bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Method for Computing the Vertical Coverage for an In-Situ Combustion Process
Authors: Mikkelsen P. L. , Ramey H. J. 
Published: December 2007

Abstract
The Dykstra-Parsons approach for computing the vertical coverage of a waterflood has been modified in order to estimate the vertical coverage for an in situ combustion process. The modified approach for combustion ignores the effect of gravity forces in determining burn thickness. It simply assumes that the burn moves to the top of the pay zone. Burn thickness is then shown to be dependent upon the reservoir permeability variation, the mobility ratio of the injected gas (containing oxidant) to the combustion gas, initial reservoir temperature and the combustion temperature.
The model was successfully applied to field core data from the Fosterton Northwest combustion project, using spreadsheet software on a personal computer. An average 31 percent burn thickness determined from the model, compared favourably with a field-observed value of 34 percent which was determined by post-burn coring. The model performance was improved by using multiple pseudo-permeability variations for the core data, instead of a single variation value, as is often used when applying the Dykstra-Parsons model.
Characterization of Residual Hydrocarbons in Produced Water Discharged From Gas Production Platforms
Authors: Callaghan D , Baumgartner W. 
Published: December 2007

ABSTRACT
An investigation is described to select the best practical technique for reducing the residual hydrocarbon in produced water discharged from gas production platforms to less than 40 mg/l. The aliphatic and aromatic components of the dissolved and dispersed hydrocarbon have been separately measured on a number of platforms, together with the droplet size distribution for the dispersed phase.
In addition to previously recognized problems caused by high pressure drops together with corrosion inhibitor, disposal of condensed vapours from glycol regeneration has been identified as a major contributor.
Significant reduction in the level of total residual hydrocarbon can be achieved in future by process modifications instead of ‘end of pipe’ solutions.
Lacq Gas Field (France): Monitoring of Induced Subsidence and Seismicity Consequences on Gas Production and Field Operation
Authors: Maury V. , Grasso J. R. , Wittlinger G. 
Published: December 2007

ABSTRACT
Between 1957 when the Lacq gas field was first put into production and 1967, a 3 cm subsidence occurred. This period corresponded to a 30 MPa depletion. From 1967 until 1989, further depletion of 25 MPa induced an additionnal subsidence of 2.5 cm which this time coincided with more than 1000 microearthquakes and earthquakes, 44 with magnitudes greater than 3 and 4 with magnitudes greater than 4.
This paper gives a brief review of earlier case histories. It then goes on to describe a local seismic monitoring network which was installed on the Lacq field. The method used for processing and interpretating the seismological data takes into account the lithologies and the mechanical properties of the rocks and the source parameters. From the information obtained, the global mechanism of the gas field deformation appears to be the lowering of a rigid block located at the top of the structure by a succession of reverse movements along preexisting fractures and faults.
The paper goes on to demonstrate the practical consequences with regard to safety and gas production, and the contribution to our knowledge of reservoir behaviour over the course of time. Close monitoring of subsidence and seismic events is a new and useful aid to understanding the reservoir response to fluid withdrawal.
Thixotropic Cementing With Coiled Tubing at Prudhoe Bay
Authors: Welch J. L. , Mason C. M. , Pavlich J. P. 
Published: December 2007

ABSTRACT
This paper presents a new coiled tubing unit (CTU) thixotropic squeeze cementing technique developed by BP Exploration (Alaska) Inc. for use in remedial cementing operations on water injection wells and other wells with low fracture gradients. Results of application of this technique are also presented.
Preliminary attempts at squeeze cementing seawater injection wells with conventional CTU cement slurries have required multiple attempts and very large volumes of cement. In some cases these conventional CTU squeezes have been relatively unsuccessful.
This thixotropic squeeze cementing technique has been utilized to successfully squeeze seawater injection wells. This is believed to be the first time a cement system designed with thixotropic properties has been successfully used as part of a coiled tubing workover technique.
Quantitive Risk Assessment of Subsurface Well Collisions
Authors: Thorogood J. L. , Tourney F. G. , Woo G. 
Published: December 2007

AbstractSubsurface separation criteria have been evolved empirically over the years. They are still largely based on un-tested assumptions about safety factors, comfort values and survey tool accuracy. A mathematical analysis of the probability of collision is presented. This calculation is linked by means of a decision tree to an assessment of the consequences of a well intersection. The mathematics can be simplified for the case where the two wells are parallel, enabling key features of the problem to be illustrated. A flow chart of the directional drilling tolerance setting procedure is used to show how the methods described can be used in day-to-day well planning operations. The risk based approach simplifies management of the operations and enhances safety and efficency because appropriate margins can be applied in each individual case.
The Flow of Real Gases in Porous Media
Authors: Clegg M.W. 
Published: December 2007

American Institute of Mining, Metallurgical and Petroleum Engineers Inc.

Abstract
The pressure dependence of the viscosity and deviation factor of real gases means that the flow equations for gases in porous media are highly non-linear. The linearisation of these equations leads to diffusion-type equations similar to those governing the flow of slightly compressible liquids in porous media. Such approximations are only porous media. Such approximations are only valid for small changes in pressure; for large pressure changes the non-linear terms must be retained.
The use of a "pseudo-pressure" variable for transforming the gas flow equation has recently been studied by a number of authors, and numerical solutions of the equations obtained. In this paper the radial flow of gas to a well is considered, and it is shown that a simple approximation technique leads to analytical solutions involving only elementary functions. These solutions agree well with the numerical results and provide a sound theoretical basis for empirical equations derived by other authors.
The possibility of extending these methods to two-phase flow systems is briefly reviewed.

Introduction
During the past twenty years an increasing amount of effort has been devoted to the study of gas flow in porous media. In spite of this activity the development of solutions for the equations governing the flow of real gases in porous media has not progressed as far as one would have hoped. progressed as far as one would have hoped. The reason for this is not difficult to discover. The equations are highly non-linear and present great problems when analytical solutions are sought. An excellent survey of the literature on the flow of gases through porous media is given in Al-Hussainy et al. porous media is given in Al-Hussainy et al. The basic equation for the flow of real gases in porous media, taking account of the variation of viscosity and deviation factor with pressure, may be written as
..........................................(1)
Relative Permeability and Low Tension Fluid Flow in Gas Condensate Systems
Authors: Haniff M. S. , Ali J. K. 
Published: December 2007

ABSTRACT
This paper summarises the results of an experimental study on fluid flow and residual saturations in a methane-propane gas condensate fluid system. Significant reduction in residual saturation and much improved flow rates are observed below a critical value of IFT (0.05mNm−1). At IFT values greater than 0.05mNm−1 phase distribution in the porous media is maintained through a balance in capillary and gravitational forces. The symmetry is, however, destroyed below 0.05mNm−1 when capillary forces become negligible and a first order transition in phase distribution takes place. Now, gravitational forces become important and the Bond Number more appropriate in interpreting the data. The micromodel work of Williams and Dawe, and Danesh et al established that under these conditions the liquid exists as a thin film along the grains while the gas occupies the centre of the pores, that is, a complete wetting situation. The absence of hysteresis effects in relative permeability curves confirm these observations. Under low IFT conditions, the liquid phase flows more easily, probably by a mechanism similar to that of gravity flow in hydrology studies, that is, as ‘free surface’. Here, the liquid surface is considered as a ‘stream line’ and flows when it intersects a ‘surface of seepage’. This could account for the phase separation caused by gravity often referred to as ‘gravity segregation’ and which generally occurs at conditions close to the dew line pressure.
Critical and Trapped Hydrocarbon Saturations in a Condensate Reservoir
Authors: Eldon M. , Puckett D. 
Published: December 2007

ABSTRACT
The Strathspey field in block 3/4a in the UK sector of the North Sea is comprised of two reservoirs. The lower is called The Statfjord reservoir and contains gas condensate, undertain by an oil rim. In order to predict the likely production from this reservoir a compositional reservoir simulation was performed. To perform this simulation, trapped and critical oil and gas saturations for both the gas condensate and oil rim regions had to be defined.
The relatively small amount of published data, and lack of critical saturation data from the Statfjord SCAL data, resulted in the decision to design a series of floods to determine these parameters using reservoir core and fluids at reservoir conditions The flood sequences were also designed to mimic the depletion processes that were expected to occur in the field.
The apparatus and experimental procedures used, together with the results obtained, are reported in this paper. Furthermore these results are compared with the published data and the effect on the final simulation results is also reported
Active Witnessing in Cement Bond Logging
Authors: Rouillac D. 
Published: December 2007

ABSTRACT
This paper describes a witnessing procedure based on a review of experience acquired during cement bond logging operations by ARTEP (French Petroleum Research Association) members.
The aim is to provide an answer, on the wellsite, to the following two questions:
– are the anomalies observed on cement logs genuine and significant? – if so, what are the chances of success of any remedial action?
The described operational procedures and standard presentation have now been successfully implemented in hundreds of cases where the oil Company witness has been helped in the interpretation of a CBL/VDL or a CET to determine the potential risk of a leaking barrier. The paper also highlights the cash savings linked to sound log quality control, when one pays exclusively for qualified and reliable data. Some case histories of insufficiently studied cement bond logs are presented.
Effect of Steerable BHA on Drag and Torque In Wells
Authors: Aarrestad T. V. 
Published: December 2007

Abstract
Steerable bottom hole assemblies are often used when drilling deviated wells. Planning of such deviated wells often include studies of torque and drag calculations for the planned well-path and BHA's in order to have a fairly good idea of friction and torque to be encountered when drilling.
The paper discusses some effects of using steerable bottom hole assemblies or other means of directional control. It is shown in the paper that in extreme situations, extensive use of directional control methods, may result in problems with high drag and torque in the wells. In some cases TD may not be reached due to large doglegs in building parts of the well.
The "Guided Owners’ Process": A New Approach to Equity Determinations
Authors: Hope M. 
Published: December 2007

ABSTRACT
The Guided Owners’ Process is designed to facilitate negotiated agreement of field unitisation between the Owners. This is achieved by replacing the usual separate Owner and Expert processes by a single negotiation between the Owners with the Expert present throughout.
The Expert works in parallel with the Owners and helps to ensure that a reasonable timetable for the technical discussions is adhered to. If agreement on key issues has not been reached by certain pre-defined deadlines ("Key Steps") each Group submits its case to the Expert for resolution. The determination then moves forward to the next Key Step : there can be no turning back and no external expert referrals.
The Guided Owners' Process is a flexible concept and can be adapted to accommodate any field's equity procedures. Two major North Sea fields have recently negotiated agreements utilising this concept.
SPT: Tool for Improved Placement of Chemicals in a Live Well
Authors: Leerloyer K. , Hughes R. H. , Misselbrook J. G. 
Published: December 2007

Summary
A straddle-packer selective placement tool has been developed that is run on coiled tubing, can pass through production tubing and can be repeatedly set in casing. The tool was built to improve the placement of chemicals in long and inhomogeneous intervals. Its capabilities and possible applications are described, together with an outline of some of the jobs done so far.
Cementing Through Coiled Tubing and Its Influence on Slurry Properties
Authors: Vidick B. , Nash F. D. , Hartley I. 
Published: December 2007

ABSTRACT
The use of coiled tubing for cement squeezing operations presents significant economic benefits for offshore workover operations. This paper demonstrates that batch mixing small volumes of slurry may, if care is not taken, lead to dramatic variations in slurry properties, especially the thickening time. A field mixing methodology based on the concept of mixing energy has been developed. Also, evidence gathered during this work indicated an even more dramatic effect on thickening time while pumping the cement through coiled tubing.
Multiple-Fracture Horizontal Wells: Performance and Numerical Simulation
Authors: Conlin J. M. , Hale J. L. , Sabathier J. C. , Faure F. , Mas D. 
Published: December 2007

ABSTRACT
Six Multiple Fracture Horizontal (MFH) Wells have been drilled in the Dan Field, located in the Danish North Sea. The field is a low permeability chalk reservoir producing under a combination of solution gas and gas cap drives.
Single well numerical models were built to determine the primary factors controlling the performance of these complex wells. In the two wells which have been successfully history matched, dynamic hydraulic/natural fracture behaviour under drawdown and gas coning were key processes. The models are being used for the management or existing MFH wells and for the optimisation of field development using the MFH well concept.
Reservoir Monitoring in the Development of Marginal Fields: Ivanhoe, Rob Roy, and Hamish
Authors: Carter P. J. , Morel E. H. 
Published: December 2007

ABSTRACT
Reservoir management of the Ivanhoe, Rob Roy and Hamish oil fields has been greatly enhanced during the first year of production by the continuous monitoring of bottom hole pressure in the production and water injection wells. By bringing on production and injection wells in a planned sequence the major flow paths within and between the five reservoir units have been identified. Observed changes in reservoir pressure during planned and unplanned production and injection shutdowns have provided further clues to the geological model and reservoir description.
Although not all the bottom hole pressure gauges have continued to function throughout the year a very large amount of daily pressure data has been collected. This has been used to modify and update the full field simulation model of the fields. The reservoirs have been shown to be much less affected by intra-field faulting than had previously been feared, and some shaley layers originally considered to be laterally extensive barriers are in fact more local. Because of this, excellent areal and vertical sweep is expected in the Main Piper sand. Recovery from the overlying Supra Piper sand will be less and will require further infill wells.
The reservoir model has been used to optimise individual well rates and minimise the risk of premature water breakthrough, and to site wells during the post-production drilling phase. The design reservoir depletion rate of 20 percent of recoverable oil per year has been easily achieved for both the Ivanhoe and Rob Roy fields.
A Gas-Lift Optimization and Allocation Model for Manifolded Subsea Wells
Authors: Edwards R. , Marshall D. L. , Wade K. C. 
Published: December 2007

ABSTRACT
The increasing need to develop marginal accumulations using subsea equipment and common facilities has highlighted the challenge of the allocation and optimum distribution of fluids within these systems. The commingling of produced fluids requires that an auditible procedure is employed to accurately back-allocate fluids produced from different fiscal regimes. Similarly, there is a requirement to optimise lift gas allocation to ensure that the available gas provides the maximum incremental oil production. A method of optimising lift gas allocation and allocating production within a manifolded subsea development has been developed for use on a portable computer. The basic requirements for the model were that it should be usable by offshore personnel and allow a quick comparison of different operating scenarios.
Horizontal Wells in the Andrew Formation: Prediction and Performance
Authors: Garlick T. , Neville G. , Smith P. J. , Webster C. 
Published: December 2007

ABSTRACT
The first few months of Cyrus field production are compared with predictions of the two horizontal wells in the field.
The modelling method used is extended to the prediction of another Andrew Formation prospect (Field 2). The approach has allowed the modelling of up to ten horizontal wells in a full-field model of Field 2.
The Use of Low-Density Particles for Packing a Highly Deviated Well
Authors: Bryant D. , Hudson T. , Hoover S. 
Published: December 2007

ABSTRACT
Packing the annulus and perforations with gravel in highly deviated wells, especially horizontal wells, is difficult. As well deviation increases, pump rates and carrier fluid viscosities increase to prevent particle settling. Increasing the viscosity can reduce fluid leakoff and perforation pack efficiency. Gravel-pack studies have shown that placement efficiency improves as particle density (Dp) and carrier fluid density (Dc) become closer. In an ideal system, these densities would be equal (Dp:Dc = 1). With this ideal design, no viscosity would be required to suspend the particles, thereby improving fluid leakoff and perforation packing. The use of sand as the packing material has limited the use of such a technique because of hydrostatic overbalance. The introduction of a pack material whose density (1.65 g/cc) is 40% less than that of sand makes this technique available without the overbalance concerns.
The paper provides the industry with technology which is applicable when gravel packing highly deviated (horizontal) wells. This paper describes: (1) a new method of completing highly deviated and horizontal wells using low-density particles and low Dp:Dc ratios, (2) computer simulations performed to aid in designing completion techniques,(3) printouts of the screenout pressure and pump rates, (4) schematics of the well design, (5) logs of the pack and (6) well performance.
Case History of Algyo Field, Hungary
Authors: Werovsky V. , Tromboczky S. , Miklos T. , Kristof M. 
Published: December 2007

ABSTRACT
The largest oil and gas occurence of Hungary with 100×10^6 m3 OOIP and 110×10^9 m3 gas reserve is an interesting example of simultaneous exploitation of oil and gas from 76 sandstone reservoirs layering mainly above each other, between 1500 and 2600 m depth and connecting in certain degree through the aquifer. 48 reservoirs of the 76 are in Lower-Pannonian sediments of poor reservoir characteristics, so 28 reservoirs in the Upper-Pannonian sequences give the 90 % of the OOIP and 70 % of the gas reserves and are of determining production importance. The discovery of the field in 1965 allowed the Algyö hydrocarbon production to reach and maintain a 1 million tons/year oil and a 3.2×10^9 m^3 gas production rate by about 1000 wells. Seven of the oil reservoirs have thin oil edge and large gas caps where the applied technology is water injection at the GOC and the WOC depending on the natural water encroachment. Great care is applied to the limitation of free gas production from the gas cap during the main oil production period by the effective control of the actual gas oil ratio. Methods of reservoir management and results of the careful inspection are discussed in the paper.
Simulation of High-pH Coreflood Experiments Using a Compositional Chemical Flood Simulator
Authors: Bhuyan D. , Pope G. A. , Lake L. W. 
Published: December 2007

ABSTRACT
This paper reports on the use of a high pH chemical flood reservoir simulator to simulate high pH coreflood experiments. The coreflood experiments include one alkaline flood, two alkaline/polymer floods under two different salinity environments and an alkaline/surfactant/polymer flood. The agreement between the experimental and numerical oil recoveries and produced chemical compositions is very encouraging and supports the validity of the mathematical model used in the simulator. The importance of the preflush brine salinity, mobility control and effective salinity gradient using a cosurfactant as observed in the experimental data are also evident from the numerical results. Most of the fundamental mechanisms known for micellar/polymer flooding also seem to apply to high pH chemical floods, especially the dominant effect of low interfacial tension. This is the first time that comparisons have been made between a mechanistic reservoir simulator and high pH coreflood experiments. Such comparisons have yielded new insights into high pH chemical flooding.
Clay Dissolution Kinetics in Relation to Alkaline Flooding
Authors: Drillet V. , Defives D. 
Published: December 2007

ABSTRACT
In order to evaluate alkali consumption for oil-field processes like alkaline flooding or clay stabilization treatment, mineral dissolution rates was determined. To do this, a steady-state method was carried out, whereby a well-mixed open reactor was used to contact mineral with alkaline solution, allowing straight forward measurement of dissolution rate in well defined conditions. The method has been tested with quartz for which dissolution rates were found in line with literature's ones. Clay dissolution kinetics were next studied with kaolinite. Initial reaction rate has been found pH-independent in the pH-range 11-13. A kinetic scheme has been worked out accounting for the steep decreasing of the dissolution rate with dissolution products concentration. The model can be used so long as no new mineral precipitates, which occurs well before the theoretical solubility product of kaolinite is attained in that pH range.