby increase efficiency and productivity.To provide instant data loading facility from fields with validation capability, thereby reducing delays in decision making.Ease of use, reduction in maintenance cost, standardized training and resource development, increase support efficiency and enhance communication.Incorporate realtime annuli pressure data for wells in a staging environment for validation and then push the acceptable data into the definitive/approved WIDMS.

The in-house build Oracle base software has been used in the filed for more than 700 wells with no limit of additional wells, the software development made to serve ADMA-OPCO well integrity activites and can be expand to the other OPCO with no additional cost. Data relevant to well integrity is widespread including annului pressure management, cased hole logging evaluation, well intervention activities, downhole safety valve management, wellhead and Xmas tree management, well integrity evaluation and certification, this type of activites present a huge challenge.
Extracting the Last Molecule of NGLs - GASCO L.P Model Experience
Authors: Ramachandran Arvind
Published: November 2017

An ADNOC operating company, GASCO is one of the world's largest natural and associated gas processing companies, with a processing capacity of 8 billion cubic feet of feed gas per day. Processing associated and non-associated gas, GASCO operates 3 desert plants for gas processing and natural gas liquids (NGL) extraction, a Natural Gas Liquids Fractionation facility and a pipeline distribution network.

GASCO plays a strategic role in the ADNOC and UAE hydrocarbon chain, which makes it a vital enabler of industrial and economic progress of UAE. Gas yields substantial revenues from exports and is key for the country's electricity generation and water desalination. In a carbon constrained world, interest in its use is growing rapidly by all users, whether residential, commercial or industrial.

As GASCO delivers on its responsibility as an economical and sustainable supplier of gas and related products, it seeks to drive operational excellence by focusing on people, performance, profitability and efficiency.

The GASCO schematic is presented below for your reference.
Novel Electric Submersible Pump Cable Operates in High H2S Production Environment
Authors: Roth B. A. , Xiao J. X. , Paquette M.
Published: November 2017

Electric Submersible Pumps (ESP's) are a widely used artificial lift technology. Conventional ESP systems provide power with a cable banded to the outside of the tubing. These systems have drawbacks in terms of installation speed and efficiency. To overcome these obstacles, a novel cable-deployed ESP system developed for use in a high H2S production environment is a future solution. This paper focuses on the material selection process and validation of the nontraditional National Association of Corrosion Engineers (NACE) selected materials.

An evaluation process was developed and used early on to narrow down several potential alternatives. A metal-jacketed power cable was selected as the most viable solution since it provided the best protection to H2S attack and provided a smooth outside diameter that could be gripped on and sealed. The cable is required to withstand H2S levels up to 15% and chloride levels in excess of 150,000 ppm for a minimum of 5 years. A major challenge was developing a method to construct the system that supported the weight of the cable inside the metal jacket. The cable was qualified through extensive physical and chemical testing.

Interlocking of the metal jacket (tubing) with the inner core (cable) was qualified through extensive mechanical testing of the power cable. Testing included pull resistance, bend, thermal growth, and mechanical splice connections. Electric testing included insulation resistance. Chemical compatibility testing was performed on a number of metallurgies using a modified NACE H2S Sulfide Stress Cracking test based upon ANSI/NACE Standard TM0177. H2S test coupons of the various metallurgies were welded and formed, for testing of the tubing. The test coupons were bent to stress levels in excess of the final design stresses.

The high chloride levels caused several metallurgies to fail even at low H2S levels. A single metallurgy successfully passed all the physical, electrical, and chemical testing and will be used for field trials of the technology.

A rigorous evaluation and test program resulted in development of a novel high-H2S-rated cable-deployed ESP (CD ESP) system that can improve the speed, efficiency, and ease of ESP deployment.
Safe, Green Approach in Drill Cuttings Waste Mangement
Authors: Hussain Ibraheem , Clapper Dennis , Doostdar Nadjmeh
Published: November 2017

Innovative technologies offering safer and greener designs for handling and transporting hydrocarbon-contaminated drill cuttings are of great interest for offshore platforms. Traditional offshore mud skips require use of crane lifts that take up large areas of rig space and hinder continued drilling under inclement weather conditions. This paper describes a unique bulk transfer system that improves offshore cuttings handling safety and provides an environmentally acceptable solution to cuttings waste management and discharge requirements.

The bulk transfer system consists of a single remote control panel unit, intermediate cuttings storage tanks, dual-pod pneumatic transfer unit, boat tanks with a logic control system, air compressor and an onshore hydraulic tipping mechanism. The unique drill cuttings storage with pneumatic transfer technology provides a means of storing drill cuttings in non-pressurized bulk storage tanks on an offshore rig. Cuttings are transferred in dense phase over long distances and heights to the boat storage tanks arrangement, enabling continued drilling over the duration of the well section.

The rig storage tanks include a self-emptying mechanism that generates full drainage, enabling continuous collection of cuttings until they can be pneumatically transferred to the boat storage tanks at variable discharge rates of up to 60 tons per hour, depending on the drill cuttings properties. The reduced height and footprint of this system optimizes space, while its improved efficiency enables reduced downtime in operations. The pneumatic blowing pump can move cuttings over 400 feet at a rate of 20 to 35 Mt/hr continuously to the storage tanks that are mounted on the support boat, enabling continued drilling in poor weather. The boat tanks are low profile and secured by ISO locks for safer navigation and quick emptying system for faster turnaround times. When the boat tanks reach the waste management facility onshore, the drill cuttings are safely emptied by a specialized hydraulic tipping mechanism that is designed to tilt the tanks up to 85 degrees for optimized discharge. The bulk storage tanks total capacity of 320 tons (290 Mg) using (100 m2) of deck space.

This bulk transfer technology enhances operational safety by significantly reducing the use of crane lift and minimizing environmental impact while enabling continuous drilling. The bulk transfer system also offers higher storage capacity, takes smaller floor space on the rig and enables mitigation of accretion or bridging in cuttings.
Building Petrophysical Groups in a Low Permeability Carbonate Reservoir Located in Transition Zone: A Case Study from Onshore Field in UAE
Authors: Khan Muhammad Faisal , Al maskari Shaymaa , Kundu Ashish , Voleti Deepak Kumar , Al-Rawahi Ali Salem
Published: November 2017

The objective of this paper is to present a unique Petrophysical Grouping (PG) approach in a carbonate reservoir located in transition zone. It is very challenging, especially in Carbonate reservoirs, exist in transition zone, to establish PG definitions due to the complexities result from reservoir heterogeneities and diagenesis. Consequently establishing a suitable Saturation Height Function to match the Log derived Saturation is another challenge. In addition, the limited coverage of Mercury Injection based Capillary Pressure data (MICP) as compared to Routine Core analysis (RCA) data provides difficulties in establishing appropriate PG definition.

In first step the MICP data was used together with porosity/permeability to define distinctive groups. The PGs were further up-scaled using deterministic and Neural Network (NN) approaches. The best method was chosen by performing a test that compares the Washburn Pore Throat Radius (PTR) with the predicted PTR. To estimate a most representative log based permeability model, independent of water saturation a NN and Self-Organization Map methodologies were adapted. The limitations of MICP samples were handled by using an analog of a larger field with 100s of MICP samples. This was used to propagate the PGs to log domain by utilizing the permeability model.

Five PGs were defined using deterministic approach in which the best one is characterized having low displacement pressure, low irreducible water saturation, high pore throat radius and high porosity and permeability responses. Winland was shortlisted after testing other methods as the most applicable PG method in the reservoir as it provides the best correlation with lab PTR (94%) and the shape of WR35, consequently provides good match with computed Sw log and the shape of the PRT curve (Gunter, 2017). Regardless of the good response of NN approach the method was not chosen due to limitation of MICP data. A good relationship of Winland based PGs were found with geology and associated facies indicate strong affinity with the depositional environment and diagenetic overprints on each existing facie associations, hence a permeability model is depicted with confidence. The permeability model was executed for two geographic sectors using density, neutron porosity and GR as main inputs. SOM and NN Permeability were blind tested which resulted in more than 80% match. The predicted Sw matches with log based Sw over the entire field thus the PGs definition and propagation to log domain are considered valid.
Improved Fracture Productivity Prediction Using Enhanced Seismic Attributes
Authors: Ramsay Travis , Hernandez Luisalic , Lomask Jesse , Sullivan Allison
Published: November 2017

Production from unconventional reservoirs is influenced by well spacing and induced fracture placement as well as the interaction between hydraulic fractures and in-place natural fracture systems. The purpose of modeling of these complex systems is to evaluate how production can be maximized while maintaining operational efficiencies, which promote reduced well pad footprints and effective fracture stage placement.

Comingled flow conduits in unconventional reservoirs exist as amalgamated fracture systems, and multidisciplinary characterization with analysis from geologists, geophysicists, and engineers is necessary to maintain a consistent subsurface representation. To extend model fidelity in the description of complex fracture systems, a workflow was developed to evaluate the spatial constraint of natural fractures based on use of a fault indicator in cases where correlation exists between faults and fractures as a result of exerted structural controls. Use of the fault likelihood attribute in the development of an unconventional reservoir confirms that some of the better producing wells have been completed near heavily faulted zones; however, such increased productivity can also be hindered when pressure communication is established between wells associated with the same fault block.

An examination of an Eagle Ford formation was conducted, highlighting how a consistent subsurface description not only enabled increased efficiency in future wells and hydraulic fracture placement but also promoted reduced drilling and completion costs as well as increased field productivity. This was achieved by combining fault likelihood constrained natural fracture network (NFN) as well as dynamic simulation of the stimulated and external reservoir volume, incorporating a petro-elastic model (PEM) to preserve geologic continuity between seismic attributes and the simulation.
Impact of Poro-Chemo-Mechanical Parameters on Pre-Stress and Cement Sheath Integrity under Well Pressure and Thermal Loadings
Authors: Onaisi A. , Urbanczyk Ch. , Lansot J-Y. , Garnier A.
Published: November 2017

More and more cement compositions used for oil and gas wells, such as resilient cement with post expansion additives, are designed to obtain elastic and strength properties as well as pre-stresses in the cement sheath that allow the cement sheath to resist tensile or shear stresses induced by pressure and thermal loads emanating from the well during its full life cycle.

The computation of stress changes induced by well loads once the cement is hardened is straightforward. Those stresses will depend on geometrical parameters such as casing and hole sizes on one side and on elastic properties of casing, cement and formation on the other side. The difficulty stems from the need to compute the pre-stress in the cement sheath which is the result of complex hydraulic, chemical, thermal and mechanical interactions during hydration. Another difficulty is to measure the evolution of relevant hydro-thermo-mechanical (HTM) parameters that affect the transition from hydrostatic pressure after placement to stress with shear components after hardening.

In the recent years, Total has developed both modeling and laboratory capabilities that allow to characterize the HTM behavior of cement under in-situ pressure and temperature conditions and to use the measured parameters to analyze the mechanical integrity of cement sheath from placement on. Those tools are now routinely used to determine the best suited ranges of mechanical properties on one side and to QC and adjust cement systems proposed by service companies. This approach allowed achieving successful cementation of wells in harsh environment such as HP-HT wells.

The development of the software and laboratory facilities with internal resources proved beneficial from many perspectives. A great advantage is to be able to know how the various parameters associated with different cement compositions are affecting the cement integrity under specific down hole conditions. More importantly, it allows Total as an operating company to perform sound validation through confrontation to real field cases.

The aim of this paper is to present the fundamental concepts used in the Total's proprietary cement integrity model called T-CemInt and to describe the associated parameters and the ways of measuring them in the laboratory. Also, the paper will show a real case study that included lab tests, modeling and post cement sheath assessment with standard logging tools.
TOTAL New Production Data Management System: from the Concept to Deployment
Authors: Allanic Christophe , Trallero Jose-Luis , Vincent Aymeric
Published: November 2017

Actual context of low barrel prices is driving all field development cost optimizations across the oil industry. This environment is also an opportunity to extend these policies to field production operations.

Developing a process oriented Production Data Management System (N-PDMS) grounded on fundamentals, industry best practices and lessons learnt from legacy systems has been the contribution of production departments within TOTAL E&P. The approach should be good enough for handling Total's operations diversity efficiently, with full transparency and traceability. Project's main objective is to continuously improve data quality from sites to offices (affiliates and headquarter teams), partners and authorities in the host countries.

A commercial product was selected to develop the N-PDMS template embedding key production processes from Well Test to Reporting passing through Well allocation, Shortfalls, Material Balance, Forecasts, Lifting Planning, Lifting Reporting and Gas Production Program. Both Production and Injection are covered. New functionalities like production forecast, automated data capture based on standard asset models and automated historical data migrations were developed along the way.

N-PDMS template is now in the deployment phase in all operated affiliates of TOTAL E&P. This paper describes how the N-PDMS was built as a process driven project; from concepts to their deliverables in a software solution.
Improving Separation of Oil and Water Using a Novel Coalescing Centrifugal Pump
Authors: Husveg R. , Husveg T. , van Teeffelen N. , Ottestad M. , Hansen M. R.
Published: November 2017

A novel centrifugal pump, which increases oil droplet sizes in produced water, has been developed. This paper investigates a concept of pumping pressure optimization with respect to downstream separation efficiency, for the new pump. The investigation shows that the coalescing centrifugal pump always increases the separation efficiency of a downstream hydrocyclone. Furthermore, it is seen that the pumping pressure can be adjusted to maximize the improvement. Experimental results demonstrate how pumping conditions, which minimize the volume fraction of droplets with a diameter smaller than the cut size of the hydrocyclone, maximize the separation efficiency. Finally, it is exemplified how the concept of pumping pressure optimization can be implemented in a typical produced water treatment plant.
HPHT Sour Gas Production- Case Study
Authors: Ahmad Mubashir , Mohamed Ihab Nabil , Yousfi Fawad Zain , Al Hajri Zaher Hilal , Al Zaabi Saleem Salman , Nasr Alaa Mohamed , Romdhane Mourad ben , Albadi Mohamed Mubarak , Al Badi Fuad Shamekh , Shamlan Abdulla Mubarak , Al-Ahmed Mohammed Hasan
Published: November 2017

The expansion in recent years in the oil and natural gas sector has a profound implication for the continuous supply of energy in the market. There is no doubt a surge in the domestic natural gas production with tremendous opportunities as gas is used extensively for electricity generation. With the increasing energy demand, it is always a challenge to bridge the supply and demand gap. The era of sweet shallow gas is fast depleting and hence developing local sour gas production having higher concentration of hydrogen sulphide (H2S) and carbon dioxide (CO2), which are toxic and corrosive is seen as the viable solution.

Currently, ADCO took up a project to study developing the sour gas reservoirs. The objective of the appraisal program was to gain valuable reservoir data including PVT samples to finalize the facilities and full field development plan including testing the reservoir in an area where seismic data indicated better quality sweet spots.

The appraisal program was carried out and the major challenges to drill, test and produce the highly sour HPHT (High Pressure, High Temperature) gas were identified and mitigated. The data from the previously drilled wells penetrating the sour Arab zone was used to drill in the sweet spots identified but additional data was required to reduce the remaining key uncertainties to firm up the Gas In place volumes as the final results were crucial for strategical decisions.

This paper highlights the work progress and then the lessons learned during each step of the operation with the proposed mitigation to safely and efficiently drill the appraisal wells in the Arab sour reservoir having 37% H2S and 10 % CO2.
Casing Swivel Tool Greatly Expands Liner Deployment Capability in the Giant Offshore Oil Field Abu Dhabi Resulting in a World Record Single-Run 6-5/8 Inch Lower Completion
Authors: Ryan James Thomas , Alvarez Juan , Clews Matthew , Reichle Melanie , Szary Tomasz , Deschamps Benoit , Espeland Kent
Published: November 2017

Extended Reach Drilling (ERD) and Maximum Reservoir Contact (MRC) well design can drastically decrease development costs. A critical ERD and MRC challenge is frictional drag encountered when running long casing and liner strings. If the frictional drag becomes too great the string will stall before reaching total depth (TD), severely compromising the completion of the well. This paper presents the implementation of the casing swivel tool to effectively mitigate this friction risk.

String rotation can provide a large reduction in axial drag by shifting the friction vector to primarily affect the torsional direction. Full string rotation offers the largest benefit, but the torque required often exceeds both the casing connection rating and top drive capability. The use of a swivel enables partial string rotation above the swivel to reduce the torque requirement. With increasing production lateral lengths the swivel was moved from the running string into the liner to increase the rotating length of pipe while managing rotational torque.

The drill pipe swivel has a long history of effectively providing a reduction in axial drag by allowing for the running string to be rotated when running long MRC lower completion liners. As lateral lengths have increased from 10,000 feet up to 20,000 feet in Extended MRC (EMRC) wells, the ratio of liner length to running string length has greatly increased. To accommodate this shift in well design the swiveling point needed to be pushed deeper into the well, from running string to the liner. The fit-for-purpose design of the sacrificial casing swivel allows it to be integrated permanently into the completion and enables increased partial string rotation.

To date the casing swivel has been deployed on eight wells, including a world record single-run 6-5/8″ production liner. In one well, the liner stalled and only reached TD after engaging the swivel. The use of the casing swivel has reduced the required well count and capital investment by enabling lateral sections of up to 20,000 feet while also decreasing drilling risk due to less overburden drilling.

The application of casing swivel in the Giant Offshore Oilfield Abu Dhabi was a first for this size and length of lower completion liner. The casing swivel has become a key enabler to maximizing the length of production laterals resulting in substantial well construction cost savings.
Experimental Phase Behavior Studies for EOS Modeling in CO2-EOR Projects in the UAE
Authors: Achuliwor N. A. , Williams J. M.
Published: November 2017

This paper presents an experimental approach to minimize uncertainties involved when modeling CO2-crude oil mixtures. Very little data on CO2-crude oil mixtures have been published in the literature, and most do not cover the range of temperatures necessary for a broader interpretation of data during equation of state (EOS) modeling. Also fluid viscosity is rarely measured. This work addresses both issues, and also develops new experimental procedures.

Phase behavior studies of CO2 mixtures with a live oil sample from a UAE field were carried out using three different temperatures (54°C, 64°C and 74°C) and maximum pressure of 4500 psi. CO2 was injected into a cell containing the crude oil at a suitable working pressure of 2500psi, and swelling tests were conducted. Fluid properties such as saturation pressures, crude oil densities, viscosities, relative oil volumes and swelling factors were determined. It was confirmed that the swelling factors increased with a rise in temperature at constant injection volumes. In addition to the phase behavior studies, a modified operating method was developed for the capillary tube viscometer which required approximately half as much sample. The procedure took into account the integrity of the homogenous mixture as well as the dead volumes of the equipment, and gas trapping effects during sample charging. Results obtained from this method were repeatable and consistent with the routine method, with an average deviation of 0.34%. At the final step of CO2 injection in crude oil, a viscosity reduction by a factor of 4.4 was recorded. The method should be beneficial for subsequent research projects involving viscosity measurements of CO2–crude systems.

A commercial software was used in the phase behavior modeling of the laboratory data. The software incorporates the Peng-Robinson equation of state (PR-EOS) for modeling the experimental data obtained for the range of temperatures. The reservoir fluid sample was first characterized into several components, and then the EOS parameters and viscosity model were tuned to match the experimental data. The outcome of the EOS modeling established that the critical properties, binary interaction coefficients, acentric factors and the selection of tuning weights were the most sensitive and influential parameters. An 11 component lumping scheme was found to accurately match experimental data at all three temperatures.
Targeting Secondary Oil Rims GOGD in a Mature 50 Year Old Development in the Sultanate of Oman
Authors: Ferrero M. Boya , Holst M. , Bazalgette L. , Unal E. , Farsi S. , Sheheimi A.
Published: November 2017

The GOGD recovery mechanism in fractured reservoirs consists of taking advantage of gravity to develop the oil stored in the matrix through the management of the position of an oil rim within the fractures, where producers are placed. Gas oil gravity drainage is an effective method to increase ultimate recovery but it is a slow process. After 50 years into the development of a giant oil field in Oman, a new strategy for placement of additional GOGD wells is proposed, with the objective to optimize the performance of specific layers and achieve top quartile performance.

The understanding of a complex fractured field is based on a thorough data analysis phase with a focus on the total picture, the conceptual interpretation of 50 years of history, the successes and the failures, to locate the remaining oil1. The data itself reveals the fluxes of the fluids within the reservoir and the physics of the recovery mechanisms taking place at all scales (mega-scale, meso-scale and micro-scale). The insights on reservoir plumbing have enabled the identification of in-fill opportunities through a better definition of faults & fracture maps and an updated fluid-fill concept (for matrix & fractures) explaining post-production contacts variability.

We have described a new well placement strategy to target parallel GOGD processes happening across scales, and specifically within the background fracture network confined between fault corridors and mechanical shale barriers, in what we call "matrix blocks". Conceptual box models have been constructed to prove feasibility of the new development strategy through dynamic simulation.

The infill development has been phased according to the ranked risk assessment of every specific location and the value of information it can provide for successive phases targeting smaller matrix blocks or more uncertain remaining oil.

Standard GOGD practice in intensively fractured reservoirs is to manage the final position of the fracture oil rim, gas and water contact within the fractures, through managed gas injection and potentially aquifer pump off wells. We hereby propose the infill drilling of additional shorter horizontal wells avoiding major fracture corridors, placed above shales at the bottom of geological sequences to maximise gravity head and fluid hold up at discrete matrix blocks. Such wells are not at field wide final oil rim depth and they do not intend to target matrix sweet spots but rather accelerate the recovery of unfaulted stacked units.
Big Bore Remote Actuated Barrier Device Development and Qualification
Authors: Beaman Daniel , Newton Daniel , Oaland Jarle
Published: November 2017

This development predominantly from four artificial islands of a giant offshore field in the United Arab Emirates (UAE) requires isolation of the reservoir during deployment of advanced ERD upper completions.

This methodology to isolate the reservoir, during upper completions, carries through to rigging down the Blow Out Preventer (BOP) and offline Xmas tree installation operations. These well construction barrier requirements are met with the use of a tubing deployed barrier device and packer within an intermediate completion that is deployed as a separate trip in the hole on drillpipe to isolate the reservoir. Prior to running the upper completion both packer and barrier device are suitably tested to confirm their barrier status.

Current barrier devices utilized in the field development require wellbore intervention with either slickline or coiled tubing to remove the internal barrier in the devices. Both of these methods pose a financial impact and operational risk to the well. In addition, they can cause delays to the rig schedule as the intervention in some cases needs to be done on critical rig path, in situations where the next well on the schedule prevents offline access. Development plans to both minimize current and future wellbore interventions with slickline or coiled tubing, and maximize Inner Diameter (ID) to allow for remedial completion operations, resulted in a requirement for a barrier device with both remote actuation and large internal bore.

The authors describe the process undertaken to develop, qualify and deploy a big bore, Remote Actuated Barrier Device (RABD) to meet the field development requirements.
Integration of Sustainable Innovation in Research and Development Related to Natural Gas Processing
Authors: Singh Prachi , Aggarwal Dinesh , Ahnaish Tasnim , Namjoshi Aditya , Geuzebroek Frank
Published: November 2017

Considering current changes in supply and demand of the oil and gas value chain, it is essential to embed sustainability measures in the business. Research and development plays an important role in achieving the sustainability in natural gas processing. Hence, this work indicates how the sustainability elements economics, environment and social can be embedded in the management of research and development portfolio. A natural gas R&D model is proposed for GASCO from the sustainability angle. Moreover, it will be shown how during the execution of research projects the sustainability aspect needs to taken into account at each stage, from concept definition till deployment of the technology. Several technologies are identified that can be further researched or evaluated for their application in natural gas processing, to eventually enhance the sustainability of current operations.
Modified Starch Gel Foam: Research and Application in Naturally Fractured-Vuggy Carbonate Reservoir
Authors: Qu Ming , Hou Jirui , Wang Qian , Su Wei , Ma Shixi , Yang Tianyuan , Li Pengyang , Bai Yu
Published: November 2017

Tahe oilfield is one of the most important naturally fractured-vuggy carbonate oil fields in China. The characteristics of this type of reservoirs are greatly complex due to its multiple flow units: matrix, fractures and vugs. Gas flooding is a practical way of enhancing oil recovery (EOR) for fractured-vuggy carbonate reservoir. The main problems during gas flooding include the complicated oil-gas relationship and gas channeling rapidly. Gel is an effective measure to control channeling. However, ordinary gel cannot adapt to the reservoir conditions in which salinity is 220000mg/l and temperature is 120°C.

Based on Tahe oil field reservoir conditions, we develop Modified Starch Gel Foam (MSGF) which has the function of salt-tolerance and temperature-resistance on the basis of laboratory experiments. In order to study the static performance, different foam volume and half-life period were recorded by varing temperature, mineralization and pressure. We also observed microscopic morphology and bubble distribution of MSGF. To evaluate the dynamic effect, fractured-vuggy physical model was designed and fabricated to present the dynamic characteristic in fractures and vuggs media.

Experimental results show that the even distribution, similar diameters of bubbles, thick liquid membrane and high viscosity prove MSGF is stable and available in the water with the salinity of 220000mg/l and temperature of 120°C. The liquid membrane including the continuous structure formed by macromolecular gel protects the bubbles from the harmful influence of ions. After the defoaming behavior, the rest solution becomes gel again, which benefits controlling gas channeling. The item which contributes to this phenomenon is proved to be the foaming stabilizer. MSGF was able to control nitrogen mobility and channeling.

Because of the salinity and temperature tolerance, MSGF can be applied in high salinity and high temperature reservoirs, especially in fractured-vuggy carbonate reservoirs. This kind of reservoirs does not have porosity which will make it possible for normal foaming system to foam again. Besides, MSGF can achieve profile control after the foaming through secondary gelation. This study could provide a constructive guide for the fractured-vuggy carbonate reservoir to improve production performance.
How Much is Steam Worth?
Authors: Aseeri Ahmed S.
Published: November 2017

This paper introduces how to accurately calculate steam cost through Combined Heat & Power (CHP) systems modeling. The major consumption of energy in industry takes place in the form of heat and power for the process plant(s). Optimizing the CHP system can lead to immense savings in the energy consumption of the plants thereby largely reducing the operating costs.

This paper provides a step-by-step construction of a CHP model and illustrates the fluctuation of steam production cost as each component of the CHP system is added or the operating mode is changed. In addition, it will highlight how to use the opportunity value of steam as an alternative to steam production cost for energy targeting purposes.

The cost of power can be easily linked to the Electricity Tariff since electricity is a common commodity. Steam cost, however, cannot be directly linked to any common commodity (including Fuel) and has to be calculated independently for each application to account for all operating factors and limitations that may impact steam production cost. Steam can be produced directly from burning fuel in boilers, making its cost very high. It also can be produced as a byproduct form waste heat recovery which makes its cost minimum. Most industrial applications will have a combination of boilers and waste heat recovery systems which makes steam cost calculation very hard without robust modeling. The inclusion of power recovery in the steam system through steam turbines will make the calculations of steam cost even more complex and varying with almost every operating mode.

This analysis is applicable to both existing plants and new projects. In existing plants, this analysis will help as a KPI for energy monitoring and an accurate measure to calculate the actual production cost in each process area as well as pinpoint areas of potential improvement. On the other hand, for new project it will help to properly size energy-efficient utilities systems to match process demands with minimum operating and capital cost. It can also help in doing what-if analysis to examine different expected operating scenarios and design change considerations.
Nanomaterials-Enhanced High-Pressure Tolerance of Borate-Crosslinked Guar Gels
Authors: Alharbi Abdulrahman , Liang Feng , Al-Muntasheri Ghaithan A. , Li Leiming
Published: November 2017

Borate-crosslinked guar gels are widely used for hydraulic fracturing treatment of wells at temperatures of about 100-300°F due to their advantages such as low cost, ability to reheal upon shearing and operational simplicity. These fluids, however, may lose some or even all of the gel viscosity under sufficient high pressure, especially at elevated downhole temperatures. Although this process could be reversed when the pressure and/or temperature drops, it may potentially cause adverse operational issues such as proppant screenout where the proppant cannot be placed.

Recently we found during the lab research studies that the viscosity loss of the borate-crosslinked guar fluids under high pressure could be mitigated with a number of novel nanomaterials. This paper examines three specific nanomaterials. These enhancing nanomaterials were applied to the borate-crosslinked guar gels as a liquid additive, with dosages typically at about 0.02%-0.12% by weight. In one example, the addition of 1 gpt of nanomaterial-I (0.02% active nanomaterials) enhanced the borate-guar fluid viscosity by about six times at the pressure of 8000 psi. In another example, when 2 gpt of nanomaterial-II (0.04% active nanomaterials) was added, the fluid viscosity was enhanced by about nine times under a pressure of 8000 psi. As the result, the viscosity boosted by nanomaterial-II under high pressure was more than enough for the fluid to function normally to render fractures and transport and place proppant. Other nanomaterials including nanomaterial-III also significantly reversed the high pressure-induced viscosity loss for the borate-crosslinked guar fluids.

These nanomaterials may have rendered more attractive interactions among the guar polymer chains, thus stabilizing the crosslinking of the fluids when the borate-guar bonding was reduced under elevated pressure and temperature. The detailed results of the lab tests at high pressure, as well as fluid chemistry will be discussed in this paper.
Parameters Affecting the Fractured Well Productivity: Proppant Pack vs. Pillar Fracture - Numerical Study
Authors: Gomaa Ahmed M. , San-Roman-Alerigi Damian P. , Alnoaimi Khalid R. , Moraes Alvaro J.
Published: November 2017

Gel damage, fines migration, multiphase flow, and non-Darcy flow are the primary effects that reduce the conductivity of the conventional proppant pack. Therefore, a recent technology was introduced to mitigate those impacts by substituting the porous proppant pack in the fracture with propped pillars surrounded by a network of open channels. In this technique, the fracture is held open by discrete conglomerations of propping materials, known as proppant pillars. Consequently, the flow capacity of the open channel is several orders of magnitude higher than that of a proppant pack. Another advantage of this method is the reduced proppant mass because more area is left open for flow. Most of the available literature investigates the formation of proppant pillars the stability at subsurface conditions. This study aims to characterize the impact of the technology in hydrocarbon production and identify key optimization parameters.

Therefore, a 3D numerical model was constructed to simulate the hydrocarbon flow from the reservoir through the fracture towards the wellbore, Gomaa et al. 2017. The model is used to investigate the relation between the fracture well productivity and different fracture and reservoir properties: reservoir effective permeability, vertical to horizontal permeability ratio, reservoir drawdown pressure, proppant conductivity in the near wellbore region, proppant conductivity in the far-field region, the radius of last proppant stage, and channel width.

The results showed that for conventional proppant pack a CFD value of 30 maximizes the Jd value; this agrees with the previous findings by Cinco-Ley and Samaniego-V (1981). In the case of pillar fracture technology with highly conductive channels, the numerical model showed a significant improvement in well productivity, even when the proppant conductivity was low. In the case of high proppant conductivity and high CFD values, the maximum increase in well productivity index was approximately 25%; however, for low CFD values, the channel fracture had a significant impact on productivity, improving it up to 120%.

Statistical analysis of the results evinced that the proppant conductivity in the near wellbore region had a major effect on the well productivity; whereas proppant conductivity in the far-field had little impact. The analysis also revealed that for every reservoir type, there are different combinations of CFD and proppant conductivity that maximize Jd, even if CFD < 0.1. These results suggest that there is a relationship between the dimensionless fracture conductivity and the near-to-far-field permeability ratio, which has a significant influence on the results.
Simultaneous Low-Frequency Data Acquisition Using Amplitude Modulated Half-Cycle Pseudorandom Sweep
Authors: Nakamura Y. , Takanashi M. , Kunishi Y. , Sakakibara J.
Published: November 2017

Simultaneous acquisition is increasingly required for efficient operation of recent high-density and high-S/N seismic. Low frequency signals plays an essential role in recent imaging technologies such as full waveform inversion. Here, we developed new sweeps designed to simultaneously acquire low-frequency multi-shot data. Unlike other methods, our technique completely decomposes simultaneously acquired data, and therefore can efficiently obtainhigh-quality shot data.

The complete decomposition is achieved by amplitude modulation for repeated sweep sources. The signal for repeated sweeps exists at discrete frequencies compared with higher frequency resolution determined by the total time. Amplitude-modulated sweeps can be completely differentiated from the original sweep because modulated signals are assigned at empty frequency components. With the use of amplitude-controllable sources, our simultaneous method is available without changing the acquisition system and sampling rate. Besides, side-lobe free, low-frequency source can be obtained by so-called Wischmeyer-type half-cycle pseudorandom sweeps. The combination of half-cycle pseudorandom sweeps and amplitude modulation achieved simultaneous acquisition of low-frequency, high-quality data.

We acquired field crosswell seismic data using piezoelectric sources and hydrophones. The depths of the source and receiver wells are 50 m and the well distance is 64 m. We excited six amplitude-modulated pseudorandom sweeps at the same time, and each hydrophone receives mixed signals. The results showed that the shot gather obtained by simultaneous acquisition is equivalent to the gather obtained by single source. Amplitude modulated sweeps successfully produces each shot record without any cross talk. It is also confirmed that pseudorandom sweeps provide broad band data without side–lobe desirable for full waveform inversion

Our approach should contribute to reductions of acquisition time and cost for borehole and shallow marine surveys. Since amplitude modulation is applicable for amplitude-variable sources with arbitrary sweep designs, our method may be applied for broadband vibrotor acquisitions.