bluuebunny/crossref_metadata_2025 huggingface dataset:
Reservoir Monitoring and Wireline Logging in Subsea Wells
Authors: Lilley I. J. , Douglas A. A. , Muir K. R. , Robinson E.
Published: December 2007

In an effort to minimize capital investment in platform installations there is an increasing trend towards drilling subsea satellite wells, with production tied back to an existing platform. A disadvantage with this type of well is that regular access for maintenance and reservoir monitoring is denied by the high cost of conventional techniques.

This paper, which discusses some new techniques for economic monitoring and maintenance of subsea wells, is divided into two sections.

The first section describes the installation and use of permanent gauges run with the completion in subsea wells. Methods of mounting the pressure gauge in the completion string and transmission of the data to surface are discussed. A field case is reviewed which highlights some of the advantages of continuous reservoir monitoring.

The second section of the paper describes a newly-developed technique for wireline logging in wells completed subsea. The method involves a specially designed lubricator and pressure-control system which can be deployed from a dynamically positioned support vessel. The discussion is focused on the practical aspects of the technique, as well as giving an overview of the types of operations that can be performed.
Maximization of Water Sweep Efficiency by Controlling Production and Injection Rates
Authors: Asheim H.
Published: December 2007

A method for computation of the best production scheme has been developed. It consists of a two dimensional, two phase reservoir simulator, search direction computation by implicit differentiation and a numerical search program. Applied to hypothetical cases of production by water drive, NPV improvements of 2-11% were achieved.
Hydrogen Stress Corrosion Cracking of High-Strength Steel in Lignosulfonate Mud
Authors: Oberndorfer M.
Published: December 2007

The resistance of high strength steels against stress corrosion cracking in lignosulfonate muds is described in this report. Soluble sulfides contained in LS muds may cause damage under certain circumstances. A failure case in a 7" casing of V 150 quality is reported. Failure analysis demonstrated a typical intercrystalline crack. Basic experiments with tensile samples in LS muds showed the conditions which can lead to a failure. Finally, the results are compared to literature experience in proposed guidelines for the use of high strength materials.
Hydraulic Optimization of PDC Bits by Visualization Methods
Authors: Bisson P. , Choux J. C. , Provo A.
Published: December 2007

The number of ways in which cutters are distributed, and the number of shapes of Polycristalline Diamond Compact (P.D.C.) bits are increasing every day. These bits can be fitted with either nozzles or crowfoot fluid outlets. The fluid will spread around the bit in a more or less complex manner depending on these outlets and on the geometry of the annulus encountered. This fluid distribution will have an influence on the efficiency with which the cuttings are evacuated and on the cooling action on the cutters, i.e. the capability to drill faster and for longer.

The methods by which flow structures can be determined, are high-performance numerical methods and visualization experiments.

This paper describes a testing sequence for flow visualization, which has been developed in the laboratory, plus the necessary equipment.

These tests reveal the hydraulic structures, and those most frequently encountered will be described.

A concrete example showing the application of our studies will be given: the case of bit profile improvement used by one of our subsidiaries on an oil field under development.

The limitations of our experiments, allowing for the tests run and the equipment available, will be discussed, as well as future lines of research.
Experimental Measurement and Modeling of Gas Solubility in Invert Emulsion Drilling Fluids Explains Surface Observations During Kicks
Authors: Swanson B. W. , Gilvary B. , McEwan F.
Published: December 2007

The solubility of methane in an invert emulsion drilling fluid has been measured up to 15000 psi [103.42 MPa] and 350F [177 C]. Resulting data describing the effects of temperature and pressure on mixture density and phase behaviour havebeen incorporated into a computer model to determine wellbore responses at surface and downhole. The model contains algorithms to model the transport of dissolved gas by dispersionand free gas by bubble rise in addition to models for fluid flow. The model is capable of simulating both controlled anduncontrolled kicks in invert emulsion drilling fluids. Gas behaviour in water based drilling fluids can also be evaluated. Surface responses including pit gain, annular flowrate and choke pressures have been simulated.

It has previously been suggested that gas kicks in deep high pressure wells and oil based drilling fluids are more hazardous than in water-based fluids because of the solubilityof hydrocarbon gas in the oil phase of the mud; the gas in solution producing only a fraction of the expected pit gain at surface. However, results from the current model indicate that when a kick is taken in a deep high pressure well the observations of pit gain at surface can be similar for both oil- and water-based muds.
The Role of Downhole Flow and Pressure Measurements in Reservoir Testing
Authors: Joseph J. , Ehlig-Economides C. A. , Kuchuk F.
Published: December 2007

In practice, a reservoir test that is successfully executed according to a specified pragmatic design will provide interpretable results satisfying the test objectives. Usually, there isanoptimal test design among several options which will minimize the cost of the test, without jeopardizing the likelihood that useful interpretations will ensue. Consequently, as numerous testing configurations have been introduced, it has become necessary to develop interpretation procedures which are as straightforward as the conventional techniques while offering a more reliable or refined answer. The use of downhole flow and pressure measurements, or even downhole shut-in devices, are cases in point. With proper design, execution and interpretation, tests which employ these configurations can provide reservoir properties that could be much more difficult to obtain by other means.

One objective of this paper is to present a methodologyfor reservoir test interpretation. This defines the hierarchy and sequence for employment of all analysis techniques, and is intended to be general enough in concept to accomodate any type of test. Field examples are used to illustrate the merits of specific acquisition procedures, and also how the methodology can aid in achieving the test objectives with consistent and coherent analyses.
A Case Study of Casing Failure and Damage Under Artificial Lift Conditions in the Montrose Field
Authors: Andrews I. J.
Published: December 2007

This paper reviews the extensive logging programme carried out since February 1987 in the producing wells of the Montrose Field to identify casing damage. The evaluation of the 9-5/8" (0.244m) casing was required because of several recent cases of casing collapse while electrical submersible pumps were operating.

This was accomplished by running electromagnetic, sonic and mechanical caliper logs to establish casing dimensions. From the results gained, three main problem areas were identified. The first was eccentric tubing/drillpipe wear, the second, general corrosion and "rogue" light weight joints of casing and finally the 9-5/8" (0.244m) casing was found to have buckled in several wells.

Collapse was therefore caused by a combination of large differential pressures imposed by the ESP's which utilize a high set packer for venting gas, underweight casing and casing damage/wear caused by drillpipe.

Analysis of the logs allowed areas of potential collapse to be identified by determining the approximate reduction in casing collapse pressures. Collapse was then averted by extending 7" (0.178m) liner over the danger area, or by changing the operating conditions.
Sound Speed Of Natural Gas
Authors: Savidge Jeffrey L. , Starling Kenneth E. , Mcfall Richard L.
Published: December 2007

We present a highly accurate correlation for ideal gas properties and a vapor phase equation of state for natural gas and related mixtures. The equations are used to compute sound speed. Results from the new methods are compared to recent sound speed measurements on pure methane and simulated natural gas mixtures. The uncertainty in the calculated values is approximately one-tenth of one percent for natural gas pipeline conditions.
Some New Mathematical Approaches for Heterogeneous Porous Medium Flow Studies
Authors: Dupuy Michel P.
Published: December 2007

American Institute of Mining, Metallurgical and Petroleum Engineers, Inc.

This paper was prepared for the 42nd Annual Fall Meeting of the Society of Petroleum Engineers of AIME, to be held in Houston, Tex., Oct. 1–4, 1967. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor of the appropriate journal provided agreement to give proper credit is made.

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

Heterogeneity of permeability in natural porous media may, in a number of cases, be described by a stationary statistical model, defined by a Permeability Autocorrelation Function (P.A.F.).

Heterogeneity effects in monophasic flow are two fold:

– a smoothing, or 'variance reductions', effect – a 'permeability averaging', or'permeability composition' effect.

If the flow field dimensions are considerably greater than the scaling parameter of the P.A.F., the porous medium appears as 'macroscopically homogeneous', and the latter effect only is to be noted.

Using a perturbation method referred to the homogeneous medium, Schwydler has analytically treated two standard flow problems and worked out illustrative examples, assuming a typical P.A.F.

Matheron has generalized the formulation and treated the permeability composition problem in two and three spatial dimensions. Conditions of validity of the geometrical averaging rule have thus been defined.

This descriptive heterogeneity model should prove valuable …

as a guide to organize flow studies by numerical simulation on computers; as a reference model in reservoir geology, for collecting and interpreting data on actual gas or oil fields.

Introduction

Permeability heterogeneity is a dominating factor for any flow phenomenon taking place in porous media.

There are, for reservoir engineering, various scales of interest (1), starting from the scale of actual oil reservoirs, and, considering, at an intermediate scale, the geological units (2) which are the basis elements of actual reservoirs.

The problem of taking account of heterogeneity for numerical prevision of flow is very difficult. A reasonable method towards solution can be stated as follows

to concentrate on the study at some given scale; at this scale, to formulate numerically the heterogeneity of the porous medium in terms of some given statistical model; to solve, on this model, the principal flow problems of interest.
A Generalized Finite Volume Discretization Method for Reservoir Simulation
Authors: Rozon Brad J.
Published: December 2007

A control volume approach to the discretization of the single-phase reservoir flow equation is presented. The finite volume formulation offers an advantage to classical Galerkin or variational finite element methods in that it permits a direct, physical interpretation of the resulting discrete equations through the enforcement of conservation principles over finite volumes or sub-domains. The scheme presented includes the conventional 5-point discrete equation obtained by conventional finite difference methods as a special case, while maintaining the generality and modelling flexibility associated with finite element methods. The finite volume discretization method provides a perspective from which finite element and conservative finite difference concepts can be implemented in a unified approach. The discrete finite volume equations for single phase reservoir flow are derived in detail and compared to those obtained using a Galerkin finite element approach. A single phase numerical example is included to illustrate the geometric flexibility of the finite volume method.
Simulation of Viscous Fingering by the Pseudospectral Matrix Element Method
Authors: Ku Hwar-Ching , Hirsh R. S. , Taylor T. D.
Published: December 2007

A pseudospectral matrix element (PSME) method which extended the formulation of the pseudospectral matrix (PSM) method to a multi-element scheme, has been applied by the authors to the studies of miscible displacement of fluids in porous media. The resulting pressure Poisson equation which satisfies the differential mass conservation (incompressible flow) is a non-separable self-adjoint operator with Neumann boundary contions in each direction. A separable preconditioner which is constructed from the original operator, in conjuction with the conjugate residual method, provides an efficient iteration scheme to the solution of pressure field. At the high mobility ratio (M = 100), an adaptive method following the idea of minimizing a functional is adopted to resolve the steep fingered front. In the diagonal five-spot model problem, a domain decomposition with the Schwarz Alternating Procedure (SAP) is used to iteratively solve two quarter concentric circles with overlapping area.

The phenomea of fingers’ growing and shielding can be observed in a horizontal slab when a small disturbance in the permeability is subject to the unfavorable mobility ratio (M = 10, 100) between oil and solvent, while in a five-spot reservoir simulation visous fingering still exists even without any permeability perturbation under the mobility ratio M = 10.
The Effects of CO2 Flooding on Reservoir Mineral Properties
Authors: Wolcott J. M. , Monger T. G. , Sassen R. , Chinn E. W.
Published: December 2007

Interactions between CO2 induced organic deposits and mineral matrices were examined. The influence of mineralogy on extent as well as site of deposition, and the effects of organic deposition on mineral properties were determined. In addition, CO2-induced precipitate composition was related to parent-oil composition and geochemical history.

Cores exposed to oil/CO2 flooding were contrasted with cores flooded with oil or CO2 alone. The effects of two different oils were compared as well as the influence of two different minerals, Berea and a carbonate. All cores contained residual brine. Changes due to the stabilization of clays were also explored. Core samples were examined using X-ray diffraction (XRD), scanning electron microscopy (SEM), pyrolysis, and thin-section microscopy.

The nature of organic deposition depended on complex interactions between oil, mineral, and CO2. Organic residue compositions were influenced by parent oil compositions as well as exposure to CO2 flooding. Site of deposition was controlled by mineralogy.
A Correlation of the Physical and Chemical Properties of Three South Louisiana Crudes With Their Degree of Biodegradation
Authors: Wolcott J. M. , Sassen R. , Constant W. D.
Published: December 2007

The effects of naturally-occurring biodegradation on the physical and chemical properties of three crude oils from reservoirs flanking a salt dome in south Louisiana were investigated. Gas chromotographic signatures and saturate/aromatic ratios were used to rank these crudes as to degree of biodegradation. Biodegradation effects decreased with reservoir depth. API gravity, viscosity, average molecular weight, C15+ content, saturate/NSO-compound ratio, saturate/aromatic ratio, elemental C/H ratio, acid number and base number increased with increasing biodegradation. Biodegradation was also found to affect the surfactant properties and molecular weight of crude oil carboxylic acids.

The acidic fractions of two biodegraded crudes were isolated and subjected to a variety of analytical techniques. Phenols and carboxylic acids were major constituents of acidic fractions. The phenolic fractions were brittle solids or tars with high aromatic contents, low elemental C/H ratios and significant quantities of nitrogen and sulfur. The carboxylic acid fractions were viscous liquids with low aromatic content, low nitrogen and sulfur content and relatively high C/H ratios.
Evaluation of an Anti-Sealant Squeeze Treatment From Pump Run Life and Radiotracer Response in Produced Water
Authors: Suzuki F. , Wood K. N. , Lee G. L. , Bawol D. A.
Published: December 2007

A field test was recently undertaken to investigate the effectiveness of an anti-scalant squeeze treatment. Its overall effectiveness was assessed by pump run life. To gain insight into chemical behaviour, a mixture of carbon-14 tagged organophosphonate anti-scalant and tritiated water was added to the treatment prior to squeezing it into the formation. Treatment flowback was monitored by analyzing produced water samples for radiotracer concentrations.

The treatment successfully extended pump run life to nearly three times its expected value. During the 6.5 month test period, 67 % of the water was recovered as compared with only 16 % of the anti-scalant. This indicates that while the bulk of the treatment was successfully placed in the near well-bore region, most of the anti-scalant chemical stayed in the formation. Squeeze treatment technique and possible mechanisms for chemical retention are discussed. The radiotracer technique is also compared with other methods for anti-scalant analysis.
The Extensional Viscosity Behavior of Polymeric Liquids of Use in EOR
Authors: Walters K. , Jones D. M.
Published: December 2007

The rheometrical behaviour of dilute solutions of a high molecular weight polyacrylamide is described, with particular reference to the dramatically high values of extensional viscosity which are possible. The effect of such factors as polymer concentration, salt concentration and mechanical degradation on rheometrical properties is outlined.

Reference is made to the qualitatively-different rheometrical behaviour experienced by comparable solutions of xanthan gum.
Financing Domestic Natural Gcis Development in the 1990's
Authors: Pollio G. , Marian W. S.
Published: December 2007

Recent analyses of the natural gas market typically ignore the sweeping changes that might be expected to follow from the elimination of the current deliverability surplus. In this paper, we explore the implications of these potential changes, both in terms of their impact on sectoral performance and the willingness of energy finance markets, above all, banks, to fund future natural gas development.
Evaluation of Procedures for Preparing and Sampling Dry-Blended Cements
Authors: Bell D. R. , Nahm J. J. , Dammel T. C.
Published: December 2007

An evaluation of bulk blending and sampling procedures was conducted using cement blends prepared at seven bulk plants located in four different regions of the United States. Blending variables investigated include batch size, number of transfers, and the effect of aeration. Three types of sampling devices were also evaluated: an automatic sampler, a specially modified ball valve sampler, and an improved diverted flow sampler. Three transfers of cement blends from one vessel to another were necessary to obtain a representative blend. Other variables evaluated had little effect on blend uniformity after three transfers. A modified ball valve sampler was safer to use than the ordinary valve type samplers, but the improved diverted flow sampler equipped with air actuators was convenient to use and provided consistent performance.
An Extended Black Oil Miscible Simulator That Rigorously Treats Variable Bubblepoint Problems
Authors: Ammer J. R. , Sams W. N. , Brummert A. C.
Published: December 2007

The extended, black-oil, miscible reservoir simulator MASTER was developed specifically to support the Department of Energy's Enhanced Oil Recovery Program. The implicit-in-pressure, explicit-in-saturation simulator contains mass balance equations for oil, water, natural gas, up to four solvent species, and a surfactant. Several options have been incorporated into MASTER to simulate the phenomena associated with gas miscible flooding: (1) including the loss of solvent to the aqueous phase, (2) choosing the degree that water blocks oil from contacting injected solvent, (3) allowing precipitation of asphaltenes with subsequent permeability reduction, and (4) reducing gas mobility as a function of surfactant concentration. MASTER was validated by comparing predicted results with results presented in the Society of Petroleum Engineers first and fifth comparative solution problems. Results predicted by MASTER compared favorably with SPE's results. Thus, MASTER can be disseminated for public use.
Applications of Nodal Analysis Technique for Appalachian Wells' Production Problem
Authors: Suhy T. E. , Hefner M. H. , Yu J. P. , Mustafa A.
Published: December 2007

A software package has been developed in which a gas simulation model and Nodal analysis model are used in conjunction with fracture simulation. The software package is also tied to a microcomputer database system to provide pertinent data for well analyses. The gas simulation model generates inflow performance for various production conditions while Nodal analysis studies the inflow and outflow conditions. Since specific Appalachian production conditions are used for both models, the software package will prove to be a useful tool for improving production in the Appalachian area.

Artifical lift "rabbit" production, bailing/swabbing operation, restimulation of the new zone and deeper drilling are the conventional methods to improve the production in the Appalachian area. Nodal analysis technique has been used with specific wells to evaluate the potential results of using each recovery enhancement method.

Nodal analysis is an optimization technique to analyze production problems and predict solutions. This technique can predict the "critical" pressure for artificial lift and can predict the inflow performance of a well. The new bailing operation can then be scheduled accordingly. In addition, this technique can also estimate the skin damage within an existing well and be used to justify restimulating the new zone or drilling deeper. In the Appalachian area, tight formations and relatively depleted reservoirs are major problems. The current marginal economic situation does not allow producers to improve production by pressure enhancement and multiple stimulation. A solution can be obtained by analyzing the problem and predicting the outcome of using various production enhancement methods. Then, the operator can select the proper method to use.
Dynamometer Test Results in the Eastern United States
Authors: Rdissi A.
Published: December 2007

Since its introduction to the Eastern United States in the early 1980's when it was received with little enthusiasm, dynamometer testing has become more accepted. Operators and field personnel have become more familiar with its applications and benefits to producing pumping wells. This paper compiles dynamometer card results from several hundred tests conducted in the region during the last few years. A wide spectrum of benefits were derived from the analysis of these tests. The benefits include an evaluation of the performance of all the pumping equipment, the correction of problems outlined by the tests, and the use of test data to design equipment for undeveloped oil fields. The major benefit is the increase in gas and oil production. Because of the tedious calculations involved in interpreting the dynamometer card, a computer program that consists of a few subroutines was written to help the engineer make a precise determination of the problem encountered. Therefore he is able to offer useful recommendations to improve the well's performance.
Production Potential and Strategies for Coalbed Methane in the Central Appalachian Basin
Authors: Kelafant J. R. , Boyer C. M. , Zuber M. D.
Published: December 2007

A regional geologic assessment of the Lower Pennsylvanian age formations in the Central Appalachian Basin has indicated that the coalbeds of the Pocahontas and Lee/New River formations have a high potential for gas production. This study, sponsored by the Gas Research Institute, has established an in-place gas resource estimate of over 5 trillion cubic feet for the six primary coalbeds in the targeted east central portion of the basin. Using a production simulator designed specifically for the unique reservoir characteristics of coalbeds, estimates of gas production under varying geographic and reservoir conditions were made. The many thin, discontinuous coalbeds of the basin suggest that gas production from multiple coal seams within a single wellbore will be the optimal completion technique.
Operational Efficiency Comparison Between a Deepwater Jackup and a Semisubmersible in the Gulf of Mexico
Authors: Childers M. A.
Published: December 2007

A commonly held industry viewpoint is that deep water (WD) jackup ( 250-350 ft plus WD) is the preferred rig type over a shallow water semisubmersible (600-1000 ft WD) from almost any viewpoint including operational, efficiency, cost, risk, and potential rig downtime. A time study was conducted with various operational scenarios that show from the time a jackup/semisubmersible starts to move on location to drill out of surface casing the semisubmersible (SEMI) should on average perform the operation in 1.8 to over 4.7 days faster than a deep water jackup. Also for the permanent well abandonment to moving off location, the SEMI on average will be able to accomplish the same in 0.6 to 1.5 plus days faster than a deep water jackup. Summing the start and finish operations for the well, the SEMI on average assuming a good, steady, reasonably trouble free operation for both type units should be quicker by 2.4 to 6.2 days. With current contract day rates, and cost of wellheads, casing, rental of BOP, etc., a shallow water SEMI total well cost will generally be less than a deep water jackup.
Mobility and Speed in a Workover/ Completion Rig for the Arctic
Authors: Gardner G. B. , Snisarenko P. P.
Published: December 2007

In April, 1984, ARCO Alaska, Inc. published specifications for a workover/completion rig for the Kuparuk oil fields, located on the North Slope of Alaska. ARCO was seeking a rig which could handle a static hook load of at least 300,000 lbs., with the capability of moving well-to-well within 3 hours and pad-to-pad inside a 5-mile radius within 12 hours.

Nordic-Calista Rig 1, designed specifically for that contract, performed its first day of production on April 4, 1985. Subject rig has, in its entire history of operation, beaten those original move time requirements 100% of the time. From daily production reports of Nordic-Calista Services No. 1, the joint venture owner and operator of subject rig, during the one year period June 1, 1987 to May 31, 1988, well-to-well move time averaged just over 22 minutes and pad-to-pad, up to a 5-mile radius, move time averaged just under 2 hours.

Built on three levels, the unit is completely self-contained, self-propelled with a top speed of approximately 2.5 miles per hour, winterized for harsh Arctic operations, and is capable of performing work-over/completion operations to a depth of 16,000 feet. Rig up and tear down time has been virtually eliminated, except where the unit is required for the Prudhoe Bay oil fields nearby. 45-foot height restrictions there in require removal of the derrick and disassembly of its wind walls in such instances.
Drillstring Design Optimization for High-Angle Wells
Authors: McKown G. K.
Published: December 2007

Drill string design for high angle wells should be optimized for all required functions of the drill string. Optimum drill string design requires a thorough review of well design and objectives in order to rank in importance the demands of a drill string. Practical considerations for drill string design for high angle wells and systematic approaches to the design process are presented.
Benefits, Limitations, and Applicability of Steerable System Drilling
Authors: DeLucia F. V.
Published: December 2007

Advances in on-demand directional control using steerable drilling systems has progressed significantly in recent years. These systems can provide tangible improvements in cost-per-foot and drilling optimization, as well as intangible benefits in wellbore quality and predictable drilling performance.

Results can be quite dramatic when the steerable system is carefully designed and is used in the appropriate drilling situation. While steerable system drilling has the flexibility to perform most directional control tasks required of traditional directional drilling operations, thorough analysis and planning will ensure that the operator achieves maximum economic and performance benefits.

This paper examines system design and operation, performance benefits, proper application and the limitations of steerable drilling system technology.
Hammer Bits Control Deviation in Crooked Hole Country
Authors: Johns R. P. , Witt C. , Frederick M.
Published: December 2007

Air percussion drilling tools, and hammer bits in particular (Figures 1, 2 and 3), are somewhat new to the oilfield. In the last three-to-five years, conventional hammer bits have been utilized in air drilling regions with great success. Hammer bits have increased penetration rates and reduced deviation problems over conventional air rotary drilling, making drilling during the recent downturn of oil and natural gas prices more attractive (1). Figure. 1Hammer bit profile specific features.Figure. 2Hammer bit profile. locking rings & driver sub.Figure. 3Pnuematic air hammer Internal workings.

A new diamond-enhanced hammer bit utilizes polycrystalline diamond technology (2). The hemispherically-shaped tungsten carbide inserts used in the hammer bits have a highly wear- resistance polycrystalline coating (Figure 4). Successful field use of the bit indicates that the tool could be a solution to severe deviation problems encountered in the Appalachian, Arkoma and, Permian Basins. Figure. 4Diamond enhanced Insert cutaway.
The Application of the Drilling Motor
Authors: Schmidt G. J. , Flickinger G. L.
Published: December 2007

Proper application of the DC Drilling Motor to drill rig equipment, including mud pumps, rotary table, top drive and drawworks, is essential in obtaining maximum performance and long life from the motor. Emphasis is placed on taking advantage of the motor's torque and speed characteristics with a variable DC voltage source such as the SCR. Comparison of the advantages and disadvantages of the shunt and series type DC motor are analyzed. Recommendations are given on proper methods of motor cooling, storage, maintenance, troubleshooting and returning the drilling motor to service.
Offshore Drilling Rig Modifications for Deep Well Drilling: A Systematic and Economical Approach
Authors: Snyder D. L. , Childers M. A.
Published: December 2007

Odeco has upgraded a Victory class semisubmersible and a Bethlehem slot jack-up rig to accommodate the heavy loads associated with drilling wells below 20,000 feet in the Gulf of Mexico. Several world records have been set with these rigs since their upgrades.

This paper will discuss the numerous operational and economic challenges a drilling contractor is faced with in order to strengthen and upgrade a rig for drilling ultra deep wells below 20,000 feet. These include analyzing rig capacities such as drilling equipment, setback, combined substructure, well control, liquid and bulk systems, solids control, deck storage, variable deck and leg loading and power plant. A precise inspection plan must be formulated before and during the well for all of the contractors equipment. Additionally, the entire analysis and upgrade must be done economically and generally in less than 60 days in order to compete in today's marketplace.

While many rigs are capable of drilling deep wells, few rigs can safely accommodate all of the demanding aspects of ultra deep drilling. It is important that the "whole" rig, its equipment, and its operational capability meet all requirements, not just a vast majority of those requirements.
RCRA Subtitle D Application to Drilling Operations
Authors: Freeman B. D. , Collins J. W.
Published: December 2007

The Environmental Protection Agency (EPA) presented the Regulatory Determination on drilling muds, produced water and associated wastes to Congress on June 30,1988. One conclusion was regulatory gaps were present in some State oil and gas programs that compromised environmental protection. EPA believes they have authority under Subtitle D to fill these gaps. However, the Subtitle D type waste management guidelines, as being formulated by EPA to regulate mining operations and municipal landfills, are not viable or cost effective when applied to Oil and Gas Industry (0GI) operations. The existing drilling waste management practices used by the OGI in a number of State oil and gas programs though are viable and cost effective to ensure environmental protection. These existing practices as discussed in this paper can be implemented in applicable State programs to fill regulatory gaps.
Drilling Contracts: Pursuit of an Equitable and Balanced Relationship Between Operators and Contractors
Authors: Moomijan C. A.
Published: December 2007

The steep rise and fall in the demand for drilling rigs during the last decade not only has created the expected swing in rig rates but also has wit-nessed a dramatic shift in commercial terms and allocation of risks in drilling contracts. Although the supply/demand ratio inevitably will control rig rates, the author suggests that the long term interests of Operators and Contractors justify implementation of a rational and standardized ap-proach to achieve equitable contract terms in both weak and strong markets. First and foremost, a drilling contract should be comprehensive, clear and enforceable. Commercial provisions, such as those addressing term extension options, rate structure and termination rights, should be written in a comprehensive fashion to fairly reflect the agreement between the contracting parties and facilitate orderly contract administration. Provi-sions addressing allocation of risks for potential losses and liabilities and the contract clauses detailing insurance requirements should be drawn in consideration of the risks customarily absorbed and insured by Operators and Contractors in order to create a clear demarcation of risks and avoid cost-ly duplication of insurance coverages.
Drilling Contractors Against Drugs: Integrity in the Workplace
Authors: Hopkins B.
Published: December 2007

A drilling contractor's service is his only product. The integrity of this service depends on well maintained and operated equipment and. most importantly, on well trained, knowledgeable, skilled and alert crews.

Drilling contractors are emphatically against drugs and have taken strong actions to enhance and preserve the integrity of their workplaces. Both land and offshore, drilling contractors are striving to eliminate the effects of drug use on their rigs.

Accidents and other operational mishaps represent serious flaws in the quality of service. An analysis of serious accidents indicates that only 10 to 15 percent are caused by equipment or mechanical problems, while 85 to 90 percent are caused by human error. Any and all things that reduce the effects of human error on a drilling rig will improve performance. This is where drilling contractor drug programs are aimed--squarely at reducing human error and increasing safety of personnel, performance of the rig, and quality of service to the customer.
The Cost of Environmental Compliance
Authors: Stewart D. A. , Templet J. D.
Published: December 2007

The objective of this presentation is to summarize the nature and scope of the more major costs of environmental compliance as they apply to the field operations of oil and gas well drilling and production. An analysis of the appropriate federal laws is also addressed and included are the necessary reporting levels in both the federal and state governments. This information should be sufficiently definitive to allow the uninitiated to reference sources and begin a compliance program. Also, the advanced reviewer will not only receive a refresher, but additional insight into potential future jurisdictional arenas that appear to be on the horizon by both federal and state regulatory agencies.
Toxicity and Performance Testing of Non-Oil Spotting Fluid for Differentially Stuck Pipe
Authors: Halliday W. S. , Clapper D. K.
Published: December 2007

Differentially pressured stuck pipe is a serious problem in the Gulf of Mexico and other areas of the world which results in costly and lengthy time delays. For years diesel oil, mineral oil, and mixtures of these oils with surfactants, clays, and asphalts have been spotted to help alleviate differentially pressured stuck pipe. With the advent of the Environmental Protection Agency's National Pollutant Discharge Elimination System (NPDES) General Permit on July 2, 1986 and the ending of the Diesel Pill Monitoring Program (DPMP) on September 30, 1987 the use of these conventional spotting fluids is becoming more stringently controlled in the offshore waters of the United States. In fact, after the use of conventional spotting fluids, the entire mud system may have to be sent ashore for disposal since offshore discharge is not allowed. In an effort to provide an environmentally acceptable alternative to oil based spotting fluids, a laboratory procedure was developed and used to measure the ability of various chemicals to free a metal bob held in a filter cake by a differential pressure. After the effective additives were identified, a few were selected for bioassay. One water-soluble agent, in addition to being highly effective in the stuck pipe simulation test, had a very low order of toxicity. This material was formulated into an experimental spotting fluid that successfully freed a differentially stuck drill string in the Gulf of Mexico.

The development of a non-oil, low toxic spotting fluid has provided a suitable alternative to conventional spotting fluids resulting in an effective and environmentally safe way to combat differential pressure sticking of the drill string.
Underreaming: Old Method with New Technology
Authors: Desai P. C.
Published: December 2007

Underreaming is a highly underrated technology. It has been viewed primarily as an undesirable, yet often inevitable, cost in too many wells or standard methodology in remedial applications. Recent advances in deeper drilling have created the need for multiplecasing strings in straight and directional wells. As a result, the demand for more durable, reliable underreamers has increased. Underreaming allows the operator to run minimum clearance casing programs which optimize casing sizes and reduce tubular costs on multiple-string wells.

The performance of conventional underreamers has been inconsistent due to several inherent problems such as short cutter life, marginal hydraulics and component weaknesses. This paper examines these problems and describes a new, innovative underreamer that incorporates design solutions. Underreaming is discussed as a system which encompasses stabilization and computerized hydraulic analysis in addition to underreaming tools. A summary of field data also is detailed.
Performance of Beta Titanium in a Salton Sea Field Geothermal Production Well
Authors: Holligan D. , Cron C. J. , Love W. W. , Buster J. L.
Published: December 2007

Carbon steel tubulars have shown an unacceptably short life in Salton Sea field geothermal production wells. Corrosion testing identified a beta titanium alloy which is immune to corrosion and cracking in the saline brine.

A development program has resulted in the commercial production of 9-5/8 in. (24 cm) betatitanium. A 1,500 ft (457 m) string was threaded with a premium connection. The string has been run and retrieved twice with less than 1% of the connections requiring shop repair.

Because of its modulus, beta titanium has a lower collapse resistance than carbon steel, butacceptable performance can be obtained by increasing the wall thickness. However, titanium's low modulus is also beneficial, because it reduces the stress level experienced when a cemented completion is thermally cycled.

Good performance in this geothermal service makes the beta titanium a candidate for some hostile oil and gas environments.
How To Build and Hold a 90° Angle Hole
Authors: Jourdan A. P. , Mariotti C.
Published: December 2007

Horizontal drilling is now a well established technique with growing popularity for exploiting a number of reservoirs which would otherwise be uncommercial.

However a horizontal well requires a substantial engineering work, compared to a conventional deviated well. The target has new dimensions. The design of the optimum trajectory must take into account a large number of datum. Directional control is severe. Drags and torque have an increased and adverse action on the overall drilling mechanics. The inverted drill string is a new concept.

This paper provides guide lines for planning a horizontal wellbore. Among the 16 horizontal wells drilled by ELF AQUITAINE, typical application of three different methods are also reported.
A Dual Shale Pore Pressure Detection Technique
Authors: Bryant T. M.
Published: December 2007

A dual-basis application of the shale resistivity pore pressure detection technique has been developed that emphasizes the availability of MWD formation resistivity measurements while minimizing input from the operator.

This method is based upon accepted petrophysical and mechanical principles.

Operator inputs are streamlined, requiring one-time-only entry of local air gap, water depth, normal pore pressure gradient, and a baseline value of shale water resistivity.

MWD shale resistivity is utilized in the Archie equation to solve for shale porosity. The Baldwin-Butler normal shale compaction relationship uses this porosity to estimate an actual vertical matrix stress component. Overburden pressure is calculated using a generalized Tertiary basin equation. The difference between normal and actual matrix stress values represents the magnitude of change from normal to abnormal pore pressure conditions.

Unlike traditional empirical approaches and other, more recent petrophysical-mechanical techniques, this technique does not need data from a normally pressured section for establishment of a normal trend, does not require the degree of local knowledge associated with the use of overlays, and involves neither guesswork nor comprehensive expertise on the part of the operator.

The model has been successfully tested on approximately 100 well locations in the Gulf of Mexico, offshore Alaska, North Sea, and Niger Delta. Field examples are presented that demonstrate the technique's consistency with principles, quantitative accuracy, and relative ease of use.
The Effect of Intercalated Barriers on Heavy Oil Recovery by Steam Injection
Authors: Zeng Yie , Wang Jianshe , Huang Yan Zhang , Liu Wenzhang
Published: December 2007

Many heavy oil reservoirs in China are charactered with multi-layer horizons with barriers in between of them. During steam injection those very tight clay layers act as heat absorbing media with heat conductivity varies with the changing of aqueous saturation and as barriers against steam transpiration and/or penetration. However, very few works have been done on this subject, and the consequent effect on steam injection remained unknown.

In this work, started with brine/air capillary pressure curve measurement of the barriers at different temperature by vapour pressure desorption method, relative permeabilities were calculated, which would be otherwise extremely difficult to be obtained by conventional appoaches if is not imposible.

Overall effects of barriers on steam stimulation and steam flooding were studied by numerical simulation based upon the experimental data on the effects of: absolute permeability; capillary force; barrier distribution; and heat loss. Results from simulation suggested that capillary forces of the barriers contribute about 7% increase in terms of heavy oil production, oil steam ratio and recovery efficiency. Attempts of explanation of these positive influence were made.
Quality Assurance for PVT Sampling and Testing - Endicott Field, Alaska
Authors: Pestak M. W. , Pande P. K. , Swanson G.
Published: December 2007

Endicott is an offshore North Slope of Alaska field with approximately 1 billion barrels of oil in place. An extensive PVT sampling program was conducted shortly after field start up in 1987 in order to capture true "initial condition" fluids for laboratory studies. This paper is a case history of an unusually successful and thorough quality assurance program which covered each step from wellsite sampling to final PVT laboratory report generation.

Wellsite sampling practices utilized to obtain representative bottomhole fluids from 5 wells and surface samples from 19 wells included well conditioning, customized sampling techniques, and field checks for sample quality.

In the PVT lab, a rigorous test sequence was followed to identify data quality problems due to loss of sample integrity or inadequately precise laboratory procedures. Raw, unsmoothed data were reviewed to track problems to their root causes. Emphasis was placed on material balance checks, calibration procedures, and comparison of properties which were measured by different techniques.

Major contributions in this paper include design details of an integrated PVT quality assurance program, a case history of implementing such a program with real problems and solutions, and a meaningful assessment of the quality of the laboratory PVT data.
A Comprehensive Analysis of Steam Foam Diverters and Application Methods
Authors: Eson R. L. , Cooke R. W.
Published: December 2007

Steam injection in California heavy oil reservoirs began in 1960 in Yorba Linda. Within the first five years, more than 280 additional thermal projects were initiated in California, thus thrusting thermal enhanced oil recovery (EOR) to the forefront. Today, it continues to dominate EOR, accounting for approximately 78% of all the oil produced by EOR methods. Despite the fact that steam injection is the most widely accepted EOR technology, it is not without its problems.

Overall, recovery of oil has always been hampered by gravity segregation within the steam flood area as well as channeling from directional permeability or viscous fingering. After steam has been injected for some period of time, these areas of high permeability tend to act as steam thieves. Once swept of oil, the pressure drops between the injector and the producer causing the depleted zones to receive the majority of the injected steam. The less permeable, oil-saturated areas remain virtually untouched by continued steaming. In an effort to reduce channeling and steam injection into the depleted, steamed-out portions of the reservoir, various foaming surfactants and methods of application have been experimented with in the laboratory. This experimentation has been progressing for more than 20 years and has been followed by extensive field testing in heavy oil reservoirs in the San Joaquin Valley.

This paper deals with the development of the field application technology from its first pilots in 1974 to current field practices. Some discussion is provided regarding outside driving forces which have a substantial influence on not only the rate of growth of foam applications, but the methods of application as well.