bluuebunny/crossref_metadata_2025_split huggingface dataset:
General Fracture/Matrix Transfer Functions for Mixed-Wet Systems
Authors: Lu Huiyun , Blunt Martin J. 
Published: December 2007

Abstract
We extend a model of fracture/matrix transfer in dual porosity and dual permeability systems to mixed-wet media, where there can be displacement due to imbibition when the capillary pressure is positive combined with gravity drainage. This can lead to a characteristic recovery curve from the matrix, with a period of rapid imbibition followed by slower recovery as buoyancy overcomes capillary forces. We refine a current general transfer function model (Lu et al., 2006) to accommodate such cases by including transfer due to horizontal and vertical displacement separately.
The model is tested against fine-grid simulation in one and two dimensions and accurate predictions are made in all cases; in contrast the conventional Kazemi et al. (1976) model gives poor predictions of rate and ultimate recovery.
New PDC Technology Solves Hard/Abrasive-Formation Challenge Drilling Vertical/Directional/Horizontal Applications
Authors: Miller Clayton , Al-Jezany Mahdy , Balhareth Mahdi , Adebiyi Ismail , Klink Zeinoun , Parham Hoss , Butt Imran , Al-Abed Hussain 
Published: December 2007

Abstract
The operator has attempted to efficiently drill the 8-3/8, 5-7/8 sections using roller cone tungsten carbide inserts (TCI) and polycrystalline diamond compact (PDC). In the 8-3/8 5-7/8 sections abrasive wear caused by hard/sharp sandstone limited PDC life. Even the toughest cutter could not withstand the abrasivity. The operator required new cutter and PDC technology.
Engineers used numerical models to optimize the interface between the diamond table and substrate that determines the cutter's response to residual and service stresses. Diamond table properties were changed to increase durability and wear resistance. The result is an abrasion-resistant cutter capable of maintaining a sharp edge in hard carbonates and abrasive sands. Patented depth-of-cut control technology provided increased stability. Directionally drilling 8-3/8 section through hard/abrasive sandstone with 105pcf overbalanced mud is challenging. TCI, delivered poor ROP while sliding while wear resulted in short runs, lost cones, causing fishing/milling. PDC was tried previously in similar formations with minimal success (cutter wear). A baseline was set using three TCI with diamond enhancements which drilled 75ft in 36.5hrs, at average ROP of 2ft/hr (cost/ft $2240). Using the new cutter technology, four bits drilled 543ft in 116hrs at average ROP of 4.68 ft/hr at cost/ft $778. One bit drilled a record 279ft at 4.73ft/hr. The new PDC technology achieved 65% reduction in drilling cost, saving over $750,000 on one well by reducing drilling time and eliminating fishing operations
The 5-7/8" lateral is drilled through the abrasive Jauf reservoir. In the Hawiyah field, the new PDC technology drilled 1620ft of hard/abrasive sand using three bits. The first sidetrack, took nine roller cones and two PDCs to drill 1207ft. The cost/foot reduction was $283/ft for a total savings of $460,000 over this section. With improved cutter technology, a second well was drilled in the same field that required two PDCs to drill 2368ft at 16ft/hr. This performance set the lowest cost per foot horizontal section in this application.
In the 5-7/8" vertical application drilling the Unayzah formation in the Ghazal Field, new PDC technology drilled 517ft of hard abrasive formation using two bits, compared to the best offset for the same section using one impregnated bit and four TCI. The cost/foot reduction was $229/ft for a total savings of $118,000.
Variations in Structural Styles Across the Burgos Basin, Mexico
Authors: Rivas-Reyes Esmer Orlando , Ziga-Rodriguez Genaro , Martinez-Vasquez Trinidad , Norte Region , Goodoff Lynne R. 
Published: December 2007

Abstract
The Burgos Basin in northeastern Mexico as shown in Fig. 1 produces from the clastic Paleocene in the western portion of the basin to the Miocene in the east. Fig. 2 is a stratigraphic chart of the Tertiary. As different Tertiary formations exhibit different structural styles, the primary structural style of each major formation will be discussed and compared. Structural features across the Burgos Basin are not uniform, but complex. Interpretation on 2D and 3D seismic data, on both regional and field development scales, has revealed faults and structures that result not only from extensional forces, but also from compressional or transverse forces. The purpose of this paper is to give a general synopsis of many of the structural styles that have been observed in the Burgos Basin. A common perception that structuring in Burgos is similar to South Texas may limit a more complete understanding of the basin's true potential.
A majority of the faults are normal faults. Fault displacements range from a few meters to greater than 2000m (along the major growth fault systems). The extensional normal faults found in the basin have listric and high angle fault planes, syndepositional and post-depositional movement. Generally, synthetic faults are down-to-the-east and antithetic faults are down-to-the-west. Extensional structures include anticlines, synclines and graben systems.
While most of the structuring is consistent with traditional Gulf of Mexico basin extensional tectonics, faults with reverse throw, normal faults along which there has been subsequent reverse movement, and anticlinal folds have been observed. These features may be related to deformation occurring in the mountains to the west of the Burgos Basin and result from transverse movement that extends as far to the east as the border with the United States. These anomalous structures are strikingly visible on 3D seismic data. A northeast-southwest or northwest-southeast trend is observed in non-extensional faults and may influence producing trends through the formation of natural fracture systems.
Petroleum Facilities Reliability Assement Model
Authors: Palmieri Luis , Alonso Pablo , Moreno Adrián 
Published: December 2007

Abstract
The purpose of this paper is to create a calculation model to estimate the operation failure probability of an oil production facility, to guarantee an operation without accidents, without dangerous failures, observing the safety and environment policy established by the company. The facility operation is considered successful when it can carry out the functions it was design for.
Once the failure rate has been obtained, the system reliability level is obtained. The quantification of the success or failure is carried out through the application of the Failure Tree technique. The Safety and Operativity systems have been separately analyzed; taking into account that each of them has to be considered independently.
The model was used in the calculation of facility reliability in an oil field. (1)
Practical Interpretation of Pressure Tests of Hydraulically Fractured Wells in a Naturally Fractured Reservoir
Authors: Tiab Djebbar , Bettam Youcef 
Published: December 2007

Abstract
The main objective of this paper is to present a practical interpretation of the pressure behavior of a hydraulically fractured vertical well located in a naturally fractured reservoir. The interpretation is based on analytical equations derived to determine permeability, fracture storage capacity ratio, interporosity flow coefficient, skin and wellbore storage from the pressure derivative plot without using type-curve matching technique.
These parameters are obtained by making use of the characteristic lines and points found on the log-log plot of pressure and pressure derivative. The point of intersection of the straight lines corresponding to the different flow regimes are very useful in checking the parameters obtained from the slopes, when the pressure derivative curve is not smooth.
The method of analysis is applicable to both drawdown and buildup tests in uniform flux, infinite conductivity or finite conductivity hydraulic fracture. A step-by-step procedure and Examples are included to illustrate the proposed technique.
Sour-Well Serviceability of Higher-Strength Coiled Tubing
Authors: Luft H. B. , Padron T. , Kee E. , Szklarz E. 
Published: December 2007

Abstract
A joint industry project (JIP) among ExxonMobil Development Company, Shell Canada Limited and BJ Services Company Canada was initiated approximately 2 years ago to extend the prior research conducted into the serviceability of coiled tubing (CT) for under-balanced sour well drilling and work-over operations, to the higher strength (90 to 110 ksi SMYS) grades. A significantly different and unique laboratory testing protocol is employed in the present JIP research. The methodology entails full-body tubing specimens that have been immersed in a sour solution of varying severity followed by testing in a bend fatigue machine to determine the low cycle fatigue performance of high strength CT materials degraded by prior exposure to the sour environment. In addition, there are several important aspects of possible CT degradation from exposure to sour wells that were not adequately investigated previously. These include the incubation times for cracks to form due to hydrogen induced cracking (HIC) or sulphide stress cracking (SSC), the tensile strength integrity of coiled tubing strings in which HIC and/or SSC have formed, the relative resistance of different CT strength grades to HIC and SSC, the benefits of H2S corrosion inhibitors and the effects of different sour environment severities and external mechanical damage. Detailed metallographic examinations of the CT material characteristics that define their relative susceptibility to failure under sour conditions were also performed. Although the JIP research is still in progress, this presentation will reveal many of the significant results obtained to date with emphasis on CT operational implications and considerations. The newly obtained test results are also being exploited for the preparation of Alberta Industry Recommended Practices (IRP-21) currently under development in Canada.
Oriented Perforating Using Abrasive Fluids Through Coiled Tubing
Authors: Nakhwa A. D. , Loving S. W. , Ferguson A. , Shah S. N. 
Published: December 2007

Abstract
Abrasive fluids have been applied in mechanical cutting and perforating systems for years, the result is a precise cut in any size tubular. In abrasive perforating, the entry hole created reveals no tubular deformation or presence of flow obstructing debris. Consequently, the sand-laden fluid moves past cement, damaged zone or filter cake and into virgin formation. At that instant, velocity generated through the nozzles propagates abrasive fluid into multiple reservoir layers creating numerous pathways. Optimizing the direction of perforations allows for cost effective stimulation through conventional fracturing techniques. Therefore, as an alternative to conventional perforating, oriented abrasive perforating is applied specifically for creating channels to natural fractures.
This paper discusses the development of abrasive perforating coupled with orienting technology for penetrating tubing, casing, drill collars, and drill pipe, all of which is deployed using coiled tubing or jointed pipe in re-completions. In addition to conventional coiled tubing tools, this system utilizes an engineered weight bar connected to a high velocity perforating sub.
This paper begins with the development of this technology and existing perforating methods, then a description of tests conducted with the abrasive perforator and subsequent results. Benefits and applications with applied case histories are also discussed including multiple stage plug setting and perforating as well as pipe recovery, followed by conclusions and recommendations.
Case Histories of Barium Sulfate Scale Removal in Offshore Wells, Brazil, Using a New Engineered Combination of Coiled-Tubing Tools
Authors: Guimaraes Z. , Franca A. B. , Duque L. H. , DéSouza R. B. , Porto M. , Neves D. , Peixoto C. 
Published: December 2007

Abstract
With today's oil and gas prices, the loss of well production creates a negative financial impact on operating companies, especially in an offshore environment.
One of the most common reasons for production loss is the development of scales inside the production strings, blocking the flow of the reservoir fluid to the surface facilities. Barium Sulfate (BaSO4) scale is among the toughest scales to remove, whether mechanically or chemically. Alternatives to remediate this problem are often quite costly.
Therefore, under this scenario, a cost-effective intervention mechanism to restore production to previous levels is imperative. One of these mechanisms is the deployment of coiled tubing intervention as it can be done while the well is still live, minimizing further loss of production.
The Namorado field in Campos Basin, offshore Brazil, has approximately 60 wells, with most of them presenting deposition of BaSO4 scale throughout their production history. Historically, in this field, the deployment of a down hole motor with coiled tubing has been effective, but limited to restoring the production path's diameter only to the outer diameter of the bit. Results with deploying a down hole motor have been satisfactory. On the other hand, chemical treatments have been extremely ineffective and are, therefore, seldom deployed.
This paper presents two case histories of successful Barium Sulfate scale removal from the production tubing by coiled tubing, utilizing a combination of mechanical and hydraulic tools. This process is different from the conventional method (downhole motor) as it provides faster cleanout rates and quicker production restoration. This combination is engineered through software that optimizes the velocity at which the coiled tubing string is run through the scale, as well as the configuration of the hydraulic tool with respect to the pump rate and selection of the jet angle.
Measuring CT and Slickline Fatigue Life Reduction Due to Corrosion
Authors: Newman Kenneth R. 
Published: December 2007

Abstract
Coiled tubing (CT) bending fatigue has been the subject of much research. Slickline (SL) fatigue is the subject of more recent, ongoing research. Fatigue life tracking and prediction systems are available for both CT and SL. However, these systems do not adequately include the reduction in life due to corrosion. This paper discusses the CT and SL fatigue, and presents a new approach to handling the life reduction due to corrosion.
Successful Implementation of Coiled-Tubing Acid Tunneling Gives Operator a Viable Alternative to Conventional Stimulation Techniques in Carbonate Reservoirs
Authors: Diaz Jose Daniel , Espina Victor , Guerrero Melvi , Colmenares Omar Gregorio , Moss Paul John 
Published: December 2007

Abstract
Conventional stimulation techniques used to treat double porosity type (low permeability / hairline fracture) carbonate formations are met with limited success where most regular acid fracture treatments yield approximately the same results as regular matrix acid treatments of a much smaller scale.
This paper outlines the details & results pertaining to some recent successful applications of a new technique whereby Coiled Tubing is used to create multiple, relatively short-length lateral holes into a carbonate reservoir using nothing but hydrochloric acid pumped through a specially designed jetting assembly. The discussed jobs were the first ever field applications of Coiled Tubing "Acid Tunneling" and the results showed one operator that this method represents a viable alternative to conventional stimulation treatments in said reservoirs.
Results indicate that this technique may be applied to all carbonate reservoirs, regardless of their inherent petrophysical properties, where a different approach to stimulation treatments is required.
Discussed are formation characteristics, acid volumes and strengths, job parameters witnessed, tools used and results obtained to date.

Field and Formation Characteristics
It is estimated that carbonate formations account for approximately 35% of the world's petroleum reservoirs yet these same reservoirs are estimated to contain about 60–70% of the world's traditional hydrocarbon reserves. Important carbonate reservoirs are found in most parts of the world with some notable ones being located in Sumatra, Borneo, China, Brazil and Venezuela. Carbonate rocks are typically low porosity/low permeability and naturally fractured, but offer two particularly useful but often-overlooked properties: mechanical integrity and high solubility in acids. Typical solubility of carbonates in hydrochloric acid is greater than 95% and often exceeds 99.5%.
The Mara field in Western Venezuela (Northwest Maracaibo Basin) is one of these petroleum producing areas that contain massive carbonate formations. This field presently has about 400 wells, of which 95 are actively being produced by means of Electric Submersible Pumps (ESP) and/or Progressive Cavity Pumps (PCP) and all of these wells are produced from the Cogollo lower Cretaceous group (95% Carbonates with a variety of micro fractures), which is comprised of the following formations:Maraca: Glauconitic and calcareous clays at the base of the formation with bioclastic massive limestone accounting for the upper portions of the zone.Lisure: Glauconitic clays, glauconitic sandy limestone with traces of shale.Apon: Black bituminous laminar limestone.
Coiled-Tubing Milling of an Incoloy Alloy 925 Safety Valve Flapper in the North Sea
Authors: Farquhar R. A. , Rattray F. A. , Annandale A. , Reid A. , Glegg S. 
Published: December 2007

Abstract
The Incoloy Alloy 925 flapper from a damaged tubing retrievable safety valve (TRSV) was blown downhole using a wireline conveyed cannon. A downhole video survey revealed the flapper to be deformed but intact, lodged above a PBR at 11,902 ft md RKB. Attempts to fish the flapper were unsuccessful and a CT milling operation was planned to reduce the size of the flapper to facilitate its recovery. Consideration of the material properties and the location of the fish indicated that milling could be challenging. Reported industry experience of similar operations was sparse and BHA selection and job design required very close co-operation between the operator, coil tubing and through tubing services providers. The flapper was successfully milled using a combination of crushed carbide and fine diamond grit dressed burning shoes and recovered with an alligator grab on slickline. In addition to presenting the case history of the operation this paper will give an overview of the planning and design considerations which contributed to a successful outcome. The paper will also demonstrate how extensive use of downhole video helped guide development of the intervention programme.
Improving Reliability and Consistency in BHA Configuration Through the Use of an Expert Tool-Selection System
Authors: Greenaway Robert , Burgos Rex , Dilling Lambert , Vreeland Cabe , Bruce Steve , Hauglund Loren 
Published: December 2007

Abstract
In an environment of high activity, large organizational growth, and the nearing of retirement age for a large proportion of the oil and gas industrial workforce (otherwise known as the "big crew change"), there is a high demand for experienced personnel to be correctly placed within an organization to bring maximum benefit for continued growth and knowledge transfer.
For a business organization to ensure its success during this challenging period, it must optimize its human capital in a way that will reap the most benefit. Part of this process includes capturing the experienced generation's design knowledge and passing it on in a way that maintains consistency and yet allows the experienced personnel to focus on more business-critical decision making or operational supervisory roles.
Configuring the bottomhole assembly (BHA) is typically a crucial point when preparing for well intervention using coiled tubing. Several strategies have been adopted by service providers to standardize and regulate the design stage and ensure continuity through the "big crew change," including: Providing intensive training and mentoring to act as a rapid handover between the experienced and the new generation of tool specialists.Creating and distributing fixed flow chart decision trees throughout the organization.Setting up a specialized group of experienced tool specialists that can be used as a geographically-mobile workforce that services the organization's global needs.Creating a dynamic technology-based computer system that captures the existing field design knowledge and also captures new lessons learned.
This paper discusses these strategies, examining the positives and negatives of each approach, and then goes into further detail of how a leading coiled tubing service provider has decided to handle this issue.
Opportunities for Rigless CT Intervention for Marginal Fields in Offshore Nigeria
Authors: Uadiale Victor E. , Asedegbega Daniel 
Published: December 2007

Abstract
Offshore well intervention with coiled tubing (CT) in the Niger Delta has traditionally been rig-based. Experience has shown this type of activity to have high cost implication both cash wise as well as in time. With the current focus on development of offshore marginal fields, it has become imperative to perform well intervention operations at a more reduced cost to the operator.
Non-rig based interventions can provide an economic advantage. However, inadequate facilities on existing offshore platforms and jackets present additional challenges. Furthermore, performing well intervention from a supply vessel is definitely not a mean task. Despite the complexity of this type of activity, the cost savings for not mobilizing a rig usually makes small intervention work that would increase oil production attractive to operators from the standpoint of ROI, vis-à-vis comparing the cost of the total intervention to the projected production gains. To the smaller operators and marginal field developers, this opens up a world of opportunities.
This paper explores these opportunities and discusses how they are being exploited to yield optimum benefit for the marginal producer. The success of carrying out various types of well intervention work on four wells (two dual completions and two single completions) is showcased as case histories.
Coiled-Tubing-Conveyed Perforating for High-Pressure/High-Temperature Environment in Mexico Marine
Authors: Molero Nestor , Garcia Sergio , Zavala Eduardo , Cordova Javier , Solis Ulises 
Published: December 2007

Abstract
In the Bay of Campeche, Mexico Marine operators have recently commenced the development of their high pressure, high temperature (HPHT) oil and gas fields in order to meet the high demand. These new developments present tough conditions for all aspects of well drilling and completion activities. They are particularly challenging for performing well intervention, which have driven operators, manufacturing and service companies to develop innovative strategies for servicing these fields.
For HPHT well developments, electric line conveyed guns is the most common technique employed to perforate wells in the area, whether dynamic or static conditions. Nevertheless, coiled tubing (CT) deployed perforating has been recently employed as a reliable option in the following cases: Electric line is not a technically suitable option due to the limited magnitude of under-balance at which it can safely operate.Drag and buoyancy forces encountered in the wellbore are close to the operational limits of the cable.Wellbore tortuosity, tubular restrictions and well configuration render electric line unable to access perforation target depth.
Initially, this paper discusses the workflow for performing technical analysis to develop safe and economical CT conveyed perforating operations for HPHT wells in offshore Mexico, which considers CT string design, surface equipment, well control equipment and associated downhole tools. It then presents case histories and lessons learned. And finally, provides conclusions and recommendations from the experiences gained for performing HPHT CT deployed perforating activities in Mexico Marine.