bluuebunny/crossref_metadata_2025_split huggingface dataset:
Upscaling and 3D Streamline Screening of Several Multi-Million Cell Earth Models for Flow Simulation
Authors: Samantray Ajay K. , Dashti Qasem M. , Ma Eddie D. C. , Kumar Pradeep S. 
Published: December 2007

AbstractNine multi-million cell geostatistical earth models of Marrat reservoir in Magwa field of Kuwait were upscaled for streamline screening in FRONTSIM and flow simulation using ECLIPSE.The scale-up strategy consisted of (1) maintaining square areal blocks over the oil column, (2) upscaling to the largest areal block size (200m x 200m) compatible with 125 acre well spacing, (3) upscaling to less than a million grid blocks for FRONTSIM streamline screening, and (4) upscaling to less than 250,000 grid blocks for ECLIPSE flow simulation. GOCAD-SCP program was utilized for scale-up. SCP employs a single-phase flow-based process for upscaling non-uniform 3D grids. Several iterations of scale-up were made to optimize the result.Sensitivity tests suggest that a uniform scaled-up grid overestimates breakthrough time compared to the fine model and the post-breakthrough fractional flow also remains higher than the fine model. However, preserving high flow rate layers in a non-uniform scaled-up model was key to match the front tracking behavior of the fine model. The scaled-up model was coarsened in areas of low average layer flow since less refinement is needed in these areas to still match the flow behavior of the fine model. The final ratio of pre- to post-scaleup grid sizes was 6:1 for FRONTSIM, and 21:1 for ECLIPSE.Several checks were made to verify the accuracy of scale-up. These include comparison of pre- and post-scaleup fractional flow curves in terms of break through time and post-break through curve shape, cross-sectional permeabilities, global porosity histograms, porosity-permeability clouds, visual comparison of heterogeneity, and finally earth model and scaled-up volumetrics.The scaled-up models were screened using FRONTSIM 3D streamline technique. The results helped in bracketing the flow behavior of different earth models and evaluating the model that better tracks the historical performance data. By initiating the full-field history matching process with the geologic model that most closely matched the field performance in the screening stage, the amount of history matching was minimized and the time and effort required reduced. The application of unrealistic changes to the geologic model in order to match production history was also avoided.The study suggests that single realizations of "best guess" geostatistical models are not guaranteed to always offer the best history match and performance prediction. Multiple earth models must be built to capture the range of heterogeneity and assess their impact on reservoir flow behavior.
Bahrain Field – An Integrated Simulation Study of 15 Reservoirs
Authors: Kumar K. , Abdulwahab Ayda E. , Al-Muftah Ali , Alcobia Victor , Carvalho Alvaro 
Published: December 2007

Abstract
The Bahrain field is an asymmetrical anticline trending in the North-South direction. The field was discovered in 1932. The field is a multi-stack carbonate and sandstone reservoirs most of them oil bearing. The fluids range from tarry oil in Aruma zone to dry gas in the Khuff zones. The geology of the field is extremely complex with a large number of faults especially in the Wasia group formations, which contain the major oil reservoirs of the Bahrain field. These reservoirs are at different stages of the production cycle.
Following a 3-D seismic acquisition campaign in the year 2000, Bapco took up an integrated study to develop numerical models as the main tool to assess alternative production mechanisms. This integrated study faced a significant number of challenges, which had to be overcome with innovative ideas.
The challenges included representing communication between reservoirs through faults, complex rock and fluid distribution from heavy oil to gas condensate, gas injection, aquifer encroachment and fracture intensity. Although the hardware required for handling the large simulation models was meticulously selected based on benchmark data of the various machines, the geological complexities posed serious problems while running the simulation models.
This paper describes the challenges faced by the joint Bapco-CGG team and the approaches adopted to overcome these challenges.
Experience on the Survey & Repair Methods of Wear Problem on High Pressure Gas Transmission Pipelines
Authors: Al-Dossary Bader 
Published: December 2007

Abstract
Over time pipelines in the field, transporting high-pressure gas, have exhibited severe external wear at support locations, especially near bends, due to expansion/contraction with respect to climatic conditions.
This paper describes on-stream inspection survey techniques and the subsequent repair/inspection methods carried out, to ensure that pipeline integrity is maintained. The first gas transmission lines were constructed around 30 years ago, meeting the code requirements of ASME/ANSI B31.8, with an operating pressure of approximately 1050 psi. In July 1998, at one location, a 12" gas transmission line leaked due to external wear of the pipe at its point contact with a transverse support.
This paper also focuses on the significance of design location class, field investigation, corrective & preventive measures, repair & acceptance methods.
Investigation of Causes of Tight Emulsions in Gas Oil Separation Plants
Authors: Al-Ghamdi Abdullah , Kokal Sunil 
Published: December 2007

Abstract
Mubarraz area which is located in the center of the giant Ghawar field in Saudi Arabia has several wet crude handling facilities referred to as gas oil separating plants or GOSPs. These GOSPs process Arabian Light crude and their primary function is to separate oil, water and gas. In the past it has been observed that the usage of demulsifier varies from GOSP to GOSP. Some GOSPs, like GOSP-2, consume higher dosage of demulsifier compared to the other GOSPs. At the request of operations engineering personnel, and in partnership with them, a research study was initiated to investigate the causes of variable demulsifier usage in GOSPs, factors that stabilize these emulsions, and to evaluate the relative performance of demulsifiers. The primary objective of this study was to optimize the use of demulsifier in GOSPs while meeting crude and water specifications.
This paper provides results of an investigative study conducted to determine the causes of tight emulsions in GOSPs. The emulsions from different GOSPs were characterized in terms of their tightness using Emulsion Separation Index1. The study has also determined the causes of emulsion tightness in these GOSPs. These include crude oil temperature at the GOSP, percentage of wells squeezed with scale inhibitor, and overall GOSP watercuts. Based on these results several recommendations have been made to optimize demulsifier usage, ways to reduce emulsion tightness in Mubarraz field and test promising demulsifiers that should result in cost savings. The paper describes the partnership with operations and production engineering to optimize demulsifier usage at the GOSPs.
An Investigation of Gas Well Testing Under Constant-Bottomhole Pressure Conditions, High-Velocity Flow Effects, and Formation Damage
Authors: Nashawi Ibrahim Sami , Qasem Fuad H. , Gharbi Ridha B. , Mir Mohammad I. 
Published: December 2007

Abstract
This paper presents an investigation of the validity of applying the constant-pressure liquid solution to transient rate-decline analysis of gas wells. Pseudo-pressure, non-Darcy flow effects, and formation damage are incorporated in the liquid solution to simulate actual real gas flow in the vicinity of the wellbore. The study shows that for constant-bottomhole pressure gas production the conventional semilog plot of the inverse of the dimensionless rate versus the dimensionless time used for liquid solution has to be modified to consider the high-velocity flow effects. This is especially true when the reservoir permeability is higher than 1 md and the well test is affected by non-Darcy flow and formation damage.
This paper also presents a novel systematic method to determine the formation permeability, mechanical skin factor, and non-Darcy flow coefficient from a single constant-pressure production test. The working equations are written in such a way that allows a graphical analysis of the variable rate with time that is analogous to the analysis of constant-rate production test. The analysis procedure is simple and straightforward. It does not require type-curve matching or correlations. The applicability of the proposed method is illustrated using several simulated examples. The input formation permeability varies from a low value of 0.1 md to a high value of 5 md. The ratio of the downhole pressure to the initial reservoir pressure ranges from 0.1 to 0.8.
A New Approach for Estimating Well Productivity and Reservoir Pressure Using Surface Performance Data
Authors: Al Qahtani Abdullah M. 
Published: December 2007

AbstractWell productivity index is an important factor by which well performance is gauged with itself or as oppose to other wells. The change in the well's productivity is quantified by monitoring the changes in its productivity index. Another factor that is equally important and of mutual reaction with the well's performance is the reservoir pressure. This issue is complicated with the changes taking place in both parameters.Conventional methods of determining well productivity and reservoir pressure involve transient testing which helps petroleum engineers diagnose well and reservoir performances and make affective well producing and reservoir management strategies. Viewed as such, it is important to run transient test in new wells or wells experiencing a drop in their productivity due to formation damage. The data during a transient test are acquired by placing a pressure gauge downhole to capture the reservoir response due to the changes in well flow. However, due to the logistics involved, it is difficult to do frequent transient testing especially for offshore wells. Transient tests are also costly and interrupt delivery of hydrocarbons. For these reasons, such tests are run less than what operators would require to help evaluate well/reservoir performances.This paper presents a new approach that is based on a mathematical model that uses surface performance data to determine the reservoir and well productivity index. This approach captures the reservoir response as a result of changing the flowing wellhead pressures and flow rates by having a variable rate tests that are presented by surface wellhead pressure and corresponding flow rates. From the established trend, regression analysis is used to obtain a fit and estimate those parameters.This approach will enable faster evaluation of well and reservoir performances, elimination of cost of wireline crews and equipment, test of wells with restricted tubing or obstruction in tubing, and conducting frequent testing on wells experiencing a drop in their productivity due to formation damage. The application of this approach in the field revealed that the results obtained using this technique compare very favorably to that measured by transient testing.
Reservoir Description and Static Model build in Heterogeneous Mauddud Carbonates: Raudhatain Field, North Kuwait
Authors: Azim Shaikh Abdul , Al-Ajmi Hussain , Rice Craig , Bond Deryck , Abdullah Shehab , Laughlin Bruce 
Published: December 2007

Abstract
The Early Aptian carbonates of the Mauddud Formation form giant hydrocarbon reservoirs in North Kuwait. Reservoir description and distribution of rock properties in 3D space are challenging due to inherent reservoir heterogeneity. A robust depositional model driven by sequence stratigraphy, petrophysics tuned to dynamic data and innovative static modeling techniques were used to characterize this complex reservoir.
The Mauddud carbonate sedimentation took place in a low angle ramp setting. The basal part of Mauddud consists of shales and low energy carbonates deposited in a transgressive systems tract. The main reservoir was deposited during the subsequent highstand systems tract. High-energy inner ramp grainstones preserve the best primary porosity and permeability. Reservoir quality deteriorates in mid ramp to inner ramp wackestones and mudstones.
Diagenetic carbonate concretions destroy porosity and permeability. It is more pronounced in mud-rich packstone / wackestone fabrics. Early hydrocarbon emplacement has terminated concretion growth in crestal areas of the field whereas concretion formation and subsequent reservoir degradation continued in the water leg through late diagenetic stages. Rudistic floatstones, radially fractured concretions and small-scale fractures in low-porosity brittle rocks are the main thief zones in the reservoir.
Through the integration of core, openhole logs, production logs, and pressure transient analysis, a deterministic permeability model has been developed that characterizes the reservoir. Logs have been reprocessed to identify zones of secondary porosity (enhanced permeability) and fracture– prone zones. Porosity-Permeability transforms for matrix properties and fracture-prone intervals were developed. This methodology results in log-derived permeability profiles that match production log profiles and well test Kh estimates.
A fine Geological model with 85 layers and 2.5 million cells has been built to capture the primary depositional units. The horizons bounding the flow units are major flooding surfaces. The lithofacies associations have been modeled as composite objects restricted to facies belts. As porosity was observed to be decreasing towards the flank, trend modeling has been used to model the effective porosity. Another geological model with 166 layers was built to capture the small-scale heterogeneity caused by vuggy zones and fractures. The vugs and fractures have been modeled as objects restricted within an area demarcated by poorer seismic coherence. The Matrix permeability was enhanced by vuggy permeability and fracture permeability.
The paper describes the challenges in reservoir description and static modeling of this complex reservoir in detail.
Creative Modeling of a Heterogeneous Carbonate Reservoir in Bahrain Field (Kharaib Reservoir)
Authors: Qassim Naji A. , Waleed A. Jawad , Abdulwahab Ayda E. 
Published: December 2007

Abstract
This paper describes a case study of creatively utilizing open-hole logs and defining rock type and geostatistical permeability versions. The paper then briefly describes the process of up scaling and simulation that followed. Defining the rock types is the first step in reservoir characterization and modeling. Three rock types were defined for Kharaib reservoir; each rock type has a characteristic porosity and permeability relationship. Stratigraphic layers were utilized to QC the rock types distribution. The simulation of porosity and permeability constrained by the rock type model for the entire reservoir. Care was taken during the rock type simulation, because the resulting model will guide the porosity and permeability simulations. Standard Sequential Simulation was used to produce the models. A modified version of the SIS algorithm is needed to ensure that final images honor the local means and spatial trends of different categories. Careful design of the simulation model, aerial grids, fine reservoir layering, quality control and up-scaling process are vital to retaining the static models main heterogeneity features of carbonate reservoir. The model was then fit into dynamic simulation for history matching and validation.
Repair Intervention of Worn Production Casing in the Sajaa Field
Authors: Pattillo P. D. , Pruitt R. D. , Al Nakbi A. I. , Gent J. L. , Young K. , Zhang X. 
Published: December 2007

Abstract
The Sajaa gas/condensate field is located onshore in the Emirate of Sharjah UAE. Production is from the Thamama limestone reservoir at 11-13,000 ft. TVD. Reservoir pressure depletion is creating an ever increasing collapse pressure differential on casing opposite overlying sediments.
Sajaa field has a history of collapsed casing on wells Sajaa 33 and 39, with two collapse events in the latter wellbore. The current study summarizes the theoretical effort to prevent collapse in the remaining Sajaa wells. A companion paper1 discusses the related live well workover program.
Current Sajaa completions are packerless, producing up the tubing or up the annulus between the production casing and a capillary string for corrosion inhibition. Coincidentally, the collapse resistance of the production casing is reduced by severe wear associated with the use of tungsten carbide hard banding while drilling the reservoir sections of the wellbore.
Setting the context for the study, the well(s) tubular program, pore and internal pressures, and design safety factors are presented. This introductory portion also clarifies the differential collapse load to which the tubulars are subjected.
Loss of collapse resistance due to severe wear is then addressed. The theory of wear prediction is reviewed, and then demonstrated, as the drilling parameters of several of the affected wells are used to predict their current state. These predictions are then compared to mechanical caliper measurements taken during intervention and repair. Further, using specially machined wear grooves, the effect of wear on collapse of a casing cross section is experimentally validated by full scale collapse tests.
Results of both the wear prediction/measurement and its effect of collapse resistance are input to a probabilistic decision tree to tailor each well&#39;s workover strategy. The decision tree permits risk-weighting of alternate strategies for repairing the Sajaa casing. An important component of the decision tree is the consideration for time varying alteration of the collapse differential pressure with reservoir depletion.
Rosetta Field Development - Designer Water Based Drill-In Fluid Ensures Gravel Pack Completion Success
Authors: El Raheem Taher Abd , Toubar El Metwalli , Gamal Medhat 
Published: December 2007

Abstract
The use of a custom-designed water-based drill-in fluid, to minimisereservoir damage and facilitate successful open hole gravel pack completions,was vital to ensure a successful operation and maximise gas production inRashpetco's Rosetta field offshore Egypt, due to the nature of the producingsand.
Prior to drilling and completion operations, extensive laboratory work wasconducted including core flood return permeability and formation/fluidcompatibility studies in addition to gravel and screen studies. The drill-influid formulation and particle size distribution was optimised to ensure athin, impermeable filter cake and minimal filtrate invasion.
The low-solids saturated salt/potassium chloride drill-in fluid systemhelped stabilise inter-bedded shales while drilling the reservoir section. Nolosses of completion brine were experienced during the gravel packingoperations and gas production flow rates on all the wells drilled in theRosetta field exceeded expectations without requiring any stimulation.
Based on this proven success, the same technique will be implemented onRashpetco's West Delta Deep Marine (Scarab/Saffron deepwater developmentcampaign) to minimise the reservoir damage and maximise production.
Water Flood Conformance in a Highly Faulted Carbonate Reservoir
Authors: Shiflett David , Simlote Vishnu , Burns Scott , Thompson Tommy 
Published: December 2007

Abstract
ISND Shuaiba is a lower Cretacious carbonate reservoir off shore of Qatar. (Figure 1) It is a low permeability, high porosity wackestone-packstone with vertical permeability barriers. Aquifer water drive is weak and reservoir pressure is slightly above bubble point. Primary recovery is low. Waterflooding is required for increased recovery. Two systems of faults/fractures at oblique angles to one another cross the reservoir and divide it into a system of semi autonomous reservoir blocks. One system of fractures is conductive to fluids. The other system of fractures constitutes a set of no flow boundaries. The reservoir compartments are mapped with a seismically driven fault model built by integrating fracture image data and drilling, lost circulation experience. The predictive and explanatory model of fracture orientation and behavior is consistent with the regional stress evaluation. An injection plan is designed to repressure the reservoir compartments and optimize EOR reserves. The strategy is to place a vertical point injector at an optimal point in each reservoir block and access multiple reservoir blocks with horizontal producing wells. Cost effective vertical point injection is achieved by employing a single horizontal injection well with multiple vertical injection laterals
Business Process Re-Engineering in the Upstream Sector of E&P Companies. A study of Staff Perceptions and Critical Success Factors
Authors: Elie Daher 
Published: December 2007

Abstract
This paper investigates the perceptions of staff with regard to critical success factors (CSFs) for successful Business Process Re-engineering (BPR) for the upstream sector of the Exploration and Production (E&P) companies. The conclusion and recommendations were drawn after a detailed review of literature discussing BPR implementations in various industries and using the results of a study performed on a specific implementation of a BPR project for Information Management in a mid-size E&P company.
This paper shows that the factors deemed most important for successful BPR included items such as top management support, commitment and understanding of BPR, communication, empowerment and alleviation of downsizing fears. Some unique characteristics for the E&P sector have particular bearing on the application of BPR. They include the existence of many intricate overlapping processes with multiple stakeholders, changes in policy direction or in Oil prices, the existence of a professional workforce and the existence of defined internal organizational boundaries. Suggestions on how to maximize the chances of success in the BPR are discussed.
Using Knowledge Mapping Techniques to Build a Living Full-Field Model of an Oil Field
Authors: Al-Rasheedi Hussain , Chapman Terrance V. , Oskay Mehmet , Al-Khamees Waleed 
Published: December 2007

Abstract
The objective of this paper is to share the knowledge mapping techniques and experiences of those involved in this activity.
The purpose of a knowledge map is to show people in the organization where to go when they need expertise or have expertise to share. A knowledge map is a picture of what exists in the company as well as where it is located. It therefore can be used as a tool to discover opportunities to be exploited and gaps to be filled. When the same reservoir has different production policies for different portions of the field, Planners from all teams suffer from incomplete data. Information is shared when available, as in the case of the full-field reservoir model. But this is not thought to be optimal, when other reservoir studies have been conducted in isolation and expertise is not shared. A more coordinated approach is required that would continuously bring together all the available knowledge and make it always freely available to analysts and decision makers.