bluuebunny/crossref_metadata_2025_split huggingface dataset:
An In-House Experiment About PVT Impact on Multiphase Metering Accuracy
Authors: Feria C. Correa 
Published: December 2010

ABSTRACT
As a new development for a gas-condensate reservoir is ongoing, metering and allocation philosophy and methodology need to be selected. Due to severe environmental regulations (minimize footprint) and complex logistics (no roads, seasonal fluvial transportation and 100% helicopter transport to well clusters), multiphase metering seems to be a very interesting option when compared, for example, with conventional 3-phase test separators (large and heavy equipment).
Multiphase flowmeters (MPFMs) suppliers have always claimed for the need of using good quality PVT data to assure acceptable metering performance but, rarely have they been able to provide the operators with quantifiable data about this dependency:
What's the % effect of a % change in the input fluid composition (i.e. due to improper sampling, recombination or analysis)? How often do we need to obtain new PVT information? Why "six months" seems to be an accepted standard? In the absence of new PVT data, can we estimate the probable metering error to account for it in the final product balance? What's the relative importance of PVT related errors compared with inherent meter uncertainties (P-T gauges, gamma ray scattering and decay…)? …
As the answers obtained from almost every MPFM where always -more or less- the same and most of these meters still remain as black boxes, we decided to perform some in-house exercises and carry on future planning based on our own estimates.
Major points of PVT influence on MPFM performance were identified and a basic flowmeter simulator was built, using a standard process simulator and common office applications. This simulator was used to sensitize the influence of produced fluids' PVT changes over time and different MPFM PVT updating schedules, trying to reflect the cumulative errors on production metering and allocation. Based on results, an optimum schedule for acquisition of PVT data can be implemented during the life of the asset.
Perceiving MPFMs as black boxes has, for sure, impaired the spreading of multiphase metering technology in the oil and gas field. Acquiring better knowledge of how it works and being able to somehow quantify the involved uncertainties, worldwide operators should feel more comfortable and confident about the use of this promising technology.
Overview: Slug-Flow Characterization for Heavy-Oil Fields
Authors: Márquez J. , Trujillo J. 
Published: December 2010

ABSTRACT
This work presents a review and selection of the mathematical models and correlations that could predict slug flow characteristics more accurately in heavy oil fields. These characteristics are slug holdup, slug length, slug velocity, translational velocity or Taylor bubble velocity, drift velocity, slug frequency and instantaneous flow. They were selected from different publications related to slug flow development both worldwide and from our multiphase flow laboratory.
The selected models and correlations are considered to predict better slug flow characteristics in heavy oil fields and therefore are recommended to be used for the Faja (Orinoco Oil Belt) surface facilities development.
Analysis of the Orinoco Oil Belt Development Through a Dynamic Simulation Model
Authors: Diaz S. , Quintero E. , Hernandez H. , Jenkins O. 
Published: December 2010

Abstract
The Orinoco Oil Belt located in eastern Venezuela contains the largest accumulation of extra heavy crude ever assessed in the world. This paper explores the opportunities for growth in this important area by using an innovative dynamic simulation model, built by the corporate team of PDVSA. It integrates subsurface, surface, economic, environmental, social, and strategic sub-models.
The situation analysis of the oil production in the Orinoco Oil Belt (OOB) aims at different forecast scenarios associated with the shortage of the use of diluents during its planned life and how it can be overcome in the future. As a consequence, options include the incorporation of exploratory activities in neighboring areas to obtain more diluents, technological investment, reallocation of resources, and the use of upgraders. All of these factors are introduced in a dynamic model and are simulated with different driving forces, such as budgetary cut by levels, market forces, and changing oil prices. We conclude that the integrated option with the upgrading process offers the best alternative investment for future plans, in conjunction with identified financing strategies. The recent oil prices variations have a strong influence as an incentive to exploration and development plans in this model.
The first dynamic simulation model in the OOB represents a significant effort to quantify the influence of different variables and their interaction for analyzing and developing scenarios when important decisions have to be taken. The prediction of future behavioral patterns of this complex system has a world scale impact, since this area represents a particular option available for the future world oil supply while oil demand continues to increase every year.
Cementing, Perforating and Fracturing Using Coiled Tubing: Rigless Completion Technique Developed for a Marginal Field in Peru
Authors: Salazar V. , de la Rosa V. , Gomez J. , Quintana J. 
Published: December 2010

Abstract
The Talara field, onshore Peru, is one of the oldest oilfields in the world. It was discovered in late 19th century and up to 2010 more than 12,000 wells have been drilled. Currently, only some 3,000 wells are active; the remaining ones have been temporarily or permanently abandoned due to low production.
Recently, a new pay zone was found above the typical producing formation in this field. However, two factors complicate any plans to recomplete the old wells and produce from the new formation. In first place, in the typical well configuration, the production casing in these wells is not cemented to surface and the cement top is below the new zone. Secondly, because the new pay zone is in a low-permeability formation, it must be fractured to be commercially produced. A conventional rig-based workover to recomplete and fracture this upper payzone is too expensive to be economically viable.
This paper presents a new rig less completion technique involving plug and abandonment of the lower zones, followed by cementing, perforating and fracture stimulating the new zone using only coiled tubing for intervention. The technique has proven to be an economically viable way to bring back to life the first 18 wells completed.
Operational details, production results and lessons learned from this first campaign are presented. The analysis demonstrates that this new system can reduce completion time and costs in open-hole wells for both mature and new fields.
Beyond the Mud-Weight Window: A Geomechanical Approach to Evaluating and Achieving Drilling Goals
Authors: Vargas Juan G. , Mateus Jefferson , Serrano Mario 
Published: December 2010

Abstract
It is well known that monitoring cuttings allows drilling engineers to take remedial solutions to control wellbore instability while drilling. Unfortunately, just the cuttings volume interpretation can be easily misunderstood and borehole instability can become unmanageable. Besides, most of the projects are drilled in very complex areas. If too much time elapses after wellbore instability begins occurring and the decision to modify mud density is taken too late, the final situation can be stuck pipe, fishing operations and finally the always expensive side track operations.
This paper presents a real example of geomechanical integration with drilling operations, not only during planning, but during the drilling stage, in an area with huge geological and geomechanical uncertainties.
During the planning stage, geomechanical and wellbore stability models were defined based on data analysis and pore pressure, mechanical properties, and stress profile predictions. As a result of the planning, the mud weight window, mud properties and formulations were defined as well as BHAs and casing points. While drilling, borehole conditions were monitored to optimize a "planning-while-drilling" wellbore stability model according to the changing wellbore circumstances. This methodology can allow all the well construction objectives to be achieved.
Integrated Production Modeling: Advanced but, not Always Better
Authors: Feria C. Correa 
Published: December 2010

Abstract
During the initial stages of a new gas-condensate field development planning, studies are performed trying to cover all possible key project factors. Reservoir performance estimations and production forecasts are, by far, the most important aspects influencing any other development requirements and future commitments (number, location and type of wells, capacity/modularity of the production facilities, sales contracts, booked reserves…). Due to the, let’s say, apparent simplicity of the project (homogeneous reservoir model, few development wells, linear gathering pipeline and small compression plant) and the uncertainty of available data, a handcrafted approach was preferred by working all models as separate items but, applying proper contour conditions for each one.
On the other hand, applying defined management methodology, project’s QA/QC explicitly required the development of an integrated subsurface-surface model, no matter the performance of the handcrafted approximation. Integrated Production/Asset Modeling (IPM or IAM) is a powerful asset design, prediction and management tool when properly used but, as with many other emerging or in fashion technologies, care should be taken when dealing with the ‘aspirin’ (good for everything) complex.
To fulfill this requirement, a full asset simulation model was built integrating the complete production cycle: numerical reservoir simulation, steady-state nodal wells, surface gathering/transport network and compression/processing facilities. The process was intensive, troubleshooting and time consuming but, as suspected, obtained results didn’t significantly improve the knowledge already available with the handcrafted initial approximation.
Being able to assess the proper use for each technology should be a basic pillar of our industry. Inefficiently and indiscriminately applying available tools without a suitable engineering criterion, could yield wrong assessments of their actual value and, lead to improper use of valuable time and workforce. Integrated Production Modeling develops real value when dealing with large systems, where the type and number of variables to be controlled lies out of the human capacity; however, simple systems still can be handcraftly managed under proper engineering judgment, without large troubleshooting processes, consuming less time and demanding less workforce. The cobbler should stick to his last.
First MPD Automated System Application in Offshore Gulf of Mexico Well Confirms Method, Huge Benefits
Authors: Ramirez S. , Aguilar R. , Herrera R. , Vallejo V. , Perez E. , Giral L. , Castiblanco G. , Sanchez H. 
Published: December 2010

Abstract
Land and offshore drilling operations along the Tabasco coastline of the Gulf of Mexico notoriously present difficulties posed by the variations in pore pressure, depleted reservoirs, and, in the majority of cases, highly fractured carbonates--the last a cause of negative windows between pore pressure and fracture pressure and, thus, whole sections with complete circulation loss. It is not surprising that the drilling of these deposits takes much more time than planned. Nonproductive-time (NPT) events are particularly associated with lost circulation and/or gas influxes in high-pressure formations, well-control processes, stuck-pipe problems, deviated wells, and in some cases, wells being abandoned without the objectives having been met. To mitigate these problems, managed pressure drilling (MPD) technology, using an automated system, was implemented. The objective was to determine the limits of the operating window and to perform an equivalent circulating density (ECD) control to find a balance between the losses and gains, reducing the losses as much as possible and minimizing volume of influx from high-pressure gas intervals.
This paper describes the objectives, planning, technology used, problems encountered, and lessons learned during the first application of MPD technology using an automated system in an offshore well in the Gulf of Mexico, along the Tabasco coastline.
Fiber-Assisted Self-Diverting Acid Brings a New Perspective to Hot, Deep Carbonate Reservoir Stimulation in Mexico
Authors: Martin F. , Quevedo M. , Tellez F. , Garcia A. , Resendiz T. , Jimenez Bueno O. , Ramirez G. 
Published: December 2010

Abstract
Carbonate reservoirs in the southern region of Mexico are characterized as deep, hot, and naturally fractured. Most wells in Cretaceous and Jurassic carbonate formations are acid stimulated at the time of completion and periodically during the life of the well to combat damage mechanisms that occur during drilling and production.
These wells are typically completed with multiple perforated intervals. Not all the intervals have the same density of natural fractures, some sections having no natural fractures. This creates a very high permeability contrast estimated to be as high as 1000:1 in extreme cases. Also, the reservoir pressure varies between the different intervals as a result of simultaneous production from zones with widely varying permeability. The contrasting permeability and reservoir pressure constitute a major challenge at the time of stimulation treatments in terms of achieving uniform zonal coverage and fluid penetration in all treated zones.
The treatments are bullheaded, so effective diverting fluids are required to ensure the complete vertical coverage of the zones of interest. The diversion, however, must be temporary and nondamaging to the reservoir and the natural fracture network. To meet this challenge, a degradable acid-diversion system has recently been applied in matrix acidizing treatments in southern Mexico.
The diversion system combines the viscosity-based effect of self-diverting acid with particulate-based diversion provided by degradable fibrous material. The combination functions synergistically to provide superior zonal coverage of matrix treatments under extreme conditions. In acid fracturing applications, the new system reduces leakoff in fissures and natural fractures, which leads to a more efficient spending of the acid and therefore longer fractures. The degradable nature of the fibers and viscoelastic surfactant result in no post-treatment damage. Furthermore, the fibers produce a weak acid while dissolving in the presence of water at bottomhole temperature, continuing to stimulate the well as they degrade.
This paper presents three case studies in which superior results were obtained by using the new diverter when compared to results achieved in offset wells in the same reservoirs and under similar conditions conventionally stimulated. Production increases in excess of 100% have been achieved where conventional treatments have failed to increase production. Lower production decline and higher flowing pressure have also been observed. The latter is interpreted to be the result of the fluid diverting from highly fractured and depleted zones into undrained lower-permeability with fewer natural fractures.
Geomechanics Aspects of the Oriente Basin, Ecuador, South America
Authors: Torres Manuel Ernesto , Frydman Marcelo , Goddyn Xavier , Medina Raul , Baker Andy , Bravo Oscar 
Published: December 2010

AbstractThe Oriente Basin of Ecuador is one of the most productive of the South American Sub-Andean Basins and it contains a sedimentary fill between Paleozoic to Recent age. Major commercial interest is confined to the Cretaceous depositional cycle and all the significant production comes from fluvio- deltaic and marine sandstones of the Hollin and Napo Formations. To reach prospective targets, the oil companies have to drill tertiary continental and transitional sedimentary formations, i.e Chalcana, Orteguaza, Tiyuyacu, Tena. The challenges to overcome could be summarized in formations reactive to the drilling fluids, tertiary overpressure clay stones, volcanic inter bedding layers, hard conglomerate intervals, limestone rocks, sand production in the reservoirs, cretaceous overpressure shales and magma type intrusions. The objective of this paper is to illustrate the geomechanic behavior of the wells drilled in Oriente Basin at a regional scale based on the geological framework model of several fields that have been drilled or stimulated by using 1D or 3D mechanical earth models- MEM, (Plumb, R.A, 2000).A compilation of data from drilling and sanding prediction analysis, open hole logs, rock mechanical data by integrating rock strength characterization at the laboratory, borehole images, and formation pressure measurements are analyzed to assist in well planning and field development and to understand the problems already encountered in the existing vertical, deviated and horizontal wells. A complete characterization of formation stresses is included using traditional techniques of estimation derived from microfracs, mini-fracs, leak-off tests, hydraulic fracture data, poroelastic strain calibration, or derived from advanced sonic stress estimation using the induced anisotropy in the presence of variation of the three shear modulus crossing dipole dispersions obtained from near-wellbore stress concentrations.
Evolution of Rotary Steerable BHA Designs in Mexico Offshore: Solution to Stop Multiple Drillstring Failures in High-Vibration Environment
Authors: Ramirez Silvestre , Aguilar Rafael , Gonzalez Luis Felipe , Lopez William , Bautista Omar , Noriega Ivan 
Published: December 2010

AbstractPemex, the local oil producer in Mexico, has identified young fields as potential alternatives to compensate for the production decline experienced in recent years. However, those with the largest reserves and the lightest oil offer the most difficult drilling conditions. Just such an example is a target field in the Marine Southwest region where production objectives have been compromised by significant delays in drilling operation. The complexity of the 17 ½-in borehole section, made so by high lateral and torsional bottomhole assembly (BHA) vibration, resulted in costly drilling incidents, such as, drillstring twist off, physical damages, and failures of downhole tools. These incidents resulted in fishing and side track operations that averaged 15 days of nonproductive time per 17 ½-in section per well.This paper will explain how rotary steerable BHA designs developed out of a need to achieve drilling stability and ultimately resulted in an enhancement on average ROP. This discovery, termed Powered Rotary Steerable System (RSS), combines, within the same BHA, a mud motor power section with a push-the-bit RSS tool. This system decouples surface RPM from downhole RPM allowing for the low revolution rotation of the drill string, thus preventing vibration but not sacrificing the rotation and hydraulic power needed by the bit to generate good rate of penetration (ROP). The design was capable of drilling the 17 ½-in section of the field in one run and reduced drilling time from 36 days to 8 days; nonproductive time due to BHA vibration was completely eliminated in additional wells.
Novel Approach for Fracture Characterization in a Metamorphic Reservoir
Authors: Velez E. , Vasquez J. , Frydman M. , Janampa H. , Meza O. 
Published: December 2010

Abstract
A new workflow reliably characterizes natural fractures in the highly complex Sechura basin in Peru, where acoustic logs alone were unable to characterize fracture networks adequately. The new approach, which integrates the response of borehole images with a dipole sonic tool, directly impacts the decision criteria of producible intervals where the zones that produce are the zones with open fractures aligned with the maximum horizontal stress. A case study of two wells in the Sechura basin shows how the methodology gives a quantitative way to better understand the fracture networks and fracture dynamics in naturally fractured reservoirs, establishing a novel criterion for fast decisions based on colored flags and horizontal stress directions.
Casing-Drilling Technology CwD Mitigates Fluid Losses in Peruvian Jungle
Authors: Gallardo H. , Cassanelli J. P. , Barret S. , Romero P. , Mufarech A. 
Published: December 2010

Abstract
This paper summarizes the experience reached drilling six wells using Casing while Drilling (CwD) technology in surface sections deeply affected by partial and total fluid losses in the Cashiriari field (Block 88 in the Peruvian jungle): three wells using a 24-in. casing drilling shoe, two wells drilled with a 12 ¼-in. casing drilling shoe and one well drilled with a 22-in. casing drilling shoe.
Total or partial fluid losses in surface (shallow) sections turn conventional drilling into a non-cost-effective way to drill this section in the Peruvian jungle. Additionally, the HSE risk and associated logistic problems were mitigated through CwD technology. Historically, fluid losses were observed in offset wells from 40m TVD to 500m TVD (Cashiriari 3 well) or 750m TVD (Cashiriari 1 well). Between 3,000 and 16,000 barrels of fluids were lost per well and conventional remedial methods were used, such as LCM pumping, cement plug, and unplanned casing points.
CwD technology demonstrated to be a beneficial technical-economical solution to drill and cement surface casing string (20- in., 18 5/8-in., 9 5/8-in.) in the Cashiriari field. CwD is the process of drilling a specific section using casing or liner as the drillstring. In the Cashiriari field, a non-retrievable casing drill shoe with polycrystalline diamond compact (PDC) cutting structures was used to drill soft to medium formations in surface sections. This technology helped to 1) reduce non-productive time (NPT), 2) improve the mechanical seal in the borehole due to the plastering effect, 3) improve the hydraulics in terms of hole cleaning due to higher annular velocity (reduced annular space between the casing and borehole), 4) reduce trip times, and 5) improve the HSE index due to a low associated risk and less personnel and equipment required. In all cases the customer goals were successfully reached. Compared with conventionally drilled wells, an average of five operating days was saved in the best cases.
The results show that this technology has significant applicability when casing rotation system is available for vertical, PDC- drillable sections. The objective is to reduce non-productive and casing running times where total and partial fluid losses make conventional drilling practices difficult or expensive.
Microseismic Hydraulic Fracture Monitoring to Determine the Fracture Geometry in Coyotes Field, Chicontepec
Authors: Gutierrez Guillermo , Sanchez Adrian , Rios Austreberto , Argüello Leopoldo 
Published: December 2010

Abstract
Due to the petrophysical characteristics of Coyotes field, it's necessary to fracture the sandstone reservoir to increase permeability to achieve commercial oil production. There are different technologies based on indirect measurements at the surface or at reservoir level that provide information about the fracture geometry generated in the well while the fracture is created, but all those techniques provide only partial information about the fracture geometry because they are limited by the depth of investigation. For this reason, PEMEX's technical team looked for new technologies for obtaining more precise information about the geometry of the fractures. The company selected a technology that offered monitoring and interpretation of microseismic events generated while the fracture propagated in the reservoir. This study documents the hydraulic fracture monitoring (HFM) of a group of wells located in Coyotes field and discusses the creation of 3D maps of the fractures produced.