bluuebunny/crossref_metadata_2025_split huggingface dataset:
Successful Use of a Cost-Effective Temporary Non damaging Gel Plug System to Isolate a Highly Permeable Producing Zone During a Stimulation Job of a Low-Permeability Gas-Producing Zone in Khuff Gas Reservoir in Bahrain — A Case History
Authors: Mirza Mohammed Saeed , Kritzler Torsten , Gazi Naz H. 
Published: December 2007

Abstract
In recent decades Bahrain has experienced a rapid growth in gas demand for industrial use, electricity generation, gas injection, and artificial lift. The main source of gas for these needs is the Khuff reservoir. The Khuff gas is currently being produced from 29 prolific gas wells.
To enhance the productivity of the Khuff reservoir a matrix acid stimulation program was undertaken using coiled tubing and a temporary non damaging gel plug system with complete regained permeability to isolate the high-permeability producing zone while the low-permeability gas-producing zone was being stimulated. Because the isolated zone is also producing, the gel system has to be completely non damaging with full regained permeability to this isolated formation.
The success of stimulating a low-permeability interval where a high-permeability producing zone is also present is primarily dependent on the ability to divert the respective stimulation fluid into the zone of lower permeability and productivity. Several methods are commonly used to divert the stimulating fluid in the non productive zone. These methods are dependent on the type of stimulation and configuration of the completion.
If coiled tubing is used for through-tubing stimulation in cased holes, inflatable packers are normally considered for isolation. However, inflatable packers have limited expansion ratios and pressure capabilities. The previous use of ball sealers gave very limited results of only 10% incremental gas production.
This paper will present the successful stimulation techniques and results of a unique and cost effective solution for a well where two intervals with different permeabilities were isolated without the high risks and costs of using a mechanical packer. Coiled tubing was used to stimulate the lower interval while the upper producing interval was isolated using a temporary chemical packer. Temperature in this well exceeded 270°F.
New Rigless Gaslift Application in Onshore Well
Authors: Abu Grain Hussain S. , Zabihi Mohammad , Al-Dusari Khalifa H. , Abbott James W. 
Published: December 2007

Abstract
In April 2002, the first retrievable straddle pack-off gas-lift assembly was installed in a Safaniya onshore well, which had been dead due to high water cut since 1993. This gas lift assembly has successfully increased the well production to an average daily liquid production rate of 2600 barrels with 30% water cut. The significant incremental production of 1800 BOPD is regularly contributing to company profit.
This paper discusses in detail the new gas lift equipment, principles of operation, installation, and trial test results. The assembly can be installed and retrieved with wireline, eliminating the need for a workover rig. It is equipped with gas lift mandrels to convert them to gas lift without pulling out the tubing. Based on its simplicity, successful operation, and considerable economical impact, there is a vast potential for this technology in Saudi Aramco.
Lessons Learned from the First Openhole Horizontal Well Water Shutoff Job Using Two New Polymer Systems - A Case History from Wafra Ratawi Field, Kuwait
Authors: Uddin Shahab , Dolan Jimmy D. , Chona Ricardo A. , Gazi Naz H. , Monteiro Ken , Al-Rubaiyea Jamal A. , Al-Sharqawi Anwar 
Published: December 2007

Abstract
With the introduction of water injection in the Wafra Ratawi Oolite reservoir, in the Partitioned Neutral Zone of Saudi Arabia and Kuwait, came the water production problems, especially after drilling horizontal wells. An economical method to reduce this unwanted water influx was needed.
The process was complicated in the horizontal openhole producing wells. Not only the water producing section of the part of the horizontal section has to be treated to reduce unwanted water production. A good, cost-effective method of temporarily protecting the producing horizontal section during this treatment was also needed to protect the potential oil-producing zone for future post-treatment production.
This requirement necessitated a good placement technique and the use of two gel systems, one to temporarily protect the oil zone and the other to permanently damage the water producing zone.
This paper describes the application and techniques of placing a nondamaging temporary gel system to isolate the oil-producing heel side of a horizontal section in an openhole horizontal well and the use of another organically crosslinked polymer system to shut off water from the toe side of this horizontal openhole wellbore.
A candidate openhole lateral horizontal well was selected for this application and the suspected high water cut from the toe side was caused by interference between a nearby injection well and this producing well.
A Feasibility Study of Mixing Disposal Water with Aquifer Water for Downhole Injection
Authors: Raju K. U. , Nasr-El-Din H. A. , Al-Shafai T. A. 
Published: December 2007

Abstract
Disposal of wastewater produced from various gas oil separation plants is a major concern for many oil companies. Mixing of wastewater with injection water has many economical and environmental advantages. The objective of the present study is to determine the feasibility of mixing produced water with the injection water obtained from a shallow aquifer.
Several samples were collected from disposal water and injection water locations. Measurements of hydrogen sulfide and total iron were conducted on site using standard techniques.
The concentration of H2S in disposal water was found to be in the range of 550 - 765 mg/L. The aquifer water contains 4 - 5 mg/L of total iron. Compatibility tests conducted in the lab and on-site showed the formation of iron sulfide. Acid solubility tests and XRD analysis confirms that this iron sulfide is present in a non-crystalline, acid-soluble form (amorphous).
The presence of iron sulfide in disposal waters is a major concern because it can cause formation damage and subsequent loss of well injectivity. Various chemicals were evaluated to mitigate the formation of iron sulfide. These chemicals ranged from formaldehyde, triazine, to tetrakis hydroxymethyl phosphonium sulfate, to oxidizers (sodium hypochlorite, hydrogen peroxide and sodium nitrite). Similarly, some iron chelating agents, such as citric acid, ethylenediamine tetraacetic acid, and nitrilotriacetic acid were evaluated.
This paper will discuss various types of H2S scavengers, reactions with H2S, advantages and disadvantages of each chemical based on extensive lab and field studies. Chelating agents for dissolved iron were also evaluated. Higher dosages of either sodium hypochlorite (hydrogen sulfide scavenger) or citric acid (iron sequestering agent) can mitigate the precipitation of iron sulfide species up to 15 vol% of disposal water in the mixture.
Sour Crude Production Practices in Inhabited Onshore Saudi Arabian Field
Authors: Al-Dejain A. A. , Al-Ghamdi A. A. , Zainalabedin Zainalabedin , Ahmad G. 
Published: December 2007

Abstract
Oil field operations involve a certain amount of risk. The risk factorincreases significantly when dealing with sour hydrocarbons due to the highlytoxic nature of hydrogen sulfide. This aspect takes a great deal of importancewhen large areas of such field are inhabited in addition to high populationdensity towns in very close proximity to the field.
This paper will address the challenges and safety concerns when developingsour crude oil fields in inhabited areas from production engineeringperspective. Application of proven technologies such as smokeless flare system, permanent downhole monitoring system, and remotely controlled wellheadequipment and data acquisition will be discussed. These systems can minimizethe impact of oil well clean-up operations on environment, frequent wellinterventions and well-site visits for safe operations in a field producingfrom reservoirs with relatively high hydrogen sulfide content in thehydrocarbons. Utilization of these systems will enhance the safety of oil fieldoperations as well as the inhabitants in the nearby areas.
Production Improvement by Controlling the Flow Regime of Gas Rich Fluid Mixtures with Slugging Devices
Authors: Ivannikov Vladimir I. , Ivannikov Ivan V. , Bakker Tom W. 
Published: December 2007

Abstract
Technology based on the use of slugging devices placed in the production tubing is presented. This technology significantly improves the performance of oil production from wells flowing at high Gas to Oil Ratio's (GOR's) and leads to better use of solution gas for the lifting process, lower waste of reservoir energy and lower production impairment due to free gas separation in the formation.
Due to this technology tests indicate that it is possible to typically increase daily oil production in high GOR wells some 20-30% and simultaneously reduce the utilization of gas by at least 1.5-2 times, depending on the particular well and reservoir conditions. As a consequence of better gas utilization for the liquid lifting process, a significant improvement of the ultimate oil recovery from a high GOR reservoir may be realized.
The technology also can be employed to improve the efficiency of gas lifting.
Applying Improved Recovery Processes and Effective Reservoir Management to Maximize Oil Recovery at Salt Creek
Authors: Genetti D. B. , Whitaker C. A. , Smith D. P. , Price L. M. 
Published: December 2007

Abstract
The Salt Creek Field, located approximately 110 miles northeast of Midland, TX, is a heterogeneous, Pennsylvanian-aged carbonate build-up in the Permian Basin. Successive implementation of infill drilling and improved recovery processes, coupled with effective reservoir management, have led to oil recovery of over 50 percent and expected ultimate recovery as high as 60 percent.
Salt Creek field was discovered in 1950 and a centerline water injection program began in 1953. A 40-acre development program was initiated in 1970 and was completed in 1984. The waterflood pattern was also changed from a centerline drive to a field wide inverted nine-spot. In 1985, a reservoir continuity study led to a 20-acre infill drilling program that added over 150 wells, changing the pattern to a five-spot. A miscible carbon dioxide (CO2) flood was initiated in 1993, and then expanded to the underlying residual oil zone.
Reservoir management has been a key element in maximizing recovery at Salt Creek. Consistent acquisition and maintenance of appropriate well and reservoir data has allowed detailed zonal tracking of production and injection volumes (CO2 and water). Geologic models, in combination with production logs and production data, have been used to manage and optimize CO2 and water injection at the flow unit level. Effective communication processes have been established between the field operators and the technical staff to calibrate engineering and geologic data with field experience and to enhance real-time decision making. A 3D seismic survey covering the entire field was acquired in 2000 to better define productive field limits and reservoir geometry. Currently, a study integrating engineering and geoscience data is underway to further improve reservoir characterization. The study is expected to result in improved sweep efficiency through better conformance control and additional drillwells to capture unswept reserves.
Low Salinity Oil Recovery – Log-Inject-Log
Authors: Webb K. J. , Black C. J. J. , Al-Ajeel H. 
Published: December 2007

Abstract
Many laboratory coreflood studies have shown increased oil recovery is achieved by waterflooding using low salinity water, compared with injection of seawater or high salinity produced water. The reasons for this improved oil recovery are thought to be due to effective wettability changes and / or controlled removal of clay constituents. This paper describes a log-inject-log field test, designed to identify whether this phenomenon could be observed within the near well region of a reservoir. The log-inject-log test was meticulously designed and executed, to ensure that flow rates were maintained at low rates, and that cross flow was minimised, to ensure that the results were representative of bulk reservoir waterflood displacement. A producing well was selected for the test to ensure that all saturation changes occurred under stringently controlled test conditions and that the results would not be affected by previous high rate water injection. 10 - 15 ‘pore volumes’ of high salinity brine, were injected into the ‘volume of interest’, to obtain a baseline residual oil saturation. This was followed by sequences of more dilute brine followed by high salinity brine for calibration purposes. Multiple log passes were conducted during injection of each brine. At least three further passes were run to ensure that a stable saturation value had been established after injection of each brine. Extensive water sampling was conducted to confirm brine salinities and increase confidence in the quantitative saturation results. The results were in line with previous laboratory tests from other fields, and showed 25 - 50% reduction in residual oil saturation when waterflooding with low salinity brine.
Managing the Challenges of Voidage in a Mature Carbonate Water Flood
Authors: Aihevba 'Leste O. , Al-Harthy Mohammed , Passmore John 
Published: December 2007

Abstract
Integrated field and well reviews followed by logical activities are being taken to address the voidage and declining pressure in Yibal. This is to ensure that target daily oil rates are achieved, and UR is maximized, in the largest oil producing asset in Oman, which delivers almost 15% of the total country production from a heavily faulted and fractured carbonate anticlinal structure, on stream since 1969. Water injection initiated in 1972 has gone through a series of stages; vertical oil phase injectors for lateral sweep, vertical aquifer injection for vertical sweep and later some horizontal deep aquifer injectors. The injection serves the dual purpose of pressure management and produced water disposal. The field has suffered negative voidage for quite some time, leading to rapid reservoir pressure depletion. Past studies have identified uneven vertical and lateral sweep due to uneven subsurface water distribution as a result of the complicated fracture and fault patterns as well as the subsurface hydro-dynamics and flow mechanisms. This has left the remaining oil in pockets that are becoming more difficult to produce. The high field average BSW has led to a situation where oil wells are closed in for surface facilities constraint and, or subsurface water injection capacity. Further, the uncertain water movement into producing wellbores makes production optimization activities risky. Recently, quite a number of injectors have been taken offline for integrity repairs and are only gradually coming back on stream after extensive and often expensive repairs.
The implementation of a voidage replacement program which includes understanding the reservoir dynamics, identification of the worst hit low pressure areas, and prioritization of the short, medium and long term remedial activities is on going. Increased focus on gross offtake management, injection well stimulation, water shut off in producers, conversion of poor producers to injectors, and drilling of new injectors is showing returns in flattening of the decline rate of oil production. The issues around water injection as well as oil producer integrity are gradually being addressed. Several learning points for the implementation of the proper reservoir and voidage management have also been captured. The importance of human resources both in terms of numbers, level of experience and skills set, has also been recognized and the optimum balance of these is being worked on.
Applications for a Full Wave Sonic LWD Tool in the Middle-East
Authors: El-Wazeer F. , El Farouk Omar , Deady Ron , Russell Richard 
Published: December 2007

Abstract
In recent years MWD/LWD formation evaluation applications have evolved to apoint where many applications usually reserved for wireline logging can now beattained from LWD data. The latest area is the applications attained from LWDsonic measurements. In a drilling environment a sonic tool has applicationsthat extend beyond standard porosity-type evaluations. MWD/LWD sonic logs canalso provide real-time seismic tie-in as well as assist in drillingoptimization. Conventional perceptions are that there are two key aspects thatcould minimize or preclude the use of sonic technology in an MWD/LWDenvironment. First, drilling noise is assumed to exist within the frequencyrange of the measurements, and minimization of it was considered impractical.Second, the interference of the tool-body mode (acoustic waves coupled to thereceivers as a result of tool body waves) is thought to be dominant, to theextent where significant manual post-processing is required to generatereasonable logs.
This paper presents some fundamental design choices and case histories fromthe Middle-East where a new Full-Wave Dual-Mode MWD/LWD sonic tool has recentlybeen run. The tool is constructed such that it operates in two modes (operatorselectable and available as either/or or both): (i) classical compressionalwave sonic tool (the equivalent to the traditional monopole source mode); (ii)enhanced shear-wave detection mode (dipole-type source). The tool has multipletransmitters and multiple receivers (arranged in a combination of arrays) thatallow operation in both modes. The tool utilizes a unique set of isolationsections that minimize the effects of drilling noise and tool-body mode. Thedesign of these isolation sections was based on extensive lab testing withscale models, as well as, the use of sophisticated 3-D analytical models. Thesestudies led to a comprehensive understanding of the dynamics of the tool bodymode and drilling noise and the best ways to reduce them. Implementation of thefinal design resulted in a negligible tool mode and nearly complete isolationfrom drillstring noise. The success of this design has been verified indrilling environments throughout the world where sonic LWD logs have beensuccessfully obtained in hole sizes from 30" down to 5 7/8".
Case histories will be presented from Abu Dhabi where the sonic LWD tool wasrecently run. The tools response in the varied formations of the Arabian Gulfand its application as a porosity device will be examined. Further applicationssuch as fracture detection will also be discussed.
Optimizing Petrophysics: The Ghawar Field, Saudi Arabia
Authors: Eyvazzadeh Ramsin Y. , Cheshire Stephen G. , Nasser Rami H. , Kersey David G. 
Published: December 2007

Abstract
Transformation of borehole logging measurements into accurate and precise porosity, lithology, permeability and fluid saturation data is the most important result of a petrophysical analysis.
A fundamental petrophysical problem is how to minimize systematic and random errors associated with data acquisition from different logging tools, variable borehole conditions and reservoir properties. Historically, errors were minimized by increasing the number of logs and/or calibration of results to core data. In the 1980's, a major development in petrophysics was the utilization of error minimizing routines to optimize the accuracy of petrophysical results. This optimization analysis combines input data with a set of response functions to find the best solution by minimizing the differences between predicted answers and actual inputs. Even though this technique appears to have technical advantages, acceptance has been limited due to underlying complex mathematics and consequently, the process is less understood.
A recent study was completed to determine the strengths and weaknesses of this type of analysis on Ghawar field, Saudi Arabia. Due to its vast areal extent, unique reservoir properties and extensive logging and core data, this field provided an ideal basis to evaluate optimizing analytical models. Data from several logging companies was used to show the combined effects of tool types and vintages, borehole conditions and reservoir properties on the utility of optimized petrophysical methods in Ghawar field.
Quantitative Characterization of Carbonate Pore Systems by Mercury- Injection Method and Image Analysis in a Homogeneous Reservoir
Authors: Beiranvand Bijan 
Published: December 2007

Abstract
The quantity of direct interest in the flow through porous media is not the properties of the matrix (e.g. grain size distribution) but rather the properties of the pore (e.g. pore size distribution). The determination of representative capillary pressures is of vital important for the mapping of the reservoir fluid distribution. Mercury porosimetry or mercury injection-capillary pressure curves are commonly used to measure the distribution of pores and pore throat sizes. Pore aperture size estimated from mercury injection tests has been used to categorize the rock by pore type, evaluate seals for traps and to explain the locations of stratigraphic hydrocarbon accumulations.
In image analysis, the OM (Optical Microscopy) images provide macroporosity information, whereas the ESEM (Environmental Scanning Electronic Microscopy) images yield information on microporosity. Comparison of total porosity determined from plugs indicates that macroporosity and microporosity values based on image analysis match the plug data, confirming the validity of the method. The combination of macroporosity and microporosity data yields pore size distribution and pore shape information that can explain the distribution of physical properties, in particular permeability. Permeability can mainly controlled by the macropore shape in high-permeability samples, and by the amount of intrinsic microporosity in the low permeability samples.
In this investigation three pore and port geometric systems have been recognized, 1) Type-1 system that belongs to mud dominated bioclastic peloidal packstone, at the top of reservoir, with good porosity and fair permeability shows large and smooth pores and ports as bimodal, 2) Type-2 system presented in mud dominated bioclastic peloidal packstone / grainstone with fair porosity and low permeability shows moderate to small pores and ports and 3) Type-3 system that has been seen in ploidal bioclastic grainstone and mud dominated planctonic foraminiferal packstone, packstone /wackestone and wackestone with low porosity and low permeability shows small pores and ports as matrix porosity.