bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of the Application of Drill Cuttings and Recovered Oily Sands on Caribbean Pines, Anzoátegui State, Northeastern Venezuela
Authors: Gómez María A. , Sucre Francisco J. , Villarroel Teresa , Robb Albert J.
Published: December 2007

As a part of an overall waste reduction initiative, beneficial reuse of materials otherwise considered oilfield waste were evaluated as an environmentally responsible and business practical method of handling theses materials. Heavy oil production by the Cerro Negro Project, within the Orinoco River region of the Anzoátegui State of northeastern Venezuela, is surrounded by Caribbean pine plantations. During 1999 and 2000, decanted drill cuttings and recovered oily sands were mixed with virgin soil (mostly sandy loams) and an agglutinate in order to produce an asphalt mixture for use as a substrate stabilizer and road base. The mixture was prepared to comply with Venezuela Ministry of Environment requirements before being spread as a road base on internal roads within the pine plantations as a stabilizer.

Studies were conducted to evaluate numerous quantitative and qualitative parameters potentially associated with impact to pine trees and the surroundings environment. These possible effects were evaluated from the following key assessment sectors: Caribe pine plantation areas near the initial mixing sites (borrow pits),Plantation areas adjacent to roadways or firebreaks where the mixture was applied, andPlantation areas where the mixture is used directly as a substratum.

The results of this study, designed to evaluate the effects of the application of the mixture of drill cuttings and recovered oily sands on the forestation species and their surrounding environment, document that the application of this mixture represents a cost-effective waste reduction option with natural resources re-use and erosion stabilization benefits. Results potentially demonstrating enhanced growth and productivity of surrounding pine plantations further document a "win-win" solution between the Cerro Negro Project operator and the plantation owners for the handling of these materials that would otherwise be considered a waste.
Collaboration in Deep-sea Biodiversity - Expanding the value from Deepwater E&P Operations
Authors: Hudson Ian R , Putt Russell , Wigham Benjamin D. , Young Sean
Published: December 2007

Oil and Gas Exploration relies heavily upon the use of Remotely Operated Vehicles and data collection in many deep-water production areas. Through collaboration projects between scientific instiutions and production companies it has been possible to gain great ecological value from existing data and new data routinely collected as part of normal offshore exploration activities.
The Issue Of Access: Confronting Community Expectations
Authors: Shrimpton Mark
Published: December 2007

Oil companies seeking to access new regions are often confronted by communities and governments that know little about the petroleum industry, its activities and their impacts. Their expectations are commonly based on stereotypes that are problematic, not least because various factors lead to an emphasis on negative impacts, rather than a balanced picture of potential costs and benefits. From a petroleum industry perspective, this can increase the costs of having exploration and development programs approved and implemented, and it may result in arduous conditions and even moratoria on activity. From the perspective of local communities, employment, business and other benefits may be delayed or foregone. These misconceptions are best countered through collaborative processes that educate about the industry, its activities, their effects, and how they can be managed. While these processes should use information about the impacts of upstream petroleum activity in other regions, such comparative study must be undertaken with care if it is to address, rather than reinforce, negative expectations.
First ISO 14001 Environmental Certification of a Danish Offshore Installation
Authors: Valeur Jens Rosendal , Hollen Ivar Helge , Clowers Michael
Published: December 2007

In October 2002, the Amerada Hess operated oil and gas producing installation, South Arne, had its Environmental Management System (EMS) certified according to the ISO 14001 requirements. The paper describes how the requirements were implemented in the existing management system, making the installation the first in the Danish sector to obtain certification.

Internal resources were used in order to ensure an in-depth implementation. The South Arne asset manager sponsored the certification initiative and had overall responsibility for the EMS. Training was carried out by internal HSEQ staff.

Environmental aspects were identified, evaluated and ranked with respect to their impact were done depending on the extent of the impact. Aspects with global or regional impact (mainly emissions to air) were compared with the overall emissions from the Danish society. Aspects with local impacts (mainly discharges to sea) were evaluated based on chemical risk assessment. Flaring and discharge of produced water have been identified as two of the major aspects, and environmental improvement plans covering these are ongoing.

Flaring during the last two years caused about 20% of the total CO2 emissions from South Arne. A new gas recovery system is planned to be installed in 2004 as a main environmental improvement regarding emissions to air. This "zero flare" system can recover essentially all of the gas that previously had to be flared resulting in significant reduction in flaring and its associated air emissions.

As the life of the field matures, the production of water will increase. With no improvement plan this would result in significant increases in produced water, with its oil and chemical content, being discharged to the sea. Re-injection of the produced water into the reservoir was successfully tested in 2003, and full-scale re-injection is planned to take place starting in 2005.
Examining the Role of Occupational Health Management in the Safety and Well-being of the Offshore Worker
Authors: Hope Lorraine , Mearns Kathryn
Published: December 2007

Previous research in the offshore environment indicates a positive relationship between good health management practices and safety performance (Mearns, Whitaker & Flin1). The current research seeks to examine the nature of this relationship and explore whether investment in occupational health, can lead to improvements in organizational climate and, in particular improvements, in safety climate and safety behaviour. The research was conducted by means of a questionnaire survey incorporating 31 offshore oil and gas installations on the UK Continental Shelf. To investigate the hypothesis that investment in health builds worker loyalty in areas such as safety behaviour, 1,928 offshore employees were surveyed using measures of health and safety climate, employers' commitment to health, colleague social support, safety behaviour and employees' commitment to the organization. Additional data was collected in relation to health surveillance and use of PPE for occupational hazards such as chemical and vibration exposure. Respondents were also required to indicate personal health behaviour in terms of diet, exercise and smoking activity. In addition to data on the frequency of sickbay visits for injuries and medical purposes, installation medics provided details of additional health checks offered and health promotion activities. Details of occupational health training undertaken (and offered) to both medics and the workforce in areas such as stress, manual handling, skin problems and HAVs were also collated. Preliminary results indicate that investment in occupational health offshore fosters greater organizational commitment, more positive health and safety climates, improved safety behaviour and more positive perceptions of employers' commitment to the workforce.
Controls on Vertical and Horizontal Flow in a Carbonate Reservoir that Impact Gasflooding and Waterflooding
Authors: Thawer Roxy , Alhendi A. , Al Mazroui Y. , Boyd Doug , Masuzawa T. , Sugawara Y. , Hollis C. , Lowden B.
Published: December 2007

Identifying the location and quantification of flow units is critical to managing a reservoir's production and achieving maximum recovery. Gas injection is planned in a limestone reservoir offshore Abu Dhabi. To understand the benefits of future full field gas flooding, a pilot covering three reservoir units is underway. Ten wells were drilled and significant log/core data acquired. Interference tests within a reservoir unit in single wells and between-wells have revealed useful insights into the vertical and lateral continuity of barriers and conduits to flow. Recovery efficiency is driven by these contrasts in the reservoir sublayers.

Significant variations in permeability occur over short vertical distances due to local facies and diagenetic changes, including dissolution events, distorting associations between porosity and permeability. Porosity cannot predict permeability to better than 1.5 decade on a logarithmic scale in this reservoir. Experimenting with NMR, Stoneley wave responses on one well, we were able to improve our predictive capabilities by combining the strengths of each tool. Predicted values fell mostly within half a log cycle of the whole core measurements. Vertical interference testing with a multi-probe Modular Dynamic Formation Tester (MDT*) used in a totally new way and using single well numerical models, proved useful in defining vertical barriers to flow. Cross-well interference testing proved that some of these barriers are discontinuous and act as baffles. Mobilities obtained from the MDTs, mimicked permeability contrasts measured in core. These contrasts confirmed the rapid response time seen in the cross-well interference tests. A full field simulation model with local grid refinement was able to match the cross-well interference test data.

The integration of core description, whole core/plug physical properties, downhole electrical images, NMR, conventional logs, mobility, down-hole vertical as well as cross-well interference tests is presented and their impact discussed.
Large-Scale Produced Water Re-Injection Under Fracturing Conditions in Oman
Authors: van den Hoek P. J. , Sommerauer G. , Nnabuihe L. , Munro D.
Published: December 2007

This paper describes the concept, initial field case studies, and observations to date on Deep Water Disposal (DWD) in one of Petroleum Development Oman's (PDO) larger mature oil assets. The concept of DWD by fractured injection on a large scale has been quite successful. Current concerns relate to the size of injected fractures, and pressure build-up within the disposal zone.

Initial simulation studies were carried out with dedicated in-house produced water re-injection software to asses the size and containment of the induced hydraulic fractures as a function of relevant injection parameters such as water quality, injection rate, injection volume and injection depth. This was essential as fractures are not allowed to break through the cap rock shale layer of the disposal zone into the overlying sand body which has communication with shallow potable aquifers. Based on stress data (minifracs, logs) and simulations it was concluded that fracture containment within the disposal zone was only guaranteed if fractures were initiated of the order two hundred metres below the cap rock.

Simulations of produced water injection were carried out also to assess well injectivity in the long-term, and to estimate the required injection pressures for the injection pumps. The simulations indicated that no injectivity decline long-term would be expected to take place. Field observations to date are in line with these simulations. Currently, each DWD well is injecting ca. 15,000-20,000 m3/d of unfiltered produced water with wellhead pressures of approx. 140 bar.

Fracture monitoring programmes are currently being carried out. Hydraulic Impedance Testing (HIT) was applied to measure fracture dimensions. It was found to be restricted to small fracture sizes due to the insensitivity of the reflected wave amplitude in the applied frequency range. Improved methods to measure fracture size such as tiltmeter surveys and downhole geophones are currently under investigation.

Pressure monitoring within the disposal zone via observation wells has shown little pressure increase to date. Characterisation of this pressure response is a key reservoir driver in deciding how much water could be disposed at each of the disposal sites.
Hole Instability in Upper Zakum Field Offshore Abu Dhabi; Need Integrated Solution
Authors: Tantawi Ibrahim Yousef , Fadaq A. S.
Published: December 2007

Hole instability is one of the serious problems adversely affecting drilling efficiency and costs. Generally, it occurred in different forms as: shale instability, unconsolidated formation eroded by mud flow...etc. The shale destabilization is the worst type of hole instability.

In Upper Zakum drilling operations, shale instability is the dominant while drilling troublesome shale sections. The major shale sections are through Nahr Umr formations and thin shale streaks in Laffan, Halul, and top part of Thamma-I formations.

This paper is primarily focused on shale instability encountered while drilling ZADCO wells in Upper Zakum field offshore Abu Dhabi. It presents an investigation and engineering analysis of the main causes and different mechanisms of shale instability; chemical interaction, mechanical deformation. The chemical shale destabilization occurs due to the chemical reaction between the reactive clays and incompatible drilling fluid formulations. This reaction leads to the dispersion of reactive shale minerals into the drilling mud. On the other hand, the mechanical destabilization of shale may result from the unbalanced formation pore pressure, hole deviation, drilling practices, even in the absence of reactive shale. The related troubles encountered while drilling the problematic shale section are; excessive torque and drag on connection and while tripping, mud solids build-up and consequently unsteady drilling fluid rheology, stuck pipe, and hole enlargement that results in poor cement jobs.

Stuck pipe has costed ZADCO millions of dollars due to non-productive operational time involved in stuck pipe, fishing jobs, and side-tracking resulting from stuck pipe.

Detailed analysis of drilled wells and observations along with the result of laboratory tests show that hole instability due to chemical destabilization can be improved by utilising compatible drilling fluid formulation and good quality mud chemicals, and optimising mud rehology. To minimize hole troubles due to mechanical destabilization of shale; it requires proper pre-planning of the wells and careful implementation of the best practice are the key issues. Hole instability needs an integrated solution including; well trajectory, mud weight and formulation, design of bottom hole assemblies, mud solids removal etc. The main objective is to stay out of the trouble better than get out of trouble or prevention is always better than cure.
Gas Seepage at the Sea Floor: The Investigation and the Diagnosis
Authors: Fawakhiri A. Y. , Rouatbi R. , Mohamed F. H. , Boyd D. , Dajani N. , Okuyiga M. , Sherbini M. , Abu Shamat M. , Cabillic J. , Ramzi Darwish M.
Published: December 2007

A small gas explosion during the cutting of the 20″ casing on a well offshore Abu Dhabi, alerted staff to a potentially serious situation. Surprisingly, the well in an early phase of drilling, had not yet penetrated any known hydrocarbon bearing formations. Soon after the explosion, gas bubbles were observed emanating from the sea floor. A 70 milliondollar gas injection platform was at risk. Senior management reacting requested a multidisciplinary task force formed with a mandate to locate the source of the gas, the magnitude of the leak and the communication path to surface. A query to industry partners and regional oil companies sought their experience with similar situations. One company replied positively. Years earlier, it was afflicted with a well leaking gas to the sea floor. The mechanism and source of their gas leak was never determined as the leak ceased naturally. With at the time, no prior cases to guide it, the task force approached the problem through Cause Tree Analysis (CTA) and Decision Tree Analysis (DTA), together with Risk Assessment. Each of the four wells on the platform was scrutinized in turn. Historical data on pressures, production, cementing, tubular goods, logs run and other relevant data provided answers but also questions. As the Cause Tree evolved and further data collected, suspicions focused on one well. Additional evidence was needed. A program of noise/temperature logs and radioactive gas tracking produced unanticipated results. This paper focuses on the processes used to arrive at conclusions rather than the conclusions themselves.
Cementing the deepest 20 inch Casing in Abu Dhabi using a combination of Noval Light Weight Slurry and Fiber
Authors: Elmoneim Hossam A. , Zaki S. , Al – Arda Hussein
Published: December 2007

The Gas Khuff well is an offshore appraisal well drilled to explore the potential of gas production from Khuff formation. The drilling objective of this well is to penetrate the top Khuff formation at 13877ft down to the lower Khuff formation at 16335 ft with 8½ hole.

It was vital to drill 26 inch hole section throughout depleted water aquifers and weak fractured limestone formations, down to the deepest possible depth (5639 ft). Moreover, the long-term integrity of the gas well necessitated cementing the 20 inch casing up to surface with low permeability, high compressive and tensile strength, and lightweight cement without the use of stage tool. Meeting these requirements shall provide long-term casing protection against corrosion, isolate sour water aquifers and reduce potential of gas migration in the future.

Loss circulation problem encountered while drilling the 26 inch hole and large slurry volume exceeding the handling capacity of the rig and required to fill the annular space, were the main challenges in meeting these objectives.

A combination of Novel light weight slurry mixed at 1.2 SG (10 PPG) and fiber were used minimize the potential of losses during the cementing job execution. Meanwhile, additional bulk storage, mixing equipment and pump unit were mobilized to the rig in order to double the bulk storage capacity and handle large volume of cement slurry.
Experimental and Theoretical Assessment of the Asphaltene Precipitation Characteristics of the Sahil Field Under a Proposed Miscible Gas Injection Scheme
Authors: Jamaluddin A. K. M. , Nighswander J. N. , Kohse Bruce F. , Mahdi Ahmed El , Binbrek M. A. , Hogg P. F.
Published: December 2007

As part of the feasibility assessment for an improved oil recovery project on the Sahil reservoir in the United Arab Emirates, it was desired to assess the potential for asphaltene formation arising from the miscible contact of a rich hydrocarbon injection gas and the Sahil reservoir fluid. In this work, experimental data for the upper and lower asphaltene onset conditions over a temperature range from 110-255 °F were measured for the reservoir fluid. In addition, three injection gas mixtures (15, 45, & 60 mole%) were also evaluated at the reservoir temperature of 255°F. The experimental data were measured using a Near Infrared (NIR) light scattering technique. Subsequently, the experimental data was used to tune an equation-of-state (EOS) based model that represents the asphaltene phase as pseudo pure component solid. Results of the work demonstrated a significant effect of temperature and injection gas concentration on the asphaltene onset conditions for the reservoir fluid. It was also shown that the chosen model could accurately represent the measured behavior of the fluids over the range of conditions tested.
Microbial Phase Behavior Laboratory Studies
Authors: Zekri Abdulrazag Y. , Al-Khanbashi A.
Published: December 2007

During the past ten years, much attention has been focused on the using of microbial enhanced oil recovery (MEOR) processes by the oil industry. Very limited data has been published that reports the interfacial tension between crude oil and bacteria solutions and there is very limited laboratory work conducted on the phase behavior of oil-microbial systems. Microbial process is complicated and in order to apply the process successfully it is essential to perform an extensive laboratory work covering all areas related to the process mechanism. The MEOR bacteria transport through the water phase and congregate in pore spaces at oil-water interface where they metabolize a very small amount of the oil to produce various biochemical: surfactants, solvents, very week acids, polymers and gases (mainly CO2). These biochemicals decrease the interfacial tension between the oil and water, reduce oil viscosity, change the system wetability and in many cases improve the volumetric sweep efficiency by removing paraffin and scale blockage from pore throats.

This project focused initially on the study of the interfacial tension (IFT) between curds obtained from four different UAE reservoirs (AH, UZ, SH and UAD) and thermophilic bacteria solutions. The bacteria were obtained from UAE local environment Several crude oil/water/bacteria fluid samples were prepared. For these samples the salinity ranged from 0-100,000 ppm, and the crude oil concentration ranged from 10% to 90%. All systems were mixed very well and kept without any further agitation for one month. An optimum salinity was observed where a middle phase microemulsion was developed. Oil concentrations, keeping other variables constant, had no effect on the over all phase behavior of the studied systems.
Validity of Archie Equation in Carbonate Rocks
Authors: Talabani Soran , Boyd Douglas , El Wazeer Fathi , Al Arfi Saif
Published: December 2007

Archie (1941) found an empirical equation for consolidate sandstone relating some formation parameters, porosity and water saturation. Archie equation is not easy to apply to rocks because formation parameters (a, m and n) are fimctions of electrical tortuosity. Electrical tortuosity is determined by pore geometry, tortuousity of the pore system and wettability which, affects oil – water distribution in the pores.

Carbonate rocks with their complex pore systems and intermediate to oil wettability are difficult to describe petrophysically with a single a, m and n over a reservoir interval. Formation Resistivity Factor (FR) is highly variable. There is often no linear and direct relation between the resistivity index (IR) and formation water saturation (Sw) as the variably sized pores desaturate at different rates. These cases are labeled as non-Archie rocks. Archie is strictly valid only when the rock is strongly water wet, clay free and has a more or less uniform pore size distribution.

An important issue that Archie equation misses is the fluid critical point for multi – component state in which different phases co-exist. It is not clear how at reservoir conditions oil and water coexist in the pore system.
Development of a High-Speed Low-Torque Drilling Device
Authors: Cannon George E.
Published: December 2007

Research on Humble's high-speed low-torque equipment research project was originally handled by a research concern on a contract basis. Under this development contract three tools were built and considerable laboratory and field testing was done. Last year this tool was licensed to a bit manufacturer, and a development agreement was signed between them and Humble. Under these agreements two tools have been built which have been subjected to one laboratory test and seven field tests as of this date. A considerable history of mechanical failure has been developed, but as a result of the latest field tests it now appears almost certain that a commercial tool will evolve from this project.

Introduction

In 1949, a research organization located in Texas, undertook an investigation sponsored by an organization formed to investigate new methods of drilling to determine the applicability of high-speed low-torque cutting elements to the drilling of wells. This work encompassed a survey of the literature and patent art and a rudimentary laboratory investigation of the ability of a wheel set with tungsten carbide cutters about its periphery to drill rock when rotated about its axis with a flexible shaft drive and with the entire unit rotated about an axis 900 to the wheel axis. Drilling rates up to about 20 ft/hour were obtained in lime while drilling a 4 -in. hole with the experimental device.

This work was dropped by the sponsoring organization since it was felt to be too closely related to conventional rotary drilling practice and, therefore, outside the scope of the organization purpose. Since Humble had patent rights on a turbine-driven drilling tool of the type making use of such a cutting technique, Humble assumed the sponsorship of the development program. Under this development agreement and extensions thereof laboratory and field development work was continued through the fall of 1955. In the summer of 1956 a bit manufacturing company undertook further development of this tool.

Discussion

The original work conducted served merely as background since the work to be done for Humble was the development of a tool for field use. This required the design and building of a suitable surface test rig, determination of the most suitable materials for erosion resistance and cutting ability, and the development of operational techniques for use in the field. The tool was originally designed to drill 6 3/4-in. hole.
Removal of Wellbore Damage from Highly Permeable Formations and Naturally Fractured Reservoirs
Authors: Crawford David L. , Coulter A. W. , Osborn Frank E.
Published: December 2007

An acid system containing effective complexing and dispersing agents has proved to be highly successful in removing wellbore damage from highly-permeable formations and naturally fractured reservoirs. Case histories are presented for many wells that failed to respond to repeated clean-up attempts with conventional systems. Treatments using conventional acid, Mud Acid and diesel oil had been tried unsuccessfully. The wells did respond however to a system that incorporated special complexing agents with surfactant dispersants.

In addition to providing case histories, this paper will describe the nature of the special agents and their action and offer a possible explanation for their downhole performance.

One of the most difficult wellbore clean-up problems is encountered in gravel-packed wells. Sand movement and production must be controlled by gravel packing in many of the highly permeable formations in the Gulf Coast area. These gravel packs present an added barrier to overcome when bringing mud and solids back into the wellbore. Lost drilling mud, in particular, is difficult to flow through a gravel pack. The complexing-dispersing system described here has proved to be effective even under these conditions.
Designed Carrying Fluid Improves Gravel Pack Performance
Authors: Constien Vernon G. , Wallace Jim L.
Published: December 2007

Production of oil and gas from unconsolidated formations often results in the migration of formation material into the wellbore. A popular and effective method for stabilizing unconsolidated formations uses a high density gravel pack which is placed around a screen and out the perforation tunnels. A thickened, retarded acid system containing fluoboric acid has been developed as a carrying fluid for placement of the high-density gravel pack. This fluid combines the functions of gravel-carrying capacity, viscosity reduction, stimulation and clay and fines stabilization into a single fluid. Laboratory flow data on unconsolidated formation material demonstrates the stimulation and clay-stabilizing properties of this fluid. Field results are included which demonstrate the effectiveness of the fluid in high density gravel-pack treatments.
Downhole Protection of Sand Control Screens
Authors: Ledlow Lewis B. , Sparlin Derry D.
Published: December 2007

A widely acknowledged problem in gravel packing is plugging of wire wrapped screens and slotted liners Clays, drilling mud, cement, formation sand and pipe dope are all known plugging contributors.

Field tests and laboratory evaluations have demonstrated that an acid soluble screen protector material may be utilized to prevent plugging as well as replace wash pipe and to serve as temporary blank pipe or casing.
Design and Implementation of a Levelland Unit CO2 Tertiary Pilot
Authors: Graham Bill D. , Bowen Jerry F. , Duane Nick C. , Warden Gary D.
Published: December 2007

Amoco Production Company installed a contained 1.5 acre (6 070m2) tertiary pilot project in the Level land Field, Hockley County, Texas in 1978 in order to measure oil displacement that could be obtained by the carbon dioxide miscible recovery process in a completely waterflooded portion of the San Andres reservoir.

The pilot was located in a previously waterflooded portion of the reservoir. Sizing of the pilot was based on available log and core data utilizing a channel flow reservoir simulator which was designed to simulate miscible flood behavior. Special steps were taken during the drilling of the pilot wells to insure controlled placement of the bottomhole locations. Extensive reservoir delineation testing took place prior to starting carbon dioxide injection. Significant information concerning carbon dioxide process feasibility is anticipated from this pilot. Steps taken to design, install, and operate the pilot are described.
Review and Analysis of Past and Ongoing Carbon Dioxide Injection Field Tests
Authors: Goodrich John H.
Published: December 2007

Under a contract with the U.S. Department of Energy, Gruy Federal, Inc. has prepared comprehensive review reports for 19 projects in 16 fields in which carbon dioxide miscible injection was used to enhance oil recovery. Information from the geological and engineering literature, raw data from public records, and limited information supplied by project operators allowed nonproprietary review and analysis of 7 full-scale (i.e., commercial intent) field projects and 12 pilot projects. Abbreviated summaries of the field reviews for the full-scale projects are presented in this paper. Analysis and synthesis of the data and information from the field projects is also related to published CO2 flooding technology.

These data indicate that injection of CO2 is a technically efficient enhanced oil recovery process over a wide range of geologic and reservoir conditions. Hence, published technical guidelines for judging applicability of CO2 injection are probably too restrictive.
Biopolymer Injection into a Low Permeability Reservoir
Authors: Carter Walter H. , Payton Joy T. , Pindell Robert G.
Published: December 2007

Xanthan biopolymer has been shown to have effective mobility control properties in highly saline environments and to resist shear degradation. The use of this material in low permeability formations has been limited because of injectivity problems arising from the presence of cellular debris. This paper presents the laboratory evaluation and field testing of an enzymatic clarification process, and subsequent polymer injection in a low permeability carbonate reservoir.

The studies show that increased solution viscosity and improved filterability can be achieved by prehydrating the polymer in fresh water, that the enzyme treatment can be effectively performed under field conditions, and that the process can lead to adequate polymer injectivity in a low permeability reservoir when good water quality and effective quality control procedures are maintained.
The Effects of Pore Structure On Displacement Efficiency in Reservoir Rocks and in Glass Micromodels
Authors: Wardlaw Norman C.
Published: December 2007

In strongly wetted reservoir rocks, the extent of non-wetting phase trapping is strongly dependent on the geometric and topologic properties of the pore system. It has been demonstrated that pore-throat size ratio and certain types of heterogeneity affect displacement efficiency adversely. Throat to pore coordination number or connectivity and the condition or roughness of pore surfaces are other important factors affecting displacement efficiency.

Under conditions of intermediate wetting, pore geometry appears to be of reduced significance as a cause of trapping and, under these conditions, displacement efficiency is greater.
VHF Electrical Measurement of Saturations in Laboratory Floods
Authors: Davis Lorne A.
Published: December 2007

The changing oil/brine saturations along linear porous media during secondary and tertiary laboratory flood experiments have been measured using an electrical field detection technique. A short length of the cylindrically shaped medium is contained within the tank circuit capacitor of a very high frequency (vhf) oscillator operating above 100 MHz. The oscillator frequency is dependent upon the material's dielectric constant, which is a sensitive function of the oil/brine saturations.

The oscillator and associated electronics comprise a small, self-contained unit free to slide along the core barrel. A coaxial cable connects this assembly to an external frequency counter. Frequency (saturation) measurements can thus be made at arbitrary flood times and points along the porous medium. The cylindrical symmetry of the flow cell is advantageous, since it maximizes the pressure containment capabilities of the necessarily non-metallic core barrel materials.

The design and performance characteristics of this core saturation monitor (CSM) are described, and its response related to oil saturation and brine conductivity. Examples include saturation scans of a sand pack undergoing oil saturation and water flood. The utility of the technique is demonstrated by contrasting the oil movement characteristics of three chemical floods.
Retention Of Polyacrylamide By Berea Sandstone, Baker Dolomite, And Sodium Kaolinite During Polymer Flooding
Authors: Meister John J. , Pledger Huey , Hogen-Esch Thieo E. , Butler George B.
Published: December 2007

Surface charge and accessible surface area control the retention of polyacrylamide by berea sandstone, baker dolomite, and sodium kaolinite. Hydrolysis of polyacrylamide increases retention by materials with a positively charged surface, such as dolomite, and decreases retention, when surface area remains constant, on materials with negatively charged surfaces, such as sandstone. Additives which form a more "theta" or less effective solvent promote retention. Water becomes a less effective solvent for polyacrylamide when its salt content is increased or when nonsolvents, such as alcohols, are added to it.

Berea sandstone cores retained over 50 percent of polyacrylamide injected under all salinities, polyacrylamide concentrations, and degrees of hydrolysis tested and sodium kaolinite retained over 90 percent of all injected polyacrylamide under the same conditions. In contrast, baker dolomite, a high purity dolomite, retains only 17.9 percent of the unhydrolyzed polyacrylamide injected. Since berea sandstone contains 7.5 percent kaolinite, these data suggest that clay content has a significant effect on total polymer retention.

Flocculating sodium kaolinite, which reduces its accessible surface area by over 80 percent, reduces retention by 70 percent, from 1,217 μg/g to 360 μg/g. With other variables held constant, reduction in accessible surface area will reduce retention of polyacrylamide by a porous medium as long as adsorption dominates the retention process.
Radon Emanation And Transect Studies
Authors: Macias-Chapa Luis , Semprini Lewis , Kruger Paul
Published: December 2007

Laboratory and field experiments are underway to determine the source and transport properties of radon in geothermal systems. Data are available on laboratory emanation studies and field transect experiments which are useful in studying transport and physical properties of geothermal reservoirs.

The emanation studies examine the "source" term for radon transport in geothermal fluids. The emanating power of radon from radium-bearing formation rock is dependent on rock type, rock size, pore fluid density, reservoir temperature and pressure. Initial experiments have shown emanation dependence on rock structure and pore fluid density. The data also suggest that emanation in geothermal reservoirs is also controlled by annealing conditions. Experiments are being run to examine the extent of hysteresis in reservoir rock annealing processes.

Radon transect experiments involve short term measurement of concentration gradients along a line of geothermal wells of known formation structure. Experiments have been conducted at The Geysers vapor-dominated reservoir. Radon concentrations along the transect are correlated to reservoir temperature and pressures. The results are used to study changes in emanation conditions in the reservoir. Fluid transport under constant emanation conditions also results in radon concentration changes due to radioactive decay. Thus the ratio of radon to stable gas component gradients along the transect provides temporal data on the reservoir transport phenomena. Constant ratios are observed in The Geysers tests.
Hydrothermal High Temperature Cements For Potential Geothermal Applications
Authors: Roy D. M. , Langton C. A. , Grutzek M. W. , White E. L.
Published: December 2007

New cementing materials with favorable physical properties are being developed for potential use at temperatures up to 400°C and pressures up to at least 70 MPa in geothermal well applications. One area of interest (in the lime-magnesia-silica-water system) involves the xonotlite-chrysotile join, and another area lies near the anorthite composition (in the lime-alumina-silica-water join), between about 45–65 weight percent silica. Phase formation and compatibility in the temperature region up to 300–400°C with pressures up to 69 MPa (10,000 psi) have been investigated, and the properties of the cementitious mixes formed have been evaluated. Replicate studies were made with different sources of starting materials, but commercially available starting materials were always included as an option. Mixes were evaluated primarily by means of measurements of compressive strength, water permeability, bond strength, and high temperature phase stability.

Maintenance of pumpability at temperatures up to 177°C (350°F) has been demonstrated for magnesium-containing mixes. Detailed studies were made of the effects of alkalies (sodium and potassium) in the mixes upon the phases formed and stabilities of the cements. The magnesian compositions were found to be relatively stable, and any new phases formed did not have deleterious effects.
Composite Equilibrium Vaporization Ratios for Separation Calculations
Authors: Latham James A. , Campbell John M.
Published: December 2007

A set of composite equilibrium vaporization ratios is presented that may be used to predict the quantity and composition of all components in separation calculations with a degree of accuracy that is satisfactory for normal field separation processes. The values presented have been obtained from a statistical analysis of seven most commonly used sets of equilibrium values and combined into one set which has more general application than any one of the individual sets from which the values were derived. These charts, therefore, offer a convenient and consistent set of values for use throughout the normal range of separation for the components of methane through heptanes-plus.

Introduction

When equilibrium vaporization ratios, or K-values, are used for calculations, the results are dependent upon the values selected. An arbitrary application of one particular set of K-values to all separation problems will produce correct results for some fluids and incorrect results for other fluids. In general, a non-selective application of one set of values will give erroneous results.

An examination of existing equilibrium data indicates that the engineer has a wide choice in the selection of K-values that he can apply to separation calculations. He frequently has to use several sets of correlations for different ranges of temperatures and pressures and/or various correction factors to correct for certain discrepancies. These discrepancies have often been a source of difficulty in routine field separation problems, company negotiations, and in the prediction of yields for proposed unitizations. Therefore, a need exists for a single set of K-values that would be sufficiently accurate for all normal separation problems.

The purpose of this investigation, therefore, has been to examine existing equilibria data statistically and prepare a series of charts that may be used to solve routine oil and gas separation problems.
Equations of Motion for a Linear Miscible Displacement
Authors: Gardner G.H.F.
Published: December 2007

Equations for the motion of miscible fluids are considered which are based on a single hypothesis, namely, the fractional flow of the invading fluid depends in a known way on its saturation and saturation gradient. They are similar in form to the equations of the Buckley-Leverett theory.

The differential equation satisfied by the fractional flow, considered as a function of the saturation and the time, is derived. A similar equation may also be obtained in the Buckley-Leverett theory for immiscible displacements. This equation, because of its simple form, is susceptible to well-known numerical methods and makes the computation of the history of a displacement a reasonable project.

A comparison of the implications of the equations with some of the published data is made. While it seems possible to reconcile some of the apparently incompatible interpretations which have been given on the ground that the techniques employed affect the nature of the motions, several differences still remain.

For a horizontal drive, in which gravity segregation enters, it is shown that a motion may exist in which the planes on which the saturation of the invading fluid is constant are inclined at a constant angle with the direction of motion.

Introduction

Many investigations have been made into the behavior of a fluid while being displaced from a porous medium by a miscible fluid. On only one occasion, however, have equations been suggested as descriptive of the motion. For this reason an account is given here of the consequences which follow from some simple hypotheses about the movement of miscible fluids. The equations are similar in form to those of the Buckley-Leverett theory for immiscible displacements and differ from them only in detail. Consequently, the method outlined here for discussing them is equally applicable to the Buckley-Leverett theory and provides a simple way of explaining and computing the formation or nonformation of a stabilized zone in that theory due to the interaction of gravity and capillary forces.

The interpretation ascribed to the many experiments on miscible flooding does not, at first sight, present a consistent picture. The dependence of the length of the mixing zone on rate, viscosity and pore structure is explained in a different way by the various authors.
Prolog – An Interactive Digital Wellsite Formation Evaluation
Authors: Frost Elton , Fertl Walter H. , Atlas Dresser
Published: December 2007

PROLOG is a computerized wellsite log analysis program package. The programs in PROLOG are designed to enhance the information obtained from Dresser Atlas Computerized Logging Service (CLS) Units.

PROLOG is based upon two basic analysis packages, Wellsite CRA for complex reservoir analysis and Wellsite SAND for clastic sediment sequences. Both CRA and SAND present detailed formation evaluation in a 4-track format supported by depth shift routines, a true vertical depth option, data edit routines including borehole (washout) and environmental (invasion) log response corrections, and crossplot routines (frequency, Pickett6, Hingle4, histograms, etc.)

The present paper provides a general discussion of the PROLOG programs along with several field examples.
Design and Operation of Micellar-Polymer Pilot Project Facilities Bell Creek Field, Montana
Authors: Belden William M.
Published: December 2007

In 1975 Gary Energy Corporation, as operator of the Bell Creek Field, entered into a cost sharing contract with ERDA (now DOE) to develop a 160 acre (6.5 × 105 m2) micellar-polymer pilot project in the Bell Creek Muddy Sand Unit "A". This paper reviews the micellar process used, design of the pilot facilities, and operation of these facilities in the successful injection of the necessary chemicals at this pilot project.
An Analysis of Pressure Transient Behavior in an Infinite Two-Layered Heterogeneous System With a Vertical Fracture
Authors: Sarabian A. R.
Published: December 2007

The analytical solution to the diffusivity equation for an infinite two-layered reservoir with a vertical fracture is obtained for the case where the initial pressure of each layer is unequal.

The equations derived in this method are used to determine the length of the fracture of the two zones, if the initial pressure of each layer is known. Additionally, this analysis determines the reservoir parameters of vertically fractured reservoir.

The solution of the diffusivity equation for this study with the proper boundary conditions for an infinite two-layered system with a vertical fracture is given in the Appendix.
FERC Filing and Gas Price Determination
Authors: Soule John G. , Buch Sandra B.
Published: December 2007

This paper discusses briefly the role of the Railroad Commission of Texas (hereinafter RRC) in the category determination process under the Natural Gas Policy Act of 1978, The category determination process ultimately determines the ceiling price at which first sales of natural gas can be made. It was not possible to relate the paper solely to the Cotton Valley. However, special emphasis has been placed on Section 107 (tight sand) gas because it is anticipated that at least portions of the Cotton Valley formation will qualify for incentive pricing under that section.
Status of Alaskan Gas Reserves and Their Potential Impact on the United States and Canada
Authors: Simasko Donald
Published: December 2007

ALASKA HAS LONG BEEN RECOGNIZED AS A STOREHOUSE OF VAST MINERAL WEALTH. WHAT STARTED OUT AS "SEWARDS FOLLY" IN 1867, MAY VERY WELL BE THE ELEMENT WHICH WILL SIGNIFICANTLY CONTRIBUTE TO THE UNITED STATES ABILITY TO MAINTAIN ITS PRESENT LEVEL OF ECONOMIC ACTIVITY AND CONTINUE A LIFESTYLE FORESEEN BY ITS FOUNDERS AND FOSTERED THROUGH MORE THAN TWO HUNDRED YEARS IF ITS EXISTENCE. AMONG THE MANY ITEMS IN THE STOREHOUSE OF THE NORTH ARE PROVEN AND POTENTIAL RESERVES OF NATURAL GAS.

THE AMERICAN GAS ASSOCIATION ESTIMATES THAT PROVED RESERVES OF GAS IN THE UNITED STATES AT YEAR-END, 1979, WERE 194.9 TRILLION CUBIC FEET. AS OF JANUARY 1, 1979, THE ALASKA OIL AND GAS CONSERVATION COMMISSION ESTIMATES THAT THERE ARE AT LEAST 33.7 TRILLION CUBIC FEET OF PROVEN RECOVERABLE GAS RESERVES IN THE STATE OF ALASKA (SEE PLATE 1). THE TABULATION PREPARED BY THE COMMISSION WAS COMPUTED FROM DATA COMPILED LAST NOVEMBER AND WAS ADJUSTED TO REFLECT ESTIMATED REMAINING RECOVERABLE RESERVES AS OF JANUARY 1, 1979.

IT SHOULD BE NOTED THAT SLIGHTLY LESS THAN 85% OF THE PROVEN GAS RESERVES IN ALASKA ARE CONTAINED WITHIN THE PRUDHOE BAY FIELD.IN ADDITION TO RESERVES CONTAINED IN THE PRUDHOE BAY FIELD, RESERVES CONTAINED IN THE KAVIK AND KEMIK FIELDS ARE ALSO LOCATED ON THE ARTIC SLOPE OF ALASKA. THE RESERVES FROM THESE FIELDS ARE UNDETERMINED BY THE ALASKA OIL AND GAS CONSERVATION COMMISSION SINCE SUFFICIENT BASE DATA HAS NOT BE ADEQUATELY DEVELOPED DUE TO LACK OF IMMEDIATE MARKET. RELIABLE SOURCES, HOWEVER, INDICATE THAT THE VOLUME OF RESERVES AVAILABLE FROM THESE TWO FIELDS COULD BE LARGE ENOUGH THAT NEARLY 90% OF THE PRESENTLY PROVEN RESERVES OF GAS IN THE STATE ARE LOCATED IN THE ARCTIC SLOPE BASIN.