bluuebunny/crossref_metadata_2025_split huggingface dataset:
Using the Low Frequency Observation Data in Automatic History Matching
Authors: Faskhoodi Majid Mohammadpour , Kelkar Mohan 
Published: December 2007

Abstract
Integration of production data in reservoir description requires solving an inverse problem. Typically, a manual procedure is used to adjust the input parameters such that the productiodata can be history matched. Recently, many new techniques have emerged which try to accomplish this objective by using automated techniques. The two most common techniques involve gradient method and adjoint method. Both methods suffer from computationally demanding algorithms, except that gradient method is efficient if number of parameters is small and adjoint method is efficient if the number of observations is small.
In a typical history matching of mature reservoir, we are faced with large number of input parameters and large number of observations. This would make both the procedures inefficient.
This study proposes a technique to reduce the number of observed data so that history matching can be accomplished more efficiently. Using the low frequency information, we demonstrate that the history matching is more efficient. We further show that the low frequency data provides more robust estimate of input parameters compared to the use of all the available data. The proposed method is validated using a synthetic example as well as actual field example.
Successful Innovative Water-Shutoff Operations in Low-Permeability Gas Wells
Authors: Chaabouni Hassan , Enkababian Philippe , Chan Keng Seng , Cheneviere Pascal , Falxa Philippe , Urbanczyk Christophe , Odeh Nadir 
Published: December 2007

Abstract
Water production from gas producing wells characterized by low productivity and low reservoir pressure zones can prematurely kill wells, leading to a considerable loss in recoverable reserves. In some cases, mechanical techniques provide a viable solution for shutting off water production, although often, such a solution will create a restriction inside the well, limiting access to deeper reservoir layers.
Even though chemical water shutoff chemicals and techniques are improving significantly, not many options are available to treat high temperature and low permeability reservoirs. It may prove difficult to squeeze cement slurries and different types of gels into such formations owing to constraints of particle sizes or fluid viscosity. It is a challenge to get a squeezable fluid into low-permeability reservoirs that will be effective in sealing the near-wellbore area and be able to withstand high differential pressure while producing. Another challenge is to determine a placement technique to prevent excess displacement of the treatment, to minimize further intervention into the well, to clean any residual treatment from the tubing, and to minimize water damage to highly sensitive producing layers.
This paper presents successful case histories of treatments that were performed to shut off water producing layers characterized by low permeability. It describes innovative techniques that were developed for this special project. The treatments were placed using coiled tubing, and only one run was required to shut off the zones in question.
Linking Well-Test Interpretations to Full Field Simulations
Authors: Al-Thawad Faisal M. , Liu Jim S. , Banerjee Raj , Agayapong Domonic 
Published: December 2007

Abstract
The objective of this study was to investigate a workflow where well test data could be used more effectively in history matching of full-field reservoir simulation models and also in situations where existing simulation models could be used in well test interpretation.
The need to effectively use information available from well test analysis in full-field simulation has long been recognized. However, only limited benefit could be obtained by reconciliation of the analytical well test model with the numerical full-field model. We present a more complete approach where a more integrated approach using a common model is advocated.. The benefits of such a workflow can be summarized as follows:
Improved well test interpretation by using simulation models that have been built using geological, geophysical, petro-physical, and dynamic data. Improved history matching of simulation models by incorporating transient pressure data. Use common data models like fluid (PVT) and SCAL data.
Existing commercial well test and near wellbore modeling software packages, were used to carry out this task. These packages provide engineering interfaces to the simulator that make their respective workflows easy. However, there were a number of situations where manual intervention and workarounds were necessary. We would like to propose an easy to use software that can provide a complete workflow for regular use.
Permeability and Water Saturation Distribution by Lithologic Facies and Hydraulic Units: A Reservoir Simulation Case Study
Authors: Shenawi Shamsuddin H. , White Jerry P. , Elrafie Emad A. , El-Kilany Khaled A. 
Published: December 2007

Abstract
In a large clastic reservoir of Saudi Arabia, rock typing by rock-quality-index (RQI) and flow-zone-indicator (FZI) proved to be an effective technique to develop porosity-permeability transforms for 8 lithologic facies in a reservoir model. Moreover, capillary pressure and relative permeability curves could be grouped into defined rock types as well. This technique provided an effective tool to distribute permeability, initial water saturation, relative permeability, and residual oil saturation per lithologic facie.
Conventional core porosity and permeability data were used to determine FZI for each core. The FZI was manipulated mathematically to group into hydraulic units (HU) in distinct integers. Each HU was then correlated to corresponding defined lithologic facies. The resulted porosity-permeability transform for each facie was applied to distribute permeability in the reservoir model. Relative permeability and capillary pressure curves also clustered together in corresponding HUs. Confidence levels in distribution of initial water saturation and residual oil saturations were increased due to this HU rock typing.
Series of J function and relative permeability curves for 8 facies were applied in the 1.4 million gridblocks reservoir simulation model. Distributed permeability and initial water saturations were validated against pressure transient analyses, core and well log data, and proved to be in excellent agreements. As a result, the uncertainty associated with petrophysical parameters was greatly reduced. The simulation model developed with the combination of HU rock typing and lithologic facies provided a higher history matching statistic (~70%) for 500 wells in a couple of weeks using assisted history matching method where facies-based petrophysical and aquifer parameters were globally modified in very narrow ranges.
This paper presents through a case study the methodology applied for generating permeability and water saturation distribution by lithologic facies and hydraulic units and its impact on simulation history match and future prediction.
Long-Term Evaluation of Low-Density Cement: Laboratory Studies and Field Application
Authors: Al-Yami A. S. , Nasr-El-Din H. A. , Al-Saleh S. H. , Al-Humaidi A. , Miller C. , Al-Yami H. , El-Marsafawi Y. 
Published: December 2007

Abstract
Cementing a string in one stage is a challenging task, especially in the presence of weak formations. Cement slurry losses during placement is highly possible in S-1 (sandstone) and S-2 (carbonate) formations, if the equivalent circulating density (ECD) exceeds 11 lb/gal during placement. A conventional method to overcome this challenge is to use multi-stage cementing by setting the stage tool above the loss circulation zone. However, the success of this tool is limited. A second method is to use low density cement.
In this study, we present extensive lab work evaluation of a low density cement system based on the use of hollow microspheres at field conditions. The tests included shrinkage, compressive strength development, porosity, gas and brine permeability. Data generated during three months supported the use the cement examined.
The hollow microspheres cement was applied in several gas wells. The technical objective of the cement job was to achieve zonal isolation across the weak S-1 & S-2 formations. The operation objective was to cement the casing to the surface in one stage without using stage tools.
This paper will discuss case histories that include job design, execution, and evaluation of the hollow microspheres cement. Field treatments were conducted without encountering any operational problems. The treatment was successful and maintained isolation for more than three years which confirmed the effectiveness of this cement system.
Expert Determination in International oil & Gas Disputes: The Impact of Lack of Harmonization in Reserves Classifications Systems and Uncertainty in Reserves Estimates
Authors: Stultz-Karim S. P. 
Published: December 2007

Abstract
The resolution of international oil and gas commercial disputes in regards to reserves determination is frequently relegated to the final and binding determination of an expert. Although expert determination (ED) is often the preferred dispute resolution method because of the technical nature of the issues and the appeal of a more timely decision than international arbitration, expert determination does not enjoy the same level of recognition or enforceability as an international arbitral award. Also, in the particular technical dispute area of reserves expert redetermination, lack of harmonization of classification systems in reserves estimates brings additional issues to consider in international oil and gas commercial disputes.
This paper is a review of current literature in the areas of expert determination in international oil and gas technical disputes, reserves classifications utilized throughout the international industry and uncertainty in reserves estimates. It will focus on the uncertainties which arise with the use of expert determination in international oil and gas disputes. These uncertainties relate to the immaturity of international law in the area of expert determination and to the lack of harmonization of reserves classification in the international oil and gas industry.
The uncertainty of the factors related to expert determination in the resolution of international oil and gas reserves disputes, however, does not mitigate the effectiveness of this dispute resolution method. Rather, with knowledge of the uncertainties, expert determination may be utilized more effectively to resolve the financially weighty reserves disputes of international oil and gas agreements.
Applications of Streaming Potential Transient Tests to Electrokinetic Characterization of Oil Reservoirs
Authors: Alkafeef Saad F. , Alajmi Nab M. , Alajmi Abdullah F. 
Published: December 2007

Abstract
Electrokinetic techniques have proven to be a valuable tool in providing direct information on charge solid/liquid interface. Today, oil industrial companies are looking into electrokinetic techniques with great interest, in order to describe the oil reservoir physics occurring in and near the well bore during production. This paper introduces a new method, which uses streaming potential transient testing to characterize the electrokinetic properties of oil reservoirs. Streaming potential exists in the movement of part of electrical double layers from the charged pore surfaces when fluid flow is induced by an applied pressure gradient. A fully computerized high pressure and high temperature core holder device is utilized to simultaneously measure streaming potential and pressure transient tests. The time behavior of the transient steaming potential is identical to that of fluid pressure when laminar flow is maintained. The transient streaming potential data is a useful quantity for determining the electrokinetic (zeta) potential values produced at the reservoir rock/fluid interface, and is considered an important electrokinetic characteristic that can play a role in reservoir rock properties. In low conductivity liquids, such as petroleum fluids, the surface conduction of reservoir rocks will cause errors in streaming potential measurements and therefore any derived electrokinetic potentials are also affected. The latter is corrected by determining the total electric conductivity of reservoir rocks, including the surface conductivity. The compressibility of reservoir fluid has been shown to affect streaming potential measurements and the results of electrokinetic potentials. We believe that this work is an important addition to the hydraulic and electrokinetic characterizations of oil reservoirs.
Applications of Mechanical External Casing Packers
Authors: Armenta Miguel , Al-Ghamdi Ali , Al-Hajji Ali 
Published: December 2007

Abstract
Field cases presented on this paper explain applications of Mechanical External Casing Packer (MECP) solving zonal isolation problems on openhole horizontal wells in Saudi Aramco. MECP is essentially a hybrid between existing cased-hole conventional packer and inflatable External Casing Packer (ECP). MECP is different than ECP in the mechanism energizing the sealing element. The packer is run as an integral part of the casing string to provide a seal between the casing and wellbore. Saudi Aramco has successfully used MECP controlling water production, isolating fractured open-hole sections, sealing casing shoe with leaking problem, and compartmenting openhole horizontal section.
Included in this paper are four different field cases for openhole zonal isolation with MECP on horizontal wells. Each field case presents a particular application for the MECP. Technical data including well configuration and casing string are included in the paper. Field operations and lesson learned from each application are also presented in this paper.
MECP has been successfully used for zonal isolation on openhole horizontal wells. Depending on the particular application, MECP can be run in combination with blank and/or screened pipe. Hole cleaning and wellbore conditions are factors affecting MECP placement.
The knowledge provided in the paper can be applied to solving zonal isolation problems on openhole horizontal sections with different rock and fluid properties. The significance of this paper is that it presents actual field experiences and lessons learned for MECP applications. Furthermore, recommended field operations for successfully placing MECP on the well are also included in this paper.
Waste Subsurface Injection: Pressure Injection and Decline Analysis
Authors: Shokanov T. A. , Nolte K. G. , Fragachan F. E. , Ovalle A. , Geehan T. 
Published: December 2007

Abstract
The economic impact of missing production targets represents high risks that demand engineering based and sound processes to ensure injection assurance.
This paper describes the results of pressure analysis conducted in injection wells, successfully utilized for Cuttings Re-Injection (CRI) and disposal of produced water because of a close monitoring of pressure injection and decline, in spite of the risky conditions. Abnormal pressure increases, and restrictions observed during injection were mitigated via engineered diagnostics.
This paper also describes the interpretation and methodology implemented to maintain safe injection assurance via regular pressure analysis until pressures reached values above overburden indicating need for associated risk assessment, including potential breach to the surface. Characterizing the disposal domain using injections monitoring and in-depth pressure analysis is a major step to enhance mitigation of waste environmental protection risks posed by CRI. Past interpretations of waste domain, appear to be in conflict with rock mechanics, hydraulic fracturing and general physics principles.
Casing-Drilling Step Improvement: PDC Successfully Drills Out Casing Bit and Finishes Hole Section at Lowest Cost
Authors: Johnstone Ian , Chomley Alistair , Cernev Gheorghe , Hoq Mahbub , Atherton Geoff , Cornel Santos Simon , Jacobs Martin , Christensen Hughes 
Published: December 2007

Abstract
Recent technological advances are driving casing drilling from a niche market into the mainstream environment. Improved connections, tubulars, advances in rig technology and pipe handling have enabled operators to consider drilling with casing/liner as an option on many new wells. In Cooper Basin, onshore Australia the need to further reduce drilling expenses in area continues to push the technology forward.
At the outset of the project, the operator's main goal was to improve drilling efficiencies with the aim of drilling more wells per rig per year. The secondary objective was to reduce costs and make the wells more economically feasible. To address these challenges, the service company recommended a specialized casing bit manufactured from a specialized steel alloy that allows technicians to braze PDC cutters directly to the one-piece bit ensuring a robust cutting structure capable of efficiently drilling new formation as well as reaming existing hole while drilling casing in place. They also recommended a new-style drill out PDC to drill through the casing bit and continue drilling formation without tripping for a new bit.
The new 6–3/4" drill out PDC bit (XDO) was run with outstanding results. It demonstrated the ability to drill through the casing drilling shoe and drilled ahead 6,000ft to TD in one run. The XDO held inclination at high WOB and did not ball up. The successful trail proves the feasibility of this technology in a full scale casing drilling application, moving the application one step closer to reality. The bit company plans to redesign the XDO to improve performance in the drill out and through the softer formations out of the shoe.
The authors will make cost comparisons with offset wells drilled with conventional drilling systems. They will also focus on lessons learned through using this new technology.
Assuring Stability in Extended-Reach Wells—Analyses, Practices, and Mitigations
Authors: Willson Stephen M. , Edwards Stephen T. , Crook Anthony , Bere Adam , Moos Daniel , Peska Pavel , Last Nigel 
Published: December 2007

Abstract
Whilst the step-out lengths of proposed ERD wells are becoming more and more challenging, wellbore stability assurance technologies - both in the pre-planning and execution phases - are developing at an equal pace. In this paper we describe several new developments in theoretical understanding and predictive capability of rock failure surrounding wells drilled at high-angle to bedding that are required to solve the problems encountered in these challenging environments. Rig-site processes for the integration of this new understanding with real-time diagnostic measurement and monitoring provide the means to deliver borehole stability assurance for ERD wells drilled in the most challenging environments.
First Full Field Steam Injection in a Fractured Carbonate at Qarn Alam, Oman
Authors: Penney R. , Baqi Al Lawati S. , Hinai R. , Van Ravesteijn O. , Rawnsley K. , Putra P. , Geneau M. , Ikwumonu A. , Habsi M. , Harrasy H. 
Published: December 2007

Abstract
Gas Oil Gravity Drainage (GOGD) of the Qarn Alam fractured low permeability carbonate reservoir is being enhanced by steam injection in the world's first full field development carbonate thermal development. Unlike a normal steam flood, the steam is used as a heating agent to enhance the existing gravity drainage mechanisms, and project has proved to be viable based on encouraging pilot results. The elegance of the thermally assisted - GOGD is that the fracture network is both used for distribution of steam and recovery of the oil. The number of wells can therefore be kept to a minimum compared to conventional matrix steam floods. Whereas the primary production performance of the Qarn Alam under cold GOGD is only expected to recover 3-5 % of the oil in place, studies to date indicate that the recovery factor under steam injection at 18,000 tonne per day will be in the range 20-35 % with Oil Steam Ratio of 0.16 -0.3 m3 oil /tonne of steam. The learning from the Pilot has not only helped understand the subsurface uncertainties but also provided significant insight into the engineering design and operational issues which are being managed right upfront during design. Energy consumption in the full field development of this project is reduced by banking on the benefit from co-generation of power and steam. Utilisation of co-generation will minimise CO2 emission and reduce gas import. The project will be under construction from 2007, with full rate steam injection reached by late 2009. The paper not only discusses how the project addresses the reservoir management challenges of this complex recovery mechanism but will address some of the engineering and operational challenges that are being managed.
An Empirical Saturation Modeling of a Complex Carbonate Abu Dhabi Reservoir Using the Routine High-Pressure Mercury and Oil/Water Capillary Pressure Data
Authors: Basioni R. E. Mahmoud , Negahban R. E. C. Shahin , Dawoud Ahmed , El Mahdi Ahmed , Bahamaish T. L. Jamal 
Published: December 2007

Abstract
Minimizing uncertainty associated with predicted log water saturation can be best achieved through the integration of log analysis (formation evaluation) and capillarity (core measured high pressure mercury and oil/water drainage capillary pressure data). Further reduction of uncertainty in predicted formation water saturation requires; first the most probable log porosity solution interpretation; second the most probable log porosity/permeability relationship (match core measured values); and third a quantitative capillary pressure model that represents measured high pressure mercury and oil/water drainage capillary pressure data.
In this paper, the classical Leverett-J method (Leverett 1941) was used in the integration of capillary pressure data with routine core analysis and petrophysical rock types to generate a robust model for predicting formation water saturation profiles. The classical interpolation method that relates capillary pressure (derived from Leverett J function) to water saturation has been used predict the wetting phase saturation. The assignment of capillary pressure curves to their corresponding rock types was accomplished by grouping rock types according to discrete ranges of the interval speed which is defined as the square root of core measured permeability divided by porosity (k/φ) data. Each range of the interval speed will have a corresponding Leverett J function from which water saturations will be interpolated according to its respective height above the Free Water Level (FWL) (using the log predicted permeability-porosity ratios). In the absence of clear fluid contact, a trial and error method is used to adjust the FWL until a good agreement between the log predicted water saturation and the predicted water saturation from the capillary pressure correlation is reached. The error in averaging was minimized by increasing the number of rock types (minimizing the ranges of interval speed) using a large number of measured high pressure mercury and oil-water drainage capillary pressure data. Furthermore, this paper presents a comprehensive comparison of the log derived and model predicted water saturations.