bluuebunny/crossref_metadata_2025 huggingface dataset:
Aircraft Safety in the Gulf of Mexico
Authors: Handy H. W.
Published: December 2007

Chevron owns and operates the largest corporate non-commercial aircraft fleet in the world. This paper describes Chevron's aircraft operations and how it supports a large exploration and production operation in the Gulf of Mexico.

Discussion focuses on Chevron's highly qualified pilots and mechanics and how they achieve and maintain their technical abilities. The Maintenance Department is described in detail, including procedures for revamping new aircraft to Chevron's standards before they are available for use. Discussion also provides a detailed explanation of the avionics group and their part in outfitting and maintaining a sophisticated flight tracking (Flite-Trak) and Loran system used for navigation.

This paper also describes Chevron's own internal safety precautions that may be unique to its operations and have proven to aid in the Company's overall safety program and related accomplishments.

The results of Chevron's Aircraft Operations cannot be measured in safety statistics alone. Passenger confidence and employee involvement are two main elements that contribute to Aircraft Operations' success. Chevron aircraft operates in a safe and cost efficient manner. Many American Petroleum Institute (API) and Federal Aviation Administration (FAA) awards have been earned for outstanding safety milestones. It is only through the dedicated efforts of all the employees of Aircraft Operations that such an outstanding organization exists. The credit for the exemplary safety record of this organization truly belongs to the employees.
Reservoir Testing Analysis in the Presence of Water Drive by Surge Technique
Authors: Sierra L. , Da Prat G.
Published: December 2007

In this work a testing technique based on analysis of the pressure transient created by formation surging is presented. The application of the technique is focused to cases where the tested well has high water cut besides strong bottom hole water drive and partial penetration. The analysis of the flow regimes shown under these conditions is presented. Several field cases are shown in order to see the application of this technique.

A major result derived from this study is that the technique can be succesfully used in cases where by conventional pressure transient analysis no resevoir parameters can be obtained mainly because no radial flow is shown due to constant pressure effects. Linear, Radial, Bilinear and Spherical flow can be identified. Therefore making possible the calculation of transmissibily and skin effects.
Methodological Approach for Reservoir Simulation
Authors: Sanchez N. , Martinez C. , Rattia A.
Published: December 2007

The reservoir simulation is a technology of generalized use in the petroleum industry to evaluate actual and future reservoir performance. However, a general methodology for reservoir simulation has not been completed defined in the literature (Refs. 1,2,3,4).

In view that reservoir simulation is a basic tool of reservoir management, Maraven S.A decided to standardize the procedures involved into a reservoir simulation study, developing a methodology aimed to eliminate engineering and computing time waste during the process of model initialization, history match, and predictions, which represent the main part of the reservoir simulation processes. Consecuently, work processes were stablished and documented including flow diagrams, and forms were prepared to obtain information, in order to keep track of the time used during the execution of each stage of the processes, allowing to use statistic control to monitore each process performance.

The application of the developed methodology allowed to identify the main time consuming activities, optimizing the studies execution process by reducing the risk of overlooking key aspects and variables, thus increasing the level of confidence of the simulation results.
Optimum Design of a Fracturing Job in the Chicontepec Formation
Authors: Navarro J. Baltinas
Published: December 2007

The Chicontepec formation, located in the State of Veracruz, Mexico has – presented a high level of difficulty in – the stimulation process. The formation is a very clayey sandstone, sensitive to water. Because of this, fracturing with proppant should be done with a gelled kerosene base fluid. This paper presents an appropriate fracturing design for this formation based on data obtained in the yield during more than 14 years of operations of this type. Also, extensive laboratory tests made on representative cores supported with computer simulations give backup to field observations.
Analysis of DST in Wells with no Flow at the Surface Using Short Producing Time Techniques
Authors: Muñoz E.
Published: December 2007

The main objective of this paper is to present an application of short producing techniques in no surface flow wells, specifically wells that need swabbing.

Due to the troubles to estimate production in this kind of wells, we are going to use the first two periods in a DST; it means the first flow and the first buildup as just one called the surge period. From the analysis it is hard to calculate skin, but we can estimate P* and permeability.

In addition, if the DST is a complete test that is consisting of four periods, first flow, first buildup, second flow, second buildup, we can verify P* and permeability from the final buildup and we can calculat skin because we have production in the second flow (swabbing); in this way, we have a good radius of investigation to obtain a more real skin.
Practical Experience with Sand Control Completions in Vertical and Horizontal Wells, Bolivia
Authors: Escobar J. A. , Turner W. H.
Published: December 2007

This paper compares sand control methods used in vertical oil and gas wells with a relatively new method used in the first horizontal well drilled in Bolivia. Even though production from the horizontal well has not exceeded that from nearby vertical wells by the expected margin, initial results are encouraging. Production from a zone previously considered low yield has been at an acceptable level and through a larger choke than normally used in the area. The sand control method utilized may be extended to vertical wells.
Libertador Field: An Integrated Approach to a Development Plan
Authors: Graue D. J. , Larsen W.
Published: December 2007

An integrated study of the geology, petrophysics, geophysics, and engineering aspects was made on the Libertador field in Ecuador. The study began after the field had produced approximately 6% of the oil originally in place.

Data from geophysics, petrophysics, geology, transient pressure analyses, laboratory core analyses, and laboratory PVT analyses were integrated in a classical black oil simulation model to allow the evaluation of alternate development methods. A history match was performed on a model which incorporated all four of the principal producing sands. This study produced an evaluation which demonstrated that the highest recovery would be achieved using a combination of infill drilling water injection, and artificial lift.
Exploration/Development Strategy for Rio Caribe Field
Authors: Chalot J. P. , Gómez R. , Gonzalez F.
Published: December 2007

This paper presents the exploration/development of the Rio Caribe field, the new technological frontier of the Venezuelan oil industry. This field comprises 26 prospects extended on a surface of 101123 acres (405 Kms2) and is part of a giant gas and condensate field discoveries in north of Peninsula of Paria. The other fields are Mejillones, Patao and Dragon discovered as a result of the exploration campaign realized by Lagoven, S.A. between 1979-1983.

The proposed strategy will be developed in several phases iniciated by an early development of the proved area and combined by an extensive effort of exploration. The very first exploitation scheme selected is recycling dry gas in order to maintain the well potential, to improve the recovery factor and to offer an early policy for the gas management.
A Comprehensive Theory of Transient Inertial Flow in Tubing, Skin Zone and Reservoir
Authors: de Swaan A.
Published: December 2007

Complete analysis of well tests, from early to late time stages, is feasible with a model that includes in a single equation the effects of: a tubing composed by pipes of different diameters; chokes; segregated gas in the tubing; skin zone; reservoir geometry; and inertia of the flowing fluid.
Modelling Horizontal Wells in a Water Drive Reservoir: Guafita Norte Field, South Western Venezuela
Authors: Cordero F. J.
Published: December 2007

This paper discusses the results of a simulation study for horizontal well implementation in a reservoir with strong water drive, located in the Guafita Norte field in south-western Venezuela. The reservoir under consideration contains a 30° API (0.87 g/cm3) sub-saturated crude with a oil viscosity of 3.9 cp (3.9* 10−3 Pa.s) at 3,000 psia (20.68 MPa).

The well production evaluations were performed by 3D simulations using a numerical model.

Emphasis was made to study the effect of the drainhole length on production forecasts. The effect of vertical/horizontal permeability anisotropy and restriction of oil rate were also investigated.

Simulation results obtained for the horizontal well project can be considered as very encouraging. A 2,000 ft (609.6 m)long horizontal well would produce around 17 MMbbls(2.7*106m3)of oil over a 15 year period. This represents more than 30% of STOIP in the G-10 reservoir of the Guafita Norte field. A vertical well having a opened interval of 30 ft (9.14 m)would produce around 9 MMbbls (1.43* 106m3) during the same production period. Cumulative production forecasts show that production is not proportional to the drainhole length. However, a drainhole length varying from 1,000 to 2,000 ft (304.8 to 609.6 m) leads to an additional production of 2 MMbbls (0.32*106 m3) without dramatic water influx due to the well inclination.

Simulation runs also show a slight influence of the Kv/Kh ratio on the horizontal well production behavior.
Horizontal Well Applications and Parameters for Economic Success
Authors: Lacy S. , Ding W. , Joshi S. D.
Published: December 2007

This paper includes a review of horizontal well field histories and applications around the globe, with special emphasis on South and Latin American applications. The paper includes descriptions of economically successful, as well as unsuccessful horizontal wells in field applications. Results of the field histories are used to summarize essential parameters for economic success.

Horizontal wells have been used in: 1) thin pay zones, 2) naturally fractured reservoirs, 3) formations with gas and water coning problems, 4) heavy oil reservoirs, 5) gas reservoirs, and 6) enhanced oil recovery (waterflood applications, miscible floods, and thermal oil recovery).

Out of about 2500 horizontal wells drilled worldwide, almost 75% are drilled in the USA and Canada. In addition, most of the U.S. welts are drilled in a few formations, namely, Austin Chalk and Bakken Shale. Host of the U.S. applications are in low permeability (*1 md) reservoirs.

Outside the U.S., the majority of applications are for gas and water coning, mainly for water coning. These applications are in high permeability (400 md to 10 Darcy) reservoirs. In general, horizontal wells have a higher success rate in water coning applications than in gas coning situations.

Recently, horizontal wells have also been used in secondary recovery applications. Horizontal wells have exhibited excellent results in miscible CO2 floods. While application of horizontal wells in waterflooding shows great potential, application in thermal oil recovery shows mixed economic results.

The key parameters for success, based upon field results, appear to be: 1) fracture intensity, 2) hydrocarbon pay zone thickness, 3) well spacing, 4) vertical coomunication, 5) formation damage and post drilling clean-up ability, 6) geological control, 7) multiwell prospect, and 8) cooperation in geological, reservoir, drilling, and completion departments.
Reservoir Engineering Studies to Implement Additional Recovery Projects in El Furrial Field
Authors: Pizarro J. Herbas
Published: December 2007

Reservoir engineering studies have been performed to aid in the definition, planning and implementation of a fluid injection project to increase the ultimate recovery and maintain oil production rates in the Furrial Field located in Monagas State in Eastern Venezuela (Fig. 1).

The furrial structure is an overpressured asymmetric anticline containing over 4364 × 106 B [634 × 106 m3] of medium oil weight (29-24° API). Variable PVT properties, and variable asphalthene content, the presence of a tar mat surrounding the flanks of the structure, high initial pressure and temperature, high initial production rates and net sand thickness over 1000 feet are characteristics of this field considered as the most important in the Eastern Venezuela.

The reservoir characterization activities undertaken during the first six (6) years of production resulted in the identification of the production mechanisms and an estimate primary recovery. Pressure maintennance requirement were identified early and an action plan was defined to implement a water injection project. Reservoir studies indicate an incremental oil relovery by water flooding of about 1350 × 106B [215 × 106 m3].
Simulation Study of a Venezuelan Reservoir to Enhance Productivity
Authors: Miranda J. , Rodriguez L.
Published: December 2007

This report presents the results of the simulation study of the NIP-101/R1 sand reservoir, NIPA-100 oil field, located in Eastern Venezuela. The objective of this study was to establish the optimum future exploitation strategy.

Originally the reservoir was undersaturated, containing 15-22 API crude at 3870 psi (26.7 MPD) and 240 F (113 C). The initial gas/oil ratio was 436 Scf/bbl (79.9 M3/M3).

A detailed geological model was constructed based on recent depositional environment concepts, using available core and log data. The study concluded that the NIP-101/R1 sand reservoir had a deltaic origin. It was divided in two different lenses in most of the reservoir, except around well NV-106, where both lenses coalesce. The top R1U lens and the bottom R1L lens are channel sands with local splays.

A satisfactory match of reservoir production and pressure history was achieved. A pressure performance history match was obtained by reducing total gas injected by 7.3% by adjusting the reservoir transmissibility.

A total of seven prediction cases were run to analize the sensivity of oil recovery as a funtion of various exploitation schemes, including horizontal wells.

The results indicated that by injecting 14 MMSCFD (.40 MMCMD) of gas, relocating the injection wells, and drilling seven additional new vertical wells, the oil recovery will be improved in 4.67 MMSTB (0.75 MMCM).
Safety Systems for Production Platforms
Authors: Lozano P. , Sánchez D.
Published: December 2007

During 50 years in operation of the petroleum industry in the western part of the country, the surface of Lake Maracaibo has become congested with approximately 10,000 structures, among them well platforms, flow stations, pumping maniflod, production and gas lift manifolds, water injection and gas compression plants, etc. this progressive increase by the number of installations has continuously limited the moving of floating units in the lake as well as increasing the risks of contamination due to the high probability of leakage occurrence in the 21,000 kms. of pipe line resting on the bottom of the lake.

Because of this situation, the LAGOVEN Western Division initiated in 1988 the perforation by groups, drilling 17 wells in two platforms to inject water into an oil bed. In 1990 the first platform was built with 10 oil producing wells, and to obtain a reliable and secure operation of the facility, during the activities of repairing and /or servicing the wells, a security system was designed which included an amergency shutdown.

In this article, we will describe the safety system mentioned above, their specifications, functions and the benefits obtainable when we have this system in operation.
A Method to define Gas Condensate from Initial Production Data, Eastern Venezuela
Authors: Cova J. , Essenfeld M. , Silva L. , Rondón C.
Published: December 2007

Using as data base a group of correlations generated from Eastern Venezuela PVT Laboratory experiments, a group of "minimum limiting conditions" based on simple field production measurements are proposed which, when met simultaneously, guarantee that the produced fluid stream is a gas condensate at reservoir conditions. It was also concluded that for each of the selected production parameters there is a "Transition Zone" in which the production stream can be a volatile oil or a gas condensate at reservoir conditions. It is concluded that the proposed method to define the existance of such gas condensates is very important for Eastern Venezuela since it expands the typical ranges that several authors have indicated to clasify the produced fluids as gas condensates at reservoir conditions.
The Application of Geochemical Kinetic Modelling to Petroleum Engineering: the Prediction of Hydrocarbon Composition
Authors: Bagge M.
Published: December 2007

Significant advances have been made in the description of oil composition and cracking under different temperature regimes. This paper describes how geochemical methods, previously applied to oil exploration, can be used in petroleum engineering studies to predict oil composition and phase behaviour when thermal processes are applied to enhanced oil recovery. Laboratory and field data from both geochemical and petroleum engineering sources are, reviewed, and then applied in a series of models generated using geochemical software.

The composition of oil and its products on cracking are very sensitive to temperature, but their prediction must be treated as a time-temperature process using chemical kinetics. Experimental evidence shows that a distribution of activation energies can be assigned to each oil to describe its composition at a range of temperatures. Kinetic models show that compositional changes and cracking occur at different rates at the high temperatures used in laboratory studies to the temperatures normally encountered in the subsurface. Furthermore, oils of different compositions, for example the heavy degraded oils common in Venezuela, can have different breakdown characteristics to paraffinic oils.

Conclusions from this work have direct applications to reservoir simulation for a complete compositional fluid description. The models could be used to describe oil composition in fields where high subsurface temperatures are encountered, and would aid the planning of enhanced recovery programmes using thermal recovery processes to predict production characteristics. Where simulators are used hydrocarbon compositions are predicted using a set of flow equations that model convective and conductive mass and heat transfer in the reservoir.

Application of this knowledge base greatly enhances our understanding of fluid behaviour in reservoirs. The ability to predict oil composition under different thermal regimes will play a major role in assessing exploration risk associated with drilling deep prospects, but also improves our ability to predict production characteristics.
A Review Of The Developments In Oil Well Drilling Techniques In The Agreement Area, 1962-1967
Authors: Parsai K.
Published: December 2007

Introduction

The Iranian Oil Exploration and Producing Company is now making considerably more footage at less cost in the Agreement Area than it was making five years ago. The estimated exploration Cost per foot for 1967 is only 47% of the actual cost in 1962 and the estimated development cost per foot 72% of that of 1962.It is the aim of this paper to indicate the factors responsible for such dramatic progress over the past five years.

Discussion

The reduction in drilling cost per foot of 53% in the exploration field and 28% in the development wells over the 5-year period 1962 - 1967 in the Agreement Area is dually significant in that we not only drill at a relatively lower cost per foot now than in 1962, but because of the generally high cost of drilling in the Agreement Area, this relatively lower cost implies a significant saving in the total operating costs of the Company. The overall progress achieved in Drilling in South Iran is attributable to improvements brought about in individual phases of operations, each of which is discussed a briefly in the following:

1. Drilling Hydraulics

A major contributor to the improved rate of penetration in the south Iranian Fields was the introduction of jet bitdrilling about 1960.

The early jet bit, however, did not achieve the degree of merit it deserved as we did not have pumps with the required pressure ratings for ultimate efficiency in jet bit drilling.
Visual Investigation of Imbibition Processes
Authors: Hayashi J. A. , Rosales C. Pérez
Published: December 2007

A new technique for making visual observations of water imbibition processes in porous media saturated with oil is described. This technique uses a two-dimensional cell built with two ground glass plates set in contact one against the other. A porous space between the two plates is formed, where the microscopic pores have a random distribution similar to that of a natural rock. Using an oil with the same refraction index as that of the glass, it is possible to observe in detail the spontaneous penetration of the water by imbibition. Based on experimental results, a theoretical model is proposed for explaining imbibition processes.
Use of Reeled Tubing in Gas Lift Completion Systems
Authors: Bortolin L. , Johnson K. J. , Bechtold H. D.
Published: December 2007

This paper will demonstrate the use of reeled (coiled) tubing applied to gas lift technology and will add another method to the growing list of service and production capabilities now facilitated by reeled tubing. By using reeled tubing to install conventional gas lift valves, production enhancement of many wells is possible without workovers or change of existing tubulars. This paper will discuss the design parameters, components and actual field results of using reeled tubing to install gas lift valves.
On Reversed Micelles, Supercritical Solutions, EOR and Petroleum Reservoirs
Authors: Carnahan N. F. , Quintero L.
Published: December 2007

Gale (1987) reported the combined solvent power of supercritical fluids with the solvent power of micellar solutions which appears promising in connection with enhanced oil recovery. Likewise, recognition of the possible formation and destruction of reversed micelles by naturally-occurring amphiphilic substances, such as those associated with asphaltenes, may explain problems experienced in some EOR projects. Lipophilic supercritical components of reservoir fluids (e.g. light hydrocarbons and CO2) interact, in a controllable manner, with hydrophilic micellar complexes to achieve selective extraction of desirable components of crude oil. Fundamentals of supercritical fluids and of micellar systems are reviewed in terms of their mutual interaction and their potential applicability in EOR processes.
The Effects of Erosion Velocity on Filter-Cake Stability During Gravel Placement of Openhole Horizontal Gravel-Pack Completions
Authors: Johnson M. H. , Ashton J. P. , Nguyen Hang
Published: December 2007

This paper describes the data obtained from multiple rate flow tests intended to simulate the circulation of typical completion fluids across open hole intervals supported by particle filter cakes of graded salt and graded calcium carbonate. All flow rates, fluid losses and changes of permeability were recorded to determine changes in filter cake stability caused by the fluid flow.
Studies, Guidelines, and Field Results of Nonviscosified Completion Brine Gravel-Pack Carrier Fluids
Authors: Johnson M. H. , Montagna J. N. , Richard B. M.
Published: December 2007

The use of high viscosity gravel pack carrier fluids in gravel packing operations has been an accepted industry practice for more than 20 years. However, experimental results obtained using an acrylic gravel pack simulator indicated completion brines were superior gravel carrier fluids when compared to viscous polymer systems. The low viscosity brines exhibited complete annular packing with very tight grain to grain compaction. The low viscosity systems also provided good perforation filling without the degree of turbulence necessary for intermixing formation and gravel pack sands. Non-viscosified completion brines have been used to complete more than 100 zones with interval lengths of < 10 ft (3.05 m) to 400 ft (121.92 m) and hole angles from vertical to 89 ° (1.55 rad) at depths in excess of 13,000 ft (3,962.4 m). The low viscosity brines have yielded excellent annular packs and exhibited superior perforation packing when compared to polymer carrier fluids. Simulator test results, gravel crushing and erosion tests, and a discussion of "Slurry Pack" versus non-viscosified carrier fluids are presented. Also, comparative field results between polymer fluids and low viscosity brines are also presented in conjunction with recommendations and procedures for gravel placement using non-viscosified completion brines.
Frac-Pack: An Innovative Stimulation and Sand Control Technique
Authors: Hainey B. W. , Troncoso J. C.
Published: December 2007

A frac-pack technique combines the stimulation advantages of a highly conductive hydraulic fracture with the sand control of a gravel pack to improve productivity in low to moderate permeability, unconsolidated formations. This paper presents the results of two offshore field tests in the Gulf of lexico which evaluate different fracturing fluids, unconventional proppant sizes and new gravel packing tools. Aspects of reservoir candidate selection, pre- and post-frac pressure testing, and production results are addressed. This paper examines the layout of equipment, fracture treatment design, and on-site fracture optimization through minifrac testing.

The first field test explores the use of platform mounted gravel pack tanks with batch mixed sand slurries in a linear hydroxypropyl guar (HPG) gel that is crosslinked with Borate on the fly. The second field test investigates the use of linear hydroxyethylcellulose (HEC) gel as a fracturing fluid with a conventional blender and gravity feed proppant silo on a stimulation boat moored along side the production platform. These field tests demonstrate a frac-pack technique can provide practical and cost effective fracture stimulation and sand control in the offshore environment.
Point Permeability Measurements Using a Liquid Minipermeameter to Study Formation Damage Mechanisms
Authors: Vassilellis G. D. , Graves R. M. , Crafton J. W.
Published: December 2007

An apparatus that enables spot measurements of permeability variations along a core measuring 2 inches in diameter and 5.5 inches in length was developed. The apparatus is based on liquid injection at the rock surface and is referred to as the "Liquid Minipermeameter" (LMP). During the LMP measurements, full saturation of the rock sample is ensured by using a saturation bath. LMP measurements are also compared against air minipermeameter measurements. During liquid injection using the LMP, flow patterns were studied through the injection of colored liquids.

Various formation damage mechanisms on consolidated rocks using conventional coreflooding apparatus have been studied in conjunction with LMP measurements. LMP measurements were conducted before and after the formation damage experiments. The present paper includes an interpretation of a complex formation damage mechanism involving precipitation of gelatinous iron hydroxide. In this case, spot permeability measurements provide valuable information on the extent of damage as it is shown from LMP spatial variations.

Advantages of the LMP measurements arise as the measurements are not destructive for the rock sample and the rock heterogeneity is not excluded from the interpretation of the formation damage experiments. Compared to air minipermeameter the LMP shows better repeatability while drying of the rocks is not necessary.
A New Technique for the Calculation of Mechanical Skin Damage of Horizontal Wells Caused by the Drilling Fluids
Authors: Malekzadeh Dariush , Tiab Djebbar
Published: December 2007

A horizontal well, due to its large contact with the formation, may be several times more productive than a vertical well draining the same volume. However, this large contact of a horizontal well with the formation will cause a more severe formation damage than the one obtained from a vertical well. Also, the time that the formation is exposed to the drilling fluid is much longer for a horizontal well compared to that of a vertical well. In addition, the design of a truly non-damaging drilling fluid may be very difficult for some formations. This becomes more complicated as the formation characteristics, such as the fraction of various types of clays, change with the horizontal distance being drilled. Therefore, during the production, some sections of the horizontal well which have severe damage will not contribute to the production. This paper presents the development of a new technique for determining the horizontal well length contributing to production, and the corresponding calculation of the correct mechanical skin damage caused by the horizontal drilling operations.

The method developed in this paper indicates that the response of a horizontal well with mechanical skin and of length Xf1 can be substituted by a horizontal well of length Xf2 with no mechanical skin. A relationship between the mechanical skin and (Xf1,Xf2) is obtained which is applicable for the case of long horizontal wells, thin formations, and formations with high vertical permeability. These are the cases which are most often present in horizontal well drilling and applications. The method developed here is also applicable to hydraulically fractured vertical wells with mechanical skin. For a horizontal well with mechanical skin damage, Xf2 is smaller than Xf1 while for a stimulated horizontal well Xf2 is greater than Xf1.
Scale Inhibition of Hydraulic Fractures in Prudhoe Bay
Authors: Martins J. P. , Kelly Roy , Lane R. H. , Olson J. B. , Brannon H. D.
Published: December 2007

Formation damage has caused production declines in many wells in the Prudhoe Bay Field. Acid stimulations have become progressively less effective in restoring productivities, and a major campaign of hydraulic fracturing has been undertaken, with excellent results.

To prevent scale deposition in the propped fractures, techniques have been developed to enable scale inhibitor to be deployed during fracturing operations, despite the high pHs, and also to be replenished in existing fractures.
Prediction of Filtration Under Dynamic Conditions
Authors: Peng Shuang Jiu , Peden J. M.
Published: December 2007

This paper presents a summary of the results of an experimental and theoretical study on filtration properties of water based drilling fluids under dynamic and static conditions. The experimental investigation of the filtration properties was conducted as a function of mud types, solids concentration, pressure and shear rate. A dynamic filtration equation was developed using a mass balance method based on the cake filtration theory prevailing in the chemical engineering industry. The results of experimental data showed substantial agreement with the filtration equation.
Extended Drillpipe Life With Tighter Specifications
Authors: Shepard J. S.
Published: December 2007

This paper is for the benefit of the drill pipe end user, and for those operators who wish to minimize their risks in the drilling of any well.

It wasn't too long ago that drilling industry focus was concentrated on drilling a straight hole. However, with increased reservoir productivity allowed with hole deviations up to and including 90 degrees, dramatic advances in technology were developed to make this possible. More sophisticated drilling fluids, measurement while drilling (MWD), new directional tools, and Top Drives have all contributed to the efficient drilling of highly deviated wells.

However, improvements to the same degree have not been made to drill pipe. This explains the growing use of higher grade drill pipe to withstand the higher stresses of deviated drilling, such as higher torque, accelerated O.D. wear, increased drag, drilling in compression, and severe amplitudes of cyclic bending stress.
Drillstring Problems Related to Internal Upset-Run-Out Area of Drillpipe
Authors: Shaffer E. A.
Published: December 2007

Throughout the history of drill pipe use there has been an ongoing problem with fatigue failure. In recent years extensive studies have been performed to gather information in regard to early drill pipe fatigue failure. A very comprehensive report was published by API/IADC at the annual International Association of Drilling Contractors (IADC) meeting in September 1990. The report clearly identifies the major area of concern is at the transition area of the internal upset. Speaking conservatively, approximately 65% of the problems in this area originate from the inside surface. With this in mind a task was undertaken to develop an inspection system capable of reliably detecting inside or outside surface fatigue cracks in this part of the drill pipe tube.

The first step in development was to determine why existing inspection techniques were not successful in locating fatigue cracks in the upset transition area. Since the majority of equipment available relies on flux leakage principles some obvious problems became quickly evident. Pipe that starts developing internal fatigue cracks in the transition area has normally been in service for many years. Examination of the internal pipe surface usually reveals cracked and pitted coating or no coating at all. A typical electromagnetic inspection (EMI) type unit may or may not produce an indication of a crack in this area, dependent on the amount of flux leakage produced. Even if the pipe is suspected of having a crack, further prove-up is typically necessary by using a magnetic particle application. The problem begins here. Unless the inside surface is sandblasted to remove excess scale and coating, many false powder builds may be present. Therefore conventional magnetic particle inspection is limited. Magnetic particle inspection, at best, is only able to locate the larger cracks. Small cracks, in the early stage of development, can be easily overlooked. Another problem with conventional EMI systems is erroneous signals received due to abrupt changes in wall thickness at the transition area.

Therefore, improved inside surface crack detection and confirmation is needed. A development consideration was to design a system that would be able to locate and identify cracks independent of wall thickness changes, inside surface scale etc. Along with thickness changes the system needed the capability to reliably differentiate between inside and outside surface indications. A final consideration was to develop a system that was not too cumbersome or slow and could reliably repeat test results. The task was undertaken to develop an ultrasonic unit for the inspection of the drill pipe transition area. (Figure 1)
An Analysis of the Field Performance of Antiwhirl PDC Bits
Authors: Clegg J. M.
Published: December 2007

"Bit whirl", the backwards whirling motion of polycrystalline diamond compact (PDC) drill bits, has been identified as a significant contributory factor in the premature failure of PDC bits in the field.1 Two SPE papers have discussed bit whirl and the testing of various potential solutions, 1, 2 and one described the field testing of PDC bits modified to produce a "low friction gauge".3 This paper describes the design and subsequent testing in the laboratory and then in the field of a PDC bit designed from scratch to resist backwards whirling motion by incorporating various design features including the "low-friction gauge" concept described by Warren et al2 (described below as an "Antiwhirl bit"). It details the importance of the magnitude of the lateral component of the resultant cutting force on the bit and the angular extent of the bearing pads that react with this force, and describes and explains the directional behaviour of Antiwhirl bits in the field.
Bi-Center Bit Performance Reduces Drilling Cost in California
Authors: Quintana J. L.
Published: December 2007

The first polycrystalline diamond compact (PDC) bi-center bit application in California reduced cost per foot and helped eliminate tight hole problems associated with Pliocene age overpressured swelling shales. The bi-center bit design drills a larger hole than the casing inner diameter through which it passes.

Casing designs for two recent wells drilled below 15, 000 feet in the southern San Joaquin valley in Kem County, California required 7.625 inch flush joint liner to be run in an 8.500 inch hole. In the first well, the tight annular clearance of this casing and hole size combination resulted in a drilling liner sticking 3700 feet off bottom. This problem was avoided in the resulting sidetrack by underreaming the 8.500 inch hole to 9.875 inches. The second well also utilized the 9.875 inch underreamer method to successfully run a 7.625 inch flush joint drilling liner to bottom.

The bi-center bit design was used on a subsequent 16, 871 foot well to drill a 9.875 inch hole below 8.500 inch drift casing to reduce cost and eliminate the need for underreaming. The inherent mechanical risk of running an underreamer was eliminated and cost per foot was reduced by an average $31/ft. The cost savings associated with running the bi-center bit was $89, 000. Also, it was learned that hole geometry opposite the bi-center bit bottom hole assembly (BHA) greatly affects bit performance.

The bi-center bit concept was used again to drill a 6.750 inch sidetrack hole below 6.500 inch drift casing. Very tight hole conditions encountered in the original 6.500 inch hole were alleviated by the increased annular clearance provided by the 6.750 inch bi-center hole.
Drilling the Deepest Horizontal Well in the Gulf of Mexico, South Marsh Island 239 D-10
Authors: Jenkins R. W. , Patrickis A. N.
Published: December 2007

Texaco drilled the deepest horizontal well to date in the Gulf of Mexico from the South Marsh Island 239 D platform in the summer of 1990. The well was drilled to a depth of 10092 ft true vertical depth (tvd) and a measured depth (md) of 12871 ft. The well bore was totally displaced from the platform by 4905 ft with over 900 ft of horizontal section being drilled in a hydrocarbon bearing zone.

The paper discusses the application of proven shallow horizontal well drilling techniques as they pertain to the deep horizontal well. The same technology, previously published by Texaco on shallow horizontal drilling projects, was utilized on the deep well bore and the successes and failures of this technology will be discussed. The paper will highlight directional planning for a deep horizontal well from a platform location as well as drilling fluid design, logging while drilling, specific hole problems, bottom hole assembly usage and completion techniques. The South Marsh Island 239 D-10 well was drilled to the proposed target without great delay considering the difficulty of the directional plan. But, this well did encounter severe problems when attempting to run the production casing upon completion of the drilling phase. The paper will discuss lessons learned from these failures as well as possible corrections to be employed on future deep (below 7000 ft) horizontal wells.
Case History of a Horizontal Well Using a High-Angle Pilot Hole
Authors: Stacey E. S. , Rogers C. T. , Bowman J. K. , Noblett B. R. , Cooney M. F.
Published: December 2007

Petro-Hunt Corporation drilled a horizontal well in the Austin Chaikin Gonzales County, Texas. A high-angle pilot hole was used to determine a target interval and horizontal borehole orientation, while satisfying a variety of operational and geological considerations.

The well was directionally drilled to an angle of 44° and intermediate casing was set. The pilot hole was then drilled at the same angle through the target formation and evaluated using openhole logs, including a circumferential acoustic imaging device. After evaluation, the pilothole was plugged back, and the horizontal borehole was kicked off and drilled to a horizontal displacement of 3, 578 ft.

This method allowed the entire target formation to be evaluated prior to committing the wellbore to a particular interval, while avoiding potential operational problems associated with a vertical pilot hole. The acoustic imaging log allowed the operator to select the optimum Stratigraphic interval in which to locate the horizontal borehole, and confirmed the proper borehole orientation. The well was successfully completed on schedule and within budget.

The planning and drilling of the well is reviewed, with emphasis placed on operational and geological considerations and the evaluation of the pilot hole.
Rock Drillability Related to A Roller Cone Bit
Authors: Morris Richard I.
Published: December 2007

Security Engineering Division of Dresser Industries has utilized the basic bit penetration mechanism of a roller-cone rotary bit in the development of a drillability index for "hard" rock mining bits. A 1/8 inch radius, hemispherical drill bit element is pressed into a flat surface of a hand sample with a hydraulic pump and ram until a distinct crater is formed. The crater depth divided by the ram load constitutes a penetration or drillability index, p'/E. From this index, bit type, drilling weight, average penetration rate and approximate bit life may be determined. Field results have been well within the degree of accuracy consistent with sampling error.

Introduction

For several years there has been a need in mining and construction for a reliable method of determining drillability of hard rock by a simple test of hand samples. Early in 1966, Security Engineering Division of Dresser Industries began development of a method to measure rock drillability relative to a roller-cone bit used in drilling large (5 to 15 inches) blast holes. A rock strength value or drillability index was considered the essential value to be determined. From that value would be determined bit type, bit weight required, average penetration rate at a given rotary penetration rate at a given rotary speed, and bit life. Standard rock properties had not yet been reliably related to drillability, therefore, the basic bit penetration mechanism was adapted to a test device.
A Field Method for Controlling Drillstring Torsional Vibrations
Authors: Sananikone Prasert , Kamoshima Osamu , White D. B.
Published: December 2007

Torsional vibrations are detrimental to the life of drillstring components (1,2,3,4). Although methods of controlling them have been proposed (1,3,4), their general dependence on strain gauges to measure drillstring torque make them unsuitable for the drilling environment. In this paper we describe a new, practical, system which does not use such a sensor, and present extensive field test results taken from a semisubmersible rig drilling in the North Sea. The system was shown to be very effective in suppressing torsional vibrations. It uses measurements of motor current, acceleration and a microprocessor to modulate the drive to the motor.

An analysis is given to show that not only does the system performs just as well as one using a strain gauges sensor, but it also performs better than a system which uses motor current only. Considerations for the system design are also discussed.

A significant reduction of drillstring torsional vibrations, DTV's, will reduce the cost of drilling wells by reducing damage to drillstring components and lost rig time. Drilling efficiency is enhanced through the suppression of "stick-slip" motion at the bit.
Field Trials of the First RA-D (Rig Automation—Drilling) Automated Drilling Rig
Authors: Simpson B. K.
Published: December 2007

The only fully convincing way to overcome doubts and concerns over a new technology is to build a first-off and demonstrate the functional and performance capabilities to those who have the need and the authority to introduce new and operationally safe equipment.

Strachan & Henshaw have designed, built and works tested a full scale "Proof-of-Concept" RA-D rig and are now carrying out field trails by performing drilling operations. The drilling industry has been awaiting early release of these results.

The 454 tonne (1,000,0001bs) hook load, modular singles rig using hydraulic power and programmable logic control, has been constructed as a response to a call from the industry for improved safety, low manning, minimum weight, consistent performance and reliability.

RA-D is the result of technology transfer from several industries and represents a significant change in the way drilling facilities and operations can be planned, and managed in the future.

The project is producing results that confirm the concept and the paper discusses these in detail.

It will be seen that the project has crossed boundaries and overcome technical difficulties to produce marketable technology.

The paper also shows how this RA-D technology can be applied to a variety of applications and give short and long term cost benefits.

This first-build programme demonstrates co-operation between Operators, Drilling Contractors, Equipment Suppliers and Government agencies. Each regard the result as a major contribution to the developing technology of drilling from platforms, jack-ups, semi's and on land.
Innovative Steerable Underreaming BHA Design Overcome BOP Restrictions
Authors: Raitt Ferrier W. S. , Boyle John
Published: December 2007

As the number of slots on multi-well templates increase and extended reach wells become commonplace, there is an increased need for directionally controlled surface hole.

When implementing the above, BOP restrictions such as riser ID have necessitated drilling of a pilot hole which is subsequently underreamed to the required hole diameter for surface casing.

This paper describes the design/operation, performance and potential applications/limitations of a proprietary steerable system comprising a bit and underreamer below a downhole mud motor. This system provides directional control while drilling and hole opening simultaneously in a top hole section.

Field experience results from the British and Dutch sectors of the North Sea are discussed.
Efficiency Drilling Techniques for Increased Penetration Rates in the Gulf of Mexico
Authors: Weakley R. R.
Published: December 2007

Numerous techniques have been applied over the years in an effort to increase the drilling efficiency of Gulf Coast wells. While there are many innovative approaches to nippling up BOP's, wellhead configurations, bottom hole assemblies, etc., this paper focuses on those applied to the drilling fluids which significantly impacted increased penetration rates.

Many sophisticated mud systems and drilling practices have been developed over the years in response to borehole conditions and in many instances have resulted in a more complex, less efficient and less cost effective solution.

Through utilization of techniques herein described, penetration rates have generally at least doubled and in some instances a four and five fold increase in penetration rate has been realized without sacrificing borehole conditions.

This paper will describe the techniques for increased penetration rates in detail. Illustrations will include pit arrangement, hydraulics information, mud properties and flowline properties. Also, some case histories of wells will be discussed and some depth vs. hours curves will be illustrated.

These techniques have been utilized on both straight holes and directional wells in the Gulf of Mexico with great success. In all instances significant reductions in the cost per foot and days to drill have been realized.