bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of Special Enzymes as a Means to Remove Formation Damage Induced by Drill -in Fluids in Horizontal Gas Wells in Tight Reservoirs
Authors: Siddiqui M. A. , Nasr-El-Din H. A. 
Published: December 2007

Abstract
Drill-in fluids contains biopolymers such as xanthan gums, cellulose and/or starch along with bridging agents like sized calcium carbonate particles. These polymers are used to enhance the carrying capacity of the mud and to form a filter cake on the formation to minimize leak-off of the drilling fluids into the formation.
Proper removal of drilling mud filter cake is essential to minimize formation damage. The damage becomes more intense in tight formations, especially in horizontal gas wells where the draw down is not high enough to dislodge the filter cake. Another source of damage is the mud filtrate where water blockage can occur in tight formations, especially sandstone reservoirs.
Thorough lab and field investigations of formation damage induced by drill-in fluids (water based mud) were conducted. A mini-flow loop was used to assess formation damaged induced by various polymers present in the drill fluid. Various cleaning fluids were examined and their effectiveness in removing the filter cake was determined. The cleaning fluids included: specific enzymes, mild acids, surfactants and mutual solvents, and combinations of these fluids. The retained permeability of reservoir cores was determined for each cleaning fluid. This paper presents results obtained from the lab and recommendation made for field application. Field treatment was conducted in a horizontal gas well which resulted in significant increases in gas production.
Al-Huwaisah Reservoir: The Long Journey to Improved Oil Recovery!
Authors: Al-Mugheiry Mohammed Adil , Mueller Guy , Braas Marcel , Materna Thomas , Davies Huw , Hsu Chia Fu , Keating John 
Published: December 2007

Abstract
After 30 years of production history in the Al-Huwaisah oil field of North Oman, it is still possible to bring best wells on stream. Both vertical and horizontal technologies have been implemented with variable combinations of gas-lifted or ESP completions and barefoot or lined reservoir sections.
In addition, these technologies are implemented on this complex carbonate reservoir characterized by a high degree of heterogeneity embedded in four depositional environments (i.e. Channel, Fore Reef, Main Reef and Back Reef) and spread over an area of 22km by 10km with zones of strong and poor aquifer support. This necessitates the need for a sound data gathering strategy to manage the subsurface uncertainties.
The improvement in recent production history was mainly the result of implementing a multidisciplinary team approach to define a more structured methodology for identifying the remaining oil targets and ranking them using basic petroleum engineering tools in a more synergistic fashion.
Past operational experience has also helped in selecting the best completion and stimulation practices. The outcome of implementing these practices on such a complex field showed that improved oil recovery requires a more flexible approach in field development philosophy in the sense that not always horizontal well technology is better than vertical or lined wells are better than barefoot.
The field is currently being evaluated for a possible application of Water-Alternate-Gas (or WAG) hydrocarbon recovery technique. Only parts of the field are found to be acceptable for the WAG pilot test according to the specified pre-requisites for this technology.
It is evident that technology solutions for complex carbonate field such as Al-Huwaisah calls for a ‘;dynamic focus’ in the sense that different parts of the field may require different types of technologies to meet the challenges of extremely variable complexity.
3D Model for Rock Strength & In-Situ Stresses in the Khuff Formation of Ghawar Field, Methodologies & Applications
Authors: Al-Ruwaili Saleh B. , Chardac Olivier 
Published: December 2007

Abstract
Knowledge of geomechanical attributes has positive merits for drilling in hydrocarbon formations. In the Ghawar field, the Khuff is a deep, carbonate gas-bearing formation. Several development wells have been drilled into this formation and conventional logging data was acquired in them. Such data has been exploited in generating geomechanical attributes along the Khuff formation in those wells. Furthermore, hard data like minifrac tests and core mechanical properties was available in some of the wells and utilized in calibrating and validating the computed geomechanical properties.
A study was conducted to develop a 3-dimensional characterization of geomechanical attributes in the Hawiyah- Khuff formation of the Ghawar field. The study was performed to provide a model that, together with existing geologic models, can be used to predict regions of drilling difficulty, provide guidance in selecting drilling bits, and help in designing drilling mud and optimizing hydraulic fracturing jobs in the field. The study established correlations between the geomechanical and the geological attributes in Hawiyah-Khuff wells. Then, these correlations were used with a pre-existing Hawiyah-Khuff geocellular model to map the geomechanical attributes away from the wells in the 3D Hawiyah-Khuff space. Rock strength, minimum and maximum horizontal stresses are among the properties that were mapped, for the first time, in the 3D Khuff horizon.
The 3-D geomechanical model is consistent with observed trends in drilling difficulty, and with the requirements for hydraulic fracturing within the Khuff horizons. The model has been used in assessing the borehole stability of deviated wells planned for the field. We present some illustrations and example applications in the paper.
An Innovative Approach for Logging Short String Side of Dual Completion Wells - A Case study from Kuwait
Authors: Al-Shaheen Saeed , Al-Mutairi Faisal , Chandran T. P. R. , Zaki Ahmed 
Published: December 2007

Abstract
This paper details an innovative technology to carry out logging operations in short string side of the dual completion wells. A program was initiated to carry out production logging in a Kuwait carbonate reservoir that recently began a secondary recovery project. The ability to measure zonal contributions and water entry in the target flood zones is critical for flood monitoring, designing future conformance control operations and profile modification jobs.
Most of the wells in the waterflood area are completed with dual tubing strings. The production logging target interval is generally in the short string of the dual completion, making wireline logging difficult due to the risk of entanglement with long string. Another concern is the fluid flow profile in the constricted area between two packers due to the presence of long string. Generally such surveillance requirements are hardly attempted, and this is considered as one of the major drawback of dual completion system itself.
A program was developed to record production logging in the short string side of a dual completion well. Coiled tubing with straightened bottom and threaded cable was used to convey production-logging tools in the short string. Several safety features were added to this system in order to ensure safe data acquisition. Upon success from first trial, the same procedure was repeated in several wells and results are quite encouraging.
Details of the initial obstacles that were faced in the beginning of the project and the methods used to resolve them will be discussed in this paper. The acquisition and processed results will be also discussed. It is worth mentioning that, all logging operations were successful and no operational problems encountered so far.
Variable Cementation Factor Determination (Empirical Methods)
Authors: Tabibi M. , Emadi M. A. 
Published: December 2007

Abstract
Cementation Factor is the most important parameter of water saturation calculations in Archie Formula. In fact the amount of this parameter defines the magnitude of pore volume in water saturation calculations. Cementation factor is not a constant value, but it largely varies according to many parameters in a field peculiar to reservoir characteristics. In addition accurate cementation factor "m" will effect on molecular diffusion coefficient in porous media in gas injection project. The most practical and reliable value of this parameter can be extracted from core analyses. In this new method, the attempt is to approach to a method of achieving variable m using the most effective reservoir parameters for any arbitrary interval of reservoir.
Smart Well Technologies Implementation in PDO for Production & Reservoir Management & Control
Authors: Al-Khodhori Shaikhan Mohammed 
Published: December 2007

Abstract
PDO currently operates more than 4000 wells in over 100 fields. The fields are diverse in terms of their reservoir, drive and development strategies. Despite this diversity, there are strong common drivers for smart wells/fields. Many fields are artificially lifted (beam pumps in S. Oman, gas lift in N. and central Oman, increasingly ESPs in all areas) with SCADA systems already in place. There is a progressive drive towards centralised, automated production facilities for reasons of safety. Reservoir depths and low drilling costs support relatively dense economic well spacing where it is technically feasible to connect large amounts of reservoir to a single wellbore; this saves development CAPEX but makes maintaining effective control of the reservoir more difficult.
Smart wells is an umbrella term referring to the systemic integration of emerging down-hole measurement, communication, control and processing technologies in well and asset design. As an integrated technology bundle, they have the potential fundamentally to change the E&P industry. A range of smart technology trials have been conducted and/or are planned, including down-hole monitoring, measurement, controlling and artificial lift optimisation.
PDO is applying many smart well technologies to monitor, measure, control and optimise production from multi lateral wells. This paper focuses on following applied technologies; Distributed Temperature Sensing (DTS) to monitor water and steam flooding wells.Down-Hole 2-Phase Metering in ESP and BP wells to measure water cut of dual lateral wells.Digital Hydraulic Control Valves to control production of a multilateral well.
The paper is intended to cover the above applied smart well technology trials, share the experience with respect to their outcomes (success and failures) during the execution. It also provides an assessment of the values of these technologies to PDO.
Sand Control during Drilling, Perforation, Completion and Production
Authors: Abass H. H. , Habbtar A. H. , Shebatalhamd A. 
Published: December 2007

Abstract
Sand control has been a challenge to the petroleum industry since oil and gas was produced from weakly cemented sandstone formations. Several techniques have been applied; 1) restricted (critical) production rate, 2) screen and/or gravel packing, 3) sand consolidation, 4) FracPacking, 5) oriented and/or selective perforation, and 6) combination of any of the above.
Sand formations may fail in compression, tension, and cohesion that trigger sand production. The compressive failure occurs during drilling where the rock cannot withstand the new stress field and/or the cementation materials have deteriorated from mud filtrate exposure. The calculation of mud weight to prevent compressive failure will be presented in this paper. Additionally the failed zone is usually oriented in the direction of minimum horizontal stress which can be avoided during perforation by orienting the perforation tunnels in the direction of maximum horizontal stress. During completion the cementation materials should be protected from completion fluids. During production a pressure drawdown is established for a given production rate. This pressure drawdown may cause rock failure in tension or cohesion (erosion) leading to sand production. The near-wellbore pressure is caused by skin damage due to reduced permeability, stressed region, convergence flow, and partial penetration. This paper presents a model to determine the critical pressure drawdown based on relating the near-wellbore pressure drawdown to the tensile and cohesive strengths of the formation. Hydraulic fracturing, referred to as FracPack, may be applied to alleviate the near-wellbore pressure drawdown below the critical value that causes sand failure. Two fracture parameters are designed to achieve this goal; fracture length and fracture conductivity. This paper presents a design criterion to determine these parameters to optimize a FracPack design for sand control.
Examples from a field in Saudi Arabia will be used to validate the application of controlling sand production using screenless FracPack completion. In these wells a FracPack treatment alone controls sand production. The multirate test used in these wells and the FracPack design for fracturing treatments will be presented.
The Use Of Surface Controlled Hydraulic Interval Control Valves For The Management Of Water Production In The Saih Rawl Field, Sultanate Of Oman
Authors: Boyle Maurice , Earl Jeremy , Ojulari Bayo , Al-Khadori Shaikhan , Al-Farsi Nasser 
Published: December 2007

Abstract
This paper presents a case history of the use of remotely operated hydraulic Interval Control Valves (ICV's) as a simple and cost effective method of controlling multiple laterals for selective water shutoff. Post installation production testing and impact on production are described.
The Saih Rawl Shuaiba reservoir in central Oman is a low permeability limestone reservoir producing light oil with pressure maintenance by means of a water flood. Extensive development started in the early 1990's when multi-lateral horizontal well technology enabled economic production rates from wells and sustainable water injection for the water flood. Multi-lateral wells of 4 to 7 legs are typically drilled for both producers and injectors with producer to injector leg spacing gradually decreasing from 250 m in the initial development to 60 m at present. As a consequence of this development philosophy, production has been accelerated, but control of sweep and water breakthrough has become a problem.
A Digital Hydraulics intelligent well completion has been successfully installed and operated in a Saih Rawl Shuaiba well that allows each of the 4 laterals legs to be independently opened and closed at will from surface using three hydraulic lines. The concept is purely a hydraulic control system that allows for multiple downhole devices to be controlled with the minimum number of control lines. This is achieved using hydraulic pressure sequencing and a mechanical decoder downhole along with a hydraulically operated control valve to give simple on/off zonal control. Retrievable hydraulic line feed-through packers are used to isolate one lateral from another.
This intelligent well system has been integrated with the ESP installation with the provision of a hydraulic disconnect, allowing replacement of the ESP (upper completion section) without affecting the lower intelligent well section. Control line hydraulic continuity is re-established upon ESP replacement.
A New Solids-Free Non-Damaging High Temperature Lost-Circulation Pill: Development and First Field Applications
Authors: Samuel M. , Marcinew R. , Al-Harbi M. , Samuel E. , Xiao Z. , Ezzat A. M. , Khamees S. A. , Jarrett C. , Ginest N. H. , Bartko K. , Hembling D. , Nasr-El-Din H. A. 
Published: December 2007

Abstract
Excessive loss of high-density brines into the formation has always been a major concern during completion operations, since it leads to formation damage and well control issues. The problem becomes more complex at high temperatures and when the treatment involves running gravel-pack assemblies and downhole sand screens.
Typically, the fluidloss-control pills are composed of very high concentrations of crosslinked polymers with or without bridging particulates. The sealing mechanism of these pills is a combination of viscosity, solids bridging, and polymer filter-cake buildup on the porous rock. Due to the instability of polymers at high bottomhole temperatures, incompatibility with some divalent brines, and the necessity to cleanup with acid, a new solids-free lost-circulation pill that is stable for prolonged periods at high temperatures was developed.
This paper introduces the development and the first field application of a new solids-free non-damaging viscoelastic surfactant-based fluid-loss pill (VES-PILL). The single-additive system forms a "gel" with most completion brines currently used in well operations. Laboratory data demonstrate that this pill could be used up to 375°F. The "gel" structure of this system sustains viscosity high enough to effectively control or stop brine-loss, while maintaining a safe differential pressure into the formation.
Several "frac and pack" completions were performed for the first time in Saudi Arabia in the Pre-Khuff sweet-gas zones. The VES-PILL was used to prevent losses after perforating, fracturing and gravel-pack operations. The pill was used in the field up to 310°F, and brine-loss was effectively controlled for more than 3 days. The effectiveness of the pill was also demonstrated by a five-fold increase in surface pumping pressure during placement. The wells were produced at rates exceeding expectations without further remediation to cleanup the fluid-loss pill.
Large Compositional Reservoir Simulations with Parallelized Adaptive Implicit Methods
Authors: Caillabat Y. , Magras J- F. , Ricois O. 
Published: December 2007

Abstract
Simulation of large compositional reservoir models in an acceptable CPU time still remains a key issue for any reservoir simulator software. Parallel computing is thus required to speed up the simulations and robust numerical solutions need to be implemented to insure accurate results especially for simulations of complex compositional physics. In that context, classical fully implicit schemes are often unusable due to memory and CPU requirements. We suggest new time discretization methods, which mix the accuracy and stability of the fully implicit methods and CPU performances and low memory consumption of the explicit ones. Within these approaches, a fully implicit scheme is applied in parts of the reservoir with highest physical property variations, and an explicit method is used in the other ones. Explicit schemes are delimited by a stability CFL condition. Explicit cells with large variations on the unknowns, are switched dynamically to implicit ones to improve global simulation CPU performances. These status computations are based on either threshold or spectral criteria. Implicit gridblocks may also be discretized using fully implicit or quasi-implicit schemes depending on the fluid composition variations.
These different schemes have been parallelized and integrated in a multi-purpose industrial reservoir simulator. The CFL criteria are discussed and tested on academic reference cases and then, comparisons of the available methods are presented for large compositional real case studies run on different parallel hardware platforms.
History Matching of Object-Based Stochastic Reservoir Models
Authors: Hu Lin Y. 
Published: December 2007

Abstract
Object-based models can be regarded as arrangements of a population of geometrical objects in space. In reservoir modeling, these models are often used for describing meandering channel systems, fracture networks etc., where geological objects can be clearly identified. Unlike pixel-based models, object-based models can provide geologically realistic representations of reservoir heterogeneities even at the appraisal stage with few well data. Although an extensive literature on object-based models is available, little has been done for constraining these models to dynamic data (history matching). This is however of great importance for their application in reservoir engineering.
This paper first reviews the basic concepts of the widely used object-based Boolean model. Then, we present a methodology for calibrating Boolean simulations to dynamic production data. This methodology is based on a generalization of the gradual deformation method that was initially developed for calibrating pixel-based Gaussian-related reservoir models to dynamic data. Finally, a simple synthetic example is presented and the results show the validity of the above methodology. In particular, this methodology is potentially applicable to history matching of fractured reservoir models.
The Contractual Form of Iran's Buy-back Contracts in Comparison with Production Sharing and Service Contract
Authors: Ebrahimi S. N. , Khouzani A. Shiroui 
Published: December 2007

Abstract
Since the Constitution of the Islamic Republic of Iran (1979) does not allow foreign companies to own equity stakes in hydrocarbon projects, Iran has developed a new mechanism in line with the Constitution to facilitate the engagement of foreign oil companies in development of oil/gas fields. Such a mechanism resembles a typical buy-back arrangement, under which a foreign company provides the funding for, and necessary equipment and services for the establishment, development or updating a project and agrees to purchase back a portion of the production such as those goods or services produced in that project. This mechanism, however, is a hybrid of a service contract and a production sharing agreement, although it is much closer to the former.
Under this mechanism a foreign oil company provides the fund for, expertise, equipment and machinery for the development of a gas/oil field. In return, the petroleum costs, constituting Capital Costs, Non-Capital Costs, Operating Costs, Bank Charges (interests), and Remuneration Fee, will be recovered through the revenues generated from the filed as the result of the development operations carried out by the foreign oil company as contractor. Alternatively, the oil/gas produced as the result of the development operations may be sold to the oil company under the Crude Oil Sales Agreement at the prevailing market price against the expenses and costs charged to the Project Account by the contractor. The development operations are carried out under the control, supervision, inspection and audit of Iranian National Oil Company (a state oil company). Although this provides a degree of control over operations of the private contractor, development operations are carried out under the management of the risk-taking foreign oil company. Thus, for instance, the risk of any shortage of revenue shall be borne by such company.
In this article, we provide a true picture of such a particular formula, distinguishing it from typical buy-back in industrial projects, service contracts and production sharing agreements in oil and gas business. To achieve that goal, a brief explanation of the basic elements of such arrangements is a prerequisite for our discussion.