bluuebunny/crossref_metadata_2025_split huggingface dataset:
Predicting Reservoir Compaction and Casing Deformation in Deepwater Turbidites Using a 3D Mechanical Earth Model
Authors: Sayers C. , den Boer L. , Lee D. , Hooyman P. , Lawrence R. 
Published: December 2007

Abstract
Production from deepwater turbidites is made more challenging by geomechanical problems arising from overpressure, reservoir compaction, casing failure, etc. The impact of reservoir compaction on field development is best examined early in the life of the field, when there is an opportunity for proactive planning. The interaction between heterogeneous reservoir layers, well trajectories and stress changes due to depletion is a complex 3D problem; it is best solved using a 3D approach. This paper illustrates the use of a 3D MEM (Mechanical Earth Model) to quantify reservoir compaction, casing failure and surface subsidence for a deepwater Gulf of Mexico turbidite.
Reservoir flow simulation data are used to evaluate stress changes, reservoir compaction, casing deformation and surface subsidence resulting from production. Geomechanical hot spots, where reservoir compaction is predicted to be greatest, are identified to allow production strategy to be optimized. Several possible modes of production-induced casing failure are examined. The likelihood of casing failure is then assessed to facilitate development of strategies for either avoiding such risks, or reducing their impact.
This work shows the importance of developing a 3D MEM early in field development. In high-porosity, pressure-compartmentalized sandstones, quantification of reservoir compaction is essential for planning the casing and completion integrity through the life of the reservoir.
Kuwait Oil Company's Latest Semiautomated Deep Drilling Rig – HAH Rig 124, The Middle East's Most Modern 3,000-HP Land Rig
Authors: Al-Kandari Ayad , Al-Saeedi Mohammed , Kingsborough Roger , Brewster T. W. , Mckinnell David 
Published: December 2007

Abstract
KOC has been drilling deep HPHT wells from the mid 1980’s, and during this time the Kuwait deep well prospects have become deeper and more challenging. The rigs utilized to drill these wells have evolved over the years to meet these challenges, with new technologies being used to improve both operational and safety aspects.
Five years ago an enhanced rig type upgrade was introduced with the application of Top Drive, additional third 1700 HP mud pump and larger 5 1/2" O.D. drill pipe. This resulted in a step-change improvement in drilling performance.
In 2003 KOC began a project to look into the radical re-design of the deep rig specifications. Hamad Al Hamad and Partners was awarded the contract to complete the detailed design, procure and operate the rig, and National Oilwell Varco was assigned as the main rig construction contractor.
For the rig design certain new concepts were to be developed in readiness for a future campaign of deep HPHT exploration wells. These included the following; the rig should be safer and more automated, the capacity of the main equipment items and the mud system should be state of the art both in capacity and equipment specifications, the 15M BOP stacks should be re-designed to minimize handling, and the rig should be adapted for operation in the harsh summer conditions in Kuwait.
This paper will discuss the evolution of Deep Drilling Rig design in Kuwait, the design and specification of the new HAH-124 rig plus the construction/rig-up of the unit. The case study will also focus on lessons learned during this process and conclude with recommendations for future new rig builds.
Gas-Liquid-Solid Coupled Flow Modeling in Fractured Carbonate Gas Reservoir With High H2S Content
Authors: Zhimin D. , Xiao G. , Yong Z. , Xuefeng Y. , Gaojun S. , Yong W. 
Published: December 2007

Abstract
Technical studies, production and operations, and management of fractured carbonate gas reservoir with high H2S-content are difficult and uneconomical tasks to perform due to high toxicity and corrosivity of H2S. The optimization of conceptual design of these reservoirs may become cost efficient through the use of integrated simulation. However, to our knowledge, previous models do not well allow for the characteristics of complex flow through porous media in fractured carbonate gas reservoir with high H2S-content, nor do they consider the influence of the special physical and chemical changes on production performance, which makes the prediction of production behavior uncertain. In this paper, mechanisms of the gas-liquid-solid migration and formation damage resulting from sulfur deposition in fractured carbonate gas reservoir with high H2S-content were investigated by means of numerical simulation. A new gas-liquid-solid coupling model in fractured carbonate gas reservoir with high H2S-content, accounting for sulfur deposition, phase behavior variation, geochemical rock-water-gas interactions, adsorption, was presented. A modified equation of state was also used to describe phase behavior variation and combined with the integrated model. The model can forecast the production mechanisms and performance of fractured carbonate gas reservoir with high H2S-content, particularly, evaluate accurately and rapidly H2S concentration, mole content spatial distribution and dynamic change with pressure or time. This work can also promote safer development design to fractured carbonate gas reservoir with high H2S-content and avoid failure in operations.
Drilling Performance and Environmental Compliance—Resolution of Both with a Unique Water-Based Fluid
Authors: Young Steven , Ramses Gamal 
Published: December 2007

Abstract
In an industry where the technical demands on a drilling fluid are ever increasing, the use of invert emulsion fluids has been seen as a necessity to meet required drilling performance criteria. At the same time there is increasing pressure to comply, and even exceed, the tightening environmental demands on our industry which has made the use and associated waste treatment of these invert fluids complex and costly. A drilling fluid, which has the drilling performance characteristics of an invert emulsion fluid, but can exhibit the benign environmental characteristics of a simple water-based fluid, has long been the goal of fluids development.
This paper describes the development and application of a unique water-based fluid that utilizes a triple inhibition approach to delivering invert emulsion-like drilling performance. Each component of the fluid system has also been designed to ensure compliance with some of the world's most demanding environmental requirements. The resulting fluid is flexible in formulation such that it can be utilized in freshwater on land wells to meet chloride discharge requirements, can be formulated in seawater for shelf wells to meet low toxicity and logistics requirements, and can be formulated in saturated salt water to meet toxicity and performance requirements for deepwater environments.
The applications of this fluid on a global basis will be evaluated, comparing the drilling performance and economics to offset wells which have utilized both conventional water-based fluids and invert emulsion fluids.
Integrated Reservoir Modeling for Evaluating Field Development Options in Agua Fria, Coapechaca, and Tajin Fields of Chicontepec Basin
Authors: Takahashi S. , Abbaszadeh M. , Ohno K. , Soto H. S. , Cancino L.O. A. 
Published: December 2007

Abstract
This paper presents a methodology for pixel-based hierarchical geostatistical reservoir characterization and flow simulation of submarine fan turbidite sandstone deposits in the Agua Fria, Coapechaca and Tajin fields of the Chicontepec basin in the Gulf of Mexico. Extreme heterogeneity of rock fabric and petrophysical properties prevails within the multiple stacks of turbidetic sequence events across the fields. Capturing this complex geologic heterogeneity in reservoir characterizations and reservoir simulation models for strategic decision making in field development is a major challenge. We first present a general methodology based on multivariate Gaussian formalism for integrating various sources of data at different scales to build high-resolution geostatistical reservoir characterization models directly at log scale for the Agua Fria, Coapechaca and Tajin fields. Multiple seismic attributes and geological diagenesis information at sequence and subsequence scales are integrated into these models to generate representative reservoir descriptions.
Next, we use the constructed geostatistical models to investigate recovery performance of Chicontepec fields under primary and waterflood processes. Sector models and pilots of multi wells in the Tajin and Agua Fria fields are considered for this purpose. The fine-scale and coarse-scale reservoir characterization models are calibrated to dynamic performance data by history matching the primary production and an actual waterflood pilot data in Agua Fria, and then used as predictive tools for other field development scenarios. The viability of waterflooding the very low permeability and highly diagenized Tajin filed is investigated, where large reservoirs are still left in-place because of loss of reservoir energy due to primary depletion.
Long-Term Comparative Evaluation of HCl/Formic Acid System Used To Stimulate Carbonate Formations at Severe Conditions in Saudi Arabia
Authors: Nasr-El-Din H. A. , Al-Driweesh S. M. , Sierra L. , van Domelen M. , Welton T. 
Published: December 2007

Abstract
The high levels of carbon dioxide and low levels of hydrogen sulfide content of some deep and high temperature gas producers contributed in the requirement to complete these wells using super Cr-13 tubings. Due to the low permeability of the formation and the associated formation damage issues, acid fracturing treatments were required to optimize the productivity of these wells.
This paper describes the selection, optimization and long term comparative evaluation of the gelled and in-situ cross-linked HCl/formic acid systems used this type of wells. The high temperatures encountered in deep wells and the susceptibility of super Cr-13 to severe corrosion in high concentration HCl systems used for stimulation purposes added one additional difficulty to the acid stimulation process. To overcome these problems, extensive experimental and field studies were performed to select an acid system to enhance the productivity of these wells.
Core flood tests performed with HCl/formic acid systems showed their ability to create deep wormholes in tight carbonate cores; however the corrosiveness of these systems at downhole conditions could be severe if the correct type and concentration of corrosion inhibitor is not used. In general, for the HCl/formic acid systems at downhole conditions (275°F) it was found that high concentrations of corrosion inhibitors are required to protect the super Cr-13 completions.
Based on lab tests study acid stimulations were performed, the flow back fluid was recovered and analyzed to observe the corrosion problems and to optimize the corrosion inhibitor.
In all the cases the wells responded very well to the acid stimulation and the completion integrity was not compromised in a short or long term. The paper also shows for the first time a comparative long term well response to the acid stimulation of the two acid systems used in the area, showing the better performance of the in-situ crosslinked HCl/formic system over the gelled HCl/formic system.
Reaction Kinetics of Gelled Acids With Calcite
Authors: Nasr-El-Din H. A. , Al-Mohammad A. M. , Al-Aamri A. M. , Al-Fuwaires O. 
Published: December 2007

Abstract
Hydrochloric acid is used to stimulate carbonate formations (both matrix and fracturing treatments). However, the reaction rate of the acid with carbonate minerals, especially calcite, is very fast. In addition, the viscosity of HCl solution is relatively low. Acid-soluble polymers are usually added to the acid to increase its viscosity, which is needed to enhance acid diversion during matrix acidizng and reduce acid leak-off rate during acid fracturing. Gelled acid is extensively used in matrix and acid fracturing treatments performed in carbonate formations. However, a few studies have evaluated the impact of these polymers on the reaction rate of the acid.
This paper uses a rotating disk instrument to measure the reaction rate of gelled acids with calcite rocks. Measurements were conducted over a temperature range of 25 to 65°C, a pressure of 1,000 psi, and rotational speeds of 100 to 1,000 rpm. Acid formulations that are typically used in the field were examined. Polymer concentration was varied from 0.5 to 2 wt%. The apparent viscosity of the gelled acid was measured using a Brookfield viscometer. Measurements were done for the same solutions tested with the rotating disk instrument. The temperature was varied from 25 to 100°C, while the pressure was maintained at 300 psi. The shear rate was varied from 57 to 1,700 s−1.
The results obtained indicated that the apparent viscosity increased notably as the concentration of polymer increased from 0.5 to 1.5 wt%. On the other hand, there is significant decrease in the dissolution rates as the concentration of polymer was increased from 0.5 to 1.5 wt%, where there was no measure difference as the concentration increased to 2 wt%. Reverse and toroidal flows were noted within the rotational spends examined. The etching pattern on the surface of the disk depends, among other factors, on the disk rotational speed and polymer concentration. The dissolution rate was found to be a function of temperature, rotational spend and polymer concentration.
Production Optimization of Turbidite Reservoirs in Russia—A Pilot Field Development Case Study
Authors: Kryuchkova T. , Igoshkin V. , Edelman I. , Ruiz H. , Kalita N. , Poettmann P. , Voicu B. 
Published: December 2007

Abstract
This paper presents a field development case study of a low permeability turbidite reservoir in Russia. The giant Priobskoye field contains 30 API crude in laminated sandstones of 0.1 to 20 md at a depth of around 2500 meters. The complex geology, lack of reservoir information and lack of technology availability caused a 20-year gap between discovery and development.
The initial pilot development was halted after poor drilling success, thus the operator invested in 3D seismic acquisition and an integrated, multidisciplinary reservoir modeling and simulation effort. The subsequent development was based on oriented water flooding patterns and massive hydraulic fracturing, together with an artificial lift system equipped with permanent pressure and rate monitoring for evaluation and real time production enhancement.
The optimization of operational practices and introduction of fit for purpose technologies enabled a production increase from an intermittent hundreds of BOPD to more than 75000 BOPD in a period of 3.5 years. The exploitation strategy of this pilot area demonstrated commercially sustainable production from the reservoir and will form the basis for full field development.
Miscible Gas/Oil Gravity Drainage
Authors: Verlaan M. , Boerrigter P. 
Published: December 2007

Abstract
Oil recovery from oil and mixed-wet naturally fractured reservoirs is difficult. Standard production mechanisms like water injection and countercurrent imbibition will not work. Gas–oil gravity drainage (GOGD) is then the production mechanism of choice. Gravity drainage with immiscible/ solution gas can result in low production rates and/or high residual oil saturation due to capillary holdup.
When the injected gas is miscible with the oil, density and viscosity reduction will occur. Miscibility adds the advantages of single-phase flow and interfacial tension reduction, which further improves GOGD rates and ultimate recovery.
The paper discusses the modeling and upscaling of first contact miscible gravity drainage as well as the differences from regular gas injection processes. The key parameters for this case were identified to be width over height ratio, layering heterogeneity and gas recycling rate. First contact miscible gas injection benefits the most from the IFT reduction and is most suitable in heterogeneous reservoirs with large capillary hold up and re-imbibition effects.
Successful Application of Exploration Lessons Learnt to Deliver Stretch HT/HP Well Delivery Objectives (Krishna Godavari Basin, India)
Authors: Kumar Suresh , Affes Sami 
Published: December 2007

Abstract
Much work has already been undertaken by various operators throughout the industry to explore frontier areas and drill into ever-deeper geological horizons. High pressures and temperatures in the range of 15,000 psi and 450-F need to be handled to safely drill and produce these targeted reservoirs.
This paper illustrates the experience of an E&P operator in the exploration process of a deep Ultra HPHT field offshore east India.
Pressure Monitoring: Key for Waste Management Injection Assurance
Authors: Fragachán F. , Ovalle A. , Shokanov T. 
Published: December 2007

Abstract
The volume of cuttings and produced waste, particularly produced water, will increase as brownfield developments progresses. Missing environmental and economic targets represent a major investment exposure. As a resut, there is an increasing demand on engineering to mitigate process risks and ensure injection and sound subsurface waste management.
This paper describes the outcome of pressure analysis successfully used for Cuttings Re-Injection (CRI) and disposal of produced water resulting from closely monitoring pressure injection and decline. It addresses proper root-cause engineering diagnostic processes that were implemented during abnormal pressures increases and restrictions observed during annulus injection in North Sea projects.
Severe risks were mitigated with injection pressures observed, on occasion above overburden, to maintain safe injection assurance. A methodology was developed and implemented, as a result of process mapping based on signature pressures from pressure decline. Their characterization represents a major step in mitigating risks posed by waste injection, providing not only engineering understanding valuable to overall drilling operations planning, but also minimizing potential environmental impact with sound engineering subsurface waste management.
Outcrop Characterization of Fractured Cretaceous Carbonate Reservoirs, Zagros Mountains, Iran
Authors: Sharp I. , Gillespie P. , Lønøy A. , Horn S. , Morsalnezhad D. 
Published: December 2007

Abstract
Well-exposed outcrops of Middle Cretaceous carbonates in the Zagros fold belt, Iran have been used to provide input data for a dual porosity reservoir model incorporating both matrix and fracture heterogeneity. The modelled outcrop area is located on the steeper dipping limb of a large-scale (10km wide, 100km long) asymmetric Tertiary anticline. The outcrop is structurally and stratigraphically analogous to producing and prospective anticlines in the nearby subsurface.
Matrix heterogeneity can be divided into primary (depositional) and secondary (diagenetic) heterogeneity. Sources of primary heterogeneity include: 1)large-scale depositional architecture (e.g. shelf margin clinoforms, depositional sequence architecture), 2) macrofacies architecture and distribution, e.g. length scale distribution and geometry of carbonate sand shoals and rudist biostromes, 3)microfacies distribution and associated variability in primary pore types. Sources of secondary heterogeneity include diagenetic alteration of primary pore systems, karstification and hydrothermal dolomitisation. We demonstrate a close link between primary heterogeneity and secondary porosity-permeability distribution in the matrix.
To construct the outcrop model, vertical stratigraphic logging and sampling were undertaken to establish a synthetic well log from which reservoir architecture, zonation, facies, microfacies, pore-type, and porosity-permeability data could be derived. "Walking-out" of depositional and diagenetic elements captured horizontal and vertical correlation length scales of porosity-permeability distribution and architectural features.
The main fractures present are normal faults and joints. Faulting was characterized using measurements of fault kinematics, orientation, displacement, length, fault zone thickness and fault zone petrology. The normal faults are nonstratabound and have power-law scaling. Faults were stochastically simulated in a discrete fracture network and then scaled up to a reservoir simulation grid. Resulting porosity-permeability distributions are highly heterogeneous.
Joints are stratabound and have an almost constant density within the same stratigraphic horizon, regardless of outcrop location (e.g. fold limb vs fold crest). In contrast, joint density varies greatly vertically according to lithology/facies. Joints were modelled using a simple parallel plate model approximation. Permeability due to joints is highly heterogeneous vertically, but laterally homogeneous.
Construction of the outcrop model has been key to reducing uncertainty in geological interpretation and modelling of subsurface data, in particular with regard to characterization of porosity-permeability distribution and in interpretation of test data. The modelling workflow presented in this paper is directly relevant to producing and prospective fractured Middle Cretaceous carbonate reservoirs elsewhere in the Middle East and in Mexico.