bluuebunny/crossref_metadata_2025 huggingface dataset:
The Auger Monitoring and Control System
Authors: Forster L. D. , Bailliet R. M. , Casada D. B. , Schafer D. R.
Published: December 2007

The paper describes the comprehensive Monitoring and Control System developed for Shell’s Auger Tension Leg Platform. The platform includes a large production facility, a full capability drilling rig and marine and utility support system. The Monitoring and Control System consists of a host computer system networked to programmable logic controllers which handle the various processes, and several specialized subsystems. The Monitoring and Control System represents a relatively seamless integration of many diverse systems. Commonality of hardware and operator interfaces ensures operator effectiveness, minimizes training, and enhances safety. The design approach taken with this system has application to large, complex facilities. With a suitable communications system, the system can be applied to facilities which are geographically separate. The system is centralized and gathers virtually all process and other operational data into a central monitoring and control room. More than 40 PLCs, all of the same family, along with several specialized subsystems are networked via fiber optics to the redundant host computer system. The system integrates marine, utility and production systems into an effective tool for managing platform operation.
Intelligent Interfaces for Fracturing Simulators: Part II—System Implementation and Application
Authors: Xiong Hongjie , Lancaster D. E. , Sherry K. J.
Published: December 2007

Hydraulic fracturing is one of the most effective stimulation methods for increasing oil and gas recovery. There are several powerful 3-D (and pseudo 3-D) numerical simulators available in the industry for designing hydraulic fracture treatments. With each model, the accuracy of the simulation results depends heavily on the input data used. Thus, it is important to prepare a complete and accurate input data set for these simulators. This can be difficult to do, however, not only because lots of data items are required, but also because many decisions must be made, such as selecting fracturing fluids, selecting proppants, and determining the optimal pumping schedule and technique.

Using artificial intelligence methods, we have developed a powerful, interactive software application that uses a series of friendly and intelligent interfaces used to acquire the large amount of data needed by fracture simulators. In these interfaces, the user is guided through a set of screens specific to his problem. More importantly, the system helps the user make many decisions, such as selecting fracturing fluids and additives, selecting proppants, and selecting pumping schedules and pumping techniques. The system includes several databases from which a considerable amount of information can be accessed automatically, such as typical formation data, fluid rheology, and proppant conductivities. The system also provides a powerful expert help facility. In addition, based on the fracture simulation results, the system produces data sets that can be used to run reservoir performance and economics software.

This paper presents the methodology we used to implement the system and fully describes the different parts of the system, including the knowledge bases, fuzzy logic evaluators, data acquisition blocks, and databases. The paper also describes the expert help facility in the system. A companion paper1 describes how we designed the system.
Evaluation of Bottom Hole Pressures in 40 Soft Rock Frac-Pack Completions in the Gulf of Mexico
Authors: Mullen M. E. , Stewart B. R. , Norman W. D.
Published: December 2007

The purpose of this paper is to share findings that resulted from a study of pressures recorded from bundle carrier and wash pipe gauges run during frac-packing operations. The original premise was to correctly evaluate and identify fracture pressure responses associated with the "tip-screen-out" techniques used for frac-pack placement. The first attempts at frac pack pressure evaluation were done using data collected from bundle carriers in the workstring. Once washpipe data was obtained, it was noted that the bundle carrier data was distorted by phenomenon below the gauges in the well bore. The fluid friction generated through the crossover tool and friction associated with the slurry path around the screen proved to be a source of the observed distortion. Data collected from bottom hole pressure gauges attached to the wash pipe below the gravel pack running tool indicated that in several cases the observed pressure increase is associated with friction and not from the fracture inflation associated with "tip-screen-outs."

It was noted that serious swabbing effects can accompany the movement of the service tool. This swabbing has in the past been considered negligible. The swab effect can potentially damage the completion beyond repair. This swab can pull formation material into the perforations tunnels and annulus, creating a severe pressure drop through that portion of the perforated interval. The implications can be detrimental to well performance. Early BHP data collection altered procedures for service tool movement and provided insight toward correcting friction pressure calculations.
A Comparative Study of Succinoglycan Gravel Pack Gel Properties to Those of HEC
Authors: Cole R. Clay , Ali Syed A.
Published: December 2007

This paper contrasts the many different characteristics of hydroxyethyl cellulose polymer gels (HEC) with those of succinoglycan (SGC), a polysaccharide biopolymer. The properties included in this study are those related to gravel packing. All data and opinions are based on a comparison of HEC gels that had been properly hydrated, sheared, and filtered against SGC gels that were not sheared but were also filtered through 3.2-micron rated paper.

This paper does not dwell on previously published shortcomings of HEC polymer,1-4 but by directly comparing HEC to SGC, it reveals unique new advantages that could improve the quality of gravel packs.
Major New Developments in Hydraulic Fracturing, with Documented Reductions in Job Costs and Increases in Normalized Production
Authors: Cleary M. P. , Doyle R. S. , Teng E. Y. , Cipolla C. L. , Meehan D. N. , Massaras L. V. , Wright T. B.
Published: December 2007

A number of developments over the past five years have led to dramatic changes in the design and execution of hydraulic fracturing treatments. Five primary new issues are described: convection, tortuosity, rock/fracture (non-linear) response, appropriate use of rheology/flow-rate and permeability variation effects. Consequences include "paradigm shifts", such as inverse relations between appropriate proppant concentration and reservoir permeability. Resulting integrated cost-effective and rewarding methodologies for fracture execution are emphasized and the methodology is illustrated with just a few case-studies, selected to emphasize a variety of technical features as against absolutely optimum execution. Suitable generic implementation and procedures, using greatly reduced fluid volumes, are outlined in sufficiently general form to allow (practically optimum) job execution on any well, particularly in low-permeability reservoirs.

The variation between (nominally identical) wells, and the vital role of real-time analysis for on-site execution of adequate jobs, is demonstrated - including unique (but essential) representation of realistic/general physics in the models used to interpret adequate data-sets. The case-studies serve to illustrate the major issues, including many ancillary features involved in proper interpretation of pressure/flow data before, during and after fracturing treatments: it is emphasized here (and in a companion paper for higher permeability) that the proper/sensible combination of all freely-collectible data, including long-term production plots, which should be a natural part of all well operations, usually leads to (practically) unique interpretation of reservoir conditions and job effectiveness: good reservoirs are properly identified and poor-success cannot be so easily ascribed to poor kH. Well procedures and costs are thereby adapted to (optimum) production.
The Current State of Homopolar Pipeline Welding
Authors: Carnes R. W. , Haase P. W.
Published: December 2007

Homopolar pulse welding (HPW) has been proposed as a one-shot, single stage welding process for the joining of pipe in the J-lay configuration. A joint industries program (JIP) has been formed to develop this process for off-shore, deep water applications. Homopolar pulse welding utilizes the high current, low voltage electrical pulse produced by a homopolar generator to rapidly resistance heat the interface between abutting pipe ends, producing a full circumference resistance forge weld requiring no filler metal in only three seconds. This five year program began in February 1993, funded by a consortium of six oil companies (Shell, Exxon, BP, Texaco, Amoco, and Mobil) and one welding contractor (CRC-Evans). The program’s ultimate goal is to produce a prototype system suitable for installation on a barge. The goals for the first two years of the program include demonstrating suitability of the process by producing and evaluating welds in different grades and wall thicknesses of three inch nominal diameter API 5L line pipe. Funding for each year of the program is contingent upon meeting program goals for the previous year. In the first five quarters of the program, eighty four welds have been produced, tested and evaluated and a method for non-destructive testing of the production welds has been identified.
Evaluation of a Crosslinked CMHEC Fracturing Fluid in Stimulation of Fruitland Coal Seams in the San Juan Basin
Authors: Ely J. W. , Zimmerman Scott
Published: December 2007

Over the past 10 years, many fracturing techniques and fluids have been utilized in stimulation of coal seams. Everything from straight water to linear gels to crosslinked guar or HPG, foam fracturing fluids, and even acid have been used in an attempt to find the optimum fracturing fluid for coal. None of these techniques appeared to work as well in relatively thick seams as the "collapsing cavity technique." Since most thinner or multi-seam coals are not applicable to collapsing cavity, the authors felt quite strongly that considerable damage was still occurring in the cleat system with conventional fracturing fluids. Additionally, straight water or slick water fracturing fluids simply did not have the proppant transport or the ability to obtain high near wellbore conductivity required for adequate coal seam stimulation.

In this paper, the authors present the results of over 60 fracture treatments that have been completed with totally residue free crosslinked CMHEC fracturing fluid.

It was felt that the colloidal solids present in broken gel, even with HPG and clay suspending agents used in continuous mix fracturing fluids, may result in damage in the very narrow cleat systems of the coal. Combined with the very clean fracturing fluid, the authors utilized the "forced closure technique," intense quality control and aggressive proppant schedules. The study has the advantage of being interspersed within wells that have been treated with foam, slick water, crosslink gel, straight water and some attempted cavitation techniques. The authors will present production data in evaluating the performance of the totally clean fluid. More than 1.5 years of production history is available.
Practical Application of In-Situ Stress Profiles
Authors: Cipolla C. L. , Liu Diabin , Kyte D. G.
Published: December 2007

This paper illustrates a comprehensive and economical approach to the application of reservoir data to optimize stimulation designs. The paper documents the selective application of in situ stress tests and dipole sonic logs to provide accurate stress profiles that can be used in concert with standard log and mini-fracture data to improve stimulation designs.

Measured stress data on 3 wells were used to calibrate open-hole logs to provide an estimate of stress profiles throughout a 300 square mile area of the Moxa Arch. Dipole sonic log-derived stress profiles were correlated to measured stress data. Calibrated stress profiles from dipole sonic logs and the measured stress data were then used to develop a correlation between gamma-ray logs and in situ stress. The log-based stress data was improved with the addition of over 50 mini-fracture tests. The combination of selected stress measurements, dipole sonic logs, and mini-fracture treatments resulted in optimized stimulation designs and cost savings of over $100,000 per well.
New, Simplified Methods for Modeling Multilayer Reservoirs Performing at Pseudo-Steady State
Authors: Ryou Sangsoo , Frantz J. H. , Lee W. J.
Published: December 2007

This paper presents new correlating parameters for boundary-dominated, constant rate production from multilayer reservoirs. These parameters allow us to model well responses for multilayer systems having equal and unequal fracture lengths and boundary sizes, with equivalent single-layer systems. The paper also shows how we can use an equivalent skin factor in a single-layer model to simulate a multilayer reservoir with unequal positive skin factors in different layers. The paper includes a field example in which we applied the correlating parameters to a well producing from multilayer, tight gas sands in the Carthage Field.
Low Areal Sweep Efficiencies In Flooding Heterogeneous Rock
Authors: Pitts Gerald N. , Crawford Paul B.
Published: December 2007

This paper shows the very low areal sweep efficiencies to be expected when water flooding in heterogeneous rock. In this study the permeability of the rock matrix was assigned different values to a 400 point grid comprising the flooding pattern. The entire matrix was composed of rock permeabilities distributed randomly between some range. When the lowest permeability was 0.1 md and the highest 100 md. the average sweep was found to be only 20 to 30 percent of the total area for a five-spot pattern. Many examples are given and charts are presented for estimating the areal sweep in flooding heterogeneous five-spot, staggered line-drive and direct line-drive patterns.

Surprisingly, the direct line-drive square pattern gives a higher sweep for very heterogeneous rock than the staggered line-drive or five-spot patterns.

Introduction

Muskat presented the areal sweep efficiencies when flooding or cycling five-spot, direct line-drive and staggered line-drive patterns several decades ago.
Use of Seismic Attributes in Geological Description of Carbonate Rocks
Authors: Castrejón-Vácio Fernando , Porres-Luna A. A.
Published: December 2007

Seismic attributes have been used widely in order to obtain geological description of petroleum reservoirs, especially as a support for the definition of horizontal continuity of strata, with special emphasis on terrigeneous formations. Nevertheless the application of seismic attributes to the study of carbonate and naturally fractured reservoirs has been limited.

This paper shows the application of seismic attributes and seismic inversion to the geological and petrophysical characterization of a naturally fractured reservoir with complex lithology, which is characteristic of the most important producing formations in Mexico.

Taking into account petrophysical and lithological data obtained from core and well logs, it was possible to define some empirical relations that link the response of the seismic attributes with the petrophysical characteristics of the strata, such as porosity and fracturing, this relations are valid only for the carbonate formations at SE of Mexico. On the other hand, the horizontal continuity of lithology, as well as the detection of discontinuities, can be inferred from pseudo-velocity data obtained from the application of some seismic inversion techniques. It was carried out an analysis with the purpose of proving the effectiveness of these techniques for this kind of formations.

To obtain appropriate results from seismic data, it is necessary to consider the map of the main faults, since in areas with high fracture intensity, an important loss of amplitude from the seismic data frequently occurs.

The results from this techniques provide the basis for the definition of a realistic geological model, which is of prime concern for reservoir's characterization, numerical studies and EOR applications.
Deepwater Production Systems for the Bay of Campeche
Authors: Heideman J. C. , Finn L. D. , Hansen R. L. , Santala M. J. , Vyas Y. K. , Wong P. C. , Pontigo F. A.
Published: December 2007

Deepwater production systems are considered for the 300500 m water depth range in the Bay of Campeche. In comparison with the northern Gulf of Mexico, the physical environment is found to have similar seafloor soils; similar winter storms; no Loop Current; less severe hurricanes; and weak earthquake-induced groundmotions. Oil reservoirs are expected to be larger than those in the northern Gulf, and well flow rates greater. Under these conditions, and based on industry experience in various offshore oil provinces, steel piled jackets, compliant piled towers, tension leg platforms, and floating production systems, alone or in connection with subsea production systems, are all judged to be technically viable candidates for full-field development with permanent structures.
Unit Equity Determination
Authors: Tetreau E.M. , Roberts L.E.
Published: December 2007

Where unitization takes place early in a pool's life, it is considered critical that the pool's life, it is considered critical that the evaluations determining participating equity be carried out quickly and accurately. Comprehensive studies of the interrelationships of all of the known variables, or commonly called unitization parameters, for a large number of land tracts with wide variance of their parameters has in the past been unwieldy and parameters has in the past been unwieldy and impractical. In order to assess accurately the impact of these unitization parameters, a computer program was developed to calculate future performance and tract value. The example used in this illustration happens to be for a unit project in the Province of Alberta, but the principle and procedures can be adapted to any project where contributory values of the tracts involved need to be assessed.

The program includes the following features:

pool allowable forecast as a time function, distribution of pool allowables on an acreage basis, together with redistribution of individual tract's incapability to the remaining capable wells, crude oil price as a function of time, present worth at several discount rates, individual tract's reserves and allowable acreage, individual tract's initial producing capacity, start of decline, type of decline (constant percentage, harmonic or hyperbolic) and abandonment rate, operating costs and expenditure scheduling, complete print-out of tractperformance over 50 years, and each company's participating equity at each discount rate.

The adaptability of the program has been demonstrated by the virtual fieldwide unitization of the Nipisi Gilwood pool in Alberta. Here 20 of the 21 operators with both wholly owned and joint interest in various parts of the pool, and under a system which grants equal allowables to all productive acreage, were able to agree despite the following variances in their major tract parameters:

tract reserves - 100 percent, tract producing capacity - 10,000 percent and percent and well spacing - 700 percent.

It is no longer necessary then to rely on previously established unitization weighting previously established unitization weighting patterns of various parameters to establish patterns of various parameters to establish unit equities.
A Multi-Phase Mud Filtrate Invasion and Wellbore Filter Cake Formation Model
Authors: Civan Faruk
Published: December 2007

Mathematical modeling for prediction of the distribution and mixing of mud filtrates in the reservoir formation surrounding a well being drilled and the filter cake build-up and its effect on the mud filtrate invasion into the formation, as well as the resulting formation damage effects is presented. The model can simulate the single and two-phase flow situations in the formation with water or oil based drilling mud cases. External particle invasion during the early period of filter cake initiation and its effect on the formation damage by particle migration and retention is considered. An application involving radial flow is given. This model is a useful tool for accurate interpretation of oil-mud-fluid system saturations and resistivity profiles which are essential for the development of efficient well-log interpretation.
Rethinking Conventional Field Development: 3D Shows Direct Detection of Bypassed Oil Reserves
Authors: Sibley D. M. , Mastoris S. S.
Published: December 2007

Accurate well to seismic correlations of several producing sands and detailed analyses of reservoir characteristics have revealed hidden reserves in an aging field that was previously determined to be uneconomic. The combination of a recent 3D survey shot over Eugene Island Blocks 338 and 339, Gulf of Mexico, and new interactive workstation technology was instrumental in identifying swept and unswept portions of different oil reservoirs and allowed new infill wells to pinpoint key targets.

Seismic attributes were extracted along mapped horizons which showed lateral variations in reservoir properties, identifying depleted zones where the water front had passed through and areas it had missed. This observed seismic response is related to changes in water saturation associated with production and was verified by seismic modeling based on Biot-Gassman-Geertsman equations.

To apply these concepts, net pay maps for key reservoirs were constructed by calibrating detuned, composite amplitudes to pay thicknesses. The top and base of these net pay surfaces were displayed in geologic cross-sections to direct the paths of infill wells.

This proved to be a useful approach to plan conventional and horizontal well paths within the difficult internal stratigraphy of complex Pleistocene reservoirs having an associated structural complexity.

The result was a successful drilling program for Chevron and its operating partner Texaco. Chevron was able to participate in 11 out of 14 development wells after making a "turnaround" decision to keep what was once thought to be a marginal property.
Logging While Drilling Applications in Latin America & The Caribbean
Authors: Husband F. J. , Palomo M. Ricardo , Roca R. Luis
Published: December 2007

The commercial use of Logging While Drilling (LWD) technology in Latin America & the Caribbean has grown significantly in the last two years as national and international oil & gas companies implement more efficient systems to locate and extract hydrocarbons. This technology has been applied to optimize drilling projects as LWD measurements are now routinely used for improved log quality, geosteering into complex horizontal targets, "insurance" logging in difficult drilling environments, and where operating rig costs create a financial need.

Case field applications are presented including drilling and logging depleted gas sands in high concentration LCM mud systems, 3-dimensional geosteering techniques, and time lapsed overlays for identification of moved fluids and wellbore stability. The examples and discussion that follow represent field experience utilizing Compensated Dual Resistivity (CDR*) and Compensated Density Neutron (CDN*) measurements to more efficiently find and produce oil and gas in Latin America.
Practical Approach to Environmental Protection in the Exploration and Production Industry
Authors: Emmons L. N.
Published: December 2007

Environmental protection is a major issue throughout the world. Effective environmental protection techniques exist that are simple, creative, practical, and often cost effective. The cornerstone of cost effective environmental protection is an environmental management system. Various techniques are also available for reducing wastes, minimizing spills, remediating soils, reducing air emissions, and protecting groundwater and surface water in exploration and production operations.
Design Of A Total Energy Management System For The Abatement Of Air Pollution
Authors: Schoeppel Roger J.
Published: December 2007

Ever-increasing utilization of fossil fuels to meet the energy requirements of our affluent society has resulted in an alarmingly high rate of pollutants being emitted to the atmosphere. Although the problem of air pollution has been existent since the earliest pollution has been existent since the earliest times, its magnitude had not been discernable. In recent years, however, this subject has attracted the attention of both the public and the Government. Of the various sources of air pollution, the internal combustion engine has been estimated to contribute about 60% to the overall problem. Since 80% of the fuel requirements for the transportation sector of our economy is shared by vehicles, mostly automobiles, buses, and trucks, the use of an alternate, nonpolluting fuel, would certainly diminish air pollution levels. Research along this direction at Oklahoma State University has resulted in the development of an internal combustion engine which uses hydrogen instead of gasoline as fuel. Unless a more viable solution to the air pollution problem is advanced, it is proposed that the oil industry consider the development of a total Energy Management System which, interalia, aims at supplying large quantities of hydrogen at relatively low cost. It is believed that the proposed system would enable optimum management proposed system would enable optimum management of energy resources and thus place minimum strain on the delicate ecological balance of the environment.

Introduction

It may seem paradoxical, but man is presently poisoning his own environment, thus presently poisoning his own environment, thus gradually disturbing the delicate ecological natural balance. Millions of tons of noxious pollutants are rejected daily to the atmosphere, pollutants are rejected daily to the atmosphere, rivers and lakes, in the United States, as a result of the utilization of some 65.5 × 10(15) is BTU of energy, as reported for 1969. In a sense environmental pollution has become a direct corollary to an ever-increasing level of energy utilization. It all began with the Industrial Revolution and, since then, the increase in energy consumption has shown a linear correlation with the increase in economic growth of the United States reflecting a gradually rising standard of living.
Simulation of Gas Well Performance by Variational Methods
Authors: Douglas Jim , Dupont Todd , Henderson Gerald E.
Published: December 2007

Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussions may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines.

A numerical method based on the calculus of variations is proposed for the solution of the problem of computing the behavior of single-phase linear or radiial gas flow. The method is shown to allow consideration of the effect of linear or radially-varying reservoir rock properties.

This paper discusses both the method of solution and the computer program which results from its application. Examples are presented which demonstrate the relevance and usefulness of the program, as well as the small computer cost program, as well as the small computer cost required for solution to a particular problem. problem

Introduction

The application of computer simulation to reservoir engineering has grown very rapidly in the past few years. This growth has paralleled the increased activity in research on numerical methods for approximating the solution of partial differential equations. Until partial differential equations. Until quite recently most of the development in numerical methods centered on the use of finite difference methods, but in the last three or four years quite a large portion of the theoretical work in portion of the theoretical work in numerical analysis has shifted to the study of variational methods and this paper is devoted to the treatment of the paper is devoted to the treatment of the single-phase flow of a gas in a radially symmetric reservoir. The specific objectives of this research are as follows:

The development of a one-dimensional, radial, one-flowing phase, unsteady-state, heterogenous gas well simulator based on variational methods. The simulator should allow the properties of formation net pay, properties of formation net pay, permeability, and porosity to vary as a permeability, and porosity to vary as a function of distance from the well. Jump discontinuities should be allowed to occur in these data. The effect of water and rock compressibility and of varying gas viscosity, gravity and Z-Factor should be included.
Crystallization Process to Reduce NORM-Containing Waste
Authors: Hayden C. G. , Kraemer T. F.
Published: December 2007

This paper describes a process of Naturally Occurring Radioactive Material (NORM) waste reduction for scales, sludges, and soils. The process involves dissolution and fractional crystallization steps that concentrate the radioactive material into a small mass of barite. The concentration of radium in the product, barite, can be increased or decreased. The NORM-containing barite product is suitable for slurry injection into sandstone formations.
Associative and Repulsive Interactions in Polymer-Surfactant Systems Studied by Gel Permeation Chromatography
Authors: Veggeland Kirsti
Published: December 2007

Polymer-surfactant interactions have been studied by Gel Permeation Chromatograhy in order to include a dynamic aspect. Associative interactions can be identified and studied with this method. Also quantitative measurements on the amount of surfactant associated with the polymer have been performed. Association between PEO and ethoxylated sulfonates decreases when the number of EO-groups in the surfactant increases. For more than 3 EO-groups the association with PEO disappears. When there are repulsive interactions, like in (P-S-)-systems, the results are difficult to interpret. A (P-S-) -system is separated in a GPC column due to osmosis and size exclusion. PS-interactions cannot explain the surprising core flood results.
New Techniques for Monitoring Cement Hydration Under Simulated Well Conditions
Authors: Luke Karen , Hall Chris , Jones Tim , Barnes Paul , Turillas Xavier , Lewis Andrew
Published: December 2007

Fourier transform infrared spectroscopy and synchrotron X-ray powder diffraction methods are described for studying cement hydration chemistry at temperatures up to 200 deg C, covering the normal temperature range of wellbore cementing. The methods provide complementary information on the transformation of silicate, ferrite and sulphate minerals. The thermal decomposition of the cement mineral ettringite is shown to occur at 114 deg C in a sealed system in contact with water. The FTIR spectrum of a well cement slurry hydrating at 150 deg C and 2000 psi is analysed. The anomalous thickening time behaviour of certain cements around 75-100 deg C is discussed in the light of new data on the hydration of a Class G cement at 65 and 95 deg C, with and without retarder.
Mechanism of Shale Inhibition by Polyols in Water Based Drilling Fluids
Authors: Reid P. I. , Dolan Bernadette , Cliffe Stephen
Published: December 2007

Polyols (e.g. glycols, glycerols, polyalkylene glycols) are now established as effective shale inhibitors in water-based muds (WBM). These water-soluble compounds are typically used at concentrations between 3 and 10% in WBM and are generally found to reduce wellbore problems associated with reactive shales, increase drilling rates and reduce the environmental impact of the drilling operation. The mechanisms by which these molecules provide shale inhibition are not well understood and the aim of this paper is to provide some insights into these mechanisms.

The adsorption of three polyols on to a swelling clay mineral (montmorillonite) was studied. The adsorption experiments were carried out from distilled water and from potassium chloride solutions. The resulting clay complexes were characterised by X-ray diffraction and infra-red spectroscopy techniques. Shale inhibition measurements were also made and the results correlated with the adsorption of the polyols.

The polyols are shown to be strongly adsorbed by the clay. During the adsorption process, water is displaced from the clay surface and ordered structures of polyol are formed. The nature of these structures and their stability in aqueous fluids is strongly controlled by the presence or absence of potassium cations: *Under most conditions, a single polyol layer forms on the clay in the presence of potassium and the resulting complexes are stable in water.*A complex containing 2 polyol layers is formed when potassium is absent. This complex is less stable in water.

The interaction between potassium ions and polyols at the clay surface is proposed as the critical factor in the provision of shale inhibition. This interaction appears to account for all the observed inhibition in the case of two of the polyols studied. For a 3rd polyol, an additional (minor) contribution may come from interactions between polyol molecules at the clay surface.

The selection of the most appropriate polyol for inhibitive muds is discussed. This is a complex issue that must consider cost and environmental acceptability as well as technical performance.
Horizontal Well Drill-In Fluid Utilising Alcohol Ethoxylate
Authors: Jachnik R. P , Green P
Published: December 2007

The drilling of horizontal wells in the last 6 years has significantly improved the economics of oil and gas production from depleted reservoirs or tight sands. This paper illustrates the application of an alcohol ethoxylate into a drill-in fluid designed to minimise formation damage in low permeability sandstones while drilling horizontal sections as long as 1,617 metres (5,306 ft) at depths approaching 6,580 metres (21,600 ft) and to facilitate formation cleanup.

The chemistry of alcohol ethoxylates/alkoxylates are described and the more popular names used within the industry will be discussed. Laboratory results are presented which illustrate colloidal phenomena not previously reported with these systems, the routes taken for successful application into a drill-in fluid and how complex these particular colloidal systems are from a physical chemical viewpoint, along with the inevitable "learning curve" required to fully optimise these systems.

Generalised case histories from the UK Southern North Sea will be described, along with field observations which back up the colloidal phenomena seen in the laboratory.
Comparative Laboratory Selection and Field Testing of Polymers for Selective Control of Water Production in Gas Wells
Authors: Ranjbar M. , Czolbe P. , Kohler N.
Published: December 2007

Intensive comparative feasibility studies were performed in different laboratories in order to select the most promising polymer based technology for water control in gas production and storage wells exhibiting low matrix permeability, high temperature and high produced brine salinity. Core flow experiments performed under reservoir conditions with different commercial available chemical systems have pointed out to the superiority of two relatively low-molecular-weight vinyl sulfonated/ vinyl amide/ acrylamide terpolymers over other polymers to decrease selectively and effectively the water permeability without affecting the gas flow. These polymers have excellent compatibility with all types of reservoir brines and good thermal stability up to 150°C. Furthermore, because of their high shear resistance, and excellent injectability even in low permeability cores, solutions of these polymers can be pumped at high injection rates with a moderate wellhead pressure.

Based on the promising results of the lab tests the first field treatment was performed in January 1993 on an abandoned gas producing well from a sandstone reservoir with a BHT of about 130°C, an average matrix permeability of 0.01 μm2 and a produced brine salinity of more than 300 g/1 TDS. This well was loaded up with water. The polymer solutions were injected at a well head pressure not exceeding 5 MPa without any problem. The treatment returned a daily gas production of more than 100,000 m3 to the well. The water production was reduced from almost 90 m3/d to less than 1 m3/d. The second treatment was performed in May 1994 on a candidate well in a gas storage sandstone reservoir with a BHT of 87°C, matrix permeability of 0.1μm2 and brine salinity of 300 g/l. According to the lab feasibility studies this time a terpolymer with a lower molecular weight was used. As a consequence of the treatment the well is showing far better gas injection characteristics. The effect on the gas and water production can only be evaluated at the end of the winter production period in March 1995.
Performance of 18 Polymers in Aluminum Citrate Colloidal Dispersion Gels
Authors: Smith J. E.
Published: December 2007

Colloidal dispersion gels are made up of low concentrations of polymer and aluminum citrate in water. These gels, which are mixed as a homogeneous solution at the surface, provide a valuable tool for in-depth blockage of high permeability regions of rock in heterogeneous reservoirs. Performance of colloidal dispersion gels depends strongly on the type and quality of polymer used. This paper provides an overview of the performance of 18 different polymers in colloidal dispersion gels. 14 of the polymers were partially hydrolyzed polyacrylamides or AMPS polymers in dry crystalline form with varying degrees of hydrolysis and molecular weight. The group also includes one cationic polyacrylamide, one carboxymethyl cellulose, one partially hydrolyzed polyacrylamide in emulsion form and one polysaccharide in dry form. Gels were mixed with the polymers at two polymer concentrations, three polymer:aluminum ratios and in different concentrations of potassium chloride. The gels were quantitatively tested at 1, 7, 14 and 28 days after crosslinking using the transition pressure test, which is a screen flow resistance test. Of the six polymer types tested, only the dry partially hydrolyzed polyacrylamides and AMPS polymers formed colloidal dispersion gels. Gel strength generally increased with increasing anionic charge and molecular weight; however, the manner in which the polymer is manufactured and the impurities present in the polymer also play roles which are more significant than originally expected.
Aspects of Oil and Gas Operations on Federal and Indian Lands of Interest to Engineers
Authors: Curtis Charles J.
Published: December 2007

It is always enjoyable to attend any meeting of the Society of Petroleum Engineers. I am happy to have this opportunity to speak to you because I believe that petroleum engineers can benefit from a better understanding of the Mineral Leasing Act and the regulations that implement the act insofar as these affect or influence your work. The regulations that implement the leasing act are commonly known as the Oil and Gas Operating Regulations. These regulations are officially described as Part 221 of Title 30 of the Code of Federal Regulations. They are printed in a small green booklet which most printed in a small green booklet which most of you have probably seen at one time or other. The requirements of the operating regulations, as specifically set forth in the booklet, or as determined by policy judgments in our various offices, can affect some aspects of your work.

I think it would be appropriate first to discuss the two types of lands, Federal lands and Indian lands, which are subject to the Oil and Gas Operating Regulations. Federal lands generally are classified in two categories, acquired land and public domain lands. Acquired lands are lands to which the Federal Government obtained title by purchase, exchange, condemnation, or private gift. These lands are scattered private gift. These lands are scattered throughout the United States and total about 54 million acres, or about 7.5 percent of the area classified as public percent of the area classified as public lands.

The public domain lands are lands to which the United States has held title since their original acquisition. There are public lands in 30 states, but the large bulk of the lands are located in Alaska and the Western States. You may recall from your history courses some of the purchases and treaties by which the United States obtained most of the lands now described as public domain lands. The Louisiana Purchase in 1803 included among the Western States most of Montana, eastern and central Wyoming, northeast Colorado, and the northern part of Texas. This treaty also included a large part of the area now generally referred to as The "Midwest". The annexation of Texas occurred in 1845 and it is somewhat surprising to realize that this included, among other lands, a strip of land through western Colorado and a rectangular shaped piece of land in Wyoming, south of Rawlins piece of land in Wyoming, south of Rawlins The acquisition of the Oregon Territory in 1846 brought into the Union parts of western Wyoming and Montana as well as what is now Idahos Oregon, and Washington.
Asphaltene Surface Activity at Oil/Water Interfaces
Authors: Sheu Eric Y. , Shields Michael B.
Published: December 2007

Small angle neutron scattering (SANS) dynamic surface tension (DST), dynamic interfacial tension (DIFT), and zero shear viscosity were used to study the surface activity of Ratawi asphaltenes in organic solvents, in the asphaltene/water/toluene emulsions and at the toluene/aqueous solution interfaces. In organic solvents, the kinetic process of micellization and the micellar structure are characterized. Their dependence on asphaltene concentration was investigated. The emulsion droplet structure and their capability in water uptake was tested. Also, the enhancement of surface activity of asphaltenes and its potential applications are briefly discussed.
Solubility and Phase Behaviour of Polyacrylate Scale Inhibitors and Their Implications for Precipitation Squeeze Treatment
Authors: Rabaioli M. R. , Lockhart T. P.
Published: December 2007

The phase behavior of a commercial phosphino-polyacrylate inhibitor (PPAA) in aqueous brine has been characterized as a function of temperature, pH, and the Ca++ and PPAA concentrations. The quantity of precipitate formed has been determined as a function of the same variables. Contrary to expectations, over a range of conditions the yield of phase-separated PPAA was found to be less than 50% and sometimes as low as 5%. Studies on a sample of isolated precipitate show that it has significant solubility even in brines with high Ca++ concentration. Ca++-induced fractionation of the polymeric inhibitor by molecular weight has been identified as the mechanism responsible for both the observed precipitation and re-dissolution behavior. The implications of these results for the optimization of precipitation squeeze treatments are discussed.
Graphical Determination of Oil Recovery in a Five-Spot Steamflood
Authors: Ali S.M. Farouq
Published: December 2007

Calculation of oil recovery by continuous steam injection is generally tedious, even if a computer program is used for this purpose. The present study is directed toward developing a graphical method of computation of oil recovery by continuous steam injection in a five spot pattern. Oil recovery from the steam-invaded zone as well as from the condensate zone ahead of the steam zone is considered in this treatment. Expansion of the steam zone and t temperature variation of density are employe compute the effective flood advance rate for the hot and cold waterflood zones ahead of the steam zone, in which Buckley-Leverett type displacement is assumed to occur. One of the basic parameters involved in the method is the parameters involved in the method is the steamflood sweep efficiency, which is based upon detailed theoretical and experimental investigations. Along with the detailed graphs, the basic equations used are also presented, in case it is desired to use the present method on a digital computer.

The end product of the computation technique presented is a curve of cumulative oil recovery presented is a curve of cumulative oil recovery vs. time. Curves of this type computed by the proposed technique are compared with experimental proposed technique are compared with experimental curves, as well as with values predicted by detailed methods, showing fair agreement.

Introduction

In recent years, steam injection has come to be recognized as an important oil recovery method. Most of the projects have so far utilized cyclic steam injection, which, in spite of its attractive feature of quick return, is basically a formation stimulation type operation marked with a low ultimate oil recovery of 6-15% of the oil in place. For this reason, increased interest is being shown in steamflooding, or continuous steam injection, with operational features similar to those for waterflooding, in order to enhance the ultimate oil recovery.

A member of methods have been proposed for the computation of oil recovery by a steamflood, the most notable being those due to Marx and Langenheim, Ramey, and Willman et al. Recently, Davies, Silberberg, and Caudle presented a method for predicting oil recovery from a five-spot steamflood, in which streamlines were approximated by straight lines radiating from the injection well, and converging to the production well. The present work develops a method production well. The present work develops a method for predicting the performance of a steamflood in a five-spot pattern, employing a combination of Marx and Langenheim's, Willman et al's, Ramey's, and Higgins and Leighton's techniques.
Static and Dynamic Adsorption of Phosphonate and Polymeric Scale Inhibitors Onto Reservoir Core From Laboratory Tests to Field Application
Authors: Jordan M. M. , Sorbie K. S. , Yuan M. D. , Taylor Kate , Hourston K. E. , Ramstad Kari , Griffin Paul
Published: December 2007

In this paper, results from static tests have been used to establish scale inhibitor adsorption mechanisms and levels in consolidated reservoir cores and to rank inhibitors for their adsorption behaviour and, in some cases, squeeze return lifetimes. The purpose of this rapid and simple type of bulk adsorption measurement is to assist in the selection of inhibitors for further coreflooding which should be carried out on a minimum number of inhibitors. A bulk adsorption sensitivity study can be carried out very rapidly compared with carefully carried out reservoir condition core floods. The value of such rapid screening tests is evident although we show that it is not always possible for all factors concerning squeeze lifetime to be determined in this way. It is still often necessary to carry out a much smaller number of reservoir condition core floods for a few (usually between 1 and 3) selected inhibitor products. This is necessary if the dynamic adsorption isotherm, T(C), is to be derived in order to develop the "Field Squeeze Strategy" or for the assessment of formation damage which might occur in the squeeze treatment. A field example of this is presented briefly in this paper although details can be found elsewhere.