bluuebunny/crossref_metadata_2025 huggingface dataset:
Asphaltene Chemistry Across a Large Field in Saudi Arabia
Authors: Abdallah Wael , Pomerantz Andrew E. , Sauerer Bastian , Mullins Oliver C. , Buiting Jan
Published: February 2017

Using laboratory and downhole fluid analyzers, it is possible to characterize lateral and vertical variations in reservoir fluid composition. Previous application of those measurementes have revealed wide spatial variations in the concentrations of asphaltenes in crude oil for many reservoirs. However many of the chemical attributes of asphaltenes have been very difficult to determine and require careful assessment. One of the industry's interests in this class is due to their interfacial activity, an important attribute related to fluid flow in the reservoir and ultimately to recovery of the crude oil. It is very desirable to get a better understanding of the spatial variation of asphaltene chemistry throughout the formation.

The aim of this work was to analyze chemical properties of asphaltenes using established spectroscopic techniques including Raman spectroscopy, laser desorption laser ionization mass spectrometry (L2MS), surface-assisted laser desorption ionization (SALDI) mass spectrometry, sulfur x-ray absorption near edge structure (S-XANES) spectroscopy, and nuclear magnetic resonance (NMR) spectroscopy. The samples were obtained from different locations in the Ghawar field all separated by more than 20 km from each other. The asphaltene chemistry of these samples was found to be typical and simple models for the asphaltenes are applicable. In addition, the asphaltenes from the samples are rather uniform, with an asphaltene structure showing a central island of aromatic rings with an average diameter of 1.48 nm (i.e. 7 to 8 aromatic rings) and a molecular weight in the range of 600 to 750 g/mol for a single asphaltene molecule. This matches other findings regarding asphaltenes in Saudi Arabian reservoirs. The implication is that models for wettability and fluid interfacial tension that rely on simple asphaltene characterization are plausibly beneficial.
Decoding the Seismic Signal: A Comprehensive Approach for Carbonate Buildup Imaging in the Red Sea, KSA
Authors: Escalona Luis , Saleh Saleh M.
Published: February 2017

The seismic data set provides geological information from stratigraphic boundaries. Commonly, different responses are reflected in terms of amplitude, phase and frequencies changes. The bandwidth of the seismic signal and processing approximations restrict the subsurface resolution. Several techniques such as seismic inversion, spectral decomposition, coherency processing has been developed to extract geological information from the seismic data, to reveal the subsurface geology and evaluate reservoir targets. This work summarizes different workflows to improve seismic imaging and provide better reservoir characterization of carbonate buildups in the Red Sea.

The process started in terms of whether the seismic attributes below the salt are robust enough to enable a seismically driven carbonate characterization. Extensive gather analysis, velocity corrections and data conditioning was performed at pre and post stages. Employing HD spectral decomposition, elastic inversion, interactive geobody extraction and integration of well data (core analysis) a successful qualitative and quantitative reservoir characterization was reached.
Virtual Geosteering
Authors: Alsanie Faisal S. , Khudiri Musab , Talhah Nezar A. , Bin Abdulrahman , Rayan H. , Muhammad Kashif , Ashraf Hamood M
Published: February 2017

In the context of current oil price volatility, every operator is trying to apply technologies to reduce the cost of the drilling phase of their horizontal operations, whereas the interpretation application holds a vast portion of success rate in geosteering.Making geosteering functions more important to achieve the optimum production target. The advancement on the utilization of real time data and modeling data in various systems are introducing more critical operationaldecisions based on these systems.

The new virtual geosteering system allows moving from complex multiple systems to a real time data solution with advance geological interpretation that supports a highly available collaborative virtual working environment for geoscientist and engineers during operations.

A virtual geosteering system makes data available in a customized cross-section visualization, where it can be paired with real-time measurements while drilling and logging while drilling (LWD) information. This paper will explain the advantages of this process, with a focus on the flow of data to and from the earth model. It will also focus on additional add-on tools, required to effectively run the remote geosteering process on a single system, through integrated workflows. Virtual geosteering improved collaboration between geologists and drillerswhere critical formation information can be made easily available to be prepared for wellbore condition changes.

Furthermore, advance interpretation tools that allows the data integration between different data sources making it possible to have a unified visualization system to support complete a suite for geosteering and modeling in the same time.
Best Practices to Prevent Stuck Pipe Incidents in Offshore Shaly Formations
Authors: Aljubran M. J. , Al-Yami A. S. , Madan M. A.
Published: February 2017

Under this climate of oil price and energy uncertainty, it is mandatory to limit the non-productive time (NPT) and achieve the highest levels of operational excellence. This is a key factor toward overcoming the evolving economic challenges, reducing budget and spending, and optimizing the return on investment. Worldwide, stuck pipe and borehole problems represent one major contributor into the NPT while drilling, reaming, tripping, casing and running completions. This NPT category becomes even more critical when dealing with shaly formations. Saudi Aramco constantly deal with offshore shaly formations in Saudi Arabia where stuck pipe and borehole problems contribute with over 24% to the overall drilling and workover NPT. Establishing best practices to minimize or prevent these problems will enhance the overall drilling performance and result in significant operating time reductions and cost savings.

The major offshore re-entry operation challenges are first screened: formation instability, hole size, well trajectory, bottomhole assembly and experience and communication. The shaly formation rock nature is analyzed to understand the stressed shale instability root cause: mechanical and/or chemical. This diagnostic step establishes the formation shale properties and behavior. In relation to this information, three basic stuck pipe mechanisms (pack-off and bridging, differential sticking, and wellbore geometry) are discussed where the major contributing factors for each category are identified. This leads to the establishment of proactive recommendations and best practices.

These practices will tackle the problem from different angles to construct an integrated solution. This includes drilling fluid design (rheology, filter cake, filtrate volume and properties, etc.), hole cleaning (rate of penetration, sweep pills, bottoms-up volume, etc.) and drilling parameters (trend analysis, flow rates, string motion, etc.). This paper will highlight the recommended practices and provide actual well examples where stuck pipe tendency was reduced in shaly formations.
Senlac, The Forgotten SAGD Project
Authors: Delamaide Eric
Published: February 2017

The Senlac SAGD (Steam-Assisted Gravity Drainage) project is Saskatchewan, Canada, does not have the same name recognition as its much bigger brothers in the Alberta Oil Sands but it certainly deserves to be known better. Senlac was the first industrial SAGD project in Canada back in 1997 and since then it has been the site for other technological innovations such as the use of solvent in addition with steam to increase recovery and reduce the Steam Oil Ratio, as well as the testing of wedge wells – wells drilled between SAGD well pairs to benefit from the heat remaining in the reservoir.

The reservoir in Senlac is the Dina-Cummings of Lower Cretaceous age and is much smaller than the McMurray formation which is the site of most of the large-scale oil sands project but the oil is only 5,000 cp thus it is mobile at reservoir temperature. This is a significant difference which allows well pairs to achieve excellent production and recovery even though reservoir thickness is only 8-16 m, well below the standard cut-off for SAGD. The presence of bottom water under parts of the field is an added challenge to the operations.

The paper will present the field characteristics and production performances as well as the main technological developments such as the Solvent Added Process and the use of wedge wells.

The paper will present a complete case study of a SAGD project in a heavy oil reservoir where oil is mobile. Most SAGD project so far have been conducted in bitumen but the paper will show the potential for this technology in thinner and smaller reservoirs.
Power Cost Optimization Using Data Analytics-Based Load Forecasting in Upstream O&G Operations
Authors: Hughes Justin T. , Silvia Shejuti , Ahmad Wajdi
Published: February 2017

Oilfield power demand is extremely dynamic in both time and space, and a lack of accurate forecasting causes increased cost for electric utilities to extend their grids to the field. It also causes increased demand charges for producers, which increases their lifting costs. As well production declines with time, electric utilities may end up with stranded assets which represent a large investment that is costly to maintain but is not being fully utilized. Therefore, both producers and utilities have a common interest in improved load forecasting to cut down on cost of power, especially during times of low oil prices. In this research, we show how data analytics can be used to predict load growth evolution in time and space. We incorporate production operational data, well location and geometry, and historical power consumption of neighboring wells into a data analytics engine to develop a platform for improved oilfield load forecasting. This data-driven approach is shown to decrease a utility's kilowatt prediction error for new well pads by 48 to 78% for annual average power and by 10 to 26% for peak power.
Optimisation and Design for WAG-CO2 Combined with Soft Micro Gel SMG in Complicated Carbonate Reservoirs Containing with High Permeability Streaks
Authors: Dandan Hu , Yuanbing Wu , Xiaocui Gao , Songhao Hu , Mingsheng Feng
Published: February 2017

Carbonate reservoirs in the Middle East are highly heterogeneous with great reservoir physical property difference in longitudinal direction, water breakthrough easily caused by high permeability streaks when the reservoirs were put into commingled production. This paper concerns a highly layered gas cap carbonate reservoir with an Upper zone and a Lower zone, which has been developed for nearly 60 years with recovery factor by 16% and water cut by 12% and remained about 52% recoverable reserve in tight zones. Nearly 40% undeveloped reserves of the oilfields lied in low permeability reservoirs, which has low well productivity with vertical well and achieved low sweep efficiency by waterflooding due to high permeability streaks. Horizontal well technology has been or will be implemented for these low permeability reservoirs to enhance well productivity in succession and WAG-CO2 combined with Soft Micro Gel (SMG) (140°C temperature resistance, 300,000 mg/L salinity tolerance) can plug off large pore throat and high permeability streaks.

The paper completed preliminary screening of CO2 WAG process for the reservoirs in B oilfield based on reservoir parameters, empirical principal, laboratory physical simulation experiment and numerical simulation. The paper optimized horizontal well pattern for the reservoirs simultaneously for horizontal waterflooding and the CO2 WAG process. Multi-parameter sensitivity analysis has been completed to establish the empirical model for the relationship of well spacing and recovery factor by CO2 WAG process. Simulation models also have been built up with relevant data of the reservoirs to provide the optimum ratio of CO2 to water, CO2 injection timing and CO2 injection rate. The paper also compared WF and CO2 WAG combined with Soft Micro Gel (SMG) through modelling result. Soft Micro Gel (SMG) can assist CO2 WAG to achieve better results and enhance vertical sweep efficiency. CO2 WAG combined with Soft Micro Gel (SMG) can enhance recovery factor by 12% to 18% for the carbonate reservoirs containing with high permeability streaks and is the most effective EOR method whether or not previous water flooding.

The study in the paper provides important EOR reference for other similar reservoirs in Middle East to achieve high ultimate RF after WF.
Re-Discovery of a Lost Zone through Successful Carbonate Rock Solids Cleanout in Open-Hole Section Using Coiled Tubing
Authors: Al-Ibrahim Abdullah , Al-Bader Haifa , Packirisamy S. , Sagar Vidya , Manimaran A.
Published: February 2017

The objective of this paper is to present an uncommon challenge of formation solids production from open-hole section while testing and completing deep HPHT carbonate formations and successful application of coiled tubing technique for effective wellbore cleanouts to rediscover the exploratory well.

A discovery of oil and gas from a new field was lost because of well complications during well completion operation. Re-entry was made in the existing exploratory well to reactivate the discovered zone since the zone of interest could not be cased due to drilling complications and completed the well in 3-7/8″ open-hole section for production purposes. Open-hole completions are difficult to manage due to the various stabilizing and destabilizing factors. While tubing check by slick line it has been found that the well was filled with sludge/solids up to the kick of point (15,830 ft.). Deeper, deviated and open-hole well presents challenging task of carrying out interventions to unlock the reservoir potential. Cleaning of rock solids in the open-hole section in this deviated well is more challenging and critical which requires new methodology in order to achieve effective well bore cleaning.

Carbonate formation solids production is different from the common problem of sand production from the unconsolidated sandstone reservoirs. As there is possibility of solid production from the open-hole section, a methodology for cleaning of solid fill in open-hole section using 1-1/5″ coiled tubing with modified jetting tool was applied. While circulating 1.5 ppg brine to clean out fill, the well became active.

The uncommon problem of formation solid production was managed well within the available resources. Mechanical restriction in a highly deviated and open-hole section was cleared successfully by using coiled tubing intervention to improve efficiency, reduce cost, reduce operating time and allow early production. The lost discovery was rediscovered by overcoming all challenges. During production phase it was observed that the solid plugging in production tubing is occurring frequently in this case study well. The solid production problem faced during testing was re-evaluated and the risks are properly addressed in future well test procedure.

This paper addresses the relevant testing, completion, solid cleaning and production issues and discusses the solutions arrived at. This paper also details the application of CT in open-hole well bore cleaning, post cleaning well performance, and lessons learned. The best practice applied in this discovery well will be useful for the future exploratory/delineation wells planned to be drilled in similar reservoir.
Radial Jet Drilling: A Technical Review
Authors: Kamel Ahmed H.
Published: February 2017

Radial jet drilling, RJD is an unconventional drilling technique that uses the jet energy of high velocity fluids to drill laterals with different geometries in both conventional and unconventional reservoirs. Many case studies are available worldwide have proven RJD as a viable alternative to traditional stimulation techniques, especially in marginal fields. RJD has a lot of application in the oil and gas industry. It is a cost effective completion technique to reach the untapped sweet spots, by-pass damaged zones near wellbore, re-complete old wells, etc.

The present paper outlines the basics of newly developed radial jet drilling technology. Advances in technologies, developments, forces imposed, jet fluid hydraulics, procedures, applications, and challenges of RJD are reviewed in this paper. Simulation studies and several worldwide case studies are discussed to evaluate the RJD technology.
Maintaining Injectivity of Disposal Wells: From Water Quality to Formation Permeability
Authors: Al-Taq Ali A. , Al-Dahlan Mohammed N. , Alrustum Abdullah A.
Published: February 2017

Sustaining injectivity of disposal wells is a challenging task in oil industry because of inconsistent injected water quality and the need to meet disposal capacity of produced water. Disposal water contains large amounts of carry over oil, suspended solids and other associated water treatment chemicals. Such water property will damage near wellbore formation permeability and consequently decline well injectivity as documented by lab and field reported data.

An extensive lab work was carried out to: 1) evaluate the effect of water quality on injectivity of disposal wells using reservoir core plugs, and 2) restore injectivity of damaged wells. Parameters such as core permeability and water quality in terms of suspended solids, particle size and oil content were examined at reservoir conditions using coreflood testing. Effect of natural clean up and different chemical treatment systems was also studied. The experimental work included water characterization in terms of geochemical analysis, total suspended solids (TSS), particle size distributions (PDS) and oil content. Solubility and compatibility tests were conducted to assess different cleanup systems.

In this paper, water quality guidelines to minimize/prevent formation damage are recommended. In addition, an optimization of conventional chemical treatments for horizontal sandstone water disposal wells is discussed. Based on lab work, a novel chemical treatment was successfully applied to restore injectivity of several damaged disposal wells. This novel treatment reduced the long operation time and cost of a typical treatment practice, while effectively stimulated the well with over two folds increase in well potential and over 70% reduction in treatment cost and operation time.
Production Optimization through Casing Vapor Recovery System for Gas Locking & Gas Interference Challenges in Beam Pumps for Highly Fractured Tight Carbonate Reservoirs
Authors: Al Kooheji Hamza , Gluscevic Andreja
Published: February 2017

This paper discusses the challenges to production caused by gas interference and gas locking in beam pump wells in highly fractured tight carbonate reservoirs in the Bahrain field. It will describe casing vapor recovery (CVR) project that was implemented in the Bahrain field to overcome these challenges. It will also highlight the project strategy that was adopted to reduce the uncertainty on gas measurements and production performance.

Case study on the Bahrain field showed a small amount of produced gas can significantly reduce beam pump efficiency and production. Therefore, this paper will describe the profound positive production and pump efficiency impact of removing all produced gas from the well annulus via casing vapor recovery system. It will illustrate a "Design of Experiment" before implementing a full field system. The paper will also describe the phase approach for implementing the project to reduce the uncertainty on gas measurements and therefore, insure cost efficiency for project implementation.

Beam Pumping as a method of oil production has been used for more than 100 years in a vast variety of oil fields due to its simple operations. The usage increases in pressure-depleted reservoirs due to pumps’ ability to maximize drawdown; hence production. Nevertheless, even after 100 years, production engineering challenges persist in dealing with issues such as gas production. Complication is also added when operating beam pumps in low reservoir-pressure highly-fractured tight and complicated carbonate reservoirs.

Many gas interference issues can be solved with some success by different well completion configurations such as gas anchors or optimizing the pumping parameters. However, casing recovery system in the Bahrain field was proven to be the most efficient and technically suitable. The project started by proving the CVR concept through Design Experiment. Then, phase approach for project implementation was taken place.

The CVR project is considered a great success not only because of oil production improvement but due to its implementation strategy which led to proper designing of CVR surface network and therefore, cost efficiency.
Steam Forced Imbibition in the Tight and Naturally Fractured Rubble Reservoir, Awali Field, Bahrain
Authors: Mohamed A. , Lambert M. , Khalifa A. A. , Al-Muftah A. , Zhang E.
Published: February 2017

A customized thermal enhanced oil recovery (EOR) process is being piloted in the heterogeneous, tight and heavily fractured Rubble formation of the Bahrain Field to overcome reservoir drainage challenges. High viscosity reduces the oil's mobility in the low permeability matrix where most of the oil resides. Steam is used to increase the matrix oil's mobility. However, due to the large contrast in permeability between the matrix and fracture systems, injected steam tends to preferentially flow into the highly permeable fractures, bypassing the tight matrix and resulting in poor thermal oil recovery. Extensive fracturing also increases the risk of pre-mature steam breakthrough by connecting injectors to producers.

On the other hand, due to the very low matrix permeability, it would be difficult to inject enough volumes of steam to sufficiently heat the matrix and reduce oil viscosity if fractures did not exist. Such a dilemma highlights the need to think of engineering designs that would manage the presence of fractures or utilize them as pathways that efficiently deliver heat to the matrix; this is when the Forced Imbibition (FIM) concept evolved.

The concept implies injecting large slugs of steam at high pressure simultaneously into closely spaced horizontal wells that are in direct communication through the fracture system, allowing the heat to soak into the matrix, and then producing all the wells together. Essentially FIM is a high pressure multi-well "huff-and-puff". The first FIM test was conducted in late 2014 and steam-oil ratios (SOR) of 5 bs/bo (barrels steam per barrel oil) or less were achieved in all 4 cycles.

This paper describes the FIM test concept and design, discusses the inputs into reservoir simulation, and examines the actual pilot results.
Parallel Implementation of Ensemble Kalman Smoother for Field-Scale Assisted History Matching
Authors: Lin Binghuai , Crumpton Paul , Dogru Ali
Published: February 2017

The objective of this work is to overcome the computational barriers that arise during large-scale ensemble-based history matching using massively parallel computers. This parallel ensemble-based method is employed to characterize the uncertainty of large-scale Middle East oil fields.

In this work, generating geologically sound ensembles conditioned on prior knowledge is decomposed into the unconditional simulation and a vectorized kriging process. The unconditional simulation utilizes the computationally efficient circulant embedding algorithm based on the Fast Fourier Transform. For each realization, the simulation is done in parallel. Parallelism of the time-consuming kriging process is achieved through decomposition of the reservoir into multiple sub-grids. The resulting prior ensemble is then applied to an improved iterative ensemble Kalman smoother, where hundreds of simulations are required for each iteration. Here each iteration exploits a large parallel cluster, both to run each reservoir simulation within the ensemble independently, and then to run each reservoir simulation in parallel. To minimize spurious long-distance correlations, localization is performed by element-wise multiplication of the localization matrix and the covariance matrix during the ensemble updating step. Due to memory consideration of the large matrices involved in the history matching procedure, the HDF5 file format is utilized for efficient out-of-core memory reading/writing of the large matrices and facilitating the matrix operations.

The iterative smoother has been applied to a 3.5 million cell dual porosity, dual permeability full field model on a 3,000-node cluster with 24 cores on each node. Each prediction run takes about 2 to 3 hours on 500 cores. For an ensemble size of 100, the parallel algorithm manages to finish the history matching process within about 10 hours. The results of the models are then combined together to reconstruct the original reservoir. The results have shown a better match to the observed data than that achieved by traditional methods. Moreover, compared to history matching results from months of effort of the engineers, the ensemble smoother (ES) takes much less manpower to achieve a better match to the data.

This parallel iterative ES has demonstrated the feasibility and performance of history matching large-scale complex real field reservoirs. By exploiting the supercomputers, the systematic history matching workflow can also be applied to large Middle East reservoirs, which generally cannot be achieved using other methods.
Evaluation of Carbonate Rocks Integrity After Sequential Flooding of Chelating Agent Solutions
Authors: Hassan Amjed M. , Al-Hashim Hasan S.
Published: February 2017

Recently chelating agents flooding have been emerged as an effective enhanced oil recovery (EOR) technique for carbonate and sandstone reservoirs. The exact recovery mechanisms leading to the significant incremental oil recovery from the use of those chemicals are not fully understood. The main objective of this paper is to investigate the impact resulting from the application of chelating agent having different concenrtations as an enhance oil recovery fluid on the limestone rock integrity. Core flooding experiments were conducted using Indiana limestone core samples under reservoir conditions using different concentrations of chelating agents at the tertiary mode after seawater flooding. In those tests, significant improvement in the permeability of all core samples used indicting significant rock dissolutions.

The effect of rock dissolution created by chelating agent on the rock properties was investigated. Computed tomography (CT) scan and nuclear magnetic resonance (NMR) measurements were conducted on the core samples before and after flooding experiments. Experimental results show that, channels/wormholes have been created inside the core samples which may lead to bypass more oil; then increase the residual oil saturation and reduce the ultimate oil recovery. Therefore, the optimum concentration of chelating agent must be determined to maximize the oil recovery without severe rock dissolution. Small improvement of rock porosity was observed, while the absolute permeability was increased significantly, with more permeability improvement observed in the core sample closer to the core inlet.

Ion concentrations in the effluents were measured to evaluate rock dissolution casued by chelating agent flooding. Significant increase in the Ca+2 concentrations was observed which indicates considerable rock dissolutions was taking place. This result revealed that leaching of calcium ions from the rock lattice should be controlled and optimized in such a way to alter the rock wettability to produce more oil, and prevent severe rock dissolutions which will result in creating wormholes inside the core samples. This can be achieved by controlling the chelating agent concentration at small level, and maintaining the solution pH at moderate to high levels to avoid strong acidic conditions. In addition, multicomponent ion exchange (MIE) phenomenon was investigated by measuring the Mg+2 concentration, slight decrease in Mg+2 concentrations below the reference concentration during chelating agent injection indicate replacement of calcium ions by the adsorbed magnesium on the rock surface.
Monitoring Landuse Changes and Encroachments Using Advanced Remote Sensing and Gis Techniques
Authors: Zhang Larry , Ab Alharth Mahdi H. , Mashoog Husain A.
Published: February 2017

Geospatial techniques of change detection by using temporal high-resolution satellite imagery and advanced GIS helps in understanding and monitoring local, regional and national landscape dynamics, including land uses and land covers like social-economic and natural characteristics on the earth surface, which are mainly used to monitor economic activities and natural disasters over time.

The paper initially reviews how the current landuse change detection workflow and land management system in Saudi Aramco are designed and implemented with advanced geospatial technology, which have been operating for a decade. And also, some of new operational challenges that we are facing will be briefly discussed.

The study comes with an innovative pilot by applying the advanced big data analytics and machine learning techniques to tackle those new operational challenges. The pilot aims to boost the innovations to find a breakthrough technique and define a new workflow through processing very-high-resolution optical satellite images and intelligently detecting landuse changes by seamless integration of "GPU-accelerated" machine learning models, which are mainly referred to deep neural networks (MxNet) and Support Vector Machine (SVM) in R and Python, especially characterized with automated landuse change detection and encroachment recognition.

Finally, the paper will report the promising results as a prototype in a purely GPU-accelerated computing environment, which demonstrate obviously potential capability to deal with time-serial raster imagery for landuse change detection through deep machine learning.
Reservoir Drill-In Fluid Minimizes Fluid Invasion and Mitigates Differential Stuck Pipe with Improved Production Test Results
Authors: Al-Ansari Adel , Parra Carlos , Abahussain Abdullah , Abuhamed Amr M. , Pino Rafael , El Bialy Moustafa , Mohamed HadjSadok , Lopez Carlos
Published: February 2017

A properly designed reservoir drilling fluid and precise control of its properties are essential to prevent formation damage issues that hamper production. An essential prerequisite for a reservoir drilling fluid are nondamaging specialty products and reduced fines and fluids invasion. This paper describes the case history of two deep gas wells in Saudi Arabia, one well showed impaired production due to screens plugging and was put on workover drilling operations whereas the other well was a regular development well. The offset data showed differential sticking, partial losses and tight spots while drilling the 8⅜ and 5⅞ in. hole sections.

The well reservoir data including the bottom hole-temperature – 300°F, permeability – roughly 10 to 20 micron pore throats and lithology – sandstone intercalated with shale, for the reservoir section were determined from offset analysis. Extensive lab testing was performed with nondamaging specialty and optimized PSD for minimized fine and fluids invasion. This engineered fluid was used to drill a 5⅞ in. vertical side track of ± 300 ft for the workover well whereas on the regular development well about ± 400 ft of the 5⅞ in. section was drilled. The fluid was continuously monitored for PSD at the rig along with the particle plugging test for fluid loss control. The hole cleaning and equivalent circulating density was monitored and programmed with a proprietary hydraulics software. All the fluid properties were determined to be within planned range. The wells were drilled without any of the offset problems as discussed above followed by running the 41/2 in. conventional sand screens to the bottom without any issue. Initial flowback production testing was performed on the workover well, which took 8 hours as compared to the usual 48 hours in the offset wells. The BS&W (basic sediment and water) from day 1 of production was 9% as compared to the 25% observed in the offset wells. The gas production rate was 200% more than was expected as per the offset information.

This paper shows the successful use of reservoir drill-in fluid on two gas wells: one was a workover well and another a regular well. The abstract presents a mutual approach between Halliburton and Saudi Aramco to address the issue of minimizing formation damage and mitigating differential sticking. Offset well data learnings, optimized PSD design, monitoring at the rig site, and the use of nondamaging specialty products delivered production optimization.
First Worldwide Successful Implementation of Coiled Tubing Compatible Novel Fiber Laden Diverter for Matrix Stimulation Using a New Generation High Rate Fiber Optic Real-Time Telemetry System
Authors: Malik Ataur R. , Yaseen Ali H. , Ogundare Tolulope M , Asiri Mohammed A. , Younis Abdulmohsin A. , Driweesh Saad M. , Shammari Nayef S. , Ahmed Danish
Published: February 2017

The objective of this paper is to highlight first worldwide implementation of coiled tubing (CT) compatible self-degradable fiber laden diverter for matrix stimulation treatment using enhanced high rate fiber optic real time telemetry system.

The self-degradable fiber laden diverter has been used in bullheading acid stimulation treatments aimed to maximize reservoir contact and enhance gas production. Recently, the physical properties of fiber has been re-engineered enabling them to be pumped down coiled tubing to enhance diversion and stimulation effectiveness. Coiled tubing with fiber optic real-time telemetry has been utilized for many years in Saudi Arabia for matrix stimulation treatments and well interventions as it provides real-time bottom-hole parameters such as pressure, temperature, casing collar locator, gamma ray, tension and compression as well as distributed temperature sensing (DTS) to optimize fluid placement. The successes achieved with previously used 2 1/8-in. bottom-hole assembly (BHA) for coiled tubing with real time telemetry system offered the maximum rate of 2.0 barrel per minute (bpm), whereas this rate became a limitation to achieve the desired fiber concentration for diversion when fiber laden fluids were used. The low rate provision by 2 1/8-in. BHA led to the need of a new generation high rate 3.25-in. BHA to be used for coiled tubing fiber optic real-time telemetry system that can enable higher pumping rates, help in achieving the desired fiber concentration.

For the first time in Saudi Arabian Carbonate reservoir, the novel fiber laden diverter was used during matrix stimulation treatment through 180 ft. perforated interval with new generation 3.25-in. bottom hole assembly (BHA) for coiled tubing fiber optic real-time telemetry system. The DTS used with the new generation coiled tubing high rate fiber optic real-time telemetry system helped in pre- and posttreatment evaluation. After successful high pressure coiled tubing stimulation using self-degradable fiber laden diverter with visco-elastic surfactant based acid system, the well performance exceeded expectation.

The encouraging result was achieved by uniform stimulation coverage throughout the long perforation interval. The operation also proved the feasibility of using the new generation of fiber optic real-time telemetry system in challenging environment.
Combined Analysis of One Tough HPHT Carbonate Gas Reservoirs in China
Authors: Xu Yandong , Pang Wei , Li Shuanggui , Zou Ning , Du Juan , Mao Jun
Published: February 2017

Shunnan Block in North-West China is one of the toughest HPHT gas reservoirs with vertical depth over 7500 m, formation temperature over 200 and pressure gradient varying from 1.3 to nearly 2. The condition is close to temperature and pressure limit of well testing tools, therefore, the tools are hard to be sent to downhole and chances are that well testing operations usually failed. The pressure buildup data are with bad quality and needed to be converted into downhole data. Meanwhile, it's hard to diagnose accurate flow regimes and interprete because the block is typically carbonate reservoirs with porous medium including pores, natural fractures and caves.

In this paper, we reviewed the exploration wells in this block and find that interpretation by pressure buildup or transient production data can only reflect part of the formation information; therefore the two kinds of data are combined to get more accurate interpretation results. For pressure buildup interpretation, three models including dual porosity model, composite model, and dual porosity with composite model are chosen and compared. For the production data, dual porosity model with boundary is selected because the wells usually show characteristics of multiple porous medium and boundary dominated flow. Parameters interpreted from pressure buildup data are simultaneously transferred into the model for production data.

Results show that the combined interpretation by pressure buildup and production data can reduce the un-uniqueness of models as well as enhancing the accuracy of formation and wellbore parameters evaluation. The model and parameters can satisfy both pressure buildup and production data history. Although Shunnan block is considered as one greatly promising reservoir from the short period open flowing, the combined interpretations suggest very limited drainage volume. Reasons for this paradox phenomenon may be that the wells are severe contaminated by drilling fluid, or the wells were only producing gas in caves and natural fractures nearby the wells while other caves are not connected.
Microwave With Assisted Ceramic Materials to Maximize Heat Penetration and Improve Recovery Efficiency of Heavy Oil Reservoirs
Authors: Batarseh Sameeh I. , Othman Haitham A. , San-Roman-Alerigi Damian , Kumaoka Shunichi
Published: February 2017

The objective of this work is to improve microwave heat penetration depth and propagation into the reservoir for maximum recovery. Research has discovered ceramic materials, known as an enabler, with unique properties that when exposed to microwave energy, for short time, heat up reaching 1000°C (temperature can be controlled). In this technique, oil is not directly heated by microwave radiation; rather the ceramic materials absorb electromagnetic energy and covert it to thermal energy; thereby heating up the crude oil, and improving heat penetration depth and propagation into the reservoir.

This paper presents several successful experimental works and proposes solutions to overcome the challenges in producing heavy oil reserves, either associated with using microwave only or steam. Several experimental studies have been conducted in the lab to compare heat penetration depth and distribution in sandstones and limestone samples; the tests were divided into two sets, the first used microwave only, and the other combined microwave with the ceramic material. The result, from all studies, showed there is a significant improvement in heat penetration depth in the rock when combining the microwave with ceramics; therefore proving that this technology can be used for in situ heat generation. On the other hand, using microwave only has limitations that can be overcome with this approach and has the potential to unlock huge heavy oil reserves, especially in deep and offshore reservoirs.

Based on the laboratory results, a numerical model is developed to characterize the optimal heating dynamics as a function of volume and spatial distribution. Next, a method for lab scale simulation of production efficiency using a heavy oil apparatus (HOA) is discussed. The outcome of these studies will be used as an example to develop a field deployment plan.
Field Proven Effectiveness of Near Wellbore and Far Field Diversion in Acid Stimulation Treatment Using Self-Degradable Particulates
Authors: Malik Ataur R. , Asiri Mohammed A. , Bolarinwa Simeon O. , Guizada Pablo H. , Driweesh Saad M. , Buali Muhammad H. , Shammari Nayef S. , Khalifa Mohamed
Published: February 2017

In acid stimulation treatments, acid will enter the most permeable or the least damaged zones. Most of the fluid will flow into the path of least resistance leaving large portions of the formation untreated. A critical factor to the success of an acid stimulation treatment is proper placement of acid so that all productive intervals are contacted by sufficient volumes of acid.

The original stimulation fluid flow was altered to achieve uniform placement of treatment fluids during acid stimulation in candidate wells. Particle bridging technique utilizing self-degrading particulates of multiple grain sizes was utilized to achieve successful diversion and fluid placement across the entire interval of interest. Particle size distribution was calibrated for use with both near wellbore bridging across perforations and far field diversion inside wormholes and natural fractures. For self-degradable particulates to be successful as effective diverter, it should have accurate particle size distribution, therefore, a comprehensive well data analysis performed during design stage to recognize the opportunity for combination of far-field and near wellbore diversion systems for acid stimulation treatment.

The combination of far-field and near wellbore self-degrading particulate diversion systems allowed the entire intervals to be treated evenly under matrix and fracture conditions, which is usually hard to achieve during acid stimulation treatments utilizing conventional chemical diversion systems, especially in cases where separate sets of perforations would need to be treated with a single stage. Evaluation of the diversion effectiveness was done by running temperature log immediately after the stimulation, which demonstrated satisfactory cool down effect across perforation intervals. This diversion technique was found to be more enhanced to effectively acid stimulate in high temperature carbonate reservoirs of Saudi Arabia.

The utilization of self-degrading particulates of various grain sizes for far-field and near wellbore diversions during acid stimulation in high temperature carbonate reservoir was a unique approach and can be further optimized to resolve the challenges of multistage acid stimulation treatments.
Investigation of Relative Permeability Characteristics for Supercritical CO2 Displacing Water and Remaining Oil after Seawater Flooding in Carbonate Rocks at Reservoir Conditions
Authors: Zhou Xianmin , Al-Otaibi Fawaz , Kokal Sunil
Published: February 2017

Supercritical CO2 (sc-CO2) miscible flooding has been successfully used as an enhanced oil recovery (EOR) method in both sandstone and carbonate reservoirs. The sc-CO2 is miscible with the remaining oil left after water flooding at injection pressures above MMP to achieve higher recoveries. During the process of the sc-CO2 injection after water flooding, there are two phases in the formation, a water phase and a miscible phase (sc-CO2dissolve into oil). To describe the flow characteristics and performance of these phase, the water (Krw) and miscible phase (Krm) relative permeability curves are needed in reservoir numerical simulation during sc-CO2 miscible injection. Surprisingly, publications of experimental data that include water and miscible phase are relatively rare due to the lack of proper experimental methods used. Usually, researchers use water and sc-CO2 relative permeability curves instead of water and miscible phase relative permeability to describe the flow characteristics when sc-CO2 displaces water and remaining oil. In this paper, we propose a modified method based on Corey's model to describe water and miscible phase relative permeability using end point values of water and sc-CO2 miscible flooding.

To obtain the end point values from water and sc-CO2 miscible flooding, four core flooding experiments were carried out on carbonate composite cores using live oil at reservoir conditions. These included two short core and two long cores. The Corey's model was used directly to predict oil/water relative permeability in the carbonate composite cores. A modified Corey model (proposed in this paper) was used to calculate water and miscible phase relative permeability and describe the flow behavior of sc-CO2. The effect of the Corey's exponents, Nw and Nm, were evaluated on relative permeability characteristics in the carbonate composite cores during sc-CO2miscible flooding.

Modified Corey model paramaters include the maximum water saturation, Sw(max), remaining oil saturation Sorw and Krw at Sorw from water flooding process, residual water and oil saturations and the maximum sc-CO2saturation from sc-CO2 injection process. The relationship between relative permeability to water and miscible phase vs. miscible saturation has been developed when the water saturation is decreasing during sc-CO2 miscible injection process. In addition, it is an obvious influence of water and miscible phase relative permeability when the Corey exponents, Nw and Nm are changed.
An Approach to Use Refurbished Bits from Previous Wells that Involves Cost Savings and Effective Bit Utilization
Authors: Tariq Bilal , Duran Roberto , Hashmi Atef , Shafeiq Mohammad
Published: February 2017

An inventive application for Roller Cone (TCI) and Polycrystalline Diamond Compact (PDC) bits (all sizes) that involves reusing the bits in future wells for similar well design types. With factory drilling being carried out in one of the Gas field (among other areas in gas) with over 50 runs a year provides an excellent opportunity to utilize rerun bits, both TCI and PDC, that have a 90-95% life remaining. Using this approach provides an effective and efficient way of cost saving during drilling.

While the cost of new bits in the country is very high compared to markets outside, mainly due to logistics issues with recent and continuous enhancements in bit designs, it makes complete sense to reuse these bits; especially when a huge inventory is available due to so many rigs drilling the similar type well designs in one or similar gas fields. The main criterion is to keep a track of all sizes of bits used on all gas rigs in the area and in the tool house (warehouse). Often, a particular size bit, either TCI or PDC, is used to drill a very short interval in a particular section due to a technical reason for the bit in the well being pulled out of hole, and is almost in brand new condition. Having an up-to-date inventory of these bits from the gas rigs, the tool house, and bit vendors makes it easy to identify such bits and utilize them in new wells, which provides significant cost savings.

Using the rerun bit approach immediately takes the bit cost for that particular hole section to 0$ and so we can achieve additional drilling optimization by utilizing a mud motor in that section, i.e., 12-in., 8-3/8 in., or 5-7/8 in., and further increasing the rate of penetration (ROP) by maintaining the same cost/ft ($/ft) in the section and even breaking bit record runs. In the last few wells it has been evident that by using this approach, the cost/ft for the 12-in. section drilling in the Gas Field field is seen as low as 52% of the new bit for the same year; providing a benchmark for the field. This would not have been possible without utilizing the rerun bits from previous wells. This approach is proving to be very beneficial. As a result of a number of these TCI and PDC bits available in reusable condition as a result of a large number of wells drilled every year in gas fields, significant cost savings have been achieved, which translates into millions of dollars in savings.

The rerun bits have substantial advantages over the new bits, primarily due to cost savings and enhanced bit designs with high durability and bit life over the last decade. For particular application in gas drilling, it is clear that having a large inventory of rerun bits available for almost all hole sizes will enable drilling cost optimization.