bluuebunny/crossref_metadata_2025 huggingface dataset:
Contingency Planning Considerations for E&P Operations Near Mexican Territorial Waters
Authors: Pertuz David R.
Published: December 2007

In recent years there has been an increased number of E&P activities in the Western Gulf of Mexico near the international Mexico – U.S. boundary, particularly the Alaminos and Keathely Canyons. Likewise, there is interest from the Mexican government and private enterprise for conducting E&P and LNG activities in Mexican waters near U.S. territorial waters. Because of well known Gulf of Mexico loop current eddies, any significant amount of oil spilled anywhere in the Alaminos or Keathley Canyon areas or even the East Breaks and Garden Banks encounters a real potential for impacting Mexican territorial waters. E&P activities near the international boundary must take into consideration existing international agreements and lessons learned for the preparation of contingency plans.

In 1980, following the June 1979 PEMEX IXTOC I spill, the United States and Mexico signed an agreement of cooperation to draft a joint marine pollution response contingency plan. The agreement delegated to the Mexican Navy and the U.S. Coast Guard the responsibility for developing such a plan. This plan, better known as the MEXUS Plan, was completed and acknowledged by both countries in the year 2000. It addresses bilateral cooperation and procedures in response to pollution incidents that could affect the coastal waters of both countries. Oil companies operating near the international U.S. and Mexican boundaries need to be familiar with the application of the MEXUS Plan.

Since the signing of the MEXUS Plan, a series of exercises has been conducted that put to test the practical applicability of the plan. Exercise sponsors have included Unocal Corporation, Shell Exploration & Production Company, the Mexican Navy and most recently PEMEX. The lessons learned from these exercises are paramount ingredients for the development of a spill contingency plan near the international boundary. Information includes: Responsible elements, notification procedures, alternative techniques for spill response, bi-national policies, available resources, joint spill management system, customs and immigration procedures for transboundary crossing of personnel and equipment during a spill response.
Adapting International SE Management Systems for Use in the Gulf of Mexico
Authors: Day Rebecca , Teti Nathaniel J. , Deetjen Caroline J.
Published: December 2007

Recent growth in deepwater E&P activities in the U.S. Gulf of Mexico has drawn operators from around the world. Many of these, particularly large multinational corporations with roots outside the U.S., bring with them existing Safety and Environment (SE) Management Systems. Having been developed in different regulatory and business environments, however, these SE systems vary from U.S. requirements and practices in significant respects. Employing such non-U.S. systems in the Gulf of Mexico could pose risks and costs ranging from noncompliance to over-compliance, and could ignore important factors associated with U.S. liability regimes for which there may be no parallels elsewhere in the world.

It is imperative, therefore, that SE Management Systems be tested against and adapted fully to the U.S. environment. Even decisions to retain the over-compliant "home" systems must be made after careful consideration of the costs and consequences.

This paper will provide an overall framework for evaluating and adapting non-U.S. SE systems in the Gulf of Mexico, as well as specific areas of concern. The latter include liability regimes in the spill and personal injury arenas; reputation issues; investigating incidents; benefits and risks of "over-compliance"; use of lawyers and other consultants; and other critical areas where the U.S. offers special SE challenges. The paper also will discuss methodologies for identifying and assessing gaps, risks and costs associated with use of non-U.S. systems in the Gulf of Mexico.
Sealing Capacity of API Connections—Theoretical and Experimental Results
Authors: Badicioiu Marius , Teodoriu Catalin
Published: December 2007

Hydraulic fracturing has become a state of the art stimulation technique. It has been proved over the years that significant production increase can be obtained by applying the right fracturing technique. Nowadays, the most advanced techniques of geothermal energy recovery systems widely use hydraulic fracturing.

The following paper presents the experimental results of the tests carried out on four different compounds using the improved "grooved plate" method. The tests have showed a large variation of the tested thread compounds sealing capacity. Starting from the experimental results and the theoretical analysis of the API connection a useful chart was built to determine the real connection resistance, based on its initial makeup torque. The chart offers to engineers involved in the design of a fracturing process the possibility to estimate the maximum pressure that may lead to a connection leak.
Underbalanced Coiled Tubing Drilling Practices in Horizontal Short Radius Re-Entry Well Applied in Hassi Messaoud - Algeria, Case Study
Authors: Amor Bachir Ben , Ferhat Ali , Messas Rafik , Arnone Maurizio , Barakat Naiem , Schoch Fritz , Qutob Hani , Chopty James
Published: December 2007

The Hassi Messaoud field (Figure 1), discovered in 1956, is the largest oil field in Algeria, covering about 2000 Km2 and currently including over 1000 Wells. The field is divided aerially into 25 zones that are separated from each other by low permeability barriers, usually faults. The Cambrian Reservoir is subdivided into four lithological zones designated from base to top as R3, R2, Ra and Ri. The Ra sub reservoir shows the best petrophysical properties with a maximum thickness of 150 m in the western part of the field. The Ra is farther subdivided into five sub zones: D1, ID, D2, D3, and D4 based on reservoir properties and depositional conditions. Figure 1Hassi Messaoud field location

Well F was the 6th re-entry well in the Sonatrach Coiled Tubing – Underbalanced Drilling campaign. A total of 363 m from KOP (303 m from landing point) were successfully drilled in a continuous underbalanced condition inside D1 and ID formations. As a result, the well productivity while drilling and while production test, the reservoir characterization and rate of penetration was significantly improved, compared with offset wells, due to the positive impacts of UBD operations.

The combination of Underbalanced and Coiled Tubing Drilling technologies has been proven to be a viable solution to successfully drill horizontal re-entry wells in mature fields where the reservoir pressure is adequate to induce underbalanced conditions using single phase or multiphase drilling fluid.

The experience in this field has validated the benefits of the combination of these technologies and has been attributed to the excellent balance between drilling cost and improved productivity. For example, the drilling cost in the short radius re-entry wells drilled with coiled tubing are highly reduced due to the elimination of pipe connection procedures, the increase in rate of penetration, the prevention of conventional drilling problems such as fluid circulation loses and related differential sticking events, the increase in the bit life and reduction in time and drilled distance to reach the profitable production level.

This paper describes the technical basis for the design and implementation of the Coiled Tubing Underbalanced Drilling project in Hassi Messaoud Field and highlights the operational key factors and challenges faced during this particular and successful application in Algeria.
Data Analysis Methodology for Reservoir Management
Authors: El Ela M. Abu
Published: December 2007

Reservoir management (starting from a development plan, implementing the plan, monitoring and evaluating the performance of the reservoir) requires knowledge of the reservoir that should be gained through an integrated data acquisition and analysis program. Data analysis program requires a great deal of effort, scrutiny and innovation. The key steps are (1) plan and organize, (2) collect and analyze, and (3) integrate and store. This approach addresses a general framework of optimizing the data analysis process. This paper attempts to highlight this type of approach.

The applicability of this work is confirmed by actual field case study (Shukheir Bay Field) in Offshore Shukheir Oil Company (an international joint venture company in Egypt). Such study is an original contribution to the knowledge of the data analysis process, which proved effective in clarifying the overall view of the reservoir performance in view of facilitating decision making for developmental plans.
SAGD Optimization With Air Injection
Authors: Belgrave J. D. M. , Nzekwu B. , Chhina H. S.
Published: December 2007

This paper discusses the recent patent application filed by EnCana Corporation on the use of air injection to improve the performance of steam assisted gravity drainage (SAGD).

EnCana's SAGD/Air Injection process employs standard SAGD well-pair infrastructure. It optimizes between the ability of steam to preheat the reservoir during SAGD and the superior (follow-up) oil displacement efficiency of in-situ combustion.

Operationally, air injection is initiated after thermal communication has been established between well-pairs with steam. One interesting feature of this operating strategy is that down-hole bulk separation of oil and gas occurs which facilitates (a) efficient monitoring and control of the combustion, (b) design of surface facilities, and (c) corrosion mitigation.

Laboratory combustion tube tests are presented that confirm the ability to initiate and sustain combustion, as well as mobilize residual oil saturation to steam, within a SAGD chamber. These experiments were initialized at oil saturations and conditions representative of those in a steam chamber. The residual oil saturations were determined from a full-hole core taken in the vicinity of a mature SAGD well-pair at Foster Creek.

Numerical simulations of post-SAGD air injection are presented that suggest the ability to displace and produce oil banks between well-pairs and that recovery factor can be increased up to 8% of the original oil-in-place over conventional SAGD.

The simulations show oil production rates and recovery factor are expected to increase with higher air injection rates. However, instantaneous air-oil ratios, which are indicative of operating costs, also increase. Thus there is an optimum continuous air injection rate that maximizes profitability. Simulations further indicate that it is possible to recycle flue gases in the injection stream without affecting oil recovery.
Remote Real Time Well Surveillance the Best Fit for Southern Part of Ghawar Area Field
Authors: Al-Amer A. A. , Dashash Alaa A.
Published: December 2007

Manual wellhead data collection is manpower intensive and requires significant time to collect and distribute in addition to the associated problems such as incomplete and missing data. Remote realtime well surveillance eliminated these problems by providing the data real-time and on demand. The data automation increased accuracy and efficiency in the workflow process, ensuring the best asset management to maximize the value of oil reserves. The real-time system was installed in the southern part of the Ghawar area field in which the reservoir is heterogeneous with poor rock quality and numerous faults and fractures. The fractures and faults represent possible challenges as conduits for early water breakthrough. Therefore, real-time well surveillance is essential to identify problems early on and would enable to set proactive solutions for any anticipated problems. Real-time wellhead and downhole pressure and rate data could be integrated into simulation and well performance analysis to gauge what is happening within the reservoir and help adjust and optimize production and injection strategies.

With real-time data acquisition and automation the workflow process has dramatically improved. This paper will discuss the improvement in transmitting well pressure and injection rate data and the resultant benefits. It will also highlight the real-time system description, the data flow process and Saudi Aramco's determination to be in the leading edge of this technology. This success story of using an automated real-time data system will illustrate Saudi Aramco's intention to overcome challenges by applying the best available technology.
An Innovative Utilization of Drilling Wastes as Building Materials
Authors: Chen Ta-Lin , Lin Sunlong , Lin Zsay-Shin
Published: December 2007

The drilling fluids and cuttings are the main sources of drilling waste in Taiwan. This research focused on the topics of reusing and resource recycling of drilling waste. Some specific recipes convert drilling wastes to building materials were investigated in this study. All the raw materials of these recipes come from waste drilling fluids and cuttings in drilling process of three different wells in Taiwan.

Considering the properties of waste, technology feasibility and product market, this study have tried to manufacture brick for building; permeable brick and concrete partial substitute from drilling waste and examine their properties with suitable specifications in laboratory. Detailed process for each product is described. The drilling wastes should be pretreated to become dry powders under 100 to 105 °C, which are the common raw materials for difference products.

According to the experimental result, the strength of permeable bricks produced from the recipe were between 350 to 1200 kgf/cm2 with permeability coefficient between 3.9×10-3 to 8.1×10-3 cm/sec (at 15 °C), which is met the CNS (Taiwan National Standard) specification requirements. The bricks for building have the strength between 110 to 280 kgf/cm2 after 7 days aged, which also fulfill the CNS specification. For the concrete partial substitute, even though the percentage of additive increased to 10% and 20%, the strength of samples still keep on 310 to 350 kgf/cm2, which are also conformed to CNS requirement.

Drilling wastes can be successfully converted into permeable bricks in this study, and all the end products meet CNS requirements. But it still needs more assessment to utilize the drilling waste as concrete partial substitute. The innovation is not only a new and cost-effective idea for drilling waste reutilization but also a great reduction of wastes impact during drilling process.
Technical-Knowledge Management Systems: Discrete Software Modules Provide an Affordable, Rapidly Deployed Alternative Solution to a Fully Integrated Approach
Authors: Pearce Julie Diane , McMillan Ian
Published: December 2007

A major challenge of any knowledge management system is to meet the varied needs of diverse constituencies, both internal and external. Comprehensive, integrated systems are costly to develop, may take considerable time to implement and often lack adaptability. For technical knowledge management related to bit development and application, ReedHycalog has avoided these limitations by employing a range of modules that meet specific needs. The comparatively narrow focus of each of these applications minimises development and maintenance costs, allows rapid introduction, and permits quick adaptation to changing needs. Integration of these diverse packages is achieved through a common software interface and established company practices, supported through user training.

This paper explores the character of ReedHycalog's principle knowledge management modules; we consider how the systems position the company to be better able to create lessons learned, and to establish best practices; we demonstrate the adaptability of the approach in the rapid introduction of a product development monitoring system; we examine, as an example of routine engineer usage, how the user interfaces with each module to produce a technically sound client product proposal.

Such an approach, using the best solutions for specific needs, yet integrated through a designed culture of accessibility and training, delivers a low cost, flexible knowledge management system. This discrete modular solution is a viable and effective alternative to a fully integrated knowledge management system.
Best Practices and Lessons Learned in Openhole Horizontal Gravel Packing Offshore Brazil: Overview of the Achievements from 72 Operations
Authors: Farias R. , Li J. , Vilela A. , Aboud R.
Published: December 2007

The challenge of the alpha/beta waves gravel packing open hole in the Brazil offshore is how to successfully displace the proppant slurry in a large wellbore with a low fracture gradient formation, deep to ultra-deep water depths, and extended reach horizontal section.

Since 2001, job data from more than 72 open hole horizontal gravel packings have been compiled into a database. This paper reviews the well information and the key gravel packing parameters: pump rate, fluid density, injection proppant concentration, inner/outer annulus area ratio, dune ratio, packing rate, packing time and packing efficiency during alpha/beta waves. The engineering implementations and challenges, the best practices and lessons learned for open hole horizontal gravel packing are also summarized. The data analysis yields a better understanding about the open hole horizontal gravel packing in the Brazil offshore and provides a good guideline for future practice. A historical review is also presented showing how the gravel packing methodology has improved packing efficiency and success rate.

Case histories are provided demonstrating how to deploy the single trip system and pack the extended reach wellbore utilizing ultra-light-weight (ULW) proppant under extreme with improved packing efficiency and the success rate.
Integrated BHA Modeling Delivers Optimal BHA Design
Authors: Chen David C. -K.
Published: December 2007

This paper presents the development of a new bottomhole assembly (BHA) program and how it is used to deliver optimal BHA design. The new program allows users to run static and dynamic models in the same application which will save time and minimize errors. For the static model, the program uses the newly developed generic algorithm for solving the Lubinski's BHA equations directly. The strengths of the new algorithm are accuracy and computation efficiency, as compared to the conventional finite-element based BHA programs. In addition, the program is designed to run fast on a personal computer (PC) with an intuitive user interface so that it can be used to optimize BHA design in the office as well as at the rig site.

The static model is primarily designed for directional drilling applications, such as optimal BHA design for maximum steerability, bending moment calculations to minimize fatigue failure, and BHA sag corrections to improve survey quality. The dynamic model is based on a hybrid of analytical and finite-element methods to calculate the critical rotary speeds of the BHA. This paper describes the significance of applying these features in a user-friendly application to improve the optimization process and maximize drilling performance.
What Role Does a Data Warehouse Play in A Service-Oriented Architecture?
Authors: Dampier M. , Tassin S. , Haines P. , Miller J. Y.
Published: December 2007

Description of the Material

Organizations have long struggled with providing integration, interoperability and data exchange among a variety of disparate databases across the enterprise. Many organizations are adopting service-oriented architectures (SOA) to provide both application and data integration services. Incorporating data warehousing into an overall service-oriented architecture is critical for enabling integrated business intelligence.

Application

Business intelligence architectures focus on delivering data from source systems to data warehouses and then to data marts for reporting and analytical applications. They have typically used ETL to move data, and more recently, EAI. SOA brings the promise of using an umbrella approach for not just batch data movement, but also for real-time application and data integration. This paper describes how data warehousing fits into a service-oriented architecture, some of the common challenges that it addresses and what the combined architecture looks like. Additionally, this paper takes a look at a common business scenario utilizing Data Warehousing within a service-oriented architecture.

Results, Observations and Conclusions

Successful business process management and access to direct transactional business intelligence are two of the main benefits resulting from the capture of timely, accurate data at the source. Creating business intelligence that performs efficiently and provides strong corporate memory requires incorporation of data warehousing into the overall service-oriented architecture model. Undertaken correctly, SOA can supplement existing technologies to deliver data and process driven business intelligence.

Significance of Subject Matter

The challenges of lack of data standards, "silos" of information, and lack of a common integration framework make the SOA promise of easier data and application integration sound very appealing. Many oil and gas companies have started implementing SOAs within their enterprises. With business intelligence solutions continuing to be a top focus for Oil & Gas IT leaders, informal surveys of this same group have found that many lack an understanding of the composite view of SOA and BI.
Beyond Queues: Using Grid Computing for Simulation Studies
Authors: Li Xin , Lei Zhou , El-Khamra Yaakoub , Huang Dayong , White Christopher D. , Allen Gabrielle , Smith John Rogers
Published: December 2007

Reservoir simulators are computationally costly and produce diverse, voluminous results. These features motivate a need for a distributed computing systems with high-level methods to manage computation, data, and workflow: the Grid computing community is working to provide such tools.

We begin by discussing the features of Grid computing environments, emphasizing features that enhance reliability and usability, and can contribute to decreased computing cost via a future market in Grid computing with high security. A Grid-based workflow for reservoir simulation is then outlined which uses software such as the Condor and Globus Toolkit to build and manage workflows, the Grid Security Infrastructure (GSI) for security, GridSphere for portal creation and management, and Cactus for parallelization.

The workflow is demonstrated for a geostatistical study of three-dimensional displacements in heterogeneous reservoirs using a parallel IMPES reservoir simulator. A suite of 5,120 simulations assesses the effects of geostatistical methods. Much of the pre- and post-processing is automated in this workflow, which is based on experimental design. Multiple runs are simultaneously executed using Grid computing. Grid services manage security, data acquisition, resource brokerage and allocation, response analysis, and visualization; the reservoir engineer is freed from micromanaging these workflow components. Flow response analyses indicate that efficient, widely-used sequential geostatistical simulation methods may overestimate flow response variability, compared to more computationally costly direct methods such as LU decomposition.

The workflow is extended to automatic history matching using Ensemble Kalman Filters in the Grid environment. Users only need to choose parameters for stochastic simulations in a Web-based Grid portal. A two-dimensional problem with one injector and four producers is created to investigate the performance of the Grid ensemble Kalman filter.

Grid computing offers a promising path toward effective use of computing resources within and between organizations. Existing tools support parallelization of code and construction of workflows. The software developed here can be adapted to drive other simulation tools, and is available for downloading.
An Experimental Approach of Matrix Acidizing of Permeability-Damaged Carbonate Reservoirs
Authors: Shedid Shedid A.
Published: December 2007

Matrix acidizing is a common well stimulation technique in which acid is injected into the producing reservoir. The main purpose of the process is to remove wellbore formation damage and/or dissolve a portion of the rock and hence, enhance the permeability in the near well-bore region. It is however, important to optimize many treatment parameters to execute an efficient acidizing job.

This study are undertaken to investigate the influences of acid injection rate, acid concentration, variation of rock permeability, reservoir temperature, and acid volume injected on the recovery of damaged rock permeability using matrix acidizing of oil carbonate reservoirs.

Sixteen core flood experiments are undertaken to investigate the above-mentioned effects on matrix acidizing process using actual cores and reservoir liquids. Every core sample was cleansed, evacuated, saturated with brine, flooded with crude oil, and damaged with bentonite water-base mud. Then, the designed acidizing run was carried out. The rock permeability was measured before and after acidizing to quantify the success of the process and to identify the effect of every factor. Models of prediction for permeability damaged factor and permeability improvement factor were developed.

The results of the study indicated that the increase of acid concentration and/or the flow rate increases the recovery of damaged permeability. Furthermore, initial rock permeability has minor effect on permeability enhancement by matrix acidizing of damaged carbonate oil reservoir rocks. The increase of acid injection rate increases the required acid volume injected regardless of the reservoir temperature under acidizing. Finally, the results reveals that carbonate oil reservoir of higher temperature require more acid volume to be injected than that reservoirs of lower temperature for the same applied acid injection rate and concentration.
New Type Curves for the Analysis of Pressure Transient Data Dominated by Skin and Wellbore Storage—Non-Newtonian Fluid
Authors: Igbokoyi Alpheus O. , Tiab Djebbar
Published: December 2007

A new type curve for well test analysis for non-newtonian fluids in petroleum reservoir is developed. The general analytical solution in Laplace variable presented by Ikoku and Ramey Jr.2 forms the mathematical basis of the proposed type-curves. The equation for the type curve was developed, following similar procedure to that of Bourdet et al10. The Bessel functions involved in the final solution of the non-newtonian case cannot be approximated by logarithm function as in the Newtonian case. Hence, the dimensionless group of the skin factor and wellbore storage coefficient used in the Bourdet et al's case was not used in this study. Instead, only the skin factor is retained. The dimensionless wellbore storage coefficient is grouped with the dimensionless time as usual.

The log-log plot of the pressure derivatives at the infinite acting radial flow lie on a straight line for each flow behavior index. This straight line intersects the Newtonian infinite acting pressure derivative line at tD/CD = 1. In addition to the unit slope line of the wellbore storage region, this point of intersection provides a fulcrum point for proper curve matching. Thus the characteristic mobility can be computed using this intersection point.

Apart from the conventional type-curve-matching method of analysis, the Tiab's direct synthesis (TDS) technique is developed for the evaluation of well test data in non-newtonian fluid flow. This is based on the long time solution as in the conventional case and the characteristic line of the type curve. The process does not involve type curve matching, but provides a direct method of evaluating the well test data from the log-log plot of the pressure and pressure derivatives. Two examples from the references 3 and 6 were used to validate the type curves and satisfactory results were obtained.
A New Practical Method To Quantitatively Evaluate the Changes in Formation Permeability During Production
Authors: Ju Binshan , Fan Tailiang , Wang XiaoDong
Published: December 2007

It is a universal phenomenon that the permeability of an oil reservoir maybe changes with formation pressure, formation damages, sand fines migration and other formation sensitivity during oil production. However, there is as yet no quantitative method to calculate the changing permeability during production. Current method such as oil productivity index, fluid productivity index, and apparent fluid productivity index, only give a semi-quantitative estimation of permeability, which has a low precision.

In order to quantitatively evaluate permeability changes during production, a new practical mathematical model based the theory of oil displacement by water is presented in this paper. The new method can be used to calculate permeability using relative permeability data and production data of an oil field. To testify the accuracy of the new method, the relative permeability and production data from H.Z.J. Oil Field is used to calculate permeability changes during production. The results obtained by previous methods and the new method given by this paper are also compared. This study shows that the previous methods such as production index reflect the total change of both permeability and fluid flow transmissibility and they can't really reflect the change in permeability. The new method presented in this paper can accurately evaluate the change in permeability caused by all kinds of formation sensitivity during production.
Cementing a Producing Formation With Low-Fracture-Pressure Gradient in Wafra Field, Kuwait
Authors: Elmarsafawi Youssef , Warman Robert , Assad Abdulla , Powell Blair , Razouqi Maen , Caillat Frederic
Published: December 2007

Achieving good zonal isolation in wells characterized by lost circulation has been a challenge in the Wafra field of Kuwait. The field is characterized by highly fractured formations with very low fracture-pressure gradients. In the Wafra field production intervals were commonly drilled with partial or complete losses, causing risk during drilling and cementing operations and damaging the producing formation. Also, uncemented columns of casing have developed leaks as a result of corrosive formation fluids. Two-stage cementing with extended slurries and top jobs were the common practices in this field in an attempt to circulate cement to surface. This technique delays the drilling progress, and the low mechanical properties of the extended slurries do not provide the required zonal isolation.

A new cementing program was introduced to combat lost circulation in this field. A slurry technology at a density of 900 kg/m3 (7.5 lbm/galUS) was used to cement the low-fracture-gradient production zone without cement losses or formation damage. Excellent set cement mechanical properties were achieved with very low set-cement permeability. In wells where high losses were expected, a surface-treated fiber was added to the cement to bridge across the problem zone. This paper presents case histories study of several wells, laboratory designs, and field data in which these new techniques successfully treated partial to complete losses encountered during cementing operations. In all jobs using the new slurry, lost circulation problems were cured and cement was circulated to surface.
Integrated Management in a Mature Field in the Brazilian Continental Margin
Authors: Silva M. F. , Malta M. S. , Zapparolli L. H. , Silva P. M.
Published: December 2007

The main objective of this paper is to describe the integrated management process in Namorado field, a shallow water field in Campos Basin, Brazilian continental margin consisting on a multidisciplinary planning, a comprehensive diagnosis of the problems and a full set of corrective actions.

The steps include tools as wireline production and saturation logs, pressure and production tests, a suitable schedule of tubing changes, perforations in unshot oil intervals and abandon of swept intervals.

Moreover, a rigorous control of mass balance on injected and produced volumes is performed, as a permanent concern of the whole production asset, resulting in a politics of gradual increase in injected water volume and, consequently, an increment in the oil production.

It also includes periodic squeezes of an inhibitor in order to prevent Barium sulfate scaling and changes in the drainage strategy as the convertion of wells from producers to injectors and vice versa.

This management is performed by an integrated teamwork: Reservoir, Production, Workover, Lifting and Economics. It has shown remarkable results as the maintainance of the oil production and the reservoir pressure at the same level during the last twelve years.
An Improved Pressure and Saturation Downscaling Process for a Better Integration of 4D Seismic Data Together with Production History
Authors: Enchery G. , Le Ravalec-Dupin M. , Roggero F.
Published: December 2007

In the recent decade, automatic history-matching has been a very active research area with significant progress reported. Workflows have been designed in order to build reservoir models consistent with production history and geology. Due to the growing use of repeated seismic and monitoring, it has become important to incorporate also 4D seismic attributes in the modeling of reservoirs. More complicated workflows have been proposed to simultaneously integrate production history and 4D-seismic data in reservoir models. They encompass the minimization of an objective function, which measures the mismatch between the collected data and the corresponding simulated answers. Thus, the objective function is used to compare the actual production data to the simulated ones and the actual 4D seismic attributes to the simulated ones. The computation of 4D seismic answers entails the use of the simulated fluid distributions. The flow simulations, which provide these fluid distributions, are usually performed at the coarse scale. A downscaling process is required to properly model the 4D seismic answers. In this paper, we propose a new method for downscaling pressures and saturations from the coarse reservoir scale to the fine geological scale. This method ensures mass conservation and allows capturing fine scale heterogeneity. It calls for local flow simulations with boundary conditions specified from the driving coarse flow simulation. A numerical example is presented to point out the improvement in the building of the constrained reservoir model.
Infill Well Modelling in Reservoirs with Multiple History-Matched Descriptions: Case Studies from Andrew and Harding
Authors: Walker Greg J. , Skinner Roger , Litvak Michael
Published: December 2007

The task of selecting and planning infill wells is critical to the ultimate recovery of hydrocarbons from a field, and in a mature basin we have progressed down the long tail of targets to the numerous but small opportunities. There is considerable value left in such targets, even with current drilling technology, but the targets require a better understanding of risk and a higher level of detail. We also face the difficulty this has to occur at a time when the industry is constrained by people resources and rig availability.

The Andrew and Harding assets have been leading members of a field trial of a system to test large numbers of alternative depletion plans to try and find the optimum for economic impact and recovery. The assets have also been early adopters of the recent advances in computer assisted workflows, using tools such as BP's TDRM1 in history matching mode to generate alternative reservoir descriptions that satisfy observations and has some measure of the range in possible outcomes.

This paper presents the results of combining infill well planning and multiple reservoir descriptions in a computer-assisted workflow of Top Down Depletion Planning (TDDP)2. The results have enabled smaller targets to be sanctioned, as there has been a better understanding of the risk. Furthermore, instead of appraising three targets in five months of effort, it has enabled the appraisal of seven targets to the same level of detail in only two months of effort, a factor of 4 increase in efficiency for the subsurface team.

The case studies have also forced advances in the data analysis, to understand how the infill wells and the alternate reservoir models interact. We can make the choice to seek the optimum choice of things that we can control, such as the depletion plan, on the average performance across the multiple reservoir models that we can't control, but we can use surveillance to try to distinguish between models if we can identify the surveillance prize.

The first case study is an introduction to the data analysis of a simple case, looking at the determination of the optimum in a single reservoir model. The second case examines Andrew in more detail, which optimizes on average performance on a range of models constrained by current surveillance. The second study does show the start of a surveillance prize, by showing that some of the different reservoir descriptions actually support consideration of a different depletion plan. The value of surveillance theme is explored in the third case study where we return to Harding and now examine the infill wells when the problem is phrased as the phasing, location and operating conditions of two wells, based on 9 alternative reservoir models.
Permanent Real-Time Downhole Flow-Rate Measurements in Multilateral Wells Improve Reservoir Monitoring and Control
Authors: Zakharov M. , Eriksen S. H. , Raw I. , Pride S. , Ridez A.
Published: December 2007

During the last decade, intelligent well completions have evolved to become engineered solutions widely used for both monobore and multilateral horizontal wells. However, a clear understanding of zonal or lateral branch flow contributions still remains an issue. Several SPE papers covering the issue have been published recently.

This paper presents the engineered solution for a TAML level 5 dual-lateral horizontal well that was drilled and completed in the Oseberg Sør field in December 2005. The solution combines hydraulic flow control valves with advanced downhole two-phase flow and density measurement provided by a Venturi-based flowmeter with a gamma ray source and detector. Real-time data were used to optimize the settings of the downhole chokes to obtain a balanced production from the two horizontal wellbores. The completion provides the capability to control and measure, in real time, flow contributions from both laterals and is the first installation of its type. This capability is critical for production and reservoir optimization.

Additional value of the technology is demonstrated by the analysis of acquired downhole data. Productivity Indices are obtained for each of the two laterals without any production loss associated with shutting down the other lateral branch. Data analysis indicated a decrease of the Productivity Index for one of the two horizontal wellbores.

The successful installation of the two-phase flowmeter in an intelligent completion is a significant milestone corresponding to the general trend in the industry to improve inflow control and the understanding of flow contributions in multilateral wells. This solution for flow control and measurement can be applied effectively in both multilateral wells and monobore wells designed for commingled production from different reservoirs where accurate production allocation is a critical issue.
Results in Construction and Completion for Extend-Instrumented Horizontal Wells Into Low-Pressure Zone: Case History—Reservoir Miocene Ll-03, Maracaibo Lake Venezuela
Authors: Pizzarelli Sergio , Alter David , Tillero Edwin , Garcia Jose Luis , Leal Tulio
Published: December 2007

One of old and most important West Venezuelan Oil fields is the LL-03 reservoir which has accumulated more than 1200 MMBN and actually represent the 30% medium oil daily production of Exploitation Unit "La Salina", Maracaibo District, PDVSA.

This reservoir is characterized for contain 30% of shale with not consolidated sand at low pressure with 450 psi at 3500 feet of depth with interleayer of clay and high permeability with lost of severe circulation risks, in order to develop the reserves of 24° API oil it was designed and execute the secondary recovery project called Fase IV through instrumented horizontal wells into low-pressure zone.

Due the depleted conditions of this reservoir it was begun the search of new alternatives for perforation fluids competitive at technical and economic levels, being one of the main challenges to ensure the success in the construction and completion for extend horizontal wells. After obtained the formulation of the optimal fluid to use it was come to design the directional plan and the mechanical completion for sand control, being considered in addition the use of permanent downhole gauge for pressure and temperature readings, conforming therefore the instrumented well.

The stability of the system, the effectiveness of the saline seal and operational practice allowed the successful perforation of 3 instrumented horizontal wells (2 injectors and 1 producer) with the formulated saline fluid in a horizontal section of 2699 feet average without observe hole instability problems having completed the wells with mesh screen for sand control and permanent downhole gauge for pressure and temperature readings in a concentric string, after removing the filter cake generated by the perforating fluid it was obtained 22 months of continuous and stable production of 900 BNPD results Vs 450 BPPD expected for PB-763 well, opening opportunities for the perforation of 3 wells in similar conditions and it was begun the project for perforation of the first multilateral well in this same reservoir.
Impact of Heterogeneity on Flow in Fluvial-Deltaic Reservoirs: Implications for the Giant ACG Field, South Caspian Basin
Authors: Choi Kevin , Jackson Matthew , Hampson Gary , Jones Alistair , Reynolds Tony
Published: December 2007

The ACG Oilfield caps an elongate anticline with three culminations - Azeri, Chirag and Gunashli - and is located in the offshore Azerbaijan sector of the south Caspian Basin. This study focuses on Azeri in the south-east of the structure, which has over 8 billion barrels of oil in place. The major reservoir interval, the Pliocene Pereriv Suite, is characterized by laterally continuous layers of variable net-to-gross (NTG) deposited in a fluvial–deltaic environment. Azeri is being developed by down-dip water injection, with up-dip gas injection on the more steeply dipping central north flank. At the planned offtake rates both recovery mechanisms are expected to be stable. However, these predictions are based on reservoir models which do not explicitly capture the full range of geologic heterogeneity present in the Pereriv Suite reservoirs.

We report the first detailed assessment of the impact of large- and intermediate-scale heterogeneities on flow. Experimental design techniques have been used to rank the impact of different heterogeneities. A key finding is that communication between adjacent high and low NTG reservoir layers significantly improves recovery, providing pressure support and a route for oil production from sandbodies within the low NTG layers which would otherwise be isolated. Heterogeneity within high NTG layers has only a small impact on recovery, but heterogeneity within low NTG layers is much more significant. In most cases, the same significant heterogeneities impact both water and gas displacements, because both displacements are stable at the planned production rates.

The results are applicable to Azeri, and to similar reservoirs in the Caspian Basin. They also represent the first comparison of water-oil and gas-oil displacements in fluvial- deltaic reservoirs using 3D geologic/simulation models derived from outcrop and subsurface data.
An Integrated Geology and Reservoir Engineering Approach for Modelling and History Matching of a Vietnamese Fractured Granite Basement Reservoir
Authors: Le Ngoc Son , Jamiolahmady Mahmound , Questiaux Jean-Marie , Sohrabi Mehran
Published: December 2007

The main source of oil production in Vietnam is from naturally fractured basement reservoirs (NFBR). The SN reservoir, which is situated offshore Vietnam in Mekong basin, consists of fractured/weathered granite and granodiorite rocks and fully encased by highly over-pressured shales, which act both as seal and source rock. To date, the existing reservoir simulation models have failed to give an adequate history match without invoking the presence of a giant aquifer, something which is not supported by the existing dynamic and geological data. Furthermore, in the original simulation models, zero capillary pressure (Pc) was assumed and a single set of relative permeability (kr) curves and endpoints was assigned for the whole reservoir. These assumptions are open to question as the porosity (Φ) and permeability (k) varies by several order of magnitude for micro- to macro-fractures of this NFBR.

In this work, we have investigated a number of possible alternative sources of energy to achieve a satisfactory history match including (i) increasing the STOOIP by increasing overall pore volume (PV) of the reservoir and (ii) using different values of rock compressibility (Cr) and (iii) accounting for rock compaction (porosity reduction by fracture closure) due to reservoir pressure (Pr) reduction during production. We found that modelling porosity reduction by compaction together with a minor aquifer gave the best history match and is geologically coherent

We also considered using a dual rock-type model, with microporosity zones (Φ<1%) consisting of a network of microfractures and weathering, developed along the macroporosity network which coincides with the major basement faults which criss-cross the granite basement. Microporosity zones were assigned non-linear kr curves with appropriate end points and Pc, while macroporosity zones were assigned diagonal kr curves and zero Pc. Dual rock-type models gave improved history matches. A comprehensive sensitivity study on variations in kr curves and their endpoints showed that these greatly affect reservoir flow behaviour. Finally we investigated variations in Pc but found that it had negligible effects in our models.