bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dynamic Behavior of a Fissured Dual-Carbonate Reservoir Modeled with DFN
Authors: Akram A. H. , Gherryo Y. S. , Ali S. M. , Thabt M. S. , Serban A.. 
Published: February 2010

Abstract
A Paleocene dolomite in northeastern Libya was modeled using three porosity types: matrix porosity (intercrystalline plus the separate vugs), horizontal-to-subhorizontal solution-enlarged vuggy porosity generated by dissolution and named "touching vugs," and fracture porosity.
The touching vugs, which acted like fractures in their dynamic behavior, are modeled as a very permeable discrete fracture network (DFN) in PETREL* seismic-to-simulation software. Their presence is known primarily due to pressure buildup analysis, and it is expected that they would be interconnected over hundreds of meters.
The primary challenge in dual-media modeling is being able to characterize and predict the dynamic behavior of the complex matrix + fracture + touching vug system. There are three wells in this area of northeastern Libya with pressure buildups that have an unusually distinct and pronounced dual-porosity signature. Each well has been matched by adjusting the five primary parameters: matrix and fracture porosity and permeability, and the sigma shape factor. Aquifer strength also had to be adjusted.
There are some aspects of the dynamic behavior of this reservoir that are of particular interest: The highly fractured low-porosity parts of the reservoir are the least productive, and the least fractured high-porosity parts with touching vugs are the most productive.The well test shows pronounced dual-porosity behavior and indicates a high level of contrast between the matrix and secondary porosity systems, both in terms of permeability and porosity.There is a strong aquifer and in reservoirs with moderate fracture permeability, we would expect to see the fractures provide a pathway for rapid water breakthrough. Owing to the very high permeability associated with the fracture system, this does not happen as expected; i.e., the reservoir acts to some extent like a tank with a level oil/water contact (OWC). There is not much coning or advancing of water in the secondary porosity system.
This paper presents the dynamic features of the reservoir and demonstrates how the simulation model was calibrated using all available information, in particular, the pressure buildups.
Gravity Data Analysis and Interpretation of Sirt Basin, Libya
Authors: Saheel Ahmed , Bin Samsudin Abdul Rahim , Bin Hamzah Umar 
Published: February 2010

AbstractThe produced Bouguer gravity map shows prominent NW-SE and N-NW trends.Total horizontal derivative gravity map of the study area shows strong horizontal gradient anomalies that are located in eastern and central parts of the area. The central part of the basin can be divided into four zones the eastern zone shows many short anomalies of NW-SE orientation; the southern zone shows N-S orientation; the northern zone shows NW-SE orientation trends; in the western zone strong NW-SE trends cut with NE-SW changing to E-W trends. Isostatic residual map is characterized by a dominant northwest – southeast trend in the study area. This is clearly evident in the isostatic residual. The main trending anomalies are in the northern and southeastern parts of the study area with NW-SE orientation. A strong NW-SE trend is truncated by E-W trending in the southeastern and southwestern parts of the area. This is consistent with change of tectonic zones.
Open-Hole Solid Expandables Eliminate Slim-Hole Configuration in Integrated Solution Workover Well
Authors: Farhat Ali , Zeghouani Rabah , Sanders Tom , Saad Marc Antoine , Roushdy Marwan 
Published: February 2010

Abstract
In Algeria about 60% of the proven oil reserves are in the Hassi Messaoud region which was discovered in the 1950's. Several oil production wells drilled over 40 years ago have been shut in and are awaiting workover plans to revive those wells and get them back into economic production. A typical workover program is comprised of extending the open-hole in the reservoir zone, below 7-inch casing, and producing that through a new 4-1/2-inch perforated production liner. At the time of initial drilling of those wells, the reservoir pressure was as high as that of the shale zone immediately above it. This reservoir pressure has now declined and can be found to be as low as one-third of the shale formation pressure.
This recent variation in formation pressures (between exposed shale and reservoir zones) has created a need to mechanically isolate this exposed shale zone immediately above the lower pressure reservoir prior to drilling ahead. Original workover programs required the use of an additional (smaller size) casing string for this purpose, with the eventuality of drilling the reservoir open-hole section with a much smaller hole-size and completing the well as with a slim-hole configuration.
This paper presents an alternative solution that was implemented to workover these type of wells and enable completion with a sufficient hole-size in the producing zone to avoid a slim-well configuration. The major technology used to facilitate this alternative workover was the installation of a solid expandable open-hole liner to mechanically isolate the high pressured shale zone above the reservoir. The aim was to still allow for a large enough open-hole passage in to the reservoir section to facilitate the use of high performance directional drilling BHA assemblies,
The overall application of this workover is discussed to detail and highlight the added-value solid expandable liners provide in such workover applications. The successful integration and planning of the solid expandable installation along with; short radius casing exit, zonal isolation, and enhanced directional drilling has proven to be a significantly superior technical and economic alternative solution.
Reservoir Simulation Explains Production Problems in Nile Delta Gas Field
Authors: El Sheriff Hossam , Reda Mohamed , Gonzalez Christine , Hassouba Almoataz Bellah , Abd El Hady Ahmed , Sidky Mahmoud 
Published: February 2010

Abstract
This paper provides a case study of how detailed reservoir modeling and simulation helped to explain existing production problems and to subsequently optimize reservoir management for a gas field in the Nile Delta. In this example the complex geology of a fluvial deltaic system was modeled using the concepts of sequence stratigraphy to build the basic reservoir architecture for the Abu Madi Formation. Then seismic attributes were used to characterize the detailed facies and permeability distribution and the interplay of sands and shale in the reservoir intervals. This allowed a representative three dimensional reservoir simulation model to be built that could more accurately reproduce the water influx and gas water contact movement that had happened in the reservoir as a result of historical production conditions. In addition it confirmed that the different reservoir intervals had different reservoir drive mechanisms and thus needed to be managed differently. This was not fully understood using conventional techniques due to the relatively low well density.
This paper will include the specific lessons learnt for three gas wells in a small Upper Abu Madi fluvial channel in the Nile Delta Field where production conditions caused rapid water influx, water production from coning and gas blocking between wells which was not recognized without the detailed geological and dynamic understanding. In addition it will document the development optimization scenarios that were performed for all reservoir levels to maximize recovery. It shows that even for relatively small reservoirs the use of reservoir modeling and simulation can be cost effective by allowing the optimization of production conditions, improved recovery and the prevention of unproductive well interventions.
The Key Challenges for Pliocene Reservoirs Exploration in West El Manzala and West El Qantara Concessions, East Nile Delta Onshore, Egypt
Authors: Salvadori Leonardo , Raslan Samir , Fathy Mohamed 
Published: February 2010

Abstract
Exploration drilling in the Nile Delta has dramatically risen over the past 3 years, jumping from 5-10 wells/year up to 20-25 wells/year. Much of this recent drilling has been targeting the highly successful Pliocene play trend and the 2008 industry success ratio approached a phenomenal 90%. Thick sequences of Pliocene deep marine sediments have been successfully drilled and led to several offshore gas discoveries. No great exploration interest had been directed towards these good reservoirs in the onshore areas of the Nile Delta. Nevertheless, Dana Gas has been one of the most active and successful operators for this exploration target in its West El Manzala and West El Qantara Concessions.
The gas sands of the Pliocene reservoirs are characterized by low velocities and densities compared with the surrounding shales and, subsequently, the top and base of the reservoirs have a "bright?? seismic amplitude response. Additionally, the gas charged Pliocene reservoirs are often associated to acoustic impedance anomalies presence. The key challenge in the Pliocene reservoirs exploration is to understand the depositional environment with respect to the amplitude and acoustic impedance geometry from 3D seismic data through the cross-correlation between seismic facies character and the depositional pattern and environment.
The main features and variations recognized in the reservoirs drilled to date in West El Manzala and West El Qantara Concessions show a slow activity in the main basin evolution stage that seems to be not affected by high turbidity current flow or significant slope channeling. The early stage broad and straight channel system valley was cut and filled by younger channelized systems. Minor incisions of channel cuts are considered to be a key feature in defining channel fill development and sand distribution.
Innovative and Cost Effective Completion Technique for Saturation Surveillance Wellbore in Ratawi Reservoir of Wafra Field PNZ-Kuwait
Authors: Utomo B.. , Cullen R.. , Elbalasy S.. , El-Gendi O.. , Razzak S.. , Al-Hamdan M.. , Pasicznyk A.. , Fadda A.. , Glaser M.. , Erdmann L.. 
Published: February 2010

Abstract
Horizontal sidetracking and waterflood are part of current Wafra Ratawi reservoir management strategies. These have proven successful to arrest production decline. A comprehensive surveillance program is considered to be the key to optimize waterflood performance. Saturation profile is one of critical parameters to understand waterflood sweep efficiency. The best way to acquire saturation data is by running saturation logs in vertical wells. Since horizontal sidetracking is one reservoir management strategy, the remaining vertical wells accessible for saturation logging are becoming limited and soon will not be available. This paper discusses an innovative and cost effective approach to this surveillance challenge. A combination of permanent fullbore oriented packer and retrievable whipstock, a selective re-entry system, was chosen to complete the wells. The existing vertical wellbore was converted to an observation wellbore before sidetracking. This technique has potential to save significant capital investment by using existing vertical wellbores to serve saturation surveillance purposes.
Since the intent is to run saturation logs periodically in the vertical observation wellbore and to produce through the horizontal lateral during normal operation, there are several operational challenges that must be resolved. These mainly include: debris falling during ESP well services, re-entry jobs in horizontal lateral by work string, and effect of squeeze cement operation on cased-hole logs readings. This paper also discusses how the proposed completion techniques overcome these issues.
Three wells have been successfully completed with this system. The first time-lapse cased-hole logs were also successfully run in one of these wells, including an attempt to re-enter the horizontal lateral by work string that went smoothly. This unique concept of saturation surveillance wellbore in horizontal producers can also be extended for new drill infill producers completed with cased pilot hole. The technique is considered to be an innovative and first time application across the globe.
New Engineered Approach to Replace Oil-Based Fluids with High Performance Water-Based Fluids in Mediterranean Sea
Authors: Attia Mohamad , Elsorafy Wael , D'Angelo Stefano 
Published: February 2010

Abstract
Oil-based fluids (invert emulsion fluids) have for many years been the fluid of choice for use in challenging hole sections. These fluid systems can bring many advantages, including optimal shale stability, low torque and drag, good resistance to contamination, and high drilling rates. One of the challenges of utilizing an invert emulsion fluid, however, has been the increasing level of environmental concern and legislation associated with its use. These challenges have driven the search for a high performance water-based fluid that will provide oil-based fluid performance and be environmentally acceptable in all offshore areas of the Egyptian Mediterranean Sea.
A novel, environmentally compliant high performance water-based fluid (HPWBF) system has been developed that has proven to be extremely inhibitive and highly lubricious.
Use of this new HPWBF system has helped operators to drill some of the most reactive shales in the Egyptian Mediterranean Sea while avoiding the high cost and safety risks associated with "skip and ship" operations. This performance is coupled with excellent cuttings integrity, increased temperature stability and good hole-cleaning properties. In the application of this system, the engineered approach matches fluid requirements with local clay characteristics, environmental regulations and operational objectives.
A HPWBF was chosen to drill Petrobel's well Karam-1 with a great success. The fluid was utilized to drill 334 meters of 12¼" hole section through the very challenging highly reactive formation of Kafr El-Sheikh stratum. The following conditions existed for this operation: Fluid must be water-based to meet environmental stipulationsThe shale section would be exposed for up to 10 days while loggingBottomhole temperature is 230°FApproximately 100 m 17½" rat hole existed below the 13 3/8" casing
This paper discusses the technical challenges and highlights the criteria for the proposed fluid system and the successes achieved in this well.
Reservoir Saturation Monitoring United with Production Flow Profile for Efficient Reservoir Management -Success Story of Workover Program on S.E. Gemsa Field by Combined Services "Production Logging and Pulsed Neutron Logging Tools"
Authors: Abugren Yosra Y. , Hassan Ahmed , Joshi Sameer 
Published: February 2010

Abstract
South East (S.E.) Gemsa is an oilfield located in Gulf of Suez (GOS) in Egypt. Many challenges have been faced in the reservoir and operation management of this field, such as: -Permeability contrast and water breakthrough in high permeability zones.-Non-uniform vertical water distribution.-Lack of water injection support across zones of low permeability.-Down hole scale build up.-Surface facility "bottlenecks".
One of the most critical problems was non-uniform water injection breakthrough into well SE-10B, which is a key oil producer in this field. This paper describes the water diagnosis and well intervention procedure carried out on this well over a period of 2 years (2007/2009) and the results achieved.
The main objectives of the conformance workover program were: -Reduce the water production.-Produce the non-contributing intervals.-Enhance the sweep efficiency by adding new intervals.
SE-10B is a deviated well (41 degrees) equipped with dual completion string to allow non-commingled production from strata with differential depletion and permeability contrast across the reservoir layers. This well was producing with very high water cut (WC) 95% from both strings. The major operational concern was to diagnose the water source; hence it was decided to run the combined Production logging and Pulsed Neutron logging tools to achieve the main objective of Water Shut-off (WSO).
The first logging run was in March 2007. The operator designed a workover program based on the interpretation results which showed the sources of main water contribution.
Workover-2007 results tended to increase oil rate by 275% (200 bopd to 750 bopd) and WC dropped to 30% in the long string. The short string did not have any water conformance intervention during this workover; it was producing at 98% WC and was shut down.
Another campaign was carried out in February 2009 for time lapse analysis and another conformance workover was implemented, which had impressive results. The short string has started producing 520 bopd with zero% WC versus mostly water before WSO. Long string has produced 1500 bopd and 25% WC versus 250 bopd and 65% WC before WSO.
The workover achieved a major reduction in WC levels of both strings, and had a significant positive impact on the daily oil rate that increased considerably to more than 300% of the value before the workover. All the objectives defined were achieved. The outcome of the workover program was completely successful and exceeded operator expectations.
Rejuvenation Issaran Field – Case Study
Authors: Samir M.. 
Published: February 2010

AbstractIssaran was discovered on 1981 and the cumulative production up to 1998 was 0.7 MMbbls from 9 wells and the total reserve were 5 MMbbls from 500 MMbbls as original oil in place which result in a recovery factor less than 1% and reflect the big challenge to produce this field.The problem was that each reservoir has its own characteristic, which requires special approach to overcome its problems and optimize its production and reserves. As Zeit Formation contain massive sand, Upper and Lower dolomite due to its shallow depth the oil could not be produced as cold production, Gahrandal formation is consisted of three limestone bodies with permeability below 20 md and the last one is Nukhul zone which give some cold oil production due to its naturally heavy fracture. Theses difference characterization lead to apply different ways of reservoir management for each zone.The challenge of Scimitar is to produce these zones and reach to a production plateau in spite of the aging of the fields and its associated problems (low pressure, water cut increase, wells potential, sand production and corrosion, …. etc). Scimitar dedicated special multi disciplinary teams to propose and implement several strategies to achieve its goal and succeeded to have stable plateau around 6000 BOPD during year 2008.This paper will highlight the results of each zone and the achievement as the total wells drilled on the field up to now is 287 well and the total OOIP increases to 700 MMbbsl, the cumulative oil production on March 2009 is more than 10 MMbbls which gives more confidence about the successful of the new strategies for each zone. The steam project applied on the Lower and Upper Dolomite is consider the first successful cyclic steam project on the Middle East. The results of the producing wells in conjunction with the numerical 3D simulation study lead to prove that the recovery factor can be reach to 45% which gives total reserve around 300 MMbbls.
Role of Steam Injection Pressure to Achieve Successful Cyclic Steam Project Issaran Field - Egypt
Authors: Samir M.. 
Published: February 2010

Abstract
Issaran fied Upper Dolomite Zone were subjected to a steam project by year 2006. The steam injection pressure is very important factor during the steam cyclic project as at any single injector difference in the performance of nearby wells may be attributed to (1) local differences in reservoir characteristics and initial fluid contents, (2) anisotropy in properties (perhaps a preferred fracture orientation), (3) effects of dip, (4) differences in well completion, operation, or impairment, and (5) differences in the location of fluid fronts in the reservoir.
Normally the injection pressure measure during thermal operations to provide (1) information on the injectivity and productivity of wells and flow resistance in the reservoir, (2) confidence that equipment and wells are being operated at design pressure levels and within safe pressure limits, (3) information on the enthalpy of fluids, and (4) information about properties and conditions existing in the reservoir through the use of diagnostic well test and continuous pressure observations.
The injection pressure play very important role on the oil production after the injection period. Here will discuss the pressure performance while steaming and its effect on the average oil production on the production period after. On Issaran Upper Dolomite fracture zone, 16 wells were subjected to two steam cycles and based on the injection performance these 16 wells were subdivide to three groups, the first group for the wells which showed a decline on the oil rate after the second cycle, second group for the wells showed sustain on the oil production after the second cycle and the third group showed an increase on the oil production after the second cycle.
This paper will highlight these results, and the methodology taken for analyzing the data, and the ways of investigation taken to reach a certain conclusion by the injection pressure should not exceed the fracture pressure otherwise during the second cycle the average oil production will be decrease.
Transient Well Performance Modeling for Reservoir Pressure Determination
Authors: Yee Hon Vai , Zainal Suzalina , Saaid Ismail 
Published: February 2010

Abstract
Continuous reservoir pressure data acquisition through intrusive well intervention has always been a challenge to the industry due to a combination of economic, operational and logistical constraints. This paper presents an alternative methodology wherein the reservoir pressure can be computed from the well's steady-state flow properties and wellhead shut-in data using an advanced transient well algorithm.
The key research element is the incorporation of mass transfer rate model into dynamic wellbore modeling for shut-in well. A mathematical workflow which incorporates the time dimension as inherited in the mass transfer theory is devised. This is a major advance on prior state-of-the-art models that assume instantaneous mass transfer upon equilibrium. This enhanced dynamic well model is able to simulate the fluid redistribution during well shut-in, by determining an accurate volume of each fluid phase at any cell in the well over time. Hence, the bottom-hole pressure over time can be calculated by adding the static head to the wellhead pressure. The bottom-hole near wellbore reservoir pressure is obtained when the well has reached equilibrium. The model also rigorously accounts for various transient behaviors of the reservoir fluids during shut-in including the reservoir fluid influx.
A number of engineering concepts are evaluated and all the elements that become the foundation of this novel methodology are presented. A sample well is used to demonstrate the robustness of the model in simulating the hydrocarbon fluid redistribution during well shut-in. A better description of wellbore dynamic behavior is obtained, ensuring an improved accuracy in transient well performance modeling.
This enhanced dynamic well model provides a vital tool for reservoir pressure determination, replacing subsurface data acquisition with surface data acquisition without well intervention. The model enables operating costs reduction associated with subsurface data acquisition, in addition to improve key data availability which will optimize production plans and recovery improvement opportunities.