bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hybrid Drill Bit Combining Fixed-Cutter and Roller-Cone Elements Improves Drilling Performance in Challenging Application in the Western Desert
Authors: Ismail Ahmed , Hussein Sameh , Eckstrom Darren , Shawkat Mahmoud , Hughes Baker , Kamel Osama , Staal BJ , Ibrahim Abd El 
Published: December 2013

Abstract
The application of hybrid bits saves the operator drilling time by out-drilling conventional roller-cone and fixed-cutter bits in difficult, dense, tough and interbedded intervals. These intervals comprise interbedded sandstone, limestone, and siltstone down to depth of 12,500 to 13,500 ft. Operators who drilled these overbalanced wells typically used conventional roller-cone and fixed-cutter bits, depending on the area of the play. The roller-cone bits consistently drilled the entire interval, yet achieved slow penetration rates due to the lack of available weight. Fixed-cutter bits have been tested to achieve higher penetration rates. They drill faster than roller-cone bits with the available weight on bit but with higher drilling torque, close to the rig limitation. Fixed-cutter bits also experience dynamic dysfunctions that prematurely damage the bits, making it difficult to complete the entire interval.
Extensive research, testing, and development have produced a hybrid bit that combines roller-cone and fixed-cutter elements to address these major challenges. The fixed-cutter elements make the bit more aggressive and provide higher penetration rates at low weight on bit. The roller-cone cutting elements drill through the harder part of the interbedded formation with much lower torque oscillations, making it easier to achieve the directional requirements, and reduce dynamic dysfunctions, improving the reliability of the bottomhole assembly and a better dull condition of the drill bit.
This paper will present analysis of drilling data from the field to provide a detailed description of the operational challenges in this application by comparing the performance of roller-cone, fixed-cutter, and hybrid bits. After describing the planning and operational execution of drilling an 8.5-in. hole section with a hybrid bit in this challenging application, the paper concludes with a discussion of the technical and economical benefits and potential of this new technology.
Wireline Borehole Images–LWD Well Placement Integration to Determine Faults in Awali Field, Bahrain
Authors: Sultan Hassan , Alhashimi Lana , Juandi Dedi , Al-Alqum Wael , Al-Hamad Nasser 
Published: December 2013

Abstract
The Awali field is a mature carbonate oil field in Bahrain. It is a giant gentle limb of anticline compartmentalized by numerous normal faults. The reservoir is intersected by normal faults that create half-graben reservoirs. Characterizing these faults through borehole data is necessary to understand the reservoir compartmentalization and improve the geologic model, which was built from seismic data of poor vertical resolution.
Fault structure was characterized by the deep directional resistivity of a logging-while-drilling (LWD) tool used to geosteer horizontal wells through faulted zones. The LWD tool detected the faults, determined their throw and estimated its extent, and mapped the bed boundaries up and down within its depth of investigation. With this information, engineers were able to place wells over horizontal sections ranging from 1,000–3,500 ft [305–1,067 m] MD within the target zone and stay just 4–14ft [1.2–4.3 m] below the roof (i.e. the top of the Kharaib carbonate reservoir).
The high-resolution wireline borehole image logs recorded after the well reached TD provided further confirmation of fault presence and strike and dip angle. On borehole image logs, normally the faults are indicated by fracture association and drag pattern on nearby structural bedding dips or by abrupt facies or textural changes. Most faults in the Awali field have NW–SE trends with high dip angle; they are considered as a normal fault regime forming the graben and half-graben reservoir traps. Combining the complementary LWD well-placement results and high-resolution borehole image log interpretation enabled us to determine the fault type and its orientation.
Modular Design for Low Cost Minimum Facilities Platforms
Authors: Nicholson Graham , Helle Yann 
Published: December 2013

Abstract
To meet the ever increasing demands for cost and schedule efficiencies in the development of marginal fields it has become necessary to streamline the design process for platforms and employ lean engineering techniques. The introduction of minimum facilities platforms in conjunction with existing infrastructure or MOPUs has enabled operators to develop marginal assets without the large capital expenditure associated with new permanent production facilities. It has been shown that minimum facilities platforms can be produced at relatively low cost and designed to suit specific fabrication and installation requirements. As a result the popularity of minimum facilities platforms has grown and has heralded a new wave of flexible design solutions for a range of applications and water depths.
The technical challenges involved in the design of minimum facilities platforms include structural strength and fatigue resistance as well as meeting installation constraints. A typical conductor supported minimum facilities platform incorporates topside, conductor legs and a subsea template. Although the external platform loading is dependent on unique local water depth and environmental conditions, the overall platform response is primarily governed in only three ways; opside load, conductor size, conductor free-span. Through the use of pre-qualified designs and methodologies it is therefore possible to quickly develop a range of structural solutions to suit a particular application. This paper explores the potential for a modular approach to minimum facilities platform design with a focus on reducing the cost and schedule for development, fabrication and installation.
Analytical and Numerical Modeling of Tracer Flow in Oil Reservoirs Containing High Permeability Streaks
Authors: Kocabas Ibrahim , Maier Friedrich 
Published: December 2013

Abstract
Tracer testing is a powerful tool for reservoir description and evaluation at every stage of the productive life of a reservoir. In this work, we present an analytical and numerical model for the transport of tracer in oil reservoirs containing a high permeability streak. The new analytical model is aimed to aid in the interpretation of tracer tests, provide a better insight into the mechanisms of tracer/EOR fluids transport, understand the role of input parameters, and provide a useful benchmark for numerical simulators. The model is validated by a numerical simulator COMSOL Multiphysics 4.3 which employs finite element technique in its ‘Subsurface Flow" module.
The new analytical model is distinguished with its ability to account for finite longitudinal and transversal tracer dispersions in the high permeability streak and the tracer loss into the bounding low permeability layers. Thus, being possibly the most comprehensive exact analytical unsteady two dimensional tracer transport model, it exhibits the roles of both boundary conditions and fluid mechanics controls simultaneously. Intuitively, one would expect that the coupled one dimensional analytical solutions may be appropriate for the systems with a large aspect ratio defined as the ratio of the length of high permeability zone to its half-width. In this work, however, we demonstrate that the parameter which controls the applicability of one dimensional models is the square root of ratio of the two characteristic times of longitudinal and transverse dispersion. While we have validated the analytical solution with a finite element simulator, the analytical solution in turn provided an advanced benchmark free of numerical dispersion and unphysical oscillations in two-dimensional domains for numerical models.
The nonlinear regression programs coded in MATLAB are employed to interpret the tracer return profiles, and hence, to be able to estimate the models parameters along with related confidence intervals.
Energy Conservation Through Flare Reduction
Authors: Dhahli Mohammed Al , Proot Michael , Rodoljub Mihajlov 
Published: December 2013

Abstract
Gas extracted from crude oil is often exported as sales gas. In Petroleum Development Oman (PDO), the story is different. The demand for natural gas is increasing with expansion of Enhanced Oil Recovery (EOR) projects within PDO (for example, miscible gas injection) and increased end user consumption across Oman. Realizing the need for gas conservation, PDO has given more focus on flare reduction projects reflecting this in the business planning.
Birba Gathering Station (BGS) is the first high sour facility in PDO where associated gas is injected for pressure maintenance purposes. The station consists of number of compression units where the gas is compressed to ~470 bar before it is injected into the reservoir. Flaring in BGS has traditionally exceeded 300 kSm3/d. To adhere to a practical minimum flaring in PDO, a flare reduction project for BGS was initiated.
As a first step, the main causes of the flaring in BGS were identified by analyzing actual field data (i.e. history trends, trip reports, etc.) and highlighted the critical role of the compressors uptime. Once the critical flaring contributors were identified, a number of concepts emerged how flaring can be reduced by improving the compressor availability and/or sparing. A technical and economical evaluation was performed to identify the ALARP (As Low As Reasonablely Practical) option which is now selected for implementation.
In summary, the paper will explain in detail the systematic approach that was used to identify the root cause of the flaring in Birba Gathering Station using the trip data. Subsequently, it will discuss the different concept options and the evaluation of the options against the project criteria. The discussion will include the economic model used and the selection of the preferred option.
Evaluating Flow Contributions and Enhancing the Design of Smart Well Completions
Authors: Al-Muailu H. A. , Al-Suwailem M. , Aldawsari S. 
Published: December 2013

Abstract
Over 70% of an onshore Saudi Arabian field maximum reservoir contact labeled wells are equipped with smart well completions; mainly to control undesirable effluent production. Several optimization best practices are routinely conducted through extensive sophisticated rate testing operations that are combined with the utilization of deployed intelligent devices. This entails the optimal setting of ICVs for ideal production and restriction of high gas or water laterals to determine their productivity indexes (PIs) and revive dead laterals.
This paper documents the utilization of Netool in evaluating smart well contributions. A case study will be thoroughly discussed whereby a smart trilateral producer with flow meter log results exhibits unexpected flow contributions. Netool was used to evaluate the flow meter log to optimize the inflow control valve (ICV) settings. The model was validated with the actual flow rates of individual laterals. Moreover, Netool was utilized in evaluating and analyzing the current completion practices in terms of the spacing between the ICVs and the optimum blank pipe size.
The results of the model contradict the flow meter log results. Several, rate tests were completed in the well resulting in more confidence in the model results. New proposed ICV settings balanced the flow rate and the pressure draw down between the three laterals. The paper will show that the greater the increase in the distance between the ICVs the greater the variance in the laterals contribution. The optimum spacing providing more balanced flow contribution came to be 300 ft. Sensitivity analysis was conducted over the blank pipe sizes, proving that a reduction of 40% pressure drop can be accomplished through having larger blank pipe between the ICVs from 3 ½" to 4½".
The Impact of Heat Flow Variations in Shale Gas Evaluation: A Haynesville Shale Case Study
Authors: Amer Aimen , di Primio Rolando , Ondrak Robert , Unnithan Vikram 
Published: December 2013

Abstract
The Upper Jurassic Haynesville Shale play covers an area extending through East Texas, northwest Louisiana and parts of southwest Arkansas. The true potential of this play as an unconventional play was largely unknown. Only after gas prices increased during the last decade oil companies started to see the Haynesville Shale as an economic shale gas play, despite its great depths of over 3000m. At present gas prices the Haynesville Shale is due to its depth once again of only marginal interest, however, in order to be prepared for renewed interest a fundamental understanding of the processes and timing controlling shale gas prospectivity is required.
In order to understand the variables of this unconventional play, we have identified the heat flow history as a critical control. Heat flow values and evolution through time can impact the critical timing of gas generation, secondary cracking of oil to gas, and oil and gas generation critical moments.
Using state of the art basin modeling software, a reconstruction of the heat flow history was performed. Predicted formation temperatures were calibrated against temperature data collected from 1644 wells drilled over the play.
Paleo-temperature evolution was calibrated against vitrinite reflectance data collected from 26 wells. Laboratory Rock-Eval analyses were utilized to assist in this study over 6 wells.
The area has been subjected to three major tectonic uplift events. After various simulation iterations we conclude that the heat flow increased slightly with each uplift event. This suggests that the uplift was accompanied by heat flow increase indicating a likely igneous control, which had a large impact on the heat flow history within the area. Such understanding proves to be vital in order to perform accurate hydrocarbon resource assessments.
Innovative Single Phase Tank Technology for In-Situ Sample Validation Enhances Fluid Sampling Integrity
Authors: Sanchez Francisco Galvan 
Published: December 2013

Abstract
Millions of dollars are spent each year drilling in deepwater areas to prove the presence of hydrocarbons. Wireline formation testers (WFT) are able to capture and retrieve multiple, discreet hydrocarbon fluid samples at in-situ conditions. Once the sample bottles are retrieved at the surface, expeditious sample validation is critical because it provides certainty on sample type and quality. The typical process for wellsite sample validation is often very expensive and risky because it requires a full laboratory restoration apparatus, a portable lab, and trained personnel to handle high-pressure samples —often under unfavorable conditions.
The Advanced Optical Cylinder (AOC) is the latest development in single-phase sampling technology by Baker Hughes. The AOC sample chamber eliminates the high risk and costs associated with sample quality validation in the field and provide clients with very valuable and timely fluid sample data. The AOC is a nitrogen-charged sample tank that provides pressure compensation to retrieve single-phase samples; it incorporates visible-near infrared (Vis-NIR) technology to obtain spectroscopic measurements of the sample within the tank. Capturing a single-phase sample is very important because the accuracy of reservoir fluid samples provides critical information needed for optimal completion and production design. Vis-NIR spectroscopy is a well-established tool used in downhole fluid analysis that provides critical information such as fluid type, sample purity and PVT properties. With the AOC, it is now possible to verify the visible-near-infrared spectra of the captured crude oil or gas sample as soon as the tanks reach the surface, and without the need for sample transfer. Benefits include avoiding lengthy waiting periods for PVT laboratory analysis, ensuring quality samples, and enhancing critical reservoir development decisions.
The AOC provides the best method for non-invasive sample validation of the captured formation fluid sample, using a high-resolution spectrometer that easily connects to the tank (to capture detailed visible and NIR spectra of the pressurized fluid sample). The spectrum is compared to fluid analysis data acquired during WFT sampling; further VIS-NIR spectra analysis j determines contamination, GOR, bubble point, and API gravity.
Field examples are used to demonstrate the application and benefits of in-situ sample validation using the AOC.
Optimization Of Drilling Fluid Rheological And Fluid Loss Properties Utilizing PHPA Polymer
Authors: Kelessidis Vassilios C. , Zografou Maria , Chatzistamou Vassiliki 
Published: December 2013

Abstract
Drilling fluids with bentonite can often cause major problems such as flocculation, loss of rheology control and excessive friction due to high clay concentration. Polymers can mitigate such problems, but all these come with much higher costs. Partially hydrolyzed polyacrylamide (PHPA) polymers are used as additives to bentonite water based fluids to stabilize shales and in HTHP applications because of better thermal stability (PHPA). It also acts as coating on cuttings preventing agglomeration minimizing fluid loss and aiding cuttings transport. There is not much published information about PHPA optimum concentration and its mode of action and we aim to identifying these and we attempt to explain the effectiveness for achieving better design of drilling fluids.
Four bentonite (2%, 3%, 4%, 5%) and five polymer (PHPA) concentrations (0.05%, 0.1%, 0.3%. 0.5%, 0.7%) were used. The rheological behavior was described very well by the Herschel-Bulkley model. PHPA addition resulted in increase of apparent viscosity, large decrease of the yield stress and in great reduction of the fluid loss and models are presented for such behavior. The morphology of the filter cakes was investigated using Scanning Electron Microscopy in order to understand the adsorption of the polymer onto the clay particles. We try to explain the effectiveness of polymer addition and its mode of action, which further enhances our understanding of the polymer-clay interaction.
This work aids into formulating better water-based fluids for such applications using optimal polymer concentrations. Better understanding of the mode of interaction of the PHPA additive with clay particles in drilling fluids has been achieved by in-depth analysis of the effect of various concentrations on rheological and filtration properties of drilling fluids. This allows industry to work with optimal PHPA concentrations for more efficient drilling.
Integrated Workflow to Evaluate and Understand Well Performance in Multi Layer Mature Gas Reservoirs, Bahrain Case Study
Authors: Eissa M. , Kumar A. , Zaouali Z. , Chaabouni H. , Al-Ghadbhan H. , Kadhim F. 
Published: December 2013

Abstract
Natural gas is the primary source of energy in Bahrain, and the Khuff reservoir is the main supplier for this gas4. The Khuff reservoir, which was discovered in 1948, is composed of four limestone layers (K0, K1, K2, and K3) separated by tight limestone and anhydrite beds that can act as permeability buffers in some areas of the reservoir.
In such a mature carbonate gas reservoir as the Khuff, managing and optimizing the performance of wells represents a challenge for the reservoir and production engineers because of the reservoir heterogeneity created by dissolution process which induced good porosity and permeability zones within a lower quality matrix rock; differential depletion, which occurs because reservoir heterogeneity creates a pressure difference between layers; and the commingle production as Khuff wells are completed comingled using either openhole or perforated completion.
An integrated workflow applied to Khuff wells helped to understand the well performance and to optimize the workover activities. The process integrates the geological information, openhole data, multirate production logging test data, time-lapse corrosion logs, multilayer transient testing, and nodal analysis and is used to determine the remedial job that is required to achieve the most favorable well performance.
The process was applied to one of the Khuff wells that was originally completed as K2 producer and then K1 and K0 were added in double casing using a small gun size because of completion limitations. The well performance after adding K1 and K0 was below expectation, and conclusion was made that the new perforations are not performing as been expected because of insufficient formation penetration. Thus, proposed remedial actions were to reperforate the K0 and K1 intervals using a bigger gun size and then stimulate them. However, before starting this costly operation, the integrated workflow process was used to assess the need for this workover operation. The integrated evaluation showed a different conclusion, which led to different workover plan, thus saving the cost of a more expensive workover operation.
Unconventional Natural Gas Potential in Saudi Arabia
Authors: Sahin Ali 
Published: December 2013

Abstract
Surge in the worldwide demand for natural gas, in recent years, has resulted in a considerable interest in the unconventional natural gas resources in many countries, including Saudi Arabia. Numerous studies indicate that the supply and demand balance can be achieved through the exploitation of unconventional resources which are located in the major hydrocarbon basins of the world. The scope of this paper is to review the main sources of unconventional natural gas with some emphasis on potential resources in the Arabian Peninsula, and to present initial results derived from a recent study of Paleozoic formations in the Rub’ Al-Khali Basin.
Besides contributing to the general knowledge on unconventional natural gas resources, the information provided in this paper is expected to guide current exploration activities on the unconventional natural gas in Paleozoic formations in the Rub’ Al-Khali Basin.
Based on the lognormal model, it has been demonstrated that the volume of unconventional gas resources in a particular basin is several times that of the proved reserves in that basin. Considering this model, it is possible to deduce that vast amounts of unconventional resources exist in the Arabian Peninsula. Potential targets have been identified to be the Paleozoic formations, including Qasim, Sarah, Qalibah, Jauf, Unayzah, and Khuff. Average porosity and permeability measurements, based on the combined data from several vertical wells intersecting each formation in the Rub’ Al-Khali Basin, have been compared with the corresponding published data from the producing tight gas formations from North American basins. Porosity and permeability values, representing various formations in the Rub’ Al-Khali Basin, compare well with the corresponding parameters from North American basins. The same data, also, revealed the differences and similarities of patterns of distributions of petrophysical parameters in formations under consideration.
Major technical contributions of this paper include: (1) appraisal of distribution of unconventional natural gas resources in the Arabian Peninsula, (2) characterization of natural gas potential of various formations, and (3) comparison of petrophysical parameters with the corresponding values from similar basins from North America.