bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Importance of Fluid Chemistry in High-Temperature Hydraulic Fracture Stimulation
Authors: Shelley Bob , Harris Phillip C. 
Published: December 2007

Abstract
This paper presents the results of a data-driven field modeling (DDFM) evaluation applied to a high-temperature reservoir in Australia for the purpose of determining the significance of chemistry, reservoir, well, and hydraulic-fracture characteristics on well production. The DDFM approach has identified key production drivers for a gas-well field in Australia. This information has been useful to explain hydraulic fracture well production and provide guidelines for future fracture stimulation success.
A DDFM process was used to develop a model for 32 wells completed in a complex, 250 to 350°F gas reservoir in Australia. This type of modeling technique uses data from the field, including chemical formulation, geology, reservoir, well, completion, hydraulic-fracture stimulation, and production results. The data is integrated into a common format and resolution, then visual and statistical evaluation is performed. Relevant correlations and useful trends are noted. Next an effort is made to develop a predictive model that can be used to provide an overall explanation as to what parameters drive production in the well field. Or, in effect, derive a high-level understanding about the effect of the fracturing process on the reservoir. This is accomplished by the use of data modeling/optimization technologies, including artificial neural network (ANN) and genetic algorithms.1-3 The resulting ANN model can then be used to evaluate the production associated with various hydraulic fracturing scenarios and/or characteristics. Validation of conclusions and/or resolution of difficult interpretation issues are done by detailed evaluation and modeling of key wells.
Hydraulic-fracture stimulation scenario evaluations performed by the ANN model have yielded some expected and some unexpected results. As expected, reservoir characteristics such as pay thickness, porosity, and water saturation have a dominant effect on well production. What was unexpected is the significance of well operations and stimulation fluid chemistry on well production. The practice of killing the well after stimulation and using inappropriate perforation techniques can reduce gas production by as much as one-half, while the use of a high-temperature gel breaker in combination with a reduction in base-gel polymer load can provide a 67% increase in production.
Quasimonotonic Continuous Darcy-Flux Approximation for General 3D Grids of Any Element Type
Authors: Pal Mayur , Edwards Michael G. 
Published: December 2007

Abstract
A family of flux-continuous, locally conservative, finite-volume schemes has been developed for solving the general geometry-permeability tensor pressure equation on structured and unstructured grids and are control-volume distributed [1,2]. The schemes are applicable to the general tensor pressure equation with discontinuous coefficients and remove the O(1) errors introduced by standard reservoir simulation (two-point flux) schemes when applied to full tensor flow approximation. The family of flux-continuous schemes is quantified by a quadrature parameterization and has been tested for ranges of quadrature points. Specific points have been observed to yield improved convergence for the family of flux-continuous schemes for structured and unstructured grids in two dimensions [3].
This paper presents a complete extension of the family of control-volume distributed (CVD) multi-point flux approximation (MPFA) flux-continuous schemes for general three dimensional grids comprised of any element type, hexahedra, tetrahedra, prisms and pyramid elements. Discretization principles are presented for each element. The pyramid element is shown to be a special case with unique construction of the continuity conditions. The Darcy flux approximations are applied to a range of test cases that verify consistency of the schemes. Convergence tests of the three-dimensional families of schemes are presented, with emphasis on use of quadrature parameterization. Monotonicity issues are also discussed and tests performed confirm optimal monotonicity of the schemes as determined by an M-matrix analysis [1].
Understanding the Factors Influencing the Formation and Control of Calcium Naphthenate Solids and Stabilised Emulsions Using a Novel Laboratory Flow Rig
Authors: Williams Helen , Dyer Sarah , Graham Gordon 
Published: December 2007

Abstract
The formation of calcium naphthenate solids and stabilised emulsions continues to be a major flow assurance issue. The ability to replicate the conditions under which naphthenates form in the laboratory has, until recently, been an unresolved challenge. Recent work by the authors has resulted in improved test methodologies, utilising a novel flow rig. The rig enables the study of the formation and control of naphthenate solids and stabilised emulsions under field-representative conditions, and allows the prediction and control of their occurrence in the varying production conditions that may be experienced over a field’s lifetime.
This paper describes the use of the flow rig to test a number of crude systems, some of which have known calcium naphthenate problems, and some of which are known to have no calcium naphthenate issues. The results from the flow rig have been compared with field observations and show excellent correlation. Data is then presented which more directly assess the influence of a number of variables, such as water-cut, brine composition, bicarbonate level, and pH, on emulsion stability and naphthenate formation than has previously been possible under conventional laboratory test methodology. This work therefore extends our understanding of "practical" naphthenate formation.
Continuous Reservoir Model Updating Using Streamline-Assisted Ensemble Kalman Filter
Authors: Arroyo-Negrete E. R. 
Published: December 2007

Abstract
The recent use of the ensemble Kalman filter EnKF for data assimilation and assessment of uncertainties in future forecast in reservoir engineering seems to be very promising. It provides ways of incorporating any type of production data or time lapse seismic information in an efficient way; however, the use of the EnKF in history matching comes with its share of challenges and concerns. The overshooting of certain values in the permeability field, possible increase in the material balance errors of the updated phase(s), and limitation to work with non-Gaussian permeability distribution are some of the most critical problems of the EnKF. The use of larger ensemble size may mitigate some of these problems but are prohibitively expensive to implement.
This paper presents a conditioning technique that can be implemented with the EnKF, which eliminates or reduces the magnitude of these problems. This allows for the use of a reduced ensemble size, thereby leading to significant saving in time during field scale implementation. Our approach involves no extra computational cost and is easy to implement. Additionally the final history matched model tends to preserve most of the geological features of the initial geologic model.
A quick look at the procedure is provided here. It enables implementation of this approach into current EnKF algorithms. We demonstrate the power and utility of our approach with an example.
History-Matching Multiple Attributes With Streamlines and Statistics
Authors: Gross H. 
Published: December 2007

Abstract
Geological consistency is often overlooked in history-matching problems, yielding matched models taht do not respect geological considerations. In reservoir modeling, geological consistency takes two aspects: the first is consistency in space, the second is consistency between the different properties. Consistency in space has been addressed in previous work, and a solution was found in the usage of local, flow-based, corrections as secondary information to a geostatistical simulation algorithm. Consistency across properties is the need for parameters such facies type, permeability, porosity, or net-to-gross, amongst others, to obey certain rules of inter-dependence. Honoring the relations across properties when correcting one parameter based on flow considerations is the topic of this paper.
Instead of using a simple analytical correlation for all collocated properties, we use a statistical treatment of field data gathered either through pore network modeling or through analog models. The central idea of this technique is to compute probabilities of occurrence of any given combination of properties, and once a correction is computed on one given property, other properties are updated according to the prior probabilities.
Management of Sulfur Disposal by Acid Gas Underground Injection
Authors: Vidiuk K. E. 
Published: December 2007

Abstract
In the ‘sweetening’ of natural gas, many waste byproducts are created; among these wastes is H2S. In this work the injection of pure H2S into a deep aquifer as a means of disposal and sequestration has been studied using a compositional numerical reservoir simulator. The primary concern of this study is the evolution of the area of influence of the H2S gas front through the aquifer. The study incorporated a sensitivity analysis to determine which parameters have the greatest effect on the area of influence of the gas. Once this is established, those that are controlled parameters may subsequently be optimized, and those that are aquifers properties may later become part of a selection process in choosing aquifers for H2S disposal. This will also determine which properties of an aquifer must accurately be tested in order to better predict the area of influence and behavior of the gas.
Rigless Installations of Safety Valves to Implement a Well-Integrity Campaign and Return Wells to Production
Authors: Afolabi Folorunso , Lacy Rodger , Asher Robert , Butler Bobby 
Published: December 2007

Abstract
Protecting the environment and health of the people by ensuring the integrity of all wells is one of the must-obey policies in Shell Petroleum Development Company of Nigeria Limited (SPDC). SPDC has been the leading producer of crude oil in Nigeria for more than 50 years. SPDC produces from many brown fields. SPDC currently has an inventory of producing wells that have been shut in because of one form or another of wellbore integrity problems. In some cases, these wells were completed decades ago when HSE requirements were considerably less stringent than they are today and wells were completed without sub-surface or downhole safety valves.
In 2003, a more stringent policy on non-integrity wells was introduced and led to an investigation of service providers for a more reliable rigless installation of safety valves or a more cost effective rig workover. However, most of the brown fields that encompass these wells are predominantly located in the Niger Delta both in the shallow waters offshore and in land locations including swamp areas. Many of the wells are located on small-unmanned production jackets which do not have the structural integrity to support even an electric line unit let alone a workover rig. In addition the current geopolitical situation in the Niger Delta is such that bringing in any heavy-duty equipment can be extremely difficult and highly uneconomical in most of these low producing wells.
It was against this background that SPDC carried out a well integrity management campaign to examine the feasibility of some kind of economic intervention to bring these wells back onto production.
In this paper the authors will examine in detail the prevailing situation, present details of the alternative solutions that were considered and describe a highly economic campaign that was put in place to rehabilitate some 40 wells and make available some 30,000 bopd of oil production, all without the use of major workover equipment.
Effective Application of an Innovative Conveyance Risk Management Methodology to Reduce Well Intervention Cost and Risks in Long/Deep/Tortuous Wells
Authors: Castillo H. C. , Wills P. 
Published: December 2007

Abstract
Some of the most important aspects to consider during the design, construction and productive life of a well are the amount and nature of the risks associated with the conveyance of downhole instruments to acquire critical formation evaluation (FE) data while the hole is open and downhole tool strings needed to service the well after installing the completion and production hardware.
With the increase in popularity of long, deep and tortuous wells, mainly in the high-cost operating environments, these risks have become more acute.
A new methodology, based on forces modeling and best practices gathered over decades, has been developed to take full advantage of new conveyance technologies intended to alleviate or eliminate these risks.
This paper describes the new conveyance risk-reduction technologies and their areas of applications, the newly developed risk management methodology and the economical value these innovations bring to our industry.
To demonstrate the merits and practical aspects of such an enterprise, we discuss here the following case study: A perforating job successfully completed using wireline and downhole tractors in a highly deviated well that was planned using the new methodology subject of this paper.
Spill Prevention, Control, and Countermeasure Plan Rule
Authors: Holliday George H. 
Published: December 2007

Abstract
The United States Environmental Protection Agency (EPA) promulgated the original Spill Prevention, Control and Countermeasure (SPCC) Plan rule in 1973. In 2002, EPA amended the rule, which became effective 16 August 2002. EPA postponed the revised rule compliance dates three times since promulgation and has proposed a fourth extension. In addition, EPA proposed and promulgated modifications to the revised rule to make the impact less severe on farmers, electric utilities, airport operators, and small businesses.
The rule modifications were promulgated 26 December 2006. Also, EPA proposed a new implementation date of 1 July 2009, but the implementation date of 31 October 2007 remains until the proposed revised date is promulgated. EPA states additional rule modifications will be proposed during 2007. Most businesses are reluctant to prepare SPCC Plans for facilities, since the contents of the final rule, if modified, are not known.
This paper reviews the 1) history of the SPCC Plan rule, 2) Agency's action to make the rule more palatable to a few selected stakeholders, 3) EPA modifications, 4) comments associated with the proposals to the EPA Dockets and 5) author's suggestions for compliance.
Bati Raman Field Immiscible CO2 Application: Status Quo and Future Plans
Authors: Sahin Secaeddin , Kalfa Ulker , Celebioglu Demet 
Published: December 2007

Abstract
The Bati Raman field is the largest oil field in Turkey and contains some 1.85 billion barrels of oil initially in place. The oil is heavy (12 °API) with high viscosity and low solution gas. Primary recovery has been inefficient, less than 2% of OOIP.
Over the period of primary recovery, from 1961 to 1986, the reservoir underwent extensive pressure depletion from 1,800 psig to as low as 400 psig in some regions, with a related production decline from a peak of approximately 9,000 Bbls/day to 1600 Bbls/day.
In March 1986, a CO2 injection pilot scheme in a 1200 acre area containing 33 wells was initiated in the west portion of the field. The gas injection was initially cyclic; "huff and puff" method was applied. Later, in 1988, the gas injection scheme was converted to a CO2 flood process. Later, the process was widespread to cover the whole field.
A peak daily production rate 13000 STB/d was achieved in 1993 in comparison to what would have been less than 1600 STB/d without CO2 application. However, since 1995, the field has undergone a progressive production decline to recent levels at approximately 5,500 Bbls/day. Polymer gel treatments were carried out to increase the CO2 sweep efficiency and arrest the decline. Multilateral and horizontal well technology was also applied on pilot scale to reach the bypassed oil. WAG is applied widespread now. Current production is 7000 Bbls/day.
This paper documents TPAO's 25+ years of experience on the design and operation of full field immiscible CO2 injection recovery project conducted in the B.Raman heavy oil field, in Turkey. The objective is to give an up-to-date status of the performance of the application; reservoir/field problems that TPAO had, unexpected occurrences and results and just a general idea of how successful the project has been.
Premobilization: Equipment Integrity Strategy for Safety Assurance in a Company in Nigeria
Authors: Gwaza Tersoo C. 
Published: December 2007

Abstract
The Lack of enforcement of Standards on equipments in the Developing World is a major challenge to the implementation of high safety standards with respect to equipment Integrity in the Exploration and Production business. A significant number of incidents in the last five years in the Shell Petroleum Development Company (SPDC) have been linked to Poor Equipment Integrity issues. The review of Incident statistics in the Company shows that one out of five incidents implicates equipment failure. SPDC has developed mandatory requirements known as Pre-Mobilization Procedures/Standards used in mobilization of high risk operational or contractual activity by the Company.
This paper discusses the pre-Mobilization process, a strategy used by SPDC to ensure personnel / equipment integrity and fitness for work before commencement and sustenance of same standards through activity/project life span and decommissioning.
Depth Conversion: Application of an Innovative Methodology: Added Value to a Fractured Carbonate Reservoir Interspersed With Tertiary and Mesozoic Salt Bodies Within a Very Complex Structural Setting
Authors: Flores Eduardo Lugo , Victoria Marcos , Roa Guillermo Sanchez 
Published: December 2007

Abstract
A Mesozoic mature oil field in Mexico's South Region shows a highly complex structural setting, salt tectonic has played a fundamental role in deposition and deformation, complex shaped salt bodies are present inserted within the tertiary and Mesozoic column. Several standard velocity modeling techniques have been applied in the field to depth convert the Cretaceous and Jurassic key stratigraphyc units. The most refined model showed in general 2D depth maps with an approximated prediction error of 200m.
To avoid shadow effects during the depth conversion process the interpreter has to extend the respective top and base of anomalous velocity bodies for the whole area of interest, it implies the building of fake horizons and a very time consuming grid merging process. The oversimplification of not considering those velocity anomalies embedded within the key zones implies the failure in the depth prognosis process.
The application of an innovative methodology helped to solve this problem. A 3D velocity grid is modeled considering the main structural and stratigraphyc features. Interval velocities from Seismic and from Check Shots are combined and populated. The anomalous velocity bodies are interpreted in the vicinity via manual tracking or seismic amplitude filtering. After being isolated, the bodies are related to different discrete properties as a facie, later the process of appending the connected bodies starts via conditional operations.
The result is a new Interval Velocity 3D grid that has considered the complex spatial geometry of high velocity shallow sands, as well tertiary and Mesozoic interspersed salt bodies. This Interval Velocity grid is vertically integrated and mathematically operated to be transformed into the Average Velocity 3D grid we used in the Depth Conversion process. Finally the error in the prognosis process is considerably reduced to a maximum of 100 m for wells with average total depth of 5000m.
Simulation Study of Drilling Horizontal Wells in One of Iranian Oil Fields
Authors: Azarkish Abbas , Khaghani Elham 
Published: December 2007

Abstract
The objective of this study is to investigate the advantages of drilling horizontal wells on oil recovery improvement. To evaluate the effect of horizontal length, porosity, anisotropy, staggered-line well pattern with gas injection (in the top layer) and water injection (in the bottom layer), different scenarios were studied.
This study is focused on simulation of formation-A of a carbonate reservoir which consists of three layers; where horizontal well is going to be drilled in layer-2 of this formation. The average thickness of formation-A is about 167.64 meters (550 feet) and we also have tilted water oil contact in this formation.
This field has produced around 146.9 MMBBL until year 2002 for the last 12 years with the Recoverable Reserve of about 237.31 MMBBL. Up to now 40 wells have been drilled in this field.
IRAP/RMS software was used to generate geological model. Based on selected reservoir black-oil model, IMEX from CMG is used for simulation task. Sector model used for simulation as we only had one productive horizontal well in the formation (scale-down method).
This study confirms simultaneous use of overbalance method and horizontal well in this reservoir in order to: A) Increase production rate up to 3 to 4.5 times by boosting productivity index (PI). B) Communicate a large area leading to a better drainage area. C) Postpone the water breakthrough by minimizing the draw down pressure.
Kuwait Employs Underbalanced Drilling Technology To Improve Drilling Performance While Simultaneously Evaluating the Reservoir
Authors: Vieira P. , Larroque F. , Al-Saleh A. M. , Ismael H. , Qutob H. H. , Chopty J. R. 
Published: December 2007

Abstract
The Shuaiba formation is a highly fractured limestone reservoir. The use of conventional overbalanced drilling technology in this formation usually results in the complete loss of drilling fluids to the formation. These losses cause drilling problems and results in the masking of the potential for hydrocarbon production. Underbalanced Drilling Technology was proposed as an alternative drilling method in order to evaluate the Shuaiba formation for producible hydrocarbons while simultaneously eliminating fluid loss to the formation and improving drilling performance.
The Shuaiba formation was successfully drilled underbalanced without any fluid loss during the drilling phase and a successful evaluation of the formation for hydrocarbons was completed for the first time. A multidisciplinary team contributed to the engineering, planning and execution of the first underbalanced drilling operation in Kuwait. This paper highlights the key factors in the underbalanced drilling design phase and the operational results of the first well drilled in Kuwait using underbalanced drilling technology.