bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the Erosion Velocity of a Cuttings Bed During the Circulation of Horizontal and Highly Inclined Wells
Authors: Martins A.L. , Campos W. , Liporace F.S. , Wei X. , Van Riet E.J. 
Published: December 2007

Abstract
Cuttings transport has been the topic of theoretical and experimental studies for many investigators, who have always focused, due to the complexity of the subject, on steady state flows. However, the adequate representation of the involved phenomena requires more realistic simulation of the process, which is typically transient. The test results presented here relates to the erosion of a solids bed, formed in a full scale flow loop, by different polymeric suspensions in annular flow, at several values of flow rates, wellbore inclinations and drillpipe rotational speeds. Adequate instrumentation allowed for the recording of the evolution of solids concentration and bed height as function of time. Analysis of the experimental data enables the prediction of the rate and time of erosion of the cuttings bed and can be used as guidelines for the optimization of the circulation of horizontal and highly inclined wellbores.

Introduction
The action of stopping drilling to flush cuttings out of the well is always a point of controversy among oilfield teams. The practice of circulating periodically the hole may avoid several operational problems during the drilling of a highly inclined wellbore. On the other hand, if minimum requirements for the cuttings bed removal are not achieved, circulation will be ineffective, time consuming and, in some cases, detrimental to wellbore stability.
The topic of drilled transport during drilling has been the subject of studies for many investigators (Iyoho, Sanchez, Peden et al.). who have all focused, on steady state flows. Martins et al. presented a discussion on the optimization of hydraulic parameters in the circulation of horizontal wells. In this study, the authors propose correlations for bed height prediction after circulation and for the critical flow rates for complete removal.
The development of drilling activities requires more realistic simulation of the process, which is typically transient, due to interruptions in the operations and instabilities of rock formations, which tend to generate higher amounts of solids than expected. Ref .4, for example, does not answer to the major question about the optimum time to circulate a well.
In the present work the authors propose a way to quantity the variation of the amount of solids removed from the annulus with time, during the circulation of horizontal and inclined wells. The main objective is to provide methods to evaluate the evolution of bed erosion for given hydraulic conditions. The study is based on an extensive experimental work conducted at University of Tulsa large scale physical simulator, as a cooperative program among PETROBRAS, SHELL INTL. E&P RTS and U. TULSA.
A Successful Short Radius Re-Entry with Aerated Mud in Venezuela
Authors: Ingold Charles , Salazar Julio , Carrasquel Jose , Vidal Jose , Ramirez Francisco , Gourgues Bernard , Paredes Juan Beltran 
Published: December 2007

Abstract
New horizontal wells drilled with aerated mud have proven to be a cost-effective way for drilling and enhancing well productivity. Reentry drilling operations using aerated mud have been used for over a year in Western Venezuela. A major operator considered for a long time to combine short radius technique and aerated mud to reduce cost per produced barrel. Several re-entry candidates appeared to be perfect for such an application.
A short radius drilling system, including articulated downhole mud motor and modified measurement while drilling (MWD) tools, combined with careful drilling engineering program has enabled a successful completion of the first two short-radius wells with aerated mud drilled in Latin America. The second of which resulted in a sixfold production increase over the average well in the area.
The first short-radius well was drilled in 13 days with 500 feet of displacement. The second well was drilled in 12 days and had 880 feet of horizontal drain (fig. 1 & 7).
This paper describes the operational aspects, and procedures followed. It emphasizes the equipment and rig selection, the training requirements, and the environmental and safety concerns. It also includes a comparison with other techniques.
Analytical Study of the Performance of Positive Displacement Motor (PDM): Modeling for Incompressible Fluid
Authors: Samuel G. Robello , Miska Stefan , Volk Len 
Published: December 2007

Abstract
Recent increases in the application of horizontal wells, in particular slim hole laterals, has triggered the need for more powerful downhole drill motors. To meet this need, motors require performance improvements which, in turn, requires development of a mathematical model.
This paper presents a mathematical model for the performance of positive displacement motors (Moineu type) for incompressible fluids. Generalized equations for the cross sectional area of the shalt, housing, volume generated and torque for multilobed motors help identify design improvements. The maximum motor torque requires an optimal relationship between the pitch of the motor and the diameter of the housing. A dimensionless index called the Performance Index (PI), helps generalize the various design parameters of the power section. Dimensionless performance plots establish a standard to compare the performance of actual motors to the ideal motor. Also, common parametric curves describe the effect of various design parameters on operating parameters.
Leakage and torque losses play an important role in the performance of a motor. These losses and their effects are also addressed. Numerical examples for incompressible fluids demonstrate the practical usefulness of the theory and optimal analysis.

Introduction
During the past two decades, extensive research and development have yielded highly efficient drilling systems to achieve cost reductions for high departure wells. The world wide acceptance of rotary drilling methods and tools made it difficult to introduce new drilling techniques. The current need to exploit low pressure oil reserves has required drilling more horizontal wells. Since many wells could probably be re-entered and completed with lateral holes, coiled tubing drilling technology (CTD) became of interest to service, major oil and gas companies. This almost mandates a downhole drill motor since coiled tubing cannot be rotated. Percussion hammer, positive displacement, turbine and electric motors can be use downhole but the positive displacement motor is currently preferred.
A variety of positive displacement motors are available but all have problems when used in coiled tubing drilling. Some simulation and performance studies exist for turbines, but no mathematical model adequately addresses performance of the positive displacement motor.
Percolation Modelling and Non-Newtonian Flows in Oil Reservoirs
Authors: Kadet V. , Polonsky D. 
Published: December 2007

Abstract
In this paper we had established the law for flow of viscous-plastic fluids in porous media with taking into account the inertial losses. Such rheological properties can be found in heavy viscous oils which contain components with high molecular weights. The obtained common relation between filtration velocity and pressure drop can be used for different applied simulations of heavy oil recovery from real reservoirs.
It has been considered the asymptotic properties of established macroscopic flow law for small and large velocities, and also investigated the correlation between macroscale limiting pressure gradient and parameters of microheterogeneity of the medium. A good qualitative agreement between the theoretical results and the experimental data was obtained. These data was taken for oil conditions of Arlanskoe field (Bashkortostan, Russia).

Introduction
The non-Newtonian behavior of many kinds of oils is a well-known phenomena for the reservoir engineering practice. That is why the problem of studying of this phenomena was in focus of investigators for a long time. However, at the most of the works it was not discussed the question about association between non-Newtonian properties of the macroscale flows and the microstructure of the porous media. The new analytical percolation approach was developed at last time. This approach allows to analyze wide spectrum of the problems of the underground fluid dynamics and gives the new understanding of the relations between peculiarities of the processes on the microscale and macroscale. Specifically, this methodology can be used for the investigations of characteristics of non-Newtonian fluid flows in porous media. In the previous works the nonlinear law for the Newtonian fluid flow in porous medium had been obtained with taking into account the inertial losses for the joints of capillaries and the phase permeabilities of a medium saturated by viscous-plastic fluids had been defined. Here we designed the model which allows us to obtain the nonlinear flow law of Binghamian plastic with consideration of the inertial losses. Also we carried out the qualitative comparison between our results and the experimental data for Arlansloe oil field (Bashkortostan, Russia). The two-phase displacement model had been investigated, and the relation between limiting pressure gradient and the saturation of porous media had been obtained for the case of steady-state flow.
Model for Predicting the Production Rate of Wells under Cyclic Steam Injection Process
Authors: Buitrago S. , Boccardo G. 
Published: December 2007

Abstract
In this work we present a methodology for matching and predicting the production rate behavior in time, for wells stimulated by cycle steam injection.
The production rate is given by the transient solution of the equation of the flow of a slightly compressible fluid in an infinite radial aquifer in a porous media. Also, expressions for the effective compressibility and permeability, based on experimental studies and production rate behavior from field data, are proposed
A function which gives the error between the production rate generated by the transient analytical model and the field production rate is presented. This function depends on the parameters associated to the expressions for the effective compressibility and permeability. A non linear global optimization technique to minimize the error function is presented in order to determine those parameters. The optimization technique combines a stochastic exploration of the domain of the error function and a heuristic calculation of a descent direction, in order to avoid stopping the algorithm at a local minimum.
The methodology was used to match the production rate behavior of several wells which have been cycle steamed in Costa Bolivar. In all cases, an excellent match with errors below 10% and similar parameters for the set of wells was achived.
Deep Duals Simplified
Authors: Webster K.R. , O'Brien T.B. 
Published: December 2007

Abstract
This paper presents information on simplified down hole dual equipment using two packer-bore receptacles installed as an integral part of the production liner. One receptacle is on top of the 5-1/2 inch casing liner and the second is at the crossover between the 5 inch and 5-1/2 inch casing as shown in Figure 1. The seal assemblies that fit into the packer-bores are both run on the long tubing packer-bores are both run on the long tubing string. The short string has a stinger with seals that fit into the upper dualflow seal assembly.
There are several advantages to dual packer-bore receptacle completions. Both packer-bore receptacle completions. Both tubing strings and seal assemblies are recovered by straight pickup, leaving the inside diameter of the casing unrestricted for remedial work. Cost to drill permanent type packers and the formation damage that takes place while drilling is eliminated. There are no mechanical devices such as latches and holddowns to stick. The simplicity and minimum number of required operations reduces the chances of mechanical failure.
Stimulation of both zones takes place the same day with all the permanent equipment and the wellhead in place. Treatment of each zone consists of several stages using 15% HCl acid. The number, size, and placement of the deep penetrating burr-free perforations is designed to produce good diversion of the acid into all intervals of interest within a zone.
Four wells have been completed by HNG Oil Company using the dual packer-bore receptacle method. Potentials and deliverabilities have ranged from very high to small, depending on the formation development. The first well has been on production without failure for 2 years at production without failure for 2 years at 30 to 40 MMCF per day.

Introduction
Four wells have been dual completed by HNG Oil Company using the dual packer-bore receptacle method. The packer-bore receptacles were installed in a combination 5-1/2 inch by 5 inch production liner. One receptacle is on top of the 5-1/2 inch casing and the other is a part of the crossover between the 5 inch and the 5-1/2 inch casing as shown in Figure 1. Both of the seal assemblies that fit into the receptacles are run on the long tubing string. The short string has a stinger with seals that fit into the upper seal assembly.
No Fluid-Loss and No Damage Gravel-Packing
Authors: Franco Z.A. 
Published: December 2007

Summary
A new method of gravel-packing a well is presented emphasizing the removal of installed damage, the prevention of new damage by avoiding formation fluid loss, and the use of an inexpensive and safe frac-pack tool.

Introduction
In unconsolidated formations, even for low overbalance, the rate of fluid loss is considerably high. The fluid loss generally causes damage which, in many cases, may require a workover job to be removed If the operator allows fluid loss to the formation, some problems such as water-in-oil emulsion, shale swelling, water block and salt precipitation may occur.
This work shows a new design in gravel-packing (GP) operation, which allows setting a sump packer, perforating, flowing the well for damage removal and gravel-packing in just one run, thus permitting to work in an underbalance way. The new design also presents a new fracpack tool which is simpler and less expensive than conventional tools.
The new design was conceived to solve critical problems in gravel packing in Dourado Field, in the northeastern Brazilian Continental Shelf. The use of the traditional methods resulted in very poor well performance. The lack of compatibility between rock and water base fluid was considered to be the main reason for the problem. The application of the new gravel-packing method turned-out to be the key for the successful development of the field.

Literature Survey
Recent papers concerning GP stress the need to avoid completion fluid interaction.
A high-density pre-pack followed by auto-injection of salt cushion to seal the perforations before GP and the utilization of a ceramic flapper-valve in the top-inside liner after GP are nowadays useful in solving this problem.
These methods do not avoid but just reduce fluid-rock contact. And they do not allow in many cases the use of a total rock-compatible fluid, as diesel oil, for instance, due to the high formation pressure gradient and the risk of overbalance trips.
Coring Samples and Obtaining Geomechanical Properties for Wellbore Stability Analysis in Deepwater Brazilian Horizontal Wells
Authors: de Sá Andréa Nicolino , Soares Antônio Cláudio 
Published: December 2007

Abstract
Deepwater exploitation is a risky and difficult task. This may be especially true when dealing with high deviated or horizontal wells producing from friable sandstone reservoirs such as those found in the giants fields Albacora and Marlim located in Campos Basin, offshore Brazil.
The determination of rock mechanics parameters in unconsolidated sandstones is an important step to better caracterize the rock, providing important inputs for better well planning, drilling, completion and production.
For poorly consolidated material, the task of keeping samples intact to be used in the Rock Mechanical Lab is very difficult. Thus a review of all the coring, core handling procedures and also the geomechanicals tests procedures to the direct measurement of rock strength and static mechanical properties is made.
Application of New Technologies to Horizontal Wells in Venezuela
Authors: Guimerans R. , Tovar J. , Pinto F. , Bolivar L. , Martinez A. 
Published: December 2007

Abstract
In Venezuela, at Maracaibo Lake (west) and Anzoategui-Monagas (east), there are reservoirs that have been under production for more than 30 years, which are presenting now low reservoir pressure. This situation has prompted the search for new technologies to maintain or increase the production in these zones. So far the technology that has been more successful is horizontal drilling, including the use of aerated drilling fluids and multilateral wells.
Up to date there are some 700 horizontal wells in Venezuela, with an average initial production of 800–1000 BPD per well. The majority of these wells are drilled setting a casing on top of the productive zone and changing the drilling fluid to one designed to properly seal and minimized formation damage. There are areas in Lake Maracaibo where the equivalent reservoir pressure is less than the density of water; the horizontal section is drilled with a mixture of air and water based fluid to achieve 3.5 – 6.5 ppg at bottom.
Multilateral horizontal technique has started with the design of wells with two arms, each in a different sand and opposite direction. Production can be commingled or set separately if needed.
This paper provides details of field applications of these technologies, production data and future projections.

Introduction
Horizontal drilling, as an emerging technology, had made possible an improvement in production from depleted reservoirs or from remnant narrow sands. In Venezuela, horizontal wells are drilled in two main areas: Maracaibo Lake in the west region and Anzoategui-Monagas in the east region, see Fig. 1.
Since the beginning of horizontal drilling in Venezuela, more than 600 wells had been drilled and over 1500 wells are expected for the year 2000 as Fig. 2 shows. These horizontal wells include mostly reentry wells to increase production of depleted reservoir from new exposed sands and new wells in narrow sands in order to incorporate remnant crude from them. From now on in this paper whenever horizontal wells are mentioned it should be taken as including both, new and reentry wells.
Due to the increase in horizontal drilling, technical aspects of the application of this technology in Venezuela are presented in this paper focused mainly in Maracaibo Lake. Improvement of application of horizontal drilling with other technologies, as aerated drilling, will be included.
The Influence of Heat Transfer on the Two-Phase Flow Behavior in a Wellbore During Transient Pressure Tests
Authors: Fairuzov Y.V. , Gonzalez J. , Lobato G. , Fuentes F. , Camacho R. 
Published: December 2007

Abstract
In this paper a numerical model was developed for the analysis of two-phase flow and heat transfer in a wellbore during a buildup test. The predictions of the model were tested with field data measured in a deep oil well. A detailed study of the influence of heat transfer between the wellbore and the surrounding earth on the bottomhole pressure response during well testing was carried out. The numerical results demonstrated that the variation of fluid temperature with time has a small effect on the bottomhole pressure buildup. The study revealed that an accurate prediction of temperature distributions in the wellbore and in the formation at the moment of shut-in is important for a correct description of the wellbore fluid flow behavior.

Introduction
Most of pressure buildup tests are performed by shutting in a well at the surface to reduce costs. In this case, at early times the bottomhole pressure response is a result of a dynamic 'interaction between the reservoir and the wellbore Therefore, understanding the physical phenomena occurring in a wellbore is important in the analysis of well tests. Several factors affect the pressure buildup during a well test, namely,
afterflow
phase redistribution,
fluid inertia and
heat transfer between the wellbore and the surrounding formation.
The first three above mentioned effects have been extensively studied in previous work. However, little information concerning the effect of heat transfer on the bottomhole pressure has been presented. Much of the past work on wellbore heat- transmission has concentrated on the development of methods for predicting the wellbore fluid temperature distribution in producing or injection wells. Most of the reported methods are based on steady-state models of wellbore fluid flow. To determine the formation temperature the transient heat conduction equation is solved analytically or numerically. However, during well testing the wellbore fluid flow is essentially unsteady. Under such circumstances, a steady-state wellbore flow model, which assumes equal flow rates at the inlet and outlet of the well, cannot be used to evaluate the effect of heat transfer on the bottomhole pressure response. The objective of this paper is to improve the understanding the processes occurring in the wellbore during a buildup test by taking into account the heat transfer between the fluid flow and the formation. For this purpose, a numerical model was developed to simulate the two-phase flow and the heat transfer in the wellbore Model validation was carried out through a comparison of computed results with field data. A detailed study was performed to investigate the effect of heat transfer on the bottomhole pressure buildup.