bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improving Multilateral Drilling and Completion Efficiency with a Hollow Whipstock
Authors: Foster Jeffrey L. , Olds Kelly T. , Stebbings R. Paul K. , Giangiacomo Leo A. , Durst Doug , Carter Thurman 
Published: December 2007

Abstract
A multilateral completion allows one or more laterals to be connected to a parent wellbore so that production from each can be isolated or commingled, and all laterals can be accessed. One of the challenges in multilateral drilling has been in regaining access to the main wellbore after the window has been milled and the lateral drilled. Typically, a solid whipstock has been used to mill the window and drill the lateral; it was then retrieved, and a hollow whipstock run to provide access to the lower main wellbore and allow for the passage of produced fluids. Difficulties were sometimes experienced, however, when retrieving the solid whipstock and realigning the hollow whipstock.
This paper will discuss a new single-trip hollow whipstock that can be used for milling a window as well as for production. This innovative design eliminates the risk posed by retrieving the solid whipstock and realigning the hollow whipstock with the window. Since the hollow whipstock is set only once, it remains aligned with the window throughout the life of the well. This assures reentry into the lateral and eliminates any restrictions due to misalignment across the window from a reset whipstock. The discussion in this paper will include information on the design, application, and testing of the new whipstock and will verify its capability to reduce the risks, number of trips, and cost of multilateral installations as well as enhance downhole performance under the challenging conditions inherent with multilateral configurations.
P. 629
Rotary Liner Drilling for Depleted Reservoirs
Authors: Sinor L.A. , Tybero P. , Eide O. , Wenande B.C. 
Published: December 2007

Abstract
This report summarizes the testing and field application of a rotary liner drilling system. Liner drilling was first attempted by Amoco Norway Oil Company (ANOC) in 1993 and there have since been eight additional wells drilled using rotary, motor, and a combination rotary/motor liner drilling system. This paper will focus on six of those wells drilled with a rotary liner drilling system. Key learnings from these well applications in the Norwegian sector of the North Sea are reviewed.
P. 879
Mathematical Modeling of Secondary Precipitation from Sandstone Acidizing
Authors: Ying-Hsiao Li , Fambrough John D. , Montgomery Carl T. 
Published: December 2007

Summary
Field and laboratory experience clearly demonstrate that besides primary dissolution, precipitation from both secondary and tertiary reactions with alumino-silicates adversely affect matrix acid treatment success. In the secondary reaction, fluosilicic acid from the primary dissolution will further react with aluminosilicates to form hydrated silica on the matrix surface. In the tertiary reaction, aluminum fluoride also extracts aluminum from alumino-silicates to form silica gel by lowering the F/Al ratio in the solution. In the presence of a high concentration of metal ions, metal fluorides and fluosilicates are also likely to precipitate.
An optimum acidizing design package can be derived for a specific formation mineralogy and damage mechanism if this complex reactive system can be modeled properly. A geochemical model for acidizing has been developed for this purpose. The numerical simulator is a reactive flow model that solves the reactive system with both reaction kinetics and chemical equilibrium calculations. All possible reactions among all species in the system are solved simultaneously. As acid spends the computer simulation shows the progress of aluminosilicate dissolution and the formation of different precipitates as the change of dissolved species along the reaction path occurs. The evolution of the damage skin can be evaluated as simulation continues. Based on the simulation, different pumping schedules with different types of acids can be quickly evaluated in order to optimize treatment volume and minimize precipitation of hydrated silica and other precipitates.
To validate the model a series of laboratory coreflood tests has been fully analyzed. The results indicate that the formation of silica gel is significant based on the HF effluent analysis. The same set of kinetic data derived from the laboratory coreflood data adequately predicts and explains a sandstone acidizing field case.
P. 27
Formation Damage Prevention by Using an Oil-Based Fracturing Fluid in Partially Depleted Oil Reservoirs of Western Siberia
Authors: Cikes Marin , Cubric Srecko , Moylashov Mekhraly R. 
Published: December 2007

Abstract
Comparing with water-based fluids, oil-based fracturing fluid is not in wide use. The main reasons are lower cost effectiveness and more dangerous handling of oil-based fluid. However, as non damaging fracturing fluid, the oil-based fluid has numerous advantages over water-based. In fact, in many cases, where water-based fluid failed, switching to oil-based fluid resulted with successful stimulation of well productivity. One of such cases is fracturing of partially depleted oil reservoirs of Bakhilov and North Khokhryakov fields in Western Siberia, Russian Federation.
The oil fields were discovered in 1983. Production started in 1987 and water injection began in 1988. The peak oil production was reached in 1991/92, followed by drop of 50%. An attempt was made to increase wells productivity by performing small hydraulic fracturing treatment using water- based fluid. Although it resulted in some increase in wells productivity, the analysis of that treatments suggested necessity for longer fractures and careful tailoring of fracturing fluid.
Recently the twenty-three fracture treatments have been performed using an oil-based fracturing fluid and pumping significantly higher quantity of proppant. The result is excellent: nearly all wells started to flow at the average initial oil rate of 70 m3/day [440 bopd] what is more than ten-folds production increase in comparison with pre-fracture production. Comparison of median values of early and late post-fracture production indicates sustained productivity improvement.
P. 121
New Single Trip Perforating and Gravel Pack Procedure with Advanced Stimulation Design Reduces Formation Damage in High Permeability Sandstone Reservoirs: Case Histories
Authors: Jones Ralph H. , Bolin Tommy D. 
Published: December 2007

Abstract
Fluid loss that can occur when performing sand control operations in high-permeability sandstone formations has traditionally caused operators much concern because of the formation damage that can result, reducing production potentials and increasing operational costs. In the Gulf Coast area, wells are usually perforated with tubing conveyed perforating (TCP) guns in an underbalanced condition. After the perforating and well flow processes have been performed, the wells are killed. Unfortunately, at any time after the well has been perforated until it is completed, fluid loss can occur.
This paper will discuss a new process in which the perforating gun assembly is incorporated with the gravel pack assembly to allow perforating and gravel packing to be accomplished in a single trip. By eliminating the time and additional trips required to perforate and clean up the well before gravel packing the zone of interest, the chance of fluid loss is significantly reduced. Other innovative methods have also been introduced to minimize formation fluid losses and eliminate the use of formation-damaging lost circulation material (LCM) during performance of the sand control procedures. Several operators have recently completed wells in the Gulf Coast area using the new single-trip perforate-and-gravel-pack procedure (STPP) and advanced stimulation design, and low skin factors have been experienced.
The operating procedures as well as the increased efficiency and cost savings for which the new procedures have been responsible will be discussed, and the post-operational data provided will verify that reduction in formation damage is experienced when the new methods are used.
Development of a New Crosslinked-HEC Fluid Loss Control Pill for Highly-Overbalanced, High-Permeability and/or High Temperature Formations
Authors: Chang F.F. , Ali S.A. , Cromb J. , Bowman M. , Parlar M. 
Published: December 2007

Abstract
The loss of brine to the hydrocarbon formations has been one of the major concerns during well completion operations. Fluid-loss control pill scontaining sized particulates, such as CaCO3 or sized salt, have often been used. However, damage to the formations and gravel packs by the solids due to solids invasion often causes reduced production and an expensive workover. The cleanup of the carbonate pill is often ineffective, especially in long intervals, since the reaction between acid and carbonate is too fast for the acid to cover the entire zone. Therefore, a reliable viscous fluid system without solids is more desirable than a particulate system. In high-permeability reservoirs, a highly crosslinked gel is needed to achieve good fluid-loss control hydroxyethylcellulose (HEC) is known for its low residue content and difficulty to be crosslinked. A highly elastic zirconium crosslinked HEC gel is achieved by using an activator and a chelant. A delaying agent is used to adjust the timing of the crosslink process. The gel is capable of stopping fluid loss in formations of 2 darcies and above at temperatures upto 290 F. Internal and/or external breakers can be used to reduce the gelviscosity to near water consistency.
P. 215
Asphaltene Near-wellbore Formation Damage Modeling
Authors: Leontaritis Kosta J. 
Published: December 2007

Abstract
When during oil production the thermodynamic conditions within the near-wellbore formation lie inside the asphaltene deposition envelope of the reservoir fluid, the flocculated asphaltenes cause formation damage. Mathematically, formation damage is a reduction in the hydrocarbon effective mobility. Three possible mechanisms of asphaltene-induced formation damage have been discussed in the literature. Asphaltenes can reduce the hydrocarbon effective mobility by a) blocking pore throats thus reducing the rock permeability, k, b) adsorbing onto the rock and altering the formation wettability from water-wet to oil-wet thus diminishing the effective permeability to oil, kO, and c) increasing the reservoir fluid viscosity, by nucleating water- in-oil emulsions. In the most frequently encountered case of asphaltene-induced formation damage where an under- saturated oil is being produced without water, the most dominant damage mechanism is blockage of pore throats by asphaltene particles causing a reduction in rock permeability k. This paper presents a rather simple, yet realistic way of modeling asphaltene-induced near-well formation damage caused by blockage of pore throats by asphaltene particles. The model utilizes both macroscopic and microscopic concepts to represent the pore throat blockages. It also utilizes the Thermodynamic-Colloidal Model of Asphaltene, TC Model SM, an existing AsphWax asphaltene phase behavior model capable of simulating the asphaltene particle size distribution as a function of the thermodynamics of the system. The new asphaltene near-well formation damage model is applied in one case where it is used to track the degree of formation damage as a function of time and the effect it has on near-wellbore and wellbore hydraulics. Similarily the model can be used to study a propr: the economics of developing a reservoir knon to contain an under-saturated aspaltenic oil.
P. 277
Use of Downhole Diagnostics Enhances Determination of Damage Mechanisms
Authors: Yeager V. J. 
Published: December 2007

Abstract
This paper presents a systematic approach used in an intensive, 2-year study that was funded by the Gas Research Institute (GRI) and Department of Energy (DOE) and undertaken to determine the damage mechanisms that affect the over 15,000 U.S. gas storage wells.1 Multiple diagnostic tools were used to determine the damage mechanisms in 32 wells in 12 different reservoirs.
The approach used included (1) transient pressure analysis and well testing to quantitatively determine if damage existed, (2) downhole video to observe the wellbore and formation areas, (3) physical sampling of downhole liquids and solids, and (4) rotary sidewall coring of the wellbore face to provide a "biopsy" of the formation of interest.
This paper also includes (1) special sampling/handling considerations and laboratory procedures that were developed and (2) illustrations of some of the various damage mechanisms that were identified.
Post-Frac Analyses Indicating Multiple Fractures Created in a Volcanic Formation
Authors: Sato Kozo , Wright Chris , Ichikawa Makoto 
Published: December 2007

Abstract
The technology of hydraulic fracturing is faced with a conceptual transition from a classical single-planar fracture to a tortuous fracture network and simultaneously propagated multiple hydraulic fractures. This new concept is applied to analyses of two propped fracture treatments conducted in a volcanic formation. In both cases, the productivity was doubled, but the treatments themselves were unsuccessful, experiencing extremely high net fracturing pressures and very premature screen-outs.
The classical concept of a single-planar fracture could not explain either the fracturing-pressure behavior or the post-frac production rate/pressure. Adopting a multiple-fracture geometry resolves this problem. The fracturing pressures are successfully simulated, and the resultant fracture geometries are consistent with both the premature screen-outs and the post-frac production performances. Combined analyses of fracturing pressure and subsequent production performances firmly confirm the creation of multiple fractures in a volcanic formation.
P. 145
A New Semi-Analytical Pressure Transient Model for Layered Gas Reservoirs Under
Authors: Gomes E. , Reza Z.A. 
Published: December 2007

Abstract
Reservoir deposition occurs over geologic period of time and thus, most of the reservoirs are layered in nature. These layers may or may not communicate with each other. This study develops a new semi-analytical model for pressure transient analysis of layered gas reservoirs. Apart from layering, in a gas reservoir the flow problem is further complicated by high velocity effect, pressure dependent gas properties, and wellbore storage and skin. Discretizing only the vertical direction term to account for the cross flow, and using pseudopressure and pseudotime approach, the diffusivity equation has been solved as a generalized eigenvalue problem. The model takes into account inter-layer crossflow, high velocity effects, wellbore storage and skin (both as thin skin and finite damaged zone), and different possible inner and outer boundary conditions.
P. 223
Effect of Friction and Leak-Off on Fracture Parameters Calculated form Hydraulic
Authors: Soliman M.Y. , Azari M. 
Published: December 2007

Abstract
Hydraulic impedance may be used to determine fracture geometry, length and height. However, the models for analysis of impedance tests presented in literature usually ignore the effect of friction and fluid leak-off. This paper presents and solves an impedance testing model that considers the effects of friction and fracturing fluid leak-off. A test that has been presented in literature has been analyzed, and this paper will show from this analysis that ignoring these two factors may cause a significant error in estimating fracture parameters.
P. 245
Formation Evaluation in Lower Eocene Reservoirs in Upper Assam Basim: An
Authors: Borah N.M. , Mallick R.K. , Choudhuri B. , Raju S.V. , Mathur N. 
Published: December 2007

Abstract
Evaluation of thin, highly permeable, stratified reservoirs in the Lower-Eocene Formation in Upper Assam, India poses a formidable challenge. The problems include identification of thin beds, ascertaining the type of fluid based on wireline log response. establishing vertical and lateral continuity of the reservoirs and stratified nature of these thin reservoirs. An integrated multidisciplinary approach has been adopted for solving these complex formation evaluation problems.
P. 315
Artificial Intelligence Approach for Well-to-Well Log Correlation
Authors: Lim Jong-Se , Kang Joe M. , Kim Jungwhan 
Published: December 2007

Abstract
This paper describes a new approach to automated well-to-well log correlation using artificial intelligence and principal component analysis. The approach to correlate wireline logging data is on the basis of a large set of subjective rules that are intended to represent human logical processes. The reliable correlation can be established from the first principal component logs derived from both the important informations around wellbore and the largest common part of variances of all available well log data. The data processed are mainly the qualitative informations such as the characteristics of the shapes extracted along log traces. The apparent geologic zones are identified by pattern recognition for the specific characteristics of the computed principal component log trace. The characteristics are collected as a set of objects by object oriented programming. The correlation of zones between wells is made by rule-based inference program.
Correlation with field log data shows that this approach can make well-to-well correlation more reliable and accurate. This method can be used for well-to-well log correlation with efficiency and accuracy.
P. 333
Array Induction Modeling Results From Indian Formations
Authors: Suryanarayana K. , Singer J.M. 
Published: December 2007

Abstract
The Array Induction Tool (AIT) has significant advantages over standard induction tools in terms of vertical resolution, depth of investigation and the ability to detect moved oil. India is generally considered Laterolog country. However in many areas the conditions are such that either Induction or Laterolog is appropriate; the Laterolog has often been chosen because of its higher vertical resolution compared to the standard Induction.
The AIT offers vertical resolution down to 0.3 Mts. and depths of investigation up to 90 inches in many conditions. This is significantly better than the Laterolog. In order to understand the response of the AIT, the resistivity characteristics of five Indian reservoirs have been examined. This study includes cases of resistive and conductive invasion, invasion profiling in shaly sandstones, invasion seen by standard induction, thin beds and response in a layered reservoir. In each case the response of the standard logs (Laterolog or Induction) have been modeled and compared with the response of the modeled AIT
The results show that in the most situations the AIT provides a better estimate of true formation resistivity, Rt. The improvement is towards reading resistivity values close to the Laterolog resistivity in the oil zone, and also reading a correct resistivity value in the water zone as expected by the Induction tool. The combined improvement enhances confidence in the computation of hydrocarbon saturation significantly. The AIT, therefore, detects moved oil more reliably, and hence facilitates decision on further investment.
The theoretical modeling work has been validated by two field cases in a sandstone environment. Comparison with the available Laterolog data clearly brings out the advantage of the AIT in terms of vertical resolution as well as in describing the invasion profile. Using the field data, the AIT logs were reconstructed through modeling. The reconstructed values match the field data, except in cases where highly irregular profiles are seen on the field data.
P. 353
Dealing with Uncertainty: Geostatistics and the New Era in Reservoir Studies
Authors: Simlote V.N. , Nikolayenko S.A. 
Published: December 2007

Abstract
Predominantly, reservoir characterization techniques involved the traditional layer-cake models, which are known to be simplistic for complex sedimentologic environments. One of the Oxy operated fields presented a problem in accounting for the heterogeneity of its reservoir. Limitations posed by the conventional models prompted the search for newer methods in order to describe this reservoir more accurately. With the help of the leading integrated geostatistical package that offered stochastic modeling Options, the new full-fledged reservoir model was successfully built. Unlike its deterministic predecessor, it demonstrated an increased flexibility in accounting for the heterogeneities in the field. The strength of the geostatistical software is in its ways of dealing with uncertainty. The software is based upon the Boolean technique that allows for building a reservoir model created from objects that have some genetic significance rather than the model being built up one elementary node at a time.
P. 383
Strategy for Control of Water and Gas Cresting in a Thin Oil Column Using Horizontal
Authors: Shrivastava Vijay K. , Singhal Ashkok K. , Wang James J. 
Published: December 2007

Abstract
The exploitation of a thin oil column overlain by a large gas cap, and underlain by a huge aquifer by horizontal wells is challenging due to an early development of gas and water crests. This paper examines a strategy for alleviating the excessive production of gas and water by controlling the movement of fluid interfaces. This is achieved by withdrawing gas cap gas, and aquifer water, by means of separate horizontal completions, one each in the gas cap and in the aquifer, which are parallel and aligned with the oil zone completion. The gas cap gas, aquifer water, and oil are produced through separate strings. The high-pressure gas can be sold or utilized, and the produced water can be disposed of at the surface or subsurface.
The simulation results indicate an increase in the oil reserves to the extent of 25–50% over a conventional horizontal well for different ratios of vertical to horizontal permeability, over a 5 years period. The proposed system offers a relatively easy effluent handling, and sustained production of normal GOR, low water-cut oil for a longer duration of time. Proper well steering, completion, and its maintenance are identified as keys to the economic success of the strategy
P. 413
Optimization of Water Injection in a Sandstone Reservoir: A Successful Case Study
Authors: Ahmed A. Elias , Murthy R.V.S. , Bharkatya D.K. , Sengupta T.K. 
Published: December 2007

Abstract
Steps taken for a speedy evaluation for successful optimization of water pattern by detailed reservoir characterization, is discussed with reference to an Eocene sandstone reservoir of Kalol field India. The reservoir without water aquifer support has 30 years of production history. Water injection was done for 25 years in a central line drive consisting 8 injectors aligned in N-S direction. The main production problem was the rapid decline in reservoir pressure in the main pool, from 237 to 77 Kg/cm2 for a production of 25% OOIP. Performance reviews carried out in 1981, 1982 and 1990 suggested various steps such as increase in water injection rates, switching to peripheral injection besides central line drive and infill drilling to arrest the decline in reservoir pressure but without success. Integrated genetic facies modeling done in 1992, suggested reduction of the amount and redistribution of water throughout the fiel away from the most permeable parts. This has improved the production performance after 25 years by way of arrest of pressure decline.
P. 465