bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rheology of Aqueous Drilling Foam Using a Flow-Through Rotational Viscometer
Authors: Chen Z. , Ahmed R. M. , Miska S. Z. , Takach N. E. , Yu M. , Pickell M. B. , Hallman J. H. 
Published: December 2007

Abstract
Safe and economical foam drilling requires a good knowledge of foam rheology and hydraulics. Compared with traditional incompressible fluids, foam is a thermodynamically unstable fluid and its rheology is rather complex. Compressibility, quality, liquid and gas phase properties, slippage at the wall, etc., can all affect foam rheology. The true rheology of foam has been hidden in many past foam rheology experiments due to the confounding effects of wall slip, mode of foam generation, foam bubble size and size distribution, etc.
This study describes foam rheology experiments conducted using a Foam Generator and Viscometer Apparatus and Process designed and developed at the University of Tulsa (US Patent number US 6,807,849), This process utilizes a flow-through Couette viscometer with roughened cups and rotors at gauge pressure 1.72×105 Pa (25 psig) and temperature 25°C (77°F). This apparatus generates foam with controllable properties and allows the foam to flow through a modified Couette-type rotational viscometer. The flow rate is regulated so that rheology of the foam is determined under constant foam quality (in-situ gas flow volume fraction), pressure and temperature. A visualization cell coupled to an image acquisition device permits structure characterization of the foam in parallel with the rheological measurements.
Wall slip and rheological properties of different foams were studied for different rotor and cup surface roughnesses. Results relating to foam rheology are discussed with emphasis on the effects of foam bubble size, quality and wall roughness. Significant rheology differences are observed for different surface roughnesses, that was explained by wall slip phenomena.
Internal Phase Breaker Technology for Viscoelastic Surfactant Gelled Fluids
Authors: Crews J. B. 
Published: December 2007

Abstract
Past viscoelastic surfactant (VES) gelled fluids used for fracpacking and conventional hydraulic fracturing have primarily relied on external or reservoir conditions to break (reduce) the fluids gel viscosity. This paper describes an internal phase breaker system developed for breaking viscoelastic surfactant gelled fluids. Laboratory rheological data is presented that shows controlled viscosity reduction can be achieved from 80°F to 225°F by the use of two or three aqueous breaker solutions. The mix waters evaluated were KCl, CaCl2, and ASTM synthetic seawater. The results show that break times typical for polymeric fluids can now be achieved for VES gelled fluids.
Accurate, Efficient Quantification of Uncertainty for Flow in Heterogeneous Reservoirs Using the KLME Approach
Authors: Lu Z. , Zhang D. 
Published: December 2007

Abstract
Accurate modeling of flow in oil/gas reservoirs requires a detailed description of reservoir properties such as permeability and porosity. However, such reservoirs are inherently heterogeneous and exhibit a high degree of spatial variability in medium properties. Significant spatial heterogeneity and a limited number of measurements lead to uncertainty in characterization of reservoir properties and thus, to uncertainty in predicting flow in the reservoirs. As a result, the equations that govern flow in such reservoirs are treated as stochastic partial differential equations. The current industrial practice is to tackle the problem of uncertainty quantification by Monte Carlo simulations (MCS). This entails generating a large number of equally likely random realizations of the reservoir fields with parameter statistics derived from sampling, solving deterministic flow equations for each realization, and post-processing the results over all realizations to obtain sample moments of the solution. This approach has the advantages of applying to a broad range of both linear and nonlinear flow problems, but has a number of potential drawbacks. To properly resolve high frequency space-time fluctuations in random parameters, it is necessary to employ fine numerical grids in space-time. Therefore, the computation effort for each realization is usually large, especially for large-scale reservoirs. As a result, a detailed assessment of the uncertainty associated with flow performance predictions is rarely performed.
In this work, we develop an accurate yet efficient approach for solving flow problems in heterogeneous reservoirs. We do so by obtaining higher-order solutions of the prediction and the associated uncertainty of reservoir flow quantities using the moment-equation approach based on Karhunen-Loéve decomposition (KLME). The KLME approach is developed on the basis of the Karhunen-Loéve (KL) decomposition, polynomial expansion, and perturbation methods. We conduct Monte Carlo simulations and compare MCS results against different orders of approximations from the KLME method. The three-dimensional computational examples demonstrate that this KLME method is computationally more efficient than both Monte Carlo simulations and the conventional moment-equation method. The KLME approach allows us to evaluate higher-order terms that are needed for the highly heterogeneous reservoirs. In addition, just like the Monte Carlo method the KLME approach can be implemented with existing simulators in a straightforward manner and are inherently parallel. The efficiency of the KLME method makes it possible to simulate fluid flow in large-scale heterogeneous reservoirs.
Integrated Visualization and manipulation of well data for maximizing data value and delivering well-informed decisions for a shallow Tar Formation
Authors: Zubari H. , Murty CRK , Ramamoorthy R. , Srivatsava A. , Stowe I. 
Published: December 2007

Abstract
The Aruma zone in the Bahrain field is a shallow dolomitic limestone with vugs filled with heavy oil and tar. Due to difficult fluid and rock properties, the reservoir was deemed unproductive and the zone was routinely cased off to reach deeper productive horizons.
Bapco has recently launched a project to investigate the producibility of the zone under advanced IOR techniques and lifting technology. A fluid and rock data acquisition program was initiated to characterize the reservoir, which included advanced logs and core acquisition. Wellbore instability made both log and core acquisition challenging. This paper discusses the experience with the rock characterization using advanced integration software.
Due to the large volume of data acquired from a variety of advanced logs and core, it was a challenge to efficiently and effectively integrate all data and ensure utilization of every piece of information. In this paper, we demonstrate the importance and value added by using a system that facilitates integration, manipulation and simultaneous wellbore visualization in 2D and 3D Canvasses in an interactive environment. We illustrate the positive impact of such visualization on data quality assessment in zones of borehole induced artifacts.
We demonstrate the several interactions that serve to add value to the acquired information. We also discuss the impact that such visualization and interaction capability has on the accuracy of decisions made on the well and on the validity of the characterization of the reservoir rock in the near wellbore region
Integration of Dynamic & Geostatic Data Improves Reservoir Characterization
Authors: Al-Henshiri M. Y. , Arisaka K. , Al-Hassani H. , Al-Yasi T. , Fujita N. 
Published: December 2007

Abstract
Integration of the dynamic data and geologic data led to a significant enhancement in understanding the reservoir flow behavior of a major limestone reservoir in the Arabian Gulf. High-permeability streaks were found to be the main factor controlling the reservoir performance and water breakthrough in the northern sector of the field.
The methodology presented in this paper integrates static and dynamic data in such a way to ensure consistency between the data and enable better understanding of the reservoir flow characteristics. The study accommodates all available data from core, well test, O.H. logs, PLT, PNC logs and production data.
Core data was used to identify the permeability variations vertically and horizontally. In order to extend the knowledge and map the area where the high-perm streaks exist, well test, production logs, TDT/PDK logs, production and injection data were used to link the reservoir heterogeneity on well-well and on a field scale basis. Statistical wire line log analysis was conducted and found that the Rxo log response was quite useful for reservoir characterization in this regard. The results of the analysis showed good consistency with what was concluded from dynamic data.
The core and dynamic data indicate the high-permeability streaks cannot be correlated all over the reservoir, they are strictly present in the northern sector. There is a clear borderline splitting the reservoir into two sectors, the high permeability northern sector, and the low permeability southern sector.
The profiles measured with the production logs (WFL & TDT/PDK) consistently indicated the presence preferential behavior that interpreted as a high–permeability streaks at the top part of the reservoir. A linear increasing WOR trend of the wet producers is a clear indication of presence of permeability contrast that interpreted as a presence of hi-permeability streaks. The dual-permeability/porosity behavior as interpreted analytically utilizing pressure transient data found to be the response of the presence of hi-permeability streaks.
This paper shows how data integration improved our understanding of reservoir performance and reduced the production uncertainty of this heterogeneous limestone reservoir. The modified 3D simulation model matched, for the first time, the reservoir water cut performance.
The Role of Strike-Slip Faulting on Deep ‘Basement’ Faults in Cretaceous Depositional History and Fiqa Channel Location, as Determined from Analysis of 3D Seismic Over an Offshore Field, Abu Dhabi
Authors: Edwards E. , Al-Rougha H. B. , Sit H. , Sultan A. , Khouri N. 
Published: December 2007

Abstract
From structural analysis of 3D seismic data over a giant field, offshore Abu Dhabi, a complex pattern of intersecting, broadly conjugate, strike-slip dominated en-echelon fault systems are observed from ‘basement’ levels up to latest Cretaceous horizons. Over geologic time these fault systems exerted fundamental controls on depositional patterns within the study area. Use of new attribute techniques, isochron mapping, flattening on key intra-Cretaceous horizons, cinematic time-slice ‘movies’ and a review of the available vertical seismic sections has indicated that many apparent velocity anomaly zones are controlled by deep-seated fault systems developed as strike-slip dominated ‘flower structures’. Spatial continuity of these fault zones, the most prominent of which trend ~NE-SW, exhibit a linear nature on a scale of several kilometers to tens of kilometers; have flower-zone geometry in cross-section but with increasingly en-echelon nature at Upper Cretaceous levels; low apparent normal offsets on long fault segments; anastomosing, convergent and divergent, patterns at different stratigraphic levels; wrench offset with respect to other deep fault systems; throw terminations with rapidly decreasing displacement gradients along en-echelon zones into the crossover zones with other fault systems. There are four prominent fault systems that exert control on the depositional systems: (1) NE to NNE trending ‘Fiqa’ direction, also delineating local depositional highs/lows and Mishrif ‘reef’ margin; (2) NW-SE zones defining depositional areas of step-wise thickening/thinning; (3) Conjugate WNW-ESE and WSW-ENE en-echelon strike-slip zones, and (4) NNW-SSE fault zones displaying local control on thinning or thickening. Temporal fault activity on these zones is linked to sedimentary thickening and thinning patterns, though deeper level faults provided only ‘soft’ links to the sedimentary sequences of early Cretaceous age. By late Cretaceous times the transtensional / transpressional fault systems provided ‘hard’ links to the deposition systems (e.g. Fiqa channel system).
Optimisation of Stimulation Techniques for HP, Deep Wells in the Harweel Cluster, Oman
Authors: Laws M. S. , Al-Riyami A. M. N. , Soek H. F. , Abdulkadir R. 
Published: December 2007

Abstract
This paper describes the strategy that was developed to optimise acid stimulation of the Harweel Cluster Phase 1 wells. Initial treatments involved bullheading 15% gelled HCl. The latter treatments involved spotting 15% HCl and Emulsified Acid with coiled tubing using a Dynamic Diversion Technique. The results of the various methods were carefully assessed during subsequent well tests. Inflow profiles before and after stimulation have been successfully adapted by the application of the Dynamic Diversion technique. In addition, the Emulsified Acid system has also shown superior diversion characteristics compared to gelled 15% HCl. All of the key learnings from these initial stimulations are presented together with a recommended way forward.
Resistivity Anisotropy and its Impact on Reserves Estimates and Technology Applications in North Kuwait Reservoirs
Authors: Azim S. A. , Abdullah S. M. , Al-Zaabi H. , Al-Awadi W. , Najeh H. M. , Bryant W. B. , Aldred R. , Steel M. 
Published: December 2007

Abstract
Laminated shaly sand sequences are often overlooked when determining pay intervals in clastic reservoirs. This is because traditional methods of calculating hydrocarbon saturations in these formations use resistivity measurements and one of the numerous shaly-sand saturation equations. These techniques generally understimate the hydrocarbon content because conventional resistivity measurements are dominated by the conductive component of the formation, in this case shale. Even when the excess conductivity due to the shale is accurately accounted for in the calculation, there is still a high degree of uncertainty in the results.
Laminated sequences such as these are commonly found in the Burgan Formation in the Raudhatain and Sabiriyah Fields in North Kuwait. They have traditionally been considered as non-pay and the hydrocarbon content of marginally shaly formations has generally been underestimated.
Recent work re-evaluating wireline log measurements in these fields, taking the shaly formations into account, has significantly increased the volume of hydrocarbons in place. However, there remained a high degree of uncertainty in the results. These new estimates can now be confirmed, and the uncertainty removed, by the combined use of vertical and horizontal resistivity measurements. The measurements, made using a multi-component induction logging tool, measure the electrical anisotropy of the formation, and as such can give a greatly improved measure of the conductivity of the thin sand layers within the laminated sequences. Additionally, these measurements can be used to determine whether the shaly sand is a laterally extensive laminated formation or a disturbed non-reservoir quality rock.
This paper will review the technology used to acquire the measurements, show examples from the wells logged in North Kuwait, and describe the impact on reserves estimates. The paper also highlights a successful case of active interaction between KOC Field Development and Research & Technology Groups and Baker Atlas as a service company.
A New Wireless Solution to Real Time Reservoir Surveillance
Authors: Brinsden M. 
Published: December 2007

Abstract
The transmission of wellbore parameters from near the sandface has traditionally been achieved using a data transmission cable containing a shielded conductor or an optical fibre bundle. The cable is installed as part of the well completion and requires wellhead and packer penetrations. There have been numerous attempts to achieve effective data transmission from the sandface to surface utilizing either the well tubulars or the formation as an acoustic or electromagnetic transmission media, without repeaters. Achieving this type of wireless telemetry has been a goal of many equipment suppliers. Trials of a new electromagnetic system for transmitting data without cables have now shown that it is indeed possible to obtain data without wires. This revolutionary technology opens up two quite contrasting opportunities to operators, firstly in obtaining data from near the sandface in both existing and new wells without permanent monitoring systems and secondly, in providing wireless flow control at the sandface. This paper specifically reviews the data transmission capabilities of the system with the help of two case studies, which demonstrate the application of wireless telemetry data acquisition in retrofit and permanently installed applications.
New Oil in an Old Reservoir: Prize from a Comprehensive, Multi-Disciplinary Reservoir Management Approach in Sabiriyah Lower Burgan Reservoir in North Kuwait
Authors: Al-Ajmi M. F. , Chetri H. B. , Khan A. N. , Al-Anzi E. 
Published: December 2007

Abstract
Prior 2001, the overall potential as well as the viability of the long-term development of the Lower Burgan Sandstone reservoir in Sabiriyah field (SA LB) in North Kuwait were somewhat uncertain. This was mainly due to two factors; wet crude handling limited capacity (given that over 70% of the producers were wet) and the fact that the reservoir produced about 65% of its reserves. Additional penetrations into this mature reservoir out side its 1998 foot print (through deepening other reservoirs' new wells to SA LB), have resulted in extending SA LB reservoir both areally and vertically indicating new development frontiers and promising a significantly increased reservoir potential.
At that time, a multi-disciplinary team was formed to evaluate the reservoir. Better understanding of the reservoir geology, rock and fluid description, and well's performance provided the frame to make effective changes in terms of management as well as development options of this high oil API/naturally pressure supported reservoir.
The well-integrated SA LB team (four to five members) comprises petroleum engineers, geologists, and reservoir engineers, with petrophysical and geophysical support. The great efficiency of the teamwork method was combined with an excellent atmosphere of communication and collaboration with the operational and service company's personnel. The new teamworking environment has yielded significant benefit in resource and technology utilization.
The previous organization approach often compromised SA LB production/potential through focusing on the other water flooded reservoirs and treated it as a swing producer. It suffered from the absence of a proper definition of the reservoir before commitment of non-representive development plan as a swing producer with no infill opportunities.
This paper demonstrates and emphasizes the importance of developing an accurate reservoir description, realistic/flexible development plan, and comprehensive management through the joint efforts of the geologists and engineers.
Water Flooding a Heterogeneous Clastic Upper Burgan Reservoir in North Kuwait: Tackling the Reservoir Management & Injectivity Challenges
Authors: Chetri H. B. , Sturrock D. , Al-Roweyah A. , Al-Dashti H. , Al-Mufarej M. , Clark R. 
Published: December 2007

bstract
Multi-layered Upper Burgan reservoir in Sabiriyah Field of North Kuwait began production in the 1950&#39;s and is currently undergoing an accelerated phase of Water flood development.Historical Oil production from the reservoir has resulted in the decline of reservoir pressure on the crest of the structure to a level close to the bubble point. In order to augment to the reservoir energy, an injection scheme was attempted utilizing an inverted nine-spot pattern at the crest of the structure in 2000, utilizing the same grid pattern as in the overlying super giant mauddud reservoir, by dueling the injectors & producers. Later on, seeing the actual water injection performance and water flood response, it was discovered that an optimistic view of the sand continuity and the injectivity in high permeability clastics was adopted in the past, while finalizing the water flood strategy.
The severe heterogeneity and compartmentalization of the Upper Burgan reservoir coupled with formation damage, poor injection water quality & poor injectivity have slowed down the pace of the water flood development of the reservoir. It is becoming apparent that in order to implement water flood in the Upper Burgan, a scheme must be developed which takes into account the complex reservoir geometry and the practical problems of injecting variable quality water into a clastic reservoir.
Several well intervention techniques, more vigilant monitoring of the injection water quality and proppant frac jobs at the injectors yielded little improvement, far below the target injection rates. Eventually, multitude of Step rate tests was conducted to find options, leading to the decision of injecting above the formation parting pressure.
A detailed geological mapping is underway, followed by a full field static/ dynamic modeling. The current depletion strategy is focused at producing the segments with reservoir pressures higher than 3000 psia and choking back the wells at the depleted crestal part. The ongoing drilling plan has also been suitably tailored to target the segments with higher level of reservoir pressures for well placement. This reservoir management strategy has led to an increase in production by about 60%, as compared to the level about 2 years back.
The case history to be presented in the paper highlights how the production growth is being achieved in a NK reservoir beating the impact of delayed water flood.
Successful Application of Production Optimization Models to Sustain Field Target and to Defer Capital Investment in Offshore Khafji Field
Authors: Ghoniem E. O. , Samizo N. , Al-Thuwainy A. 
Published: December 2007

Abstract
Khafji field, lies in the Arabian Gulf 40 km offshore east of Al-Khafji, Saudi Arabia, commenced production in 1961, and is currently producing with average rate of over 300MBOPD.
The artificial lift, by limited capacity of 25 MMSCF/D of lift gas, was introduced in 1988 which could successfully sustain field target.Although the additional artificial lift energy was required to sustain the target rate, production optimization was found one of the solutions to prolong to sustain the target, which could result in deferring a huge capital investment.
The paper describes the construction and use of general optimization and allocation models for Khafji field which simulates the combined performance of the reservoirs, wells and surfaces gathering network.
Individual well models and surface gathering network have been built from the mid of perforations to separators at GOSPs.The more accurate multiphase flow correlation has been selected to generate performance curves.These models were calibrated and validated against actual field data with (−1.2%) average percentage error, (2.5%) average absolute percentage error and (3.5%) standard deviation, then lift gas was automatically re-distributed between wells.
A marginal gain of approximately 12,000 BOPD was concluded by lift gas optimization, and an additional gain of 15,000 BOPD can be obtained by flowline de-bottlenecking with some additions and revisions of flowline network to reduce wellhead back pressure.
Finally, these models are useful tool for production optimization to sustain field target also for routine production operations taking into account the field and system constraints, furthermore prediction of future system requirements.