bluuebunny/crossref_metadata_2025_split huggingface dataset:
Geomechanical Analysis for Resak's Extended-Reach Drilling - A Case Example
Authors: Ong Seehong , Baim Ahmad Shah , Ibrahim Mohd Zaki , Zheng Ziqiong 
Published: December 2007

Abstract
This paper presents a case example to illustrate how a consistent geomechanical approach and coherent data integration are used to provide the basis for the evaluation of formation mechanical properties, characterization of in-situ stresses, identification of wellbore failure mechanisms, and calibration of a wellbore stability model. The calibrated model is then used in conjunction with the proposed build-and-hold and catenary well profiles to generate the mud weight windows for an ERD well. To provide further insight into the wellbore stability with respect to wellbore trajectories and in-situ stresses, contour plots of mud weights are generated for a critical depth interval. These contour plots delineate potential instability areas and are critical for predrilled well trajectory designs. Additionally, an innovative approach to establish the lower limit of mud weight for wells that cannot be drilled without failure zones (breakouts) forming around the wellbore is presented. This approach enables difficult wells to be drilled, with the lower mud weight reducing the risk of formation damage and increasing the rate of penetration.
Analysis of Extended Reach Drilling Data Using an Advanced Pressure and Temperature Model
Authors: Bjørkevoll K. S. , Anfinsen B.-T. , Merlo Antonino , Eriksen Nils-Harald , Olsen Espen 
Published: December 2007

Abstract
Two North Sea extended reach wells have been analyzed in detail by comparing downhole pressure and temperature measurements with results from an advanced pressure and temperature simulator. Drilling of 12 ¼ in. and 8 ½ in. sections are studied.
Early indications of hole cleaning problems were observed both on temperature and pressure. Calculations predict that downhole temperature is very flow regime dependent, and flow regime depends on eccentricity of the inner string, which therefore is important to take into account. It is also demonstrated that the presence of tool joints may influence temperature dramatically.
Improvements in the planning and modeling of the drilling of extended reach wells are suggested.
Modelling of Transient Cuttings Transport in Underbalanced Drilling
Authors: Doan Q. T. , Oguztoreli M. , Masuda Y. , Yonezawa T. , Kobayashi A. , Kamp A. 
Published: December 2007

Abstract
Underbalanced drilling holds several important advantages compared to conventional drilling technology. These include elimination of formation damage, faster penetration rate, ability for evaluation of reservoir productivity during the drilling process. As underbalanced drilling technology matures, it has also been used more and more. However, many aspects of underbalanced drilling technology remain poorly understood. The model presented in this paper seeks to understand the mechanisms involved in the transport of cuttings in underbalanced drilling.
The model simulates the transport of drill cuttings in an annulus of arbitrary eccentricity, and includes a wide range of transport phenomena including cuttings deposition and re-suspension, formation and movement of cuttings bed. The model consists of conservation equations for the fluid and cuttings components in the suspension, and the cuttings deposit bed. Interaction between the suspension and the cuttings deposit bed, and between the fluid and cuttings components in the suspension, are incorporated. Solution of the model determines the distribution of fluid and cuttings concentration, velocity, fluid pressure, velocity profile of cuttings deposit bed at different times.
The model is used to determine the critical transport velocity for different hydrodynamic conditions. Results from the model agree quite closely, qualitatively and quantitatively, with experimental data obtained from a cuttings transport flow loop at JNOC's Kashiwazaki Test Field in Japan. These results show the importance of slippage in the formation of the cuttings deposit bed. The model is useful in evaluating the minimum flow rate for effective cuttings removal in underbalanced drilling.
Reducing the Risk, Complexity and Cost of Coiled Tubing Drilling
Authors: Portman Lance 
Published: December 2007

Abstract
This paper focuses on arguably the most cost-effective application for coiled tubing drilling. The application is the non-steered extension of an existing well in the underbalanced state. This operation can be very fast and efficient with coiled tubing. However, the job design must minimize the associated risk to ensure problem free execution. This paper describes the steps required to minimize risks and therefore costs, and illustrates by way of example these steps in action.
Equipment for Mechanized Running of Tubulars on a Fifth-Generation Semi Submersible—Commissioning and Field Experience
Authors: Kinzel Holger , Peyon Albert , Lorenz Joerg 
Published: December 2007

Abstract
Despite the downturn in the industry, a new generation of Semi Submersibles has been developed and put into operation. This so called fifth generation of Semi Submersibles has ambitious goals in regards to operational safety and efficiency. The rig concept includes new ideas on how to make-up and run drillstring components, riser pipe as well as casing and tubing. Doubles, Triples or even Quadruples of pipe are being made-up at special "Mouse-hole stations" including their own mechanized handling and make-up equipment. By this means, many functions such as prefabrication of stands of risers, drill pipe and casing stands can be carried out offline without interrupting or delaying drilling operations. Considerable time- and cost saving is anticipated.
The paper describes the planning, development and implementation of the modular concept of the PowerFrame carrying the fully remote controlled power tongs that were installed on three of those rigs built in Brest/France and in Singapore. Actual field experience from a drilling location was not available when this paper was written (May 2000), as the first rigs are scheduled to arrive on location by June 2000. However, during the commissioning sufficient experience was gained to allow the prediction that the ambitious goals set in regards to time saving will be achieved.
Swiss Cheesing to Bring in a Jack-Up Rig at Anding Location
Authors: Maung U Mya , Ahmad Che Ku Mazuan 
Published: December 2007

Abstract
In April 1999, rapid spud can penetration was experienced while pre-loading a jack up rig at the Anding–A platform. The bow leg punched through a stiff clay layer at 11 meters, which caused the hull to tilt, resulting in all the three legs becoming bent and damaged.
After repairing the rig, it was towed back to the platform, and 26 inch diameter holes drilled in a grid pattern to break up and weaken the stiff clay layer below the aft spud can foot prints. This procedure subsequently allowed the rig to be pre-loaded and jacked up safely.
This "Swiss Cheese" technique of pilot hole drilling has been found successful in allowing an independent leg jack-up rig to be safely positioned on locations where the presence of a thin layer of stiff clay, underlain by soft / weaker soils, indicates the potential for punch-through. It is may also be useful in enabling a jack-up rig to be positioned on a location where there is a compatibility problem between rig spud-can spacing, and existing footprints.
Multi-Phase Flow in Several Layers Limits the Applicability of Conventional Buildup Analysis
Authors: Iakovlev S. V. , Lee W. J. 
Published: December 2007

Abstract
Conventional buildup analysis techniques are based on analytical solutions to the diffusivity equation that are subject to well-known assumptions. Single-fluid flow in a homogeneous reservoir is among them. During actual well tests multi-phase flow is often observed in several layers with different properties.
We investigated the applicability of the conventional pressure buildup analysis technique to the interpretation of complex cases involving flow of oil and gas in two layers communicating through the wellbore only. In this study we estimated the degree of error we should expect when conventional techniques are used. Our research shows that calculated values of average effective oil permeability and skin factor depend on a wide range of parameters, such as contrast in layer properties, production mode, production rate and production time prior to shut-in. We used a commercial black oil simulator with variable bubble-point to generate pressure and production data.
Several production forecasts were made using calculated values of permeability and skin in a single-layer reservoir model. A single-layer analogy produces acceptable results if the contrast in layer properties is not too great. If the contrast is high the forecasts generated by single-layer and two-layer reservoir models can differ significantly.
Oilfield Visualization on the PC Platform
Authors: Buckalew Chris , Mehdizadeh Masoud 
Published: December 2007

Abstract
Oilfield visualization software is still widely viewed as the province of expensive graphics workstations. Applications involving visualization of volumes and very large datasets are usually automatically assumed to require workstations. As PCs gain speed, functionality, sophisticated development tools, and fast graphics cards this assumption is less and less valid. This paper describes an oilfield visualization application developed for the PC platform, the tools implemented (including custom visualization tools for geologists), and the development process. As a result of this PC application, 3D visualization becomes less expensive and available to a wider variety of users.
Complex Hydraulic Fracture Behavior in Horizontal Wells, South Arne Field, Danish North Sea
Authors: Cipolla C. L. , Jensen L. , Ginty W. , de Pater C. J. 
Published: December 2007

Abstract
This paper provides a case history of complex fracture behavior in Horizontal wells in the South Arne Field, Danish North Sea (9500 ft TVD, chalk formations).1 The first three propped fracture treatments attempted in the South Arne Field "screened-out" very early in the design due to excessive fracture complexity and fluid leakoff. A detailed study of the rock mechanical properties, wellbore stress & fracture initiation characteristics, far-field stress regime & fracture orientation, and fluid leakoff behavior was integrated with fracture modeling studies to evaluate this problem. These studies were used to improve the fracture treatment strategy for future wells, resulting in essentially 100% success placing the designed proppant volumes and achieving aggressive tip screen-outs (TSOs) on over 60 fracture treatments.
Factors That Affect the Success of Mechanical Water Shut-off in Wells
Authors: A/Fotuh Mahmoud , Macary Sameh 
Published: December 2007

Abstract
Today, as the production life of most of the Gulf of Suez Petroleum Company (GUPCO) oil fields enters into maturity, the large offshore quantities of produced water represent severe problems from both technical and cost bases. Over-loading of surface facilities, excess gas required for lifting fluids, corrosion, and damage of the production strings are some of these problems. The handling of produced water becomes even more crucial due to ever-growing ecological and environmental interests and requirements. These constraints nowadays represent tough challenges for the petroleum industry. Therefore, water shut-off (WSO) processes become vital and strategic, especially under offshore production conditions. The present study investigates the history of rigless WSO jobs taken place in various reservoirs of different offshore fields operated by GUPCO. A new database was designed to compile the last 8 years of WSO jobs in GUPCO. The study also represents the most popular reasons for WSO decisions and provides some beneficial conclusions and recommendations based on GUPCO’s wealth of experience in this area. The statistical analysis of the available data has resulted in an optimized mechanical plan for MBPT. The analysis took into consideration all types of technologies, bottom hole conditions and the nature of the problem. The paper also provides a probabilistic analysis of these water shut off jobs to estimate the probability of success under particular circumstances
The Importance of Hydration Heat on Cement Strength Development for Deep Water Wells
Authors: Romero J. , Loizzo M. 
Published: December 2007

Abstract
After placement of cement on conductor and surface casing, the temperature anomalies caused by the hydration of cement can be substantial. From volumetric considerations, it is known that the maximum temperature anomalies depend on the size of the casing-annulus gap and the cement/water ratio as well as on reaction kinetics. For deepwater wells, because of the low temperature and large annular gap, special attention should be paid to the hydration process of the cement to properly design and evaluate the cement treatment. Currently, there is no universally accepted way of defining temperature schedules for testing cement setting. Operators and field locations rely mostly on local experience, and API-proposed temperature schedules are not applicable conditions where setting time is important such as deep-water conditions.
In an effort to better understand the dynamics involved with cement temperature during hydration, a numerical model was developed to predict the temperature evolution in the wellbore, cement and formation during the setting of cement. The model takes into account heat exchange with the formation and casing fluid (heating or cooling effect) as well as the heat generated during the hydration of the cement. The key parameters (formation thermal conductivity, cement thermal properties and annulus size) were assessed with the model.
Based on the model, a study was completed to characterize temperature and cement strength development. And this in turn is essential to properly design conductor and surface casings in deepwater conditions, which represent the most critical sections for ensuring a competent cement hydraulic seal and support the casing. The results of the study allow to define compressive strength schedules that effectively mirror down-hole conditions and thus give reliable estimates of the necessary wait-on-cement time that could lead to substantial savings for deepwater drilling operations.
New Developments in Aerated Mud Hydraulics for Horizontal Well Drilling
Authors: Sunthankar A. A. , Miska S. , Kuru E. , Kamp A. 
Published: December 2007

Abstract
Drilling using aerated muds offers a major advantage in controlling mud effective density, enabling both underbalanced and balanced drilling. However, planning of aerated mud drilling operations is difficult due to complex hydrodynamics of aerated mud flow, resulting in a lack of confidence in predicting and controlling operational variables. It is, therefore, necessary to better understand the hydraulics of aerated mudflows in order to be able to accurately calculate bottomhole pressure and optimal flow rates for drilling.
Pressure losses are a strong function of gas-liquid flow patterns. The existing methods of predicting flow patterns are based on an extrapolation of results from pipe flow to flow in annuli. Therefore, to verify the applicability of this existing practice, the present study focuses on hydraulics of aerated fluids through a large-scale annulus.
Extensive experiments were performed in a unique field-scale low-pressure flow loop (8" X 4.5", 90’ long) in horizontal position with and without drillpipe rotation. The liquids used were water and aqueous polymer solution (CMC+XCD+water), at flow rates in the range 75–360 gpm and air in the range 10–1000 scfm. Measurements of pressure drop and average liquid holdup over the entire annular section were carried out. To our knowledge, no such data has been published before.
It was observed that intermittent flow was present for most of the cases, which is contradictory to some existing field and simulation practices that assume homogeneous gas-liquid flow. Also, the flow pattern boundaries are shifted as compared to pipe flow, which necessitates the modification of flow transition criteria. To account for these changes, a pipe flow model for prediction of flow pattern boundaries was modified for flow in annuli.
Higher frictional pressure drop was observed in case of flow with drillpipe rotation. Also, a higher frictional pressure drop was found in case of air-non-Newtonian fluid flow as compared to air-water flow. The results of this study show that two-phase pipe flow models, modified for two-phase flow in annuli, considerably under-predict pressure drop occurring during the two-phase flow in annuli.
Advanced Permeability and Anisotropy Measurements while Testing and Sampling in Real-Time Using a Dual Probe Formation Tester
Authors: Proett Mark A. , Chin Wilson C. , Mandal Batakrishna 
Published: December 2007

Abstract
Three new pressure-transient testing methods are employed to determine horizontal and vertical permeability using a dual probe formation tester. Real-time interpretation during acquisition of pressure data, is the focus of all three new pressure-testing techniques. In the first, a new spherical flow model with anisotropy, storage, and skin is developed from first principles for dual probe analysis. Historically, pressure transient solutions are presented as Laplace transforms and approximated in the time domain using numerical techniques. Typically, early, intermediate and late time periods are identified using derivative plots; but very often, the selection of appropriate data results in confusion. Here, the Laplace transform is inverted to yield a single, exact, closed form, analytical, time domain solution valid for all times, making real-time parameter matching possible with high accuracy.
The second technique uses an oscillatory displacement source at the piston face, and the phase delay of the pressure pulse between the probes is used to determine permeability and anisotropic index. This technique is particularly useful when the second monitoring probe signal is weak (as in high permeability zones) or where there is large spacing between the probes. Pulse timing can usually be detected more accurately than its magnitude, thus extending the range of permeability and anisotropic measurements. This methodology, which is based on a derived relationship between wave phase and permeability, was developed by mathematical analogy with resistivity determination methods used in induction logging.
In the above method, it is often possible to encounter "phase wrapping" for excessively tight formations, leaving an indeterminate permeability. To circumvent this problem, in the third method, a short, abrupt "pulse" having a well-defined "center frequency" is produced at the piston face, and its travel time is measured until arrival at the receiver probes. The harmonic, closed form expression is then used to translate this travel time to permeability. This new method is analogous to sonic wave models; although, of course, "waveforms" are often smeared due to the diffusive nature of the problem.
Simulation results using a detailed finite element, dual probe model are compared against the above analytical methods to assess the effects of near wellbore parameters such as mudcake effectiveness, probe, and packer size. Field-test results are shown to demonstrate the successful implementation of these new testing methods. The three methods described above provide a practical level of redundancy in permeability prediction. Also, monitoring permeability and anisotropy changes while sampling are shown to be beneficial in identifying fluid type changes.
Quantifying Uncertainty in Production Forecasts: Another Look at the PUNQ-S3 Problem
Authors: Barker John W. , Cuypers Maarten , Holden Lars 
Published: December 2007

Abstract
A synthetic reservoir model, known as the PUNQ-S3 case, is used to compare various techniques for quantification of uncertainty in future oil production when historical production data is available. Some results for this case have already been presented in an earlier paper1.
In this paper, we present some additional results for this problem, and also argue an interpretation of the results that is somewhat different from that presented in the earlier paper. The additional results are obtained with the following methods: (i) rejection sampling, (ii) history matching of multiple models using a pilot-point approach, and (iii) Markov Chain Monte Carlo (MCMC).
A Novel Approach for Reservoir Forecasting under Uncertainty
Authors: Mishra S. , Choudhary M. K. , Datta-Gupta A. 
Published: December 2007

Abstract
This paper presents a novel approach for developing statistical estimates of uncertainty in reservoir performance from only a limited number of multiphase flow simulations while using information from a full suite of geostatistical realizations. The proposed methodology involves ranking and weighting geostatistical models on the basis of a surrogate performance measure, and estimating the mean/variance of the desired performance measure via a weighted average of simulation results from a few selected realizations. The streamline time-of-flight based volumetric sweep efficiency is used as the surrogate performance measure to rank geostatistical models, and their weights are determined from a moment-matching algorithm which enables the approximation of a continuous distribution by a discrete distribution. A field example is used to demonstrate the applicability and computational efficiency of the proposed methodology.
Gas Cap Monitoring in high flow rate, low porosity clastic reservoirs in Colombia gives big economic returns
Authors: Bullion David , Gonzalez Fabio , Markley Marvin E 
Published: December 2007

Abstract
Cased hole neutron logging has been around for a long time and is often used to monitor gas movement in reservoirs behind pipe. This often works well in high porosity reservoirs but is rarely successful in low porosity reservoirs. In Colombia, there are high flow rate reservoirs with significant permeability, that have low porosity (5-6 PU).
The challenge was to monitor gas cap expansion, fluid movement due to re-injection, and voidage. At the same time the objective was to identify low GOR intervals behind pipe for possible recompletion.
A number of different examples are shown to illustrate both the technique and the economic benefit of the monitoring program. Many of these wells contributed significant additional oil from bypassed zones that were initially thought to be dry gas. In some wells, the instantaneous incremental production was over 10,000 BOPD from a single recompletion.
Gas cap monitoring in very low porosity reservoirs in Colombia proved to be not only feasible, but extremely profitable by differentiating dry gas zones from low GOR zones.