bluuebunny/crossref_metadata_2025 huggingface dataset:
Alternate Acid Blends for HPHT Applications
Authors: Van Domelen Mary S. , Jennings Alfred R.
Published: December 2007

Protecting completion and production equipment is of utmost concern during acidizing. The higher the temperature, the more difficult it is to protect metal against corrosion, and the required inhibitor loadings increase with temperature, resulting in greater likelihood of formation damage. In addition, the protection times are reduced dramatically, which can potentially limit well stimulation treatments (for example, fluid volumes caused by pump time limitations). These problems become increas-ingly severe in formations with bottomhole temperatures greater than 250°F (120°C).

Even if adequate corrosion protection can be achieved during stimulation, post-treatment production of chlorides associated with the injected HCl-based acids remains a prob-lem. There is increasing concern when the wellbore contains high-alloy metals, such as stainless and duplex steels, which are susceptible to hydrogen embrittlement and chloride stress cracking. When combined with the possibility of erosion corrosion caused by high production rates, acidizing high- pressure, high-temperature (HPHT) wells poses risks.

A combination of organic acids (acetic and formic) can be used instead of hydrochloric acid (HC1) to minimize corrosion problems in high-temperature applications. The blends are designed so that the dissolving power is equivalent to HC1 with significantly reduced corrosion rates and the absence of Cl' ions. Some of the gelling agents developed for HC1 yield higher viscosities in organic acids on an equivalent polymer-loading basis. The end result is an organically based, high-temperature acid system that uses existing technology and is technically and economically more attractive than an HCl-based system.

The example application includes the use of an organic acid blend to effectively stimulate the 350°F (175°C) Arun limestone formation in Indonesia. A total of 17 large-scale acid fracs and a similar number of large matrix-acidizing treatments have been performed over the past 3 years. Rheology and corrosion data will be presented with the details of the treat-ment procedures and production responses.
Subsea Well Intervention from a Monohull Vessel
Authors: McGennis Eamonn
Published: December 2007

Subsea wireline well intervention has been performed from the Multi functional Support Vessel (MSV) Seawell since 1988. In a joint Coflexip Stena Offshore (CSO) and Cameo venture, an impressive track record in wireline work and abandonment has been created. Despite this, there is a growing need for developing the range of services to provide deep water well intervention and coiled tubing activities. This paper presents Coflexip Stena Offshore's current capability and experience and future strategy. This includes extending the range of the existing system for operations in water depths down to 3,300 ft (1,000m) and modifying it to allow for riser and coiled tubing compatibility.

The CSO Seawell is certified as an offshore installation capable of handling hydrocarbons at surface. Utilising a derrick structure, situated above a dedicated 22fl (7m) x 16 ft (5m) moonpool, well re-entry, wireline, pumping and abandonment tasks can be performed. Such tasks include gas lift logging, perforating, cementing and setting plugs. Observation Remote Operated Vehicles (ROV) are an integral part of every well senicing operation, and the vessel can be equipped with a work-class Multi Role Vehicle (MRV).

The first stage of developing Coflexip Stena Offshore's integrated subsea well intervention services is to extend the range of the existing system from 600 ft through to 3.300 ft Modifications required include a new umbilical, incorporating an MRV operated panel on the lubricator and upgrading the lubricator winch wire and the four guide wires. The existing MRV unit has been successfully utilised in deep water diverless pipelay operations and can be fully equipped for well servicing operations

Following the above modifications a coiled tubing and tie-back riser system will be developed. This new system will allow for a smooth subsea changeover from normal wireline to tie-back riser activities by incorporating a high angle connector on the lubricator, compatible with the tie-back riser and the lubricator stuffing box. Coiled tubing equipment will be efficiently located on the vessel by modifying the existing equipment and vessel handling systems This will include a purpose built injector head lifting frame to allow the injector assembly to be racked back into the derrick when not in use. A hydraulic control system will be required to power the coiled tubing equipment and will be a permanent feature on the vessel. Thus only an injector head and tubing reel would have to be mobilised for standard coiled tubing jobs, reducing time for overall mobilisation.

The development of this integrated service from a dynamically positioned monohull will place Coflexip Stena Offshore in a unique position to take up the challenges of deep water West of Shetland and world wide.
Coiled Tubing Stimulation Treatment in an Offshore Injection Well: A Case History
Authors: Boyle David , Bell Gavin J. , McGinn Paul
Published: December 2007

A coiled tubing stimulation treatment featuring a new high flash-point solvent was performed on an offshore injection well in the Ninian Field. This stimulation treatment was performed to remove hydrocarbon residue and deep clay damagestimulate low-permeability zonesincrease water injection rates in an offshore well

The target zone was treated with 587 bbl of sequential HF acid to prevent swelling of near-wellbore fines, solids, and clay. The application of sequential HF acid increased permeability 10-fold over standard HF acid treatments. An inflatable packer was placed between the upper zones and suspected weak tubing, confining the treatment to the target zones. The treatment successfully reduced the formation skin factor, which increased the injection rate by 100% (0.25 bbl/min to 0.5 bbl/ min) and reduced the surface pressure by 3%.
Managing Seismic Exploration in a Nearshore Environmentally Sensitive Area
Authors: Macduff-Duncan C. R. , Davies G.
Published: December 2007

Esso/Shell were awarded 4 exploration blocks in June 1993 in the North Irish Sea. This is an environmentally sensitive, nearshore area where several environmental groups were opposed to exploration taking place. The area is of ecological importance with a diverse wildlife and supports several hundred thousand migrating birds during the winter. Commercial fishing is also of importance to the local communities. An added complexity is that the area is adjacent to three separate authorities, eg. Scotland, England and the Isle of Man.

Our challenge and that of our contractors was to demonstrate that we could operate safely and in an environmentally sound fashion. A project manager was appointed to oversee all aspects of the Exploration programme.

An environmental review was carried out prior to licence award and an environmental assessment prior to the seismic operation. All environmental sensitivities, eg. birds, fish and sea mammals etc. were assessed and all potential sources of inputs/disturbances from the seismic operation were reviewed.

In order to understand local concerns and communicate our plans in an area not familiar with oil exploration an extensive communication programme was also undertaken.

The next step was to develop ways in which to mitigate the potential impact on the environment and local marine users. This was done by working with the local authorities, fishing and environmental groups and the seismic contractor to establish acceptable operating practices. Procedures were then incorporated into the seismic contractors plan. The key sensitivites in the area are commercial fishing, seabirds and the Ministry of Defence (MOD) who have a Gumnery Range in the area, Some examples of procedures adopted to protect these features were slow start-up of airguns, the use of an onboard bird/mammal observer, the use of local fisning iiaison skippers and local chaseboat, reduction of exhaust smoke emissions, distribution of survey area maps to key people, and a safety review of MOD range operations and procedures.

At the start of the survey a safety/environmental review meeting was held with the seismic crew on board the survey vessel to increase their knowledge of the area and gain their commitment to the operational procedures established.

The survey took 80 days to complete and finished without significant incident. The procedures put in place were practical, and cost effective and ultimately successful considering the pressures on operators in nearshore sensitive areas.
Drill Cuttings Disposal into a Producing Sandstone Formation
Authors: Wood G. L. , Hulbert G. , Cocking D.
Published: December 2007

Thirty thousand barrels of slurried drill cuttings waste, generated during the Wytch Farm Extended Reach Drilling programme, have been successfully injected into a producing sandstone formation as an environmentally acceptable means of disposal. Injection was through an existing water injection well into the producing formation because alternative shallow disposal horizons contain fresh water aquifers used to supply local drinking water. The disposal well continued to inject water in die periods between injection of the individual cuttings slurry batches, thus minimising the impact on the field management strategy.

Detailed monitoring data indicated that there was a significant increase in local formation stress at the injection well dining the operation, raising injection pressures, but that these had fully relaxed within five months of die end of the operation. Fracture growth was seen to be contained by die stress contrasts induced (thermoelastically) in the disposal formation by the long period of water injection prior to die cuttings injection operation. This provided confirmation that there had been no risk of contamination of die shallow fresh water aquifers by the slurry through vertical fracture growth.
Continuous Oil in Water Measurement
Authors: Frost M. , Huber E. E.
Published: December 2007

Oil in wastewater causes environmental problems. The official control method of its content is, at present, done by extraction and subsequent measurement via IR absorption. There has been an increasing interest in continuous measurements. The method discussed in this paper is fluorescence measurement. The molecules of many oil components are exited in the UV and yield fluorescent light in the VIS range. The "sum parameter" of fluorescence is neither identical with that of IR measurement nor that of the total oil mass. Thus, these data correlate only if the composition of the oil does not change drastically. That means in general that a calibration is good only for one specific oil and for the corresponding drilling site. A factory calibration is discussed and compared with the situation on site. It will be shown which measuring ranges are realistic for this method. An optical schematic of a dual beam fluorescence photometer for continuous oil measurements is introduced. This setup allows drift flee measurement and accounts for interferences of solids in a moderate concentration. A solution to prevent finding and the required steps are introduced.
Hudson - A Phased Field Development
Authors: Lane R. L. , Currie S. , Scott G. C. , Woods J. S.
Published: December 2007

This paper describes the two phase development of the Hudson field and the production performance in Phase I that was used to modify the development plan. The paper follows field development into the first months of Phase II and covers plans for future reservoir management.

Like many current and future Northern North Sea developments, the Hudson field is relatively small and within reach of existing infrastructure (figure 1). Limited appraisal data and the desire to limit up front capital expenditure (CAPEX) led to an innovative phased development concept with early cash flow from leased production facilities funding the later full field exploitation. Reservoir data gathered in Phase I would be used to optimise the Phase II expansion.

The highly successful Phase I development was from 2 wells producing to the Petrojarl I floating production storage and offtake vessel. There was no water injection. Results yielded information about aquifer connectivity, geological layering and well deliverability that have influenced several aspects of the development plan in addition to producing 17.5 mmstb of oil to fund the remainder of the project.
Real Time Stimulation Evaluation in Deepwater Well Completions
Authors: Morgenthaler Lee N. , Malochee Sharon B. , Smith Chris D.
Published: December 2007

Shell Offshore Inc.'s (SOI) Auger tension leg platform was installed in 2860 feet of water, 215 miles southwest of New Orleans. Nine producing wells were completed during 1994. These well completions presented many unique challenges which have been documented elsewhere.1,2 Paramount among these was the requirement that each well produce at high rates of at least 6000 BOPD in order to make the project economically viable. To yield the desired rates, efficient completions were essential.

Although the target completion intervals at Auger were very deep (>20,000 ft measured depth), the unconsolidated and uncemented nature of the turbidite sands made sand control necessary. In these deep, geopressured, long (>150 ft) interval completions, acid stimulation was used extensively. Because of the critical nature of these wells, industry's best practices and up-to-date technology were applied to ensure effective stimulation. With respect to acid stimulation, this meant application of Paccaloni's3,4 concepts for treatment design, coupled with real time monitoring of treating data. In this report, we will show how these processes combined to achieve our productivity objectives.

Paccaloni's design concepts were used here to scale treatment volumes, rates, and diversion strategies to anticipated well productivity. The design objective is to pump sufficient acid to remove near wellbore damage from the entire completion interval. Maintaining wellbore treating pressure as high as possible without fracturing maximizes acid injection into damaged zones. It is essential to avoid fracturing to maintain injection control. This can be accomplished by maintaining a high injection rate, increasing acid viscosity, or applying diverters. All three approaches were combined in the Auger designs.
Estimating Fracture Geometry in the Naturally Fractured Antrim Shale
Authors: Hopkins C. W. , Frantz J. H. , Hill D. G. , Zamora F.
Published: December 2007

The Antrim Shale of the Michigan Basin has been an active gas play with over 3,500 wells drilled over the last 5 years. There is substantial evidence that the Antrim must be fracture stimulated to be economical and that two-stage treatments provide the best results. However, due to the shallow depths (500-2300 ft) and naturally fractured nature of the Antrim, fracture geometry is complex, and determination of optimal fracture treatments is not straight forward. Because historical field comparisons did not provide insight on the optimal fracture treatments, the Gas Research Institute (GRI) instituted a field-based project for the specific purpose of evaluating the geometry of hydraulic fractures in the Antrim.

Open- and cased-hole tests were performed on two separate Antrim wells - a shallow producer (600 +/- ft) and a deep producer (1550 +\- ft). Open-hole testing and data collection consisted of in-situ stress and mechanical property testing with Halliburton’s THE™ Tool (9 tests) and a detailed suite of geophysical logs including dipole sonic logs and natural fracture detection logs. Cased-hole testing consisted of pre-and post-fracture injection/falloff tests, minifracture treatments, multiple isotope tracer and tracer logs, and treating pressure and production data analysis.

Analysis of open- and cased-hole data from the shallow and deep wells suggests that subvertical fractures are being created and are probably following existing natural fracture planes. The shallow depths, low in-situ stresses, and extremely fractured nature of the Antrim probably results in the preferential opening of existing fractures instead of the creation of new fracture planes. As a result, the creation of multiple fractures and severe near wellbore tortuosity is likely. Therefore, the natural fractures are responsible for increased leakoff and will greatly impact created fracture geometry. The results also suggest that creating long propped hydraulic fractures in the Antrim is not likely due to the creation of multiple fractures.
An MWD Downhole Assistant Driller
Authors: Hutchinson Mark , Dubinsky Vladimir , Henneuse Henry
Published: December 2007

Identification of drilling problems is most commonly achieved by simple comparisons of surface and downhole time-averaged measurements of weight and torque, or by shock and vibration sensors located either downhole or at the surface. Various drilling phenomena are more complex than can be described by these simple shock and vibration measurements. The interpretation of drilling vibration data collected at the surface requires specialized expertise, and can be difficult. Sometimes downhole phenomena are not interpretable at the surface. The diagnosis of bottom hole assembly (BHA) vibrations measured directly by a downhole tool is much easier.

A prototype downhole assistant driller measurement-while-drilling (MWD) device has been constructed that unambiguously diagnoses drilling phenomena from sensors that are located in the BHA, and that are sampled at a high frequency. Processing algorithms programmed into the prototype identify bit bounce, stick-slip, backward rotation, torque shocks, BHA whirl, pressure anomalies and excessive stress. Drilling efficiency and specific energy at the bit are also calculated. Average weight and torque values as well as drilling diagnostics are transmitted to the surface and enable the driller to make real-time improvements to the drilling process in a timely manner.

A key requirement for enhancing drilling performance is the ability to simply and clearly display information about the drilling process on the rig floor. The prototype display not only informs the driller about the severity of drilling phenomena, but also provides advice about how to eliminate particular drilling inefficiencies before they become problematic. The real-time drill floor display effectively completes the loop between the MWD prototype in the bottom hole assembly and the driller's controls. Additional displays and logs permit the post-drilling assessment of data from previously drilled intervals.

The downhole assistant driller helps optimize the rate of penetration, and reduce bit, motor, MWD and other BHA component failures. Downhole drilling parameters, together with quality conventional surface measurements, identify drilling problems and help drillers better decide when to make short wiper runs, or when to trip for a bit.

A method for closed-loop drilling operations is presented. This paper reviews the test program and draws conclusions from long term research with both downhole and surface drilling measurements. Actual field results demonstrate how downhole measurements provide a clearer feel for BHA behavior, and allow the driller to optimize the drilling process, reduce BHA component damage, and improve the efficiency of the drilling operation.
Improved Formation Evaluaton Using Azimuthal Porosity Data While Drilling
Authors: Evans M. , Best D. , Holenka J. , Kurkoski P. , Sloan W.
Published: December 2007

Measurement of formation porosity and lithology in azimuthal quadrants around the borehole is now available. This new information is provided by a nuclear tool that makes azimuthal density, photoelectric factor and neutron porosity measurements while drilling. In addition, an ultrasonic sensor provides a tool standoff measurement in each quadrant. While rotating, the quadrants are defined by a magnetometer and oriented with the gravity vector, so that bottom, left, right and top quadrants are identified.

The tool can be run with several different stabilizer sizes or without a stabilizer, giving the driller more latitude in configuring the bottomhole assembly. The azimuthal capability allows the measurement of porosity with an unstabilized or "slick" tool without degradation of the measurement. This is accomplished by computing the porosity from the bottom quadrant where there is little tool standoff in deviated or horizontal wells. Utilizing bottom quadrant porosities also results in improved measurement accuracy in cases where borehole conditions are poor due to enlargement or washouts.

When the tool is stabilized, the quadrant porosity and lithology measurements result in improved geosteering as well as providing a quantitative measure of formation heterogeneity. At bed boundaries, comparison of top and bottom logs in real time results in better bed boundary detection and confirmation of the tool location within the pay zone, When the tool is between boundaries, an heterogeneity indicator can be computed from the quadrant density, lithology and neutron porosity logs to better evaluate complex formations.

The measurement of tool standoff per quadrant provides information on borehole size, shape and rugosity. The data can be used to indicate borehole stability on subsequent bit trips.

The paper describes the method of the measurement, hardware implementation and log examples illustrating the tool features.
A New Simplified Approach of Controlling Properties Of Invert Emulsion Drilling Fluids at the Well Site
Authors: Sinha B.K.
Published: December 2007

This paper points out some of the limitations of the present day testing procedures commonly in use and procedures commonly in use and describes a method used to obtain more meaningful data to control the properties of a fluid at a desired properties of a fluid at a desired optimum level with conventional equipment.

The retort unit which measures the volumetric percentages of oil, water and solids in a mud has been found to be most useful. Experimental data obtained using this equipment fall within the experimental error range of the calculated volumetric percentages of oil, water and solids percentages of oil, water and solids for muds of different densities.

As the oil-water ratio of an invert emulsion drilling fluid is increased, the density of the liquid phase (oil and water) decreases. The volume percent solid contribution from the percent solid contribution from the dissolved salt (NaCl) in the water phase to the total retorted solids phase to the total retorted solids percentage of the system also decreases. percentage of the system also decreases. Therefore, to maintain a constant mud density, additional amounts of barite are needed as the oil-water ratio is increased. Any change in the volume percent of salt caused by an alteration percent of salt caused by an alteration of the oil-water ratio is approximately balanced by a corresponding change in the volume percent of barite.

Thus, a linear relationship between the volume percent solids and mud density is obtained which is practically independent of the amount practically independent of the amount of oil and water in the system. Representation of the above relationship in a graphical form has been proven to be of valuable assistance in controlling the properties of invert emulsion drilling fluid at the well site.

It has been observed both in the laboratory and in the field that by maintaining the percentages of oil, water and solids within a specified range, all the measured properties (rheological, fluid loss and electrical stability) fall automatically within the desired range when measured under identical conditions.
Moxa Arch Frontier Development Success Through Increased Fracture Conductivity – Part 2
Authors: Schubarth S. K. , Chabaud R. A. , Penny G. S.
Published: December 2007

Successful development of the Frontier formation in southwest Wyoming begins with the hydraulic fracture treatment design and implementation. Without a design to effectively stimulate the Frontier formation and a proper implementation of that design in the field, production rates will be limited. This paper will describe the results from an extensive drilling and completion program conducted by Bannon Energy Incorporated in the Frontier formation on the Moxa Arch.

Information from over 100 fracture treatments and the production response from over 550 wells will be used to demonstrate the significant improvement in gas production resulting from the fracture treatment designs and implementation methods employed. The effect of fracture conductivity on gas recovery from this formation will be demonstrated along with the effect of multi-phase flow on fracture conductivity.
Cybernetics, A New Method Proposed For Estimating Performance Of Water Driven Reservoirs
Authors: Caseli Umberto Antonio , Crawford Paul B.
Published: December 2007

Cybernetics has been under development for almost 50 years but only during the past 20 years has it evolved into a scientific approach to aid in the analysis of systems existing in the so-called "black box". Petroleum reservoirs are always in the black Petroleum reservoirs are always in the black box category in that the precise reservoir shape, rock and fluid physical properties are never really known even though the reservoir is produced to abandonment.

Cybernetics has been applied to a water-drive reservoir near abandonment conditions. The cybernetic method was found to forecast the performance of this reservoir quite accurately when only a small fraction of the fluid had been produced. Cybernetics does not require detailed information such as rock porosity, permeability, areas, thickness, fluid porosity, permeability, areas, thickness, fluid compressibilities, etc., desired for the conventional influx calculation.

Introduction

In the past 30 years the science of petroleum reservoir engineering has emerged petroleum reservoir engineering has emerged as a well-defined and highly technical branch of petroleum engineering. Extensive investments in facilities and personnel for the recovery of oil and gas are now made routinely on the basis of reservoir performances predicted by reservoir engineering studies. Reservoir engineers and research investigators are pioneering and developing new techniques for pioneering and developing new techniques for improving recovery of oil and gas. Greater accuracy in reservoir performance calculations will bring the industry closer to the ultimate goal of obtaining the maximum efficiency in the exploitation of petroleum reservoirs.

The van Everdingen and Hurst technique of estimating performance of water-drive reservoirs based on compressible flow theory has been presented in the literature as the most generally successful. However, their method applies to radial reservoirs surrounded by infinite or radial aquifers of constant rock and fluid properties. k complete knowledge of the properties of the reservoir and aquifer is desired for applying the technique. The method also requires knowledge of the pressures at the boundary of the reservoir and quifer. Average reservoir pressures are usually used when the boundary pressures are not known.

In practice, besides incomplete knowledge of reservoir properties, there is uncertainty in the aquifer properties, which are generally estimated from wells drilled in the reservoir. On the other hand, there exists uncertainty in the reservoir pressure history. Thus, all of these factors combined contribute to make the van Everdingen and Hurst technique of limited value in many practical cases.
Directional Drilling and Circular Arc Deflection Of Long Beams
Authors: Dareing D.W. , Godhwani Shyam
Published: December 2007

This paper is concerned with the mathematical development and solution of a nonlinear differential equation of bending which relates to the directional drilling of oil and gas wells. The directional drilling concept in this paper is unique and is based on the premise that a directional wellbore having constant curvature will be drilled if the deflection of the bottom portion of the pipe [or drillstring] has portion of the pipe [or drillstring] has constant curvature; the constant curvature or circular arc deflection is due primarily to gravity. To achieve a circular arc pipe deflection due primarily to gravity, pipe diameter must vary along the pipe according to the solution to the differential equation of bending; pipe diameter is the dependent parameter in the pipe diameter is the dependent parameter in the differential equation. The broader purpose of the research is to develop directional drilling technology which relates the many drilling variables, such as bit weight, drilling fluid, and drill collar design, to wellbore geometry.

Introduction

It is sometimes desirable, when drilling for oil, to drill away from the vertical so that the bottom end of the well is at some appreciable horizontal distance away from the vertical. Wells of this geometry are called "directional" wells and are sometimes drilled from offshore platforms to reduce the number of offshore structures in a particular oil field. particular oil field. At the present, directional wells are drilled somewhat by the trial-and-error method, i.e., measurements of drill bit orientation are made periodically and appropriate changes are made in weight on the drill bit to increase or decrease the orientation of the bit. Stabilizers are also used near the bit to control the rate of hole deviation from the vertical.

There are several articles in the literature which discuss directional drilling [and hole deviation, crooked holes, dog-legs, etc.]; however, except for very few technical papers most of the publications are general discussions of the directional drilling problem. A literature survey indicated there are very few, if any, technical publications which relate drilling variables to wellbore curvature. This report represents an attempt to develop a directional drilling technology which relates drilling variables to wellbore curvature.

The directional drilling concept discussed in this report is based on the premise that a wellbore having constant curvature will be drilled if the deflection of the drill pipe directly above the bit is always circular. The circular arc deflection is developed in the section of pipe directly above the bit by using nonuniform pipe whose diameter [or cross-sectional moment of inertia] varies over its length according to the theory presented in this paper.
Behavior of Anisotropic Rocks under Combined Stresses
Authors: Yang J.H. , Gray K.E.
Published: December 2007

Torsional strength tests on slate and Green River shale were performed at various orientations of the cleavage or bedding planes and at various states of stress to study the strength-deformation behavior of anisotropic rocks. The strength characteristics of the rocks, as a function of both the state of stress and the orientation of anisotropy, were determined by twisting cylindrical specimens at a constant rate of 0.1 radian/min. under confining pressures of 5,000 to 30,000 psi, with pore pressure held constant at atmospheric pressure, and under axial loads of 0 to 10,000 pressure, and under axial loads of 0 to 10,000 psi. Samples having an orientation of the plane psi. Samples having an orientation of the plane of anisotropy relative to the cylindrical axis of 0, 30, 45, 60 and 90 degrees were used.

In general, torsional failure strength of the rocks studied increased with mean pressure; the strength was a function of the initial state of stress and the orientation of the plane of anisotropy. Several failure criteria for anisotropic rocks were discussed and compared with experimental data. It was found that current failure criteria could be applied with some degree of success to experimentally generated data.

The orientation of the maximum and minimum torsional strength for both rocks were found to be independent of the initial stress state studies. The failure angle was affected by anisotropy for cleavage or bedding plane over a limited range of orientations. The failure angle was also affected by the initial state of stress. The average modulus of rigidity increased with increasing confining pressure and decreased with axial compressive load. The cohesive strength and the coefficient of internal friction varied with the orientation, and the specific variance was a function of the type of anisotropy.

Introduction

The fundamental problem of rock mechanics in drilling is to determine the state of stress necessary to cause failure. Unfortunately, the failure mechanisms and strength characteristics of rock are not constant. They depend upon rock type, pressure, temperature, strain rate, foliation, type of loading and presence of pore fluid. Therefore, a better understanding of the aspects which govern rock failure may contribute to the solution of drilling and fracturing problems.

Early works by von Karmon and Boker [cf. Nadai], Robertson, Griggs, Handin, Heard, Robinson and Serdengecti have provided considerable information about the effects of temperature, rate of loading and confining and pore pressures on the mechanical behavior of rocks. Inhomogeneity and anisotropy are inherent in the process of sedimentation.
Notes On Gas Well Performance
Authors: Miller B.J.
Published: December 2007

THIS IS AN ACADEMIC PAPER WITH THE PURPOSE OF ILLUSTRATING THE EFFECT ON GAS WELL PERFORMANCE OF CHANGES IN VISCOSITY AND GAS DEVIATION FACTOR WITH PRESSURE DEPLETION, OF COOLING OF THE FLOWING GAS AS THE PRESSURE IS REDUCED AT THE WELL BORE, AND OF "TURBULENCE" OCCURRING IN THE LARGER PASSAGES AS GAS FLOWS TOWARD THE WELL BORE. EACH OF THESE THREE EFFECTS PASSAGES AS GAS FLOWS TOWARD THE WELL BORE. EACH OF THESE THREE EFFECTS IS DESCRIBED INDEPENDENTLY OF THE REMAINING TWO USING SELECTED EXAMPLE WELLS. THE BASIC EQUATION FOR THE FLOW OF GAS THROUGH A POROUS MEDIA IS QUOTED FROM THE LITERATURE WITH THE HOPE THAT WORKING FROM THIS BASIS WE MAY BETTER UNDERSTAND GAS WELL PERFORMANCE. THE EQUATION IN GENERAL USE TODAY IS AS APT AS THE TERM "BACK-PRESSURE". A FURTHER NEED IN PETROLEUM TECHNOLOGY IS A WORD OR WORDS BETTER DESCRIBING WHAT IS CALLED HERE TURBULENCE IN POROUS MEDIA.

IN AN ACADEMIC PAPER OF THIS TYPE CONCLUSIONS ARE NATURALLY LIMITED TO A PLEA TO STUDY THE PERFORMANCE OF ACTUAL GAS WELLS TO DETERMINE THE EFFECT OR LACK OF EFFECT OF THE COMPONENTS DESCRIBED HERE. THE JUSTIFICATION FOR SUCH A STUDY IS THE NEED FOR A MORE ACCURATE METHOD FOR PREDICTION OF DELIVERABILITY OF INDIVIDUAL GAS WELLS DURING THE IMPENDING GAS SHORTAGE.
Optimizing High Temperature Steam Stimulation Operations
Authors: Angove T.J.
Published: December 2007

Continental Oil Company began cyclic steaming operations in Cat Canyon Field, Santa Barbara County, California in 1965. Since that time, Conoco has encountered some unusual problems resulting from the high temperatures and pressures required to steam wells up to 4300 feet in depth.

Several different techniques have been tried in order to eliminate casing failures and reduce operating costs to a point where steaming is economical. These experiments have resulted in the adoption of a standardized completion procedure for new wells; several techniques for steaming older wells with conventional completions; and methods for scheduling and selecting the best wells to be steamed, including the amount of steam to be injected into each well. The success of these procedures is illustrated by the increasing production and lower per barrel operating cost.

This discussion will involve examples of the different methods employed to make steam stimulation a profitable venture as well as reasons for the success or failure of each method.

Introduction

In 1965 Continental Oil Company began cyclic steam injection operations in the Cat Canyon Field in Santa Barbara County, California. Prior to steaming, Conoco was producing approximately 1000 BOPD from 36 wells. The economics at that time were very poor. The original steam stimulation program utilized one steam poor. The original steam stimulation program utilized one steam generator and has since been expanded to include four steam generators. Early results were somewhat discouraging because of casing failures caused by the high temperatures required to obtain high quality steam. Through improved casing protection techniques, these problems have been reduced to a point where cyclic steam operations have become profitable. In June, 1970, Conoco produced over 120,000 barrels of oil from the 76 wells in the Sisquoc reservoir which is under the influence of cyclic steam injection. Approximately 60,000 barrels of this total is attributable to steam stimulation. The average sale price of the crude was $1.58 per barrel. Operating costs have been reduced by over 25% and are well below a dollar per gross barrel of oil produced.

Continental holds five leases in which the Sisquoc reservoir produces in the Cat Canyon Field. produces in the Cat Canyon Field.
Project Rulison: A Status Report
Authors: Reynolds Miles , Bray Bruce G. , Mann Robert L.
Published: December 2007

Project Rulison was designed to use underground nuclear technology to determine the potential of this technique for commercial development of the deep, thick, lenticular, low permeability Mesaverde Formation of the Rulison Field in Garfield County, Colorado. A method of stimulation, far greater in magnitude and efficiency than conventional hydraulic fracturing, is needed to recover this gas at economic rates.

The Project Rulison exploratory well, R-EX, was completed in May, 1968. Detailed testing of this well provided data on geology, hydrology and reservoir characteristics. The data obtained from the testing have been used to determine the flow capacity of the Mesaverde reservoir. The reservoir characteristics were then used as input data to make predictions of post-shot reservoir performance in the nuclear stimulated well.

A nuclear explosive with a design yield of 40 kilotons was emplaced in a 10-3/4" hole at a depth of 8426' below ground surface and detonated on September 10, 1969. Appraisal of the data taken at shot time indicate that the explosive behaved as predicted. The explosion was completely contained underground as predicted and no major seismic damage occurred.

The post-shot drilling program, to re-enter the chimney, and test program, to determine the degree of reservoir stimulation achieved, are discussed. Data taken during the initial phases of the post-shot re-entry and evaluation phase will be given.
A Corporate Outlook Toward Our Environment
Authors: Granberry R.C.
Published: December 2007

Although the current problems involving pollution of the environment result primarily pollution of the environment result primarily from the demands and activities of an expanding population, industry — and particularly the population, industry — and particularly the petroleum industry — has expressed a disproportionate petroleum industry — has expressed a disproportionate share of pollution concern. The petroleum industry, aware that the products and materials handled by it and its customers can contribute to pollution, has long practiced environmental conservation while meeting the energy needs of the nation. Increasing public disfavor stemming from widely publicized incidents demands, however, that the industry should adopt objectives and appropriate even more capital to further improve environmental conservation performance.

Introduction

I am sure that this group is primarily concerned with our environment from the standpoint of the producing segment of the oil industry and in the corporate attitude toward the specific problems which that particular segment of our industry creates. In order to discuss these problems in the proper perspective, however, I think it important that we first review the history of 'pollution' from its first beginnings to its present status.

Contamination of the air and water dates from the beginning of life on earth. Volcanic eruptions, dust storms, forest fires, and pollen from plants poured contaminants into pollen from plants poured contaminants into the air; run off from rains and melting snow washed silt into the rivers; and man contributed his part by dumping trash and wastes into the streams, and in building fires which produced smoke and soot. The Industrial produced smoke and soot. The Industrial Revolution accelerated man's contamination of the earth, and as technology advanced more machines and factories began emitting contaminants. Thus, while industrialization was raising man's standard of living, it was simultaneously lowering the quality of his most vital resources of air and water.

Today, just as in the past, both men and machines contribute to the problem. Increased contamination of our air and water with its undesirable and even dangerous side effects stems directly from the ever widening activities of more and more people. Industry is not the main source of pollution.
A New Blowout Control Technique
Authors: Rowley Kermit G.
Published: December 2007

Wells blowing out of control have long been a scourge to the oil industry. As more and more emphasis began being placed on pollution control, it became evident that a pollution control, it became evident that a better method of controlling "blow-outs", particularly in offshore areas, should be devised. particularly in offshore areas, should be devised. It was imparative that this method minimize pollution. pollution. This paper discusses such a method as devised by Tenneco Oil Company. Steps employed are as follows for offshore wells:

Holes are cut below the water line in the succeeding casing strings to expose the tubing. The tubing is "hot-tapped" and a crimp is applied to the tubing at a distance above the hot-tap hole. Lost circulation material is introduced through the hot-tap hole and is carried up to the crimped area by the escaping well fluids. This lost circulation material forms an impermeable plug and the well then is killed by pumping through the hot-tap hole.

Advantages of this method are:

The well effluent can be allowed to burn until the well is under control, thus preventing surface pollution. preventing surface pollution. All work is performed underwater where there is little danger of fire or explosion. Control of the well should be faster because there is no need to remove surface debris prior to initiating the control method. A smaller and less expensive work force should be required.
Microbiological Aspects Of Oil Pollution
Authors: Traxler Richard W.
Published: December 2007

Observations from the Torrey Canyon episode indicate that seawater-oil emulsions are formed which make it difficult to estimate oil loss by evaporation. The oil itself had little injurious biological effect. The major biological damage was caused by detergent treatment. The biological damage was primarily on the shoreline and in the sublittorial zone. These findings were confirmed in the case of the Arrow accident on the Novia Scotia coast in 1970. There is evidence that natural microbial population are active in the degradation of spilled petroleum. The feasibility of using bacterial systems for cleanup is discussed, and a brief discussion is presented on the effect of pollution in the ocean. Preliminary studies in Alaska and Louisiana Preliminary studies in Alaska and Louisiana indicate that bacteria normally found in the ocean are capable of petroleum degradation even at low temperatures.

Text

Today there is considerable discussion on the topic of the environment and the pollution of it by human forces. This is not a new topic for discussion since man has always been a polluter of his environment. In the late 13th polluter of his environment. In the late 13th century, Florence, Italy, had a vigorous enterprise consisting of wool and grain merchants and moneylenders, all of this bringing the city immense riches and a bustling economy. The city had schools, paved streets, well-run hospitals and ordinances against unsanitary butchering and against smoke nuisance from burning coal. These may have been among the first pollution ordinances enacted to protect the environment. The scientific, as well as the lay communities, have become polarized on this issue in 1970. There are those who spell the doom of mankind at the one pole, and at the other pole those who claim the whole business of environment and pollution is just a fad that it is hoped will pollution is just a fad that it is hoped will soon pass away. As with any polarized situation there is a middle which separates the two extremes.

The subject of marine pollution was brought to the attention of the general public early in 1967, when the Torrey Canyon was grounded off the English coast, with the release of 117,000 tons of crude oil. Since 1967, this episode is usually referred to as the "Torrey Canyon disaster". A rather complete account is available in the report of the Plymouth Laboratory of the Marine Biological Asso. of the United Kingdom.

Some of the findings from this episode were that the formation of emulsions with seawater made it difficult to predict the rate of oil loss by evaporation, but that the drift of the oil could be easily predicted. The oil in the open water was found to have little biological effect except for the destruction of sea birds.
Threshold Displacement Pressure - Considerations for Caprocks of Abnormal Pressure Reservoirs
Authors: Katz Donald L. , Ibrahim Maher A.
Published: December 2007

Threshold displacement pressures were measured for shale caprocks of underground gas storage reservoirs and found to be as high as 2,000 psi or more. These measurements were under approximate simulated reservoir conditions. As a result, some new considerations have been set forth as to the possible mechanisms of sealing of abnormal or geo-pressured reservoirs.

The presence of abnormal pressure reservoirs, information gathered while drilling them and some physical properties of rocks under abnormal pressures were reviewed to shed light on these new considerations. Field examples of abnormal pressure reservoirs in the Gulf Coast were analyzed.

A new concept based on the surface phenomena in shales has been developed phenomena in shales has been developed explaining the retention of hydrocarbon fluids below caprock of abnormal pressure reservoirs. The process of compaction, its rate and the decrease of permeability under effect of overburden pressure have been suggested as some of the controlling factors leading to the present capillary sealing of abnormal pressure present capillary sealing of abnormal pressure reservoirs.

Introduction

Before the inception of American Gas Asso. research project PR26-47 on threshold displacement pressure in gas storage, consideration had been pressure in gas storage, consideration had been given to Gulf Coast reservoirs with geo-pressures of as much as 0.8 lb/ft of depth. The caprocks to these reservoirs must have a severe pressure gradient in them similar to the pressure gradient in caprocks submitted to high threshold displacement pressure tests. It was known that these values could be as high as 2,000 psi or more and that study of these abnormal pressure reservoirs in the Gulf Coast might shed some light on the threshold pressure displacement phenomenon. The question may be raised as to what extent this naturally occurring high pressure reservoir can be used to verify that high threshold displacement pressure can be expected for high quality pressure can be expected for high quality caprocks. In looking into the matter, some new considerations are set forth as to the possible mechanism for the abnormal pressure reservoir and its overlying caprock of reaching its present state. There appears to be no doubt present state. There appears to be no doubt that surface phenomena are involved in the forces which retain the hydrocarbon fluids below the caprock; these forces are the same as those which retain natural gas in underground storage reservoirs with positive delta pressures.