bluuebunny/crossref_metadata_2025_split huggingface dataset:
Managed-Pressure Drilling Reduces China Hard-Rock Drilling by Half
Authors: Shen Chen , Niu Xinming , Nas Steve , Holt Calvin 
Published: December 2007

Abstract
This paper describes the experiences of nine months of managed pressure drilling (MPD) operations conducted in hard-rock and sour-gas formations in the Sichuan Province of southwestern China. Percussion drilling with compressed air and foam was applied in both top-hole and nuisance-gas formations, while near-balanced operations are being planned for the sour-gas reservoir.
Initially a two-well project, it was commissioned to determine whether percussion air drilling technology could provide rate-of-penetration (ROP) benefits. Because the feasibility report determined that wellbore stability could be an issue, a certain amount of project risk was involved. In addition, the main reservoir is sour, and potential sweet-gas secondary zones are located above it. Conventional 5,500-m wells were being drilled and completed in +350 days. The first air-drilled well was spudded in March 2006, and immediate benefits were realized. More than 60 days in the main 311-mm section were saved. Subsequent wells (+4) have improved ROPs by 94%, eliminating an additional 60 days from the drilling curve. Wells are currently being drilled in 240 days.
As the project progresses, near-balanced drilling, using MPD techniques, will be applied in a stepped approach to drill the sour-gas reservoir, improve ROP performance, and reduce overall well times.
Weatherford is the only western service company in the field, and lessons learned during this project have significantly affected MPD and percussion air drilling in China. Enhanced engineering reviews, better implementation of procedures, management of change processes, improved client awareness, and closer co-operation between service provider and operator are enabling successful execution of remote MPD projects in China and Asia Pacific.
Unique Pivot Stabilizer Geometry Advances Directional Efficiency and Borehole Quality With a Specific Rotary-Steerable System
Authors: Barton Steve , Clarke Alan , Perez Daniel G. , Peach Simon 
Published: December 2007

Abstract
The geometry of a stabilizer, when it is used as a near-bit pivot within specific point-the-bit rotary-steerable bottomhole assemblies (BHAs), is critical to both stability and deflection to provide optimal directional response. This paper describes the testing of a rotary-steerable system (RSS) and unique ring gauge pivot stabilizer at a purpose-built, full-size drilling test facility. The extensive, systematic testing of a point-the-bit RSS with both full ring gauge and conventional pivot stabilizer has enabled a direct comparison of the directional response, hole quality, and drillstring vibration to be made for the various combinations tested.
Aside from comparison of the ring gauge stabilizer against conventional pivot, the testing also evaluated the interaction between the gauge design of the bit and the pivot stabilizer. Test monitoring required use of a proprietary downhole dynamic data recorder (DDDR) in a specially modified housing. The DDDR was used to assess both lateral and torsional stability of the stabilizer geometries and their relationship with bit gauge style and length.
Further to the laboratory testing, trial applications have been sought where severe vibration issues are problematic to efficient operation of the RSS. Use of full ring stabilization geometry with an RSS in these applications will advance the industry's understanding of downhole dynamics. Enhanced understanding, in turn, will enable more efficient drilling of better-quality directional wellbores, significantly reducing cost per foot.
Development of a Deep-Penetrating Emulsified Acid and Its Application in a Carbonate Reservoir
Authors: Sarma Dilip Kumar , Aggarwal Pavan , Rao Eashwar , Kumar Pradip 
Published: December 2007

Abstract
The goal of matrix stimulation of carbonate reservoirs is to improve near wellbore conductivity by generating wormholes and increasing the effective wellbore radius, bypassing damaged areas. In naturally fractured carbonates, the wormholes connect the existing fractures, creates longer flow channels. Most widely used stimulation method in carbonate reservoirs is matrix acidization using HCl with various concentrations. The rapid reaction of HCl with carbonate matrix does not allow the reactive fluid to penetrate deep inside the formation before the acid spends. Therefore, the efficiency of conventional acid is limited, where deep penetration is needed. Stable emulsified acids are found very effective, to combat the challenge. The basic advantages of using emulsified acid are: generates longer wormholes by deep penetration into the formation; better zonal coverage; preferential stimulation of oil zones and less corrosive to workstring and downhole/surface equipment.
Based on the extensive laboratory studies, a stable deep-penetrating emulsified acid has been developed for carbonate reservoirs. The formulation is a mixture of HCl with compatible additives, diesel and some suitable emulsifiers. The ratio of the dispersed acid and external diesel phase is maintained as 70:30. Stability of the system is a major concern for adequate retardation and penetration deep inside the reservoir. Stability of emulsion largely depends on reservoir temperature and the HLB number of emulsifier. Two surfactants were identified for the system and the HLB number has been maintained in the range of 5.1-5.2 by optimizing the ratio of two surfactants for achieving the maximum stability. The developed acid system has been applied in some wells of an offshore field of India with encouraging results. The field comprises of naturally fractured limestone formation with number of hydrocarbon bearing sands. This paper describes the development of the Deep Penetrating Emulsified Acid and its application in the field along with treatment methodology and outcomes.
First Application of Underbalanced Drilling in Fractured Carbonate Formations of Iranian Oil fields Leads to Operational Success and Cost Savings
Authors: Hooshmandkoochi A. , Zaferanieh M. , Malekzadeh A. 
Published: December 2007

Abstract
Underbalanced drilling techniques (UBD) are evolving at a fast pace as oil companies learn how to use the technology to maximize well production and lower finding costs.
Although there was some air drilling through surface drilling activities in Iran for the past decade, the full package of UBD equipment and other UBD techniques were not introduced until National Iranian Oil Company (NIOC) supplied the package for a pilot project in southern Iran. The first well selected to be drilled UBD was GS 333, the reason for selecting that particular well was because the Gachsaran field is depleted and sever mud losses is experienced while conventional drilling, also, the UBD technique is expected to increase productivity of the well by decreasing formation damage resulted from drilling fluid losses.
The drill pipe injection technique was proposed to be utilized in this well because of its suitability for the well conditions where it is not expected to drill through the gas cap and the well will be completed in 8 ½" open hole.
This paper discusses the well design, UBD design parameters, Underbalanced modeling considerations and the lessons learned from this job which all led to the success of this project. It is also describe the process used to address HSE issues of the project in the face of the potential presence of H2S while drilling. The drilling and production results that were achieved were significant to the future operational potential and viability of this mature field. Of equal importance was the success of the operation from a health, safety and environmental (HSE) perspective in an environment in which the industry has been traditionally reluctant to use UBD techniques.
Mitigating Risks From Waste Subsurface Pressure Injection and Decline Analysis
Authors: Fragachán F. E. , Shokanov T. A. , Ovalle A. P. , Nolte K. G. 
Published: December 2007

Abstract
The progression of new field developments, including brownfield and deepwater, subsequently increases the volume of cuttings and production waste, and particularly produced water, considerably. The economical impact of missing drilling and production targets due to the failures in the drilling waste injection process represents high risks that demand sound engineering processes to ensure injection assurance.
This paper describes the solution and detailed pressure monitoring methodology implemented to maintain safe injection assurance via regular disposal fracture diagnostics. Timely identification and a thorough evaluation of non-ideal pressure signatures observed during injection and post shut-in periods provided critical information required to detect sub-surface anomalies. This can be an effective tool for the sub-surface risks identification and characterization.
The application of comprehensive fracture-mapping techniques is a major step in mitigating the environmental risks posed by waste. Waste mapping represents valuable information, not only in the overall planning of drilling operations, but in the fundamental and invaluable need to provide sound engineering for waste location and fracture containment assurance, thus minimizing environmental impact. Previous, oversimplified interpretations of multiple fracturing systems (or so-called uniform disposal domain) and new fracture initiation process are demonstrated to be in apparent conflict with fracture mechanics, stress calculations and the general principles of physics.
The authors also describe the results of pressure analysis conducted in a North Sea injection well, which simultaneously was used for production. The well was utilized successfully for Cuttings Re-Injection (CRI) and for the disposal of produced water. The success of the operation was a direct result of close monitoring of key injection parameters and in-depth analysis of injection pressure, despite risky geological conditions. Abnormal pressures increases and restrictions observed during injection were mitigated and addressed via a proper root-cause engineering and sound pressure diagnostic process. The drilling waste injection took place below a 13 3/8-in. casing shoe through the B annulus, in an open-hole section at the depth of 1220m TVD with a 240 deviation in the injection interval. The injection took place in close proximity to a major fault axis.
Qualifying a New Expandable Reservoir Completion System
Authors: Wood Pierre-Charles , Duhrkopf Don , Green Annabel 
Published: December 2007

Abstract
Over the past decade BP's primary sand control techniques have been dominated by Frac Packs in the Gulf of Mexico and Open Hole Gravel Packs (OHGP) and Stand Alone Screens (SAS) in the rest of the world.
In 2003, BP formed a collaboration agreement with Weatherford to develop a new Expandable Reservoir Completion (ERC) system. The collaboration aimed to develop a cost competitive high performance sand control system, which would provide open hole productivity with cased hole functionality in an 8 ½″ open hole.
The system would be run and expanded in a single trip to ensure efficient installation, an essential requirement in making the new system competitive with more established sand control technologies in high cost environments.
BP's Exploration and Production Technology Group (EPTG) together with several Business Units, supported the development of this new ERC System. Through the initial development phase from 2004 through 2006 a total of 5 installations (3 producers, 1 injector and one Stack up Test) have been completed to test the functionality of the completion equipment and associated expansion tools.
This paper will describe the development of the ERC system and review some of the most significant lessons learned during the qualification testing and field trial installations.
Careful documentation of all preparation and installation activities has been supplemented by focused data acquisition during installations. Recording high resolution borehole images and caliper data and critical downhole expansion parameters has allowed detailed post job analysis capability. Subsequent well performance data has also been used in evaluating completion durability and effectiveness.
The complications associated with combining single trip functionality with rotary expansion and the importance of the well trajectory with respect to downhole torque will also be discussed.
The data collected will show the new 7″ ERC system has to date provided comparable sand control and productivity / injectivity performance when compared to other well established sand control techniques.
High-Integrity Wellbore Surveys: Methods for Eliminating Gross Errors
Authors: Ekseth Roger , Torkildsen Torgeir , Brooks Andrew , Weston John , Nyrnes Erik , Wilson Harry , Kovalenko Kazimir 
Published: December 2007

Abstract
An earlier paper by the same authors, SPE 1037341, pointed out the potential safety and commercial costs of unreliable directional survey data. It described how a significant degree of reliability can be achieved with the application of quality control checks internal to the directional data, but it also identified the fact that such checks fall short of providing comprehensive reliability assurance.
This paper documents weaknesses in conventional directional survey quality control (QC) procedures through theoretical considerations, statistical analyses of real survey data, and real examples of failed surveys that have made it through conventional QC procedures without detection. The paper defines principles for survey programme design and implementation to eliminate these weaknesses. It proposes a new set of minimum requirements for survey validation, which, in general, incorporate the need for an overlapping verification survey or other independent observation. This requirement is not generally acknowledged in most of today's directional surveying QC procedures, which may be too weak to ensure the validity of a given error model and thus the integrity of the final well survey.
This paper also discusses how analysis of a sufficiently large quantity of data, with the recommended QC methods applied, allows validation and refinement of the error model.
This paper is the product of a collaborative work in the SPE Wellbore Positioning Technical Section (WPTS).
Aggressive Drilling Parameters Capitalize on Cutter Technology and PDC Frame Advancement in Mature Field
Authors: Langille Peter , Hildebrand Jason , Massie Kyle 
Published: December 2007

Abstract
The encroachment of PDC drilling upon previously roller cone dominated fields continues to occur at an ever-increasing rate. In many fields, the mere introduction of standard PDC technology can result in monumental improvements in performance. However, in southwest Washita County, Oklahoma the conversion to a PDC dominated drilling program has proven difficult utilizing standard PDC technology and operating procedures due to the shallow showing (5,000 – 6,000ft TVD) of the highly abrasive weathered granite conglomerate, known as the Granite Wash formation. Recently, the combination of new bit technology and operational practices has resulted in performance improvements allowing for a 41% reduction in drilling time.
In much of the surrounding Anadarko Basin, the interval to 11,000ft (where the Granite Wash is typically encountered), is dominated almost exclusively by PDC bits. However, as recently as nine months, many operators in the SW Canute area were forced to utilize a drilling program comprised solely of roller cones due to the shallow arrival of the Granite Wash and the inability of standard PDC technology and operating parameters to drill this formation. This paper will document how a major operator in the area utilized the concept of aggressive high WOB/low RPM drilling parameters, typically reserved for roller cone bits, coupled with innovative PDC bit frames designed to increase the load/cutter ratio, and new cutter technology to replace the typical 6–8 roller cones required to drill to 10,700ft with just two PDC's thereby realizing an approximate cost savings of $201,000.
Development Approach Appraisal: An Effective Way To Evaluate Employees' Performance
Authors: AbouHeif Moustafa 
Published: December 2007

Abstract
There are two prevalent approaches to performance appraisal; the traditional approach and the developmental approach.
The traditional approach is primarily concerned with the overall organization and is involved with past performance rather than being forward looking through the use of setting objectives or goals. It is usually tied to the employees' salary review. Dealing with salary generally overwhelmed and blocked creative, meaningful, or comprehensive consideration of performance goals.
The developmental approach to performance appraisal is more related to employees as individuals and it is forward looking through the use of goal setting. This approach is concerned with the use of performance appraisal as a contributor to employee motivation, development, and human resources planning. Besides its traditional purposes, the developmental approach performance appraisal has the following extra goals:
Provide employees with the opportunity to formally indicate the direction and level of their ambition; Show organizational interest in employee development, which was cited to help the enterprise retain ambitious, capable employees instead of losing the employees to competitors; Provide a structure for communications between employees and management to help clarify expectations of the employee by management and the employee; and Provide satisfaction and encouragement to the employee who is trying to perform well.
This paper presents our new approach towards performance appraisals - the Developmental Approach.
Shifting from the subjective - traditional - past performance evaluation, towards the objective -developmental - stretching performance evaluation was mandatory to the progress of our organization. Although this cultural change was not an easy task, the outcomes were very encouraging and positively reflecting at all our business aspects.
Pressure Transient Behavior of Horizontal and Slant Wells Intersecting a High-Permeability Layer
Authors: Gill Harmohan , Al-Zayer Rayed , Issaka Mohammed Ben 
Published: December 2007

Abstract
This paper describes numerical simulation studies designed to investigate the behavior of horizontal wells that intersect high permeability layers sandwiched between two lower permeability layers. The paper investigates the pressure transient behavior of 1) purely horizontal wells drilled in the middle layer and 2) slant horizontal wells that intersect all three layers, as the permeability of the high permeability layer is varied.
A previous paper1 focused on late time interference effects and radial composite behavior caused by a limited high permeability layer. This study focuses on the early time dual permeability effect and its impact on recognition of conventional horizontal well diagnostic derivative slopes.
The horizontal well simulations show a dual permeability effect as the contrast between the high permeability layer and the adjacent layers is increased. The vertical radial flow regime is seldom visible and masked by wellbore storage effects. Interestingly, what is observed however, is a plateau (or sometimes valley) caused by the dual permeability effect followed by a transition to horizontal radial flow regime. This may be explained as a combined effect of recharge and linear flow in the lower permeability layers. The plateau (or a valley) caused by the dual permeability effect, can easily be confused as representing the vertical radial regime. Similarly, the transitional data prior to horizontal radial flow, which includes the dual permeability effects, can be incorrectly analyzed and lead to misleading results.
This paper will demonstrate the increased complexity of the pressure transient behavior when the well is slanted through all layers while intersecting the high permeability layer.
Experimental Study of Hydraulic Fracturing in Sand as a Function of Stress and Fluid Rheology
Authors: de Pater C. J. , Dong Y. 
Published: December 2007

Abstract
We present an experimental and numerical study of the mechanism of hydraulic fracturing in unconsolidated rocks. We performed hydraulic fracturing experiments on loose sand samples under various confining pressures. We have developed a large biaxial set up in which cylindrical sand samples of dimensions 0.4×0.51 m can be tested under confining stress up to 40 MPa. We prepare a sand sample by pouring the sand into the sample vessel, which is filled with water to obtain a fully saturated sample. There is a borehole (injection system) with an open section in the middle of the vessel. The open section is closed during the sample preparation. After compacting the sample and applying the confining pressures, the injection system is opened and fluid is injected.
For modeling of the injection process we used a distinct element model in which we incorporated fluid flow that is coupled to the flow of the grains.
The injection tests resulted in either infiltration or generating fractures. Injecting viscous Newtonian fluid and cross-linked gel yielded in most cases only infiltration and wellbore expansion. Clear fractures were induced when injecting cross-linked gel with quartz flour and bentonite mud. Tests were run at a stress level between 0.2 and 20 MPa. At high confining stress we observed a strong tendency for shear fracturing during fracture initiation. The fracture initiation pressure was about 2.5-3.5 times the confining pressure. The stress level had a strong influence on the ratio of initiation pressure to confining stress. Also, it appeared that much higher pressures were obtained on dense sand samples, compared with less compacted sand.
Determination of Free Water Levels in Low-Permeability Chalk Reservoirs From Logged Saturations
Authors: Bech N. , Frykman P. , Vejbæk O. V. 
Published: December 2007

AbstractThe present paper describes a technique for determination of the free water level (FWL) in low-permeability chalk reservoirs along slanted or horizontal wells from logged saturations and porosities. The calculation is done by utilizing existing empirical correlations for drainage and imbibition capillary pressure curves. For each logged saturation and corresponding porosity the FWL is determined so that the calculated saturation equals the logged value. The method takes into account possible imbibition, which results in a FWL that is shallower than the original paleo FWL.The method has been applied to field data from the North Sea and it is shown that it can capture a tilting water level along a horizontal well.