bluuebunny/crossref_metadata_2025_split huggingface dataset:
Water Cone Subsidence Time of a Horizontal Well
Authors: Lee Robert L. , Nath Shyamal , Khan Mashiur , Permadi Pudji 
Published: December 2007

Abstract
Because of a localized decrease in pressure, water may rise to a height above the oil-water interface and be produced through a horizontal well. The localized increase in the water-oil interface elevation creates a cone of water near the well. If a large enough drawdown is exerted on the reservoir, water will start replacing the oil in the production stream. The instant when water first enters the well is known as the critical drawdown or threshold drawdown. As the producing water-oil ratio increases, the operating cost of the well as well as the oil production cost will start increasing. At some point, the well may need to be shut-in to allow the water-oil interface to subside. In this situation, an optimum shut-in time exists, and it is dependent upon the subsidence time of the water cone.
Analytical solution for subsidence of water cone under a horizontal well is being presented in this paper. Usually, wells require a shut-in period if the drawdown exerted on the reservoir is above a critical value. But, depending on the amount of the drawdown exerted, the water cone can have a wide variety of shapes at the post-critical drawdown condition. To avoid this, the initial water cone shape in this solution, after the well is shut-in, is defined at the point of critical drawdown.
The water cone shape under a horizontal well at the point of critical drawdown is estimated here by developing an empirical formula. The cone shape is found to be a function of the critical oil production rate.
The water cone subsidence time is determined by solving the diffusivity equation using the separation of variables technique. The resulting solution shows that the subsiding instantaneous cone heights are exponentially related to time and are effected by hydraulic conductivity of reservoir, coefficient of specific storage of porous medium, the critical oil production rate and the reservoir geometry. Finally, the cone subsidence time is presented in a series of type curves that assumes various reservoir parameters.
Well Design for Shallow Gas
Authors: Murray S. J. , Williamson M. D. , Gilham Steve , Thorogood J. L. 
Published: December 2007

Abstract
Shallow gas and its associated operational procedures have been the subject of much opinionated debate. Previous work in the area has focused either on regulatory issues or on the steps that can be taken while drilling to minimise the consequences of a shallow gas kick. Although some attention has been given to modelling the behaviour of wells under shallow gas blowout conditions, this has not resulted either in a practical design tool nor in a structured procedure for checking well designs.
This paper puts forward a provisional framework which highlights the design checks that should be made to ensure that rig systems, well designs and operational procedures are safe and fit for purpose.
The framework should permit engineers to approach the problem of shallow gas well design in an analytic and structured fashion, using a specified set of analysis techniques. These techniques are reviewed and transient well unloading and quasi-steady blowout simulations are identified as critical elements. The basis and operation of a practical software tool which addresses these elements is described. Some examples of its use are given and areas where modelling improvements could be made are suggested.
Allowable Torque of Tubular Connection Under Simulated Running and Working Conditions
Authors: Tsuru Eiji , Maruyama Kazushi , Inowaki Ryuichi , Tochikawa Tetsuro 
Published: December 2007

ABSTRACT
In field operations, the make-up torque of tubular connections depends on compensated axial weight and environmental temperature. Also, in running operations, torsion can be applied to casings with connections under loading.
This paper deals with the torque resistance of tubular connections, with regard to field operating conditions. The results indicate that the make-up torque increases when the grease quantity is small and the temperature is low, and the torque resistance improves under loading. Using the predicted torque resistance, the true safety of the connections can be evaluated for their torsional strength.
The World's First Multi-Year Slimhole Exploration Project — A Successful Partnership Between Operator and Contractor
Authors: Spoerker H. F. , Cambar Edgar , Nunez Jose 
Published: December 2007

Abstract
For the last decades, slimhole rigs were scarcely available, because drilling contractors wouldn't invest in new equipment without signed contracts in their hands, and operators were reluctant to enter in long-term slimhole exploration contracts. Maraven, S.A., and Corpoven, S.A., both operating affiliates of Venezuela's oil and gas holding PdVSA, have entered into multi-year contracts for two purpose-built slimhole drilling rigs, allowing the development of state-of-the-art drilling equipment and for the first time showing the technical and economic benefits attainable by fully applying slimhole technology over two entire exploration projects.
The paper presents the experience from more than two years drilling and completing slimhole wildcats in Venezuela. Based on 8 case studies from the wells completed so far, typical drilling problems and their solutions are discussed, new operational procedures developed during the project are listed, and the current state of slimhole technology is defined. Challenges originating from drilling in highly environmentally sensitive areas, such as full helicopter transportability and zero discharge drilling, as well as drilling slimholes to more than 13000 feet on the tectonically stressed southern flank of the Andes chain are presented. The organizational structure of the operation and the benefits derived from close partnership between the operator and contractor are outlined.
To quantify the success of the program, the economics of drilling these first 8 wells to depths of more than 13000 feet are presented, and the savings inherent to slimhole drilling technology are clearly defined. Comparisons to an alternative, standard drilling program are given, and the specific reasons for selecting slimhole technology for these projects are dicussed.
The Effect of Rheology on Rate of Penetration
Authors: Beck F. E. , Powell J. W. , Zamora Mario 
Published: December 2007

Abstract
Field data have been collected and analyzed to 1) identify the characteristics of a drilling fluid that enhance rate of penetration, and 2) quantify the impact of particular fluid properties on rate of penetration. The information is being used to evaluate the economics of a fluid treatment program in order to deliver optimal drilling performance and minimum drilling cost, rather than minimum fluid cost. Additionally, it is demonstrated how bit hydraulics can be improved through rheological modification without adjusting flow rate or nozzle size.
Commonly Used Biodegradation Techniques for Drilling Fluid Chemicals, Are They Appropriate?
Authors: Slater Monica , Hille M. H. , Molversmyr Åge 
Published: December 2007

ABSTRACT
In order to assess the suitability of commonly used biodegradation techniques to simulate the environmental behaviour of pseudo oil-based fluids in the sea, a comprehensive study has been conducted. More than 40 biodegradation experiments, using different techniques, have been performed on one particular synthetic base fluid (an acetal). The results are compared to large scale simulation tests and a seabed survey in an attempt to identify the biodegradation method that most closely resembles the natural biodegradation process.
Case History of Directional Drilling in the Cusiana Field in Colombia
Authors: Skelton J. , Hogg T. W. , Cross R. , Verheggen L. 
Published: December 2007

Abstract
A "J"-shaped directional well was successfully drilled in record time without problems to total depth (TD) in the Cusiana Field in Colombia. The drilling conditions in this field have historically proven to be very difficult because the basin is heavily faulted and tectonically stressed. Previous wells in the area have encountered major drilling problems that have been primarily related to wellbore stability and directional drilling.
The Buenos Aires Well B-6 was drilled using only rotary bottomhole assemblies (BHA); no motor runs were planned or were made. Significant improvements in directional drilling practices were made as. a result of careful planning, close teamwork, and careful execution. The paper describes the keys to success in planning and drilling this 3500-ft step out well in a heavily faulted and tectonically active basin.
Subsea Drilling Riser Wear: A Case History
Authors: Poss G. T. , Hall R. W. 
Published: December 2007

ABSTRACT
Wear in subsea drilling risers and BOP equipment while drilling can be an expensive problem. If the wear causes loss of riser integrity the risk to personnel and equipment is potentially significant due to the well control situation that could result. This paper presents information on a serious riser/BOP wear occurrence that resulted in serious well control problems and an expensive equipment repair. The case study presented here occurred in only 295 ft of water in a relatively short period of drilling time. The approximate cost of the resulting problems was in excess of US$3.5 million. This paper will also present a simple model that can be used to estimate the wear in a riser and flex joint. The calculations in this paper will provide a means to determine the relative effects of such parameters as riser angle and tooljoint hardbanding abrasiveness. With this knowledge it is possible to develop an informed riser wear management program.
Optimization of Bit Selection Leads to Improved Performances Onshore Thailand
Authors: Besson A. , Rabis P. , Scott D. E. , Torgerson T. 
Published: December 2007

ABSTRACT
The lithology of northeastern Thailand features compacted shales, siltstones and claystones interbedded with hard and abrasive quartzitic sandstone and volcanic Stringers. Owing to the difficulties encountered in drilling this lithology, earlier wells were plagued by unacceptably low ROP and bit life. Further, unstable hole walls often led to excessive reaming, while use of heavier mud to maintain the hole wall would severely impact rate of penetration.
This paper describes the methodology and results of a partnership between operator and service company that greatly improved the drilling performance and economics of the subsequent exploration well. Central to the improvement was close cooperation between operator and service company in the early planning stages of the well and the decision to use advanced technology to reduce the risks. A detailed analysis of offset wells, including detailed dull bit analysis, led to the recommendation to use aggressive TCI bits with such premium features as metal face seals and active shear cutting diamond gauge inserts and selective placement of PDC bits where suitable.
The systematic selection of more aggressive cutting structures with active shear cutting diamond gauge inserts for drilling the very plastic shales with quartzitic sandstones instead of more traditional style medium formation TCI bits led to a higher ROP with no sacrifice in bit life.
The use of the active shear cutting diamond gauge configuration, usually applied in abrasive formations, led to increased life and reliability in the tough reaming operation in swelling / sloughing shales with excellent gauge holding performance and seal life. The more aggressive design yielded increases in ROP.
Results of the cooperative program – improved ROP, bit life and savings of more than $600,000 – will be presented and explained.
Prediction of Barite Sag Potential of Drilling Fluids from Rheological Measurements
Authors: Saasen Arild , Liu Dawei , Marken C. D. , Sterri Njål , Halsey G. W. , lsambourg Patrick 
Published: December 2007

Abstract
Barite sag under static and dynamic conditions has been studied in the laboratory. Static sag has been related to viscoelastic properties of several fluids. These viscoelastic properties are related to gel formation which needs to be sufficient to keep barite in suspension. This static sag was not predictable by the use of standard VG viscometers. Dynamic sag can be severe even when static sag is negligible. The understanding of dynamic sag is much more difficult than sag under static conditions.
Wellsite Action on Drilling Mechanics Information Improves Economics
Authors: Burgess T. M. , Martin C. A. 
Published: December 2007

Abstract
A major concern in the process of drilling is the high incidence and economic impact of lost time problems. In one study, it was shown that 75% of lost time incidents were associated with drilling mechanics problems. Obvious costs of poor drilling mechanics include lost rig time and damaged equipment. However hidden costs can add to this with low rate-of-penetration, more trips, lost-in-hole charges and increased service company charges.
Numerous technical papers in the past have documented specific drilling mechanics techniques. This paper summarizes the latest proven drilling mechanics techniques which have been applied to drilling operations to reduce these costs. The three major areas discussed are the following:
Stuck Pipe Prevention – Prevention of stuck pipe starts in the planning process where formation drillability is evaluated and borehole tortuosity is minimized. The operational phase of stuck pipe prevention involves continuous real time monitoring of drilling events, both for early detection of incipient sticking and to identify potential trouble spots while tripping.
Drillstring Failure Prevention – Shock and vibration often lead to extreme damage to drillstring and bit, broken downhole tools, and reduced rate-of-penetration. Mathematical models and surface measurements for failure prediction and detection have severe limitations. Downhole measurements of shock and vibration, in combination with surface measurements, can be used to determine which changes to drilling operational parameters can lead to the greatest reduction in downhole shock and vibrations.
Rate-of-Penetration Optimization – Using downhole drilling mechanics measurements, it is possible to increase weight transfer efficiency, reduce bit wear, optimize PDC bit performance, and improve PDM efficiency, all leading to improved penetration rates and more favorable economics.
Each of these broad areas is illustrated with field examples.
Fracturing Improvements Enhance Infill Drilling
Authors: Miller B. J. , Gillstrom R. L. 
Published: December 2007

ABSTRACT
The production history of a one thousand well field extension drilled in the early 1980's showed that additional wells could not be drilled at current oil prices and oil recovery. Step out drilling and production history showed that an additional one hundred infill and development wells could be drilled if the recovery could be increased. Multiple production logs indicated the upper half of the zone was not open at the well bore. Thus, if the upper zone could be more effectively completed, the well recovery had the potential to be increased to a level where future development would be feasible. The low reservoir pressure and high permeability contrast requirements demanded that a much higher viscosity fluid system needed to be used that also had the ability to clean up easily. The nitrogen foam frac yielded these desired characteristics. Five infill wells were drilled in 1991 and 1993 utilizing a nitrogen foam frac system. Production from the wells has shown a projected ultimate recovery from the wells of approximately twice the original wells.
Process Redesign of Production Maintenance Operations
Authors: Rankin Mark , Lowe Bruce , Disney Vernon , Spilman Kirk 
Published: December 2007

Abstract
This paper describes a methodology for the systematic redesign of traditional production maintenance operations as they relate to subsurface failures of sucker rod pumped wells. The paper advocates an organized approach to process definition, refinement and redesign such that improvement objectives are clearly communicated, appropriate human and physical resources are brought to bear, and a system of improvement measurements becomes the overriding focus of the operation. Specific examples of the use of statistical process control tools in the production maintenance quality improvement effort are explored.
Design, Installation and Operation of a Pressure Maintenance Project: A Case Study
Authors: Campbell S. M. , Osisanya S. O. 
Published: December 2007

ABSTRACT
A major concern facing operators in pressure maintenance projects involving gas injection wells and gas compressors is maintaining the safety of the equipment, the people, and the environment in case of a system's failure. A safety system was designed and installed as one continuous supply gas loop to ensure complete shut down of the plant facility. Compressed air was used for the power-drive of the system. Automatic fire sensors and extinguishers were installed throughout the facilities to decrease the chance of fire. Total cost of installation of this safety system was 60% of the original estimated authorization for expenditure (AFE). This paper discusses the process of designing, installing and operating a cost-effective safety system for a pressure maintenance project operated by Mewbourne Oil Company in the South Higgins Field, Ellis County, Western Oklahoma.
A Field Example of a Gas Orifice Meter with Debris-Ridden Liquid in Mist Flow
Authors: Chisholm J. L. , Mooney C. V. , Datta-Barua L. , Feldmann R. J. 
Published: December 2007

ABSTRACT
A field example of debris-ridden liquids in an orifice meter is presented in this paper. Flow conditions in gas pipelines containing hydrocarbon liquids and particulate matter are discussed. Known effects on measurement of the presence of these materials in orifice meters is presented. By definition, gas measurement is accurate if performed on a "clean and dry" flow stream. This paper demonstrates the importance of removing as much liquid and debris as possible prior to measurement.
Selective Gel Treatments in the Countyline Unit, Oklahoma
Authors: Jasti J. K. , Zambrano L. G. 
Published: December 2007

Abstract
A waterflood optimization work program was conducted in a "Type" fault block in the Countyline Unit, Sho-Vel-Tum Field, Oklahoma. Selective gels were used to block random thief zones in the Upper Fusulinia Formation. There were eleven workovers, selective gel treatments in five injection wells, and a shift of water injection to downdip wells. Results show that the program has been successful in increasing production and ultimate recovery with significant improvements in the water injection profiles.
In addition, a new gel injection procedure has been discovered while carrying out the project. The procedure involves "pulsing" the reservoir to increase the amount of gel that can be injected into the matrix (while maintaining the injection pressure below the formation fracture pressure), thereby improving the gel's blocking capability.
Decentralized, Continuous-Flow Gas Anchor
Authors: Podio A. L. , McCoy J. N. , Wood M. D. 
Published: December 2007

ABSTRACT
A novel gas separator design has been developed and successfully tested in several beam pumped wells which were subject to severe gas interference. This paper presents a detailed description of various designs to cover various ranges of fluid production for the most common sizes of completions(4-1/2 to 7 inch casing) and rates from 120 to 825 barrels of liquid per day.
The new design is based on two innovations:
Decentralization of the gas separator in the casing, insures that a minimum amount of gas enters the separator. The presence of two ports located on the narrow side of the annulus and placed a significant distance apart allow continuous flow of fluids into and out of the separator during both the upstroke and downstroke of the pump.
These innovations have resulted in a gas separator efficiency much greater than that of conventional designs.
Drilling Mud Rheology and the API Recommended Measurements
Authors: Clark Peter E. 
Published: December 2007

ABSTRACT
Drilling fluids are, among other things, expected to transport cuttings and control fluid loss. The rheology of drilling fluids plays an important roll in both of these aspects of drilling fluid performance. A number of years ago the American Petroleum Institute established a set of standards for evaluating the rheology of drilling fluids. While drilling fluid technology has evolved and drilling fluids have become more rheologically complex, the standards have not changed sufficiently to adequately characterize the new generation of drilling fluids.
A New Polymer/Glycol Water-Based System for Stabilizing Troublesome Water-Sensitive Shales
Authors: Jarrett M. A. 
Published: December 2007

ABSTRACT
The oil and gas industry is emphasizing more and more attention to choosing alternative safe aqueous drilling fluid designs as substitutes to environmentally hazardous oil-based drilling fluids as regulations become more restrictive for offshore and land operations, particularly in the United States and Europe.
This paper discusses the research and development of a new polymeric aqueous drilling fluid alternative, incorporating glycol and salt technology with improved performance in stabilizing water-sensitive shales with better environmental acceptance and biodegradability.
The Evolution of an Applied Hydraulic Fracture Project, Frontier Formation Moxa Arch, Wyoming
Authors: Harkrider J. D. , Aud W. W. , Cipolla C. L. , Hansen J. T. 
Published: December 2007

ABSTRACT
This paper demonstrates a methodical approach in the implementation of current hydraulic fracturing technologies. Specific examples illustrating the evolution of a consistent reservoir/hydraulic fracturing interpretation are presented in a case history of three GRI-Industry Technology Transfer wells. Detailed modeling of these project wells provided an overall reservoir and hydraulic fracture description that was consistent with respect to all observations. Based on identification of the fracturing mechanisms occurring, the second and third project wells show the capabilities of realtime diagnostics in the implementation of hydraulic fracture treatments. By optimizing the pad volume and fluid integrity to avoid premature screenouts, significant cost savings and improved proppant placement were achieved. The production and pressure build-up response in the first project well verifies the overall interpretation of the reservoir/hydraulic fracture model and provides the basis for eliminating the use of moderate strength/higher cost proppant over sand in low permeability/higher closure stress environments.