bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Case-Based System to Cut Drilling Costs
Authors: Irrgang R , Damski C , Kravis S , Maidla E , Millheim Keith 
Published: December 2007

Abstract
The best wells in a basin may be drilled twice as quickly as the worst. New technologies such as slimhole and extended reach drilling are not easily mastered. What factors determined the success of the best wells? What caused the delays? Data management processes and computational tools for planning new wells have been developed to utilise past experiences recorded in drilling data and reports. The Case Based Reasoning technique is applied to derive new scenarios (alternate drilling plans) based on previous "cases". A number of oil companies are collaborating to form a "Drilling Club" and have contributed well data and drilling reports from around the world. An immense amount of data and experience is available from many wells but engineers would prefer to see just the relevant information. The system assists by extracting an intelligent summary and structuring information to highlight key factors that will result in the greatest cost savings on a proposed drilling operation. Scenarios using alternative technologies can also be tested with risks calculated based on previous similar cases.
A Mechanistic Model for Gas-Liquid Flow in Pipes with Radial Influx or Outflux
Authors: Ouyang Liang-Biao , Aziz Khalid 
Published: December 2007

Abstract
A new mechanistic model for gas-liquid two-phase flow with mass transfer through the pipe wall, which accounts for the effects of wall inflow or outflow on wall friction, acceleration and flow pattern transition, has been developed. Four individual flow patterns, including stratified flow, annular-mist flow, bubble flow and intermittent flow, are considered in the mechanistic model. Models for individual flow patterns have been developed. Transition mechanisms among different flow patterns are discussed and new transition criteria are proposed.
Predictions by the new mechanistic model are compared with experimental data obtained on a large industrial facility.
High Temperature Blow-Down Experiments in a Vuggy Carbonate Core
Authors: Dehghani Kaveh , Kamath Jairam 
Published: December 2007

Abstract
Steam injection followed by pressure reduction (high temperature "blow-down") has been recently proposed to improve recovery from a light oil vuggy carbonate reservoir.1 We conducted experiments on a core sample from this reservoir in order to quantify the recovery mechanisms. These comprise thermal expansion, thermally enhanced solution gas drive, dry distillation, and in-situ steam drive.
We used Computed Tomography (CT) imaging of a miscible flood to characterize the connectivity of the vugs and matrix rock. We then conducted a series of blow-down tests. Here we heated the core to 300 degF and used a backpressure regulator set just above the bubble point of the oil at 300 degF. The pore pressure was then reduced at a constant rate from one end of the core sample. The first blow-down test was with the core at initial oil saturation with pressure reduction from the top of the sample; the second at initial oil saturation with pressure reduction from the bottom; and the third at residual oil saturation to water with pressure reduction from the top. The volumes and compositions of the produced fluids were measured in all the blow-down tests. We also CT imaged the initial and final oil saturation distribution for the second blow-down experiment.
The CT images reveal that the core sample contains vugs, high permeability matrix, and low permeability matrix rock; and that the vugs are connected through the high permeability matrix. The blow-down experiments show that 50-68% of the oil is recovered; with 8-20% due to thermal expansion, 20-24% due to thermally enhanced solution gas drive, 12-16% due to dry distillation, and 8-10% due to in-situ steam drive.
An Investigation of the Steam-Assisted Gravity-Drainage Process in the Presence of a Water Leg
Authors: Doan L. T. , Baird H. , Doan Q. T. , Farouq Ali S. M. 
Published: December 2007

Abstract
Many heavy oil and oil sand reservoirs are in communication with water sand(s). Depending on the density (°API gravity) of oil, the water sand could lie above or below the oil zone. Steamflooding a heavy oil or oil sand reservoir with a contiguous water sand (water which may lie below or above the oil-bearing zone) is risky due to the possibility of short circuiting the steam chamber.
The Steam Assisted Gravity Drainage (SAGD) process was first tested at the Underground Test Facility (UTF) in Fort McMurray, Alberta. The successful application of this process to Athabasca-type oil sands has extended its application to other heavy oil and oil sands reservoirs. To date, the application of this process to a variety of different reservoirs has shown mixed results due to a variety of reasons. In our opnion, the success of these projects depends on: 1) accurate reservoir description, 2) efficient utilization of heat injected into the reservoir, 3) understanding displacement mechanism, 4) understanding of geomechanics (the interaction between the fluids and the reservoir at elevated temperatures and pressure), and 5) overcoming various operational constraints. This paper looks at how the SAGD process is affected by the presence of water sand, and determines how heat is distributed in these reservoirs.
Results of this numerical simulation study show a relationship between ultimate recovery, heat accumulated in the reservoir and the thickness of the water sand (bottom or top water). For the base case run, an average rate of 80 m3/d was maintained for 1400 days before it started to decline. Ultimate recovery was approximately 70% of the OOIP after 9 years of steam injection, and the cumulative OSR was 0.3 m3/m3 (CWE). The presence of a bottom water sand has a lesser impact on recovery than the case where an overlying water sand is present. As the thickness of the water sand increases, the recovery efficiency decreases. Increasing the areal coverage of the bottom water sand resulted in slightly reduced recovery as compared with the confined bottom water sand. On the other hand, increasing the areal coverage of the overlying water sand, that is 9m thick, severely reduced the recovery efficiency of the process as heat is diverted (or channeled) into the "thief" zone. The oil steam ratio (OSR) in this run was below 0.15 m3/ m3 (CWE) after 400 days of injection. When a bottom water layer is present, the BHFP (bottom hole flowing pressure) of the horizontal producer could be operated at or above the pressure of the aquifer to prevent water coning and hence only effecting the heat source slightly.
Reservoir Characterization and Development Plan of the Wasson San Andres Denver Unit Gas Cap
Authors: Coalmer M. S. , Hsu C. F. , Cooper J. C. , Ward J. B. , Voto J. G. , Way K. F. , Valdez R. 
Published: December 2007

Abstract
A plan has been developed to produce the Wasson San Andres Denver Unit Gas Cap reserves without adversely effecting the existing tertiary, CO2 flood of the oil column. This paper: (1) describes the reservoir characterization studies validating hydraulic isolation between the uppermost San Andres gas bearing zones and oil-bearing zones currently under water and CO2 flooding, (2) details the field testing programs, including extensive PTA work and fracture control modeling, that proved technical viability of producing the gas cap without effecting the oil column, (3) details the Wasson field, 3-D, fully compositional, simulation model used for predicting effects on the oil column and developing gas production forecasts and (4) highlights plans for construction and installation of gas gathering facilities adjoined with the existing Denver Unit CO2 recovery plant and/or third party processors. The development plan was approved April 14, 1998 by the Texas Railroad Commission, who agrees that no loss in oil recovery will result from producing the stratigraphic gas-bearing zone termed the First Porosity in the Wasson San Andres formation.
Host Country and Industries Working Together: A Case Study of Indonesia's ONWJ Gas Development
Authors: Suyasa I Made , Saifullah Saifullah 
Published: December 2007

Abstract
In the early 1990's, Indonesia's increasing energy demand required the Government of Indonesia to work closely with the oil companies operating under Indonesia's Production Sharing Contracts (PSC) to resolve the energy shortfall. The numerous fields located in the Offshore Northwest Java (ONWJ) contract area contained almost 2 TCF of certified gas reserves to supply West Java's gas demand. These ONWJ reserves, operated by ARCO Indonesia, Inc., provided a natural fit for the market since they were located in close proximity to Jakarta's high gas demand area. However, expected development costs initially made development of these reserves uneconomic. To overcome this obstacle, ARCO and the Government of Indonesia needed work together to meet both parties’ requirements.
The project was divided into several phases of developments, called Gas Tranches. The first Gas Tranche (Tranche I) was initiated in September 1993 with gas from the KLX/KLY fields to supply 260 BBTUPD of gas sales to PLN (State Electricity Company), with swing up to 325 BBTUPD. At the end of the 11 years contract life, approximately 1 TCF of gas will have been delivered. Following this Tranche I sales agreement, two shorter term contracts were signed: 1) Cilamaya market sales (eastern part of West Java) at 60 BBTUPD for 3 years starting in October 1995; 2) PGN (State Gas Company) sales, called Mini Tranche, at 50 BBTUPD for 10 years starting in September 1997. The Tranche II gas development was then proposed to anticipate additional West Java gas demand.
Since the ONWJ contract area covers an area 160 miles long by 70 miles wide, significant investment was required to build the gas network infrastructure. Wells, well platforms, main pipelines, compressor modules, automation system, and modifications to existing facilities all needed to be installed. With this large capital investment, the gas development was uneconomic under the existing PSC terms. Therefore, special incentives were required from the government.
The Indonesian government and ARCO entered into negotiations to develop these incentives. At the same time, other issues such as the gas development plan, gas markets, supply/sale contractual terms and delivery procedures were discussed and negotiated. To resolve the economic hurdle, ARCO proposed an interest cost recovery incentive, which was one of the possible alternatives available under the ONWJ PSC contract terms. After extended negotiations, Interest Cost Recovery of LIBOR + 1.5% was finally granted by the government to lift the Gas Tranche project's ROR to an acceptable level based on the agreed gas price. The project was then successfully implemented.
Field Testing of Multiphase Meters
Authors: Al-Taweel Ahmed B. , Barlow Steve G. 
Published: December 2007

Abstract
During the past few years, Saudi Aramco has installed and field tested eight different types of multiphase flow meters (MPFM). These newly developed, compact MPFM are targeted for wellhead installation at remote onshore fields and unmanned offshore platforms, where weight and space are major concerns. MPFMs could provide continuous well test data, which would lead to more accurate production allocation and better reservoir management. The application of MPFMs in Saudi Aramco’s production operations, if proven successful, will provide continuous online well production monitoring, and eliminate large conventional test separators, test lines, and offshore test barges. As a result, tremendous economic savings could be realized due to the significant reduction in capital and operating expenditures associated with well testing activities.
The test installations cover a wide range of multiphase applications from over six different oil fields. The objective of the field testing program was to establish the ability of each meter to accurately measure the three production phases (oil, water and gas), and to determine meter reliability in a field environment.
Field test results of the multiphase meters are compared to reference conventional test separators. The paper also presents the current status of multiphase metering technology, and discusses in detail the multiphase metering evaluation program at Saudi Aramco.
Increased Resistance to Proppant Flowback by Adding Deformable Particles to Proppant Packs Tested in the Laboratory
Authors: Stephenson Chris J. , Rickards Allan R. , Brannon Harold D. 
Published: December 2007

Abstract
Numerous proppants, additives and remedial treatments now exist for the control of proppant flowback, yet it continues to be a problem in many oil and gas wells. These approaches to the problem can have certain merits but as a general rule they negatively impact production and are more costly than proppant alone. The importance of these criteria must be balanced against the effectiveness of the chosen approach.
It has been observed in laboratory testing that a deformable proppant material, blended with a typical fracturing proppant, can significantly increase a proppant pack’s resistance to failure under flowing conditions. The fluid exerts a drag force on the structure of the pack and indeed on the individual particles within. These drag forces appear to be much less than the overburden forces that maintain a proppant pack in a stable configuration, prior to fluid flow. In essence proppant packs of typical fracture width, when tested in the laboratory are inherently unstable, unless the individual particles within are anchored or reinforced in some way.
When a deformable proppant is blended into the pack, the deformation between the surrounding proppant grains allows locking of these grains in place. The friction between the grains is effectively increased and thus, the forces required to push the material out of the structure also increase. Addition of deformable particles typically allows the drag forces at failure to be increased by 100% to 300%, while pack conductivity remains better or on a par with the proppant alone, since the material added does not adversely reduce porosity.
New Method for Improving Oil Droplet Growth for Separation Enhancement
Authors: Finborud Anne , Faucher Mark , Sellman Erik 
Published: December 2007

Abstract
Produced water quality is a function of the reservoir conditions, the fluid chemistry and the upstream process. The oil droplet size distribution in produced water is influenced mainly by choke valve pressure drop causing shear effects thereby droplet break down, and further the oil droplets ability to coalesce to larger droplets. Factors preventing coalescence include the droplets negative electrostatic charge, stabilization by surface active components and steric stability caused by fines. The larger the oil droplets in the produced water the easier they are to separate (Stokes' Law). Hydroflokk is a newly developed process for pre-treatment of produced water in order to optimize its separability. In this process oil droplets are subjected to combined chemical and mechanical action to accelerate coalescence and the formation of larger, more separable flocs.
The Hydroflokk system was developed by Norsk Hydro on behalf of the Troll Oil Unit Committee, to be qualified for installation on the Troll B platform in the North Sea. There the Hydroflokk system has been operated successfully since the installation in March 1996. The system has successfully been tested at several offshore platforms with a containerized test unit and has been incorporated in the produced water system for the Troll C platform to go on stream in 1999/2000.
Designing Tomorrow's Compact Separation Train
Authors: Arnold Kenneth E. , Ferguson Patti L. 
Published: December 2007

Abstract
Newly developed compact separation technology may be an attractive alternative to conventional separation methods in certain oil and gas applications. The purpose of this paper is to compare the new compact separators to conventional separation methods and explore the possible applications of this new technology. The size of conventional separators is based on liquid retention time, droplet or settling velocity for gas, and, for three-phase separators, water droplet settling time in the oil phase. Compact separators perform the same function as conventional separators but require a smaller shell. They have great potential where cost savings due to smaller size and lower weight are greater than the cost of more complex equipment. Both the benefits and problems associated with using compact separation techniques for downhole processing, subsea processing, and surface facilities will be discussed in this paper. It is necessary for a design engineer to understand the benefits and detriments of using compact separators so that this new technology may be used effectively in the production of oil and gas.
An Investigation of Density Derived from Pulsed Neutron Capture Measurements
Authors: Neuman C. H. , Sullivan M. J. , Belanger D. L. 
Published: December 2007

Abstract
Each service company that offers pulsed neutron logs includesmeasurements based on the gamma rays from inelasticscattering. The gamma rays that originate from the high-energy neutrons that undergo inelastic scattering necessarilyoriginate near the source. The number of these gamma raysthat reach detectors relatively far from the source reflects thegamma ray scattering by and thus the density of the materialbetween the scattered neutrons and the detector. Because thereare many factors other than density that influence the numberof gamma rays detected, service companies offermeasurements based on inelastic scattering as empirical tracesthat are used in combination with measurements based onneutron scattering. Such combinations are useful primarily torecognize gas and distinguish gas from low porosity. Onecompany offers a trace that represents density from the gammarays due to inelastic scattering, but the process of deriving thedensity involves the very empirical step of subtractingdifferent portions of the gamma rays attributed to factors otherthan inelastic scattering until a satisfactory approximation todensity is achieved.
This paper presents a method for predicting the gammarays from thermal neutrons to be subtracted from the totalgamma rays measured during the neutron pulse and acomparison of the density-like trace so derived with open-holedensity logs recorded in Cabinda, Angola, Africa.
The method presented for predicting gamma rays due tocapture is based on representing the decay of gamma rays afterthe neutron burst by two exponential decays. The fraction ofgamma rays due to thermal neutrons is different at differenttimes during the pulse, but the overall effect is predicted fromthe amplitudes and decay times that fit the data used torepresent sigma. While this removes variations in the fractionof capture gamma rays subtracted to create a density-like trace,the relationship between the amplitude of the trace and densityis still determined empirically.
The comparison with open-hole logs makes use of the factthat many of the logs run were run to distinguish brine from oilthrough casing. This enables comparison of the densitiesderived from cased-hole logs to those recorded from open-holelogs under conditions where the open-hole logs still representthe reservoir. Some of the log data studied were from intervalswhere gas saturations changed between the open- and cased-hole logs, and these afford a chance to compare changes indensity with changes in neutron porosities. Examplecomparison are presented and limitations discussed.
A New Technique for Carbon-Oxygen Logging Through Gravel Packs and Other Special Completions
Authors: Wanjau P. K. , Joseph J. , Ciammetti P. , Lassel K. , Akunna P. 
Published: December 2007

Abstract
Productive horizons in the Niger Delta basin of West Africa comprise clastic tertiary sequences that formed coastal barrier bars, beaches, tidal distributor channels and lagoonal deposits. Such reservoirs are often made up of very high permeability unconsolidated sands that require gravel-packed completions for efficient production. Water influx from edge- or bottom-aquifers is a dominant drive mechanism, and in this basin water salinity is often less than 30 kppm (i.e., predominantly fresh). It is no surprise that in this low-salinity environment carbon-oxygen (C/O) logging has become particularly popular for reservoir monitoring.
In the past, operators were often forced to exercise the high-cost option of pulling the completion string in order to run C/O logs. This was necessary because no logging tool was rated for saturation evaluation inside gravel-packs or other special completion elements such as blast joints. In this paper a new characterization for a slim C/O logging tool is presented that now extends its applicability to these special completion types. The technique is based on laboratory measurements made with the tool inside typical Niger Delta gravel-pack and formation lithology environments. These measurements were used to benchmark a Monte Carlo nuclear model from which a database was constructed. The questions of gravel-pack quality and of the pack's fluid content have been addressed in this work, as has the impact of uncertainties associated with these variables upon the final saturation answer.
The new characterization database has been used to evaluate C/O logs run in several wells in the Niger Delta. Three examples where the tool logged inside an internal gravel-pack (IGP) completion are presented in this paper. The examples demonstrate a significant improvement over a qualitative approach and provide for a more robust and reliable saturation computation.
Dynamic Multi-parameter Interpretation of Dual-Detector Carbon/Oxygen Measurements
Authors: Mickael Medhat , Trcka Darryl , Pemper Richard 
Published: December 2007

Abstract
Traditional C/O interpretation methods that rely on a limited set of data can not provide the fidelity and accuracy needed to interpret C/O data in complex completions, mixed lithology, or under variable holdup conditions. New interpretation methods based on computer modeling can now furnish accurate C/O response data, not only for applying sequential environmental corrections, but even for treating simultaneous variations in the logging conditions.
In this paper, we present new concepts of interpreting C/O data that fully utilize the power of computer modeling. The C/O response is dynamically generated at every depth level of the log based on a non-linear model that simultaneously accounts for variations in completion geometry, borehole diameter, formation porosity and mineralogy, and borehole holdup. The model also allows for normalizing the C/O response in a shale or a low-porosity zone.
A new treatment for dual-detector instruments is also presented that takes advantage of the precision and sensitivity of the two detectors rather than simply using one or the other. Data from the two detectors are combined in such a way that the error of the measured saturation is minimized, which should provide an optimum measurement under any condition.
Log examples are presented to show the degree of fidelity and accuracy of the new interpretation method. Examples are also shown that demonstrate the ability to normalize the C/O response in shale and low-porosity zones.