bluuebunny/crossref_metadata_2025_split huggingface dataset:
Screening Wells for Tight Gas From Single Point Flow Data
Authors: Cook David C. 
Published: December 2007

Abstract
On July 14, 2000 the Federal Energy Regulation Commission (FERC) issued a Final Order reinstating tax credits under Section 29 of the Internal Revenue Code (Section 29 tax credit) for wells producing from tight gas formations. In addition, some states such as Texas provide a severance tax credit for certain wells producing from tight gas formations. This paper provides a method to quickly screen for wells that may qualify for these tax credits using single-point flow test data.
In order to qualify for these tax credits a well must lie in an area that has been classified as a tight gas formation, that is an area where the available data suggests that the in-situ permeability is less than 0.1 md. This paper uses the same ONEPT technique Lee, Kuo, and Holditch presented in 1984 to estimate formation permeability from single-point flow data (SPE 12847) to screen wells for potential tight gas qualification.
This paper analyzes the sensitivity of the different variables involved in the Lee, Kuo, Holditch method of estimating permeability and develops a graphical screening tool to determine the likelihood that a well can be classified as a tight gas formation. Although, there are many variables involved in the Lee, Kuo, Holditch method, it is possible to screen wells graphically for tight gas using only four variables: the initial reservoir pressure, bottom hole flowing pressure, gas rate, and an estimate of reservoir thickness. This data is readily available from a typical single-point flow test and can be plotted to determine the likelihood that the well produces from a tight gas formation. Both unstimulated and fracture stimulated wells can be screened. The screening tool is verified by comparing it to known permeability data.
3D Stress Characterization from Hydraulic Fracture and Borehole Breakout Data in a Faulted Anticline, Wyoming
Authors: Miskimins Jennifer L. , Hurley Neil F. , Graves Ramona M. 
Published: December 2007

Abstract
The North LaBarge Shallow Unit (NLBSU) is a geologically complex field located in the Green River basin of southwest Wyoming. It produces from shallow Mesaverde (Cretaceous) sandstones at a depth around 2,000 ft. 3D seismic data was acquired in the field that confirmed the presence of several faults including major thrust faults, a tear fault, four major strike-slip faults, and a "horsetail" splay termination.
Fourteen wells were chosen for the study based on their locations relative to these faults and quality of certain data. Borehole breakout data provided maximum horizontal stress orientation. G-function analysis was used to determine minimum horizontal stress magnitudes. Integration of density logs provided overburden stresses. Well testing provided pore pressure data. Maximum horizontal stress magnitude windows were determined from combinations of minimum horizontal stress magnitudes, pore pressures, and fracture breakdown data.
Combined stress and orientation results led to complete or partial three-dimensional (3D) stress profiles for six wells. The results of the study indicate that complex faulting in the field influences horizontal stress magnitudes and orientations. Increased minimum horizontal stress magnitudes are observed near faults. Stress-controlled production is evident and suggests a horizontal well would likely provide a significant reserve increase. Results also indicate great care should be given to producer and injector locations to improve sweep efficiency and limit water breakthrough.
Optimized Performance by the Use of Rotating Separators as an Alternative to Shale Shakers
Authors: Botnmark K. , Mikalsen K. , Jensen O. D. , Saasen A. , Hoset H. , Kalvenes Ø. , Sørgård E. , Mathiassen Svein 
Published: December 2007

Abstract
Occupational hygiene requirements for operations on the Norwegian shelf when drilling with oil based drilling fluids favours the use of enclosed system for solids control. Personnel working with shale shakers are often exposed to a base oil mist and vapour at an unacceptable level. A principle with the use of rotating separators as an alternative to shale shakers was therefore developed.
The paper describes the principle with rotating separators as an alternative to shale shakers in detail. The paper focuses on tests where the separator efficiency from the rotating separator is compared with the efficiency from conventional shakers. The separator principle is to feed the drilling fluid with cuttings from the mud line into a slowly rotating separator that forces the cuttings to move along a very long screen section with selected screen sizes. The drilling fluid is effectively removed from the cuttings since the area outside the screen is slightly vacuumed. This principle result in an apparatus with an effective solids separation being among the better separation results obtained by conventional shale shakers.
The paper also describes the improvement on the occupational hygiene and the environmental impacts resulting from the use of the rotating separator compared to the current status from using conventional shakers. Norwegian drilling equipment standards require that the noise level from a device in the drilling area should be less than 83 dB. The paper describes how this requirement is satisfied and that the noise level is far below the requirement level when using the rotating separator.
Aggressive Drilling Parameter Management Based on Downhole Vibration Diagnostics Boosts Drilling Performance in Difficult Formation
Authors: Hood J. A. , Leidland B. T. , Haldorsen H. , Heisig G. 
Published: December 2007

Abstract
Exploiting the reservoir under the Ula platform in the Norwegian North Sea requires directional drilling through very challenging inhomogeneous formations, which may contain chert. In offset wells, drilled with steerable motor systems, an average of 6 to 7 runs and 3 to 4 bits were required to drill the 12 ¼" sections.
In two recent wells, the 12 ¼" sections were drilled with rotary steerable systems with aggressive PDC bits and a new downhole dynamics tool that provided continuous diagnostics of the downhole drilling conditions to the surface. This tool combination was applied for the first time worldwide. The versatility of the rotary steerable system allowed for the instantaneous adjustment of drilling parameters in response to the downhole feedback on the drilling conditions. As a result, integrity of the drilling system could be maintained and bit life extended. Both 12 ¼" sections were drilled with just two bits, in three runs, and in half the time of the best offset well.
This case study describes the planning and execution phase of the wells, and presents several examples of rigorous drilling parameter changes to overcome drilling dynamics problems such as stick-slip and BHA whirl.
Wellbore Position Errors Caused by Drilling Fluid Contamination
Authors: Wilson Harry , Brooks Andrew G. 
Published: December 2007

Abstract
Recent improvements in magnetic survey quality control have revealed the presence of systematic azimuth anomalies, affecting the calculated trajectories of a significant number of wells. Although these anomalies display some features commonly associated with drillstring magnetic interference, they cannot be removed by traditional magnetic correction techniques. New magnetic survey quality control procedures have identified the problem as an attenuation of the transverse component of the earth's field, similar to that caused by magnetically permeable material surrounding the magnetometers. The drill collars housing the sensors were inspected but showed no magnetic susceptibility, which led to suspicion that the problems were caused by magnetic particles suspended in the drilling fluids. Laboratory testing has confirmed the magnetic properties of these fluids, and chemical analysis has verified the presence of iron in significant quantities. Field examples demonstrate the use of a multiple-survey quality control and correction method for identification and removal of these survey anomalies.
Practical Issues in Using Risk-Based Decision Analysis
Authors: Davidson Lynn B. 
Published: December 2007

Abstract
Mark Twain once said, "The art of prophecy is difficult, especially with respect to the future."
Mark Twain's remark summarizes management's challenge in deciding which E&P projects to pursue. Project outcomes are always prophecies fogged in uncertainty.
Risk-based methods have been developed to help pierce the fog and make better decisions.
This paper examines practical barriers to effectively using risk-based decision tools and provides guidelines to overcome the barriers.
Microbiology of Oil Degradation in Reservoirs
Authors: Blanchet D. , Grabowski A. , Vandecasteele J-P 
Published: December 2007

Abstract
The microbial alteration of crude oils in reservoirs is a widespread phenomenon. Its knowledge is of prime importance from an economical point of view, specially in offshore prospecting. The understanding of conditions that favored hydrocarbon biodegradation constitutes key information to conduct exploration. This understanding requires a better knowledge of the microbial communities present in these specific ecosystems. Our views of the microbial life and of its involvment in biodegradation of hydrocarbons in such deep anoxic environments have entirely been transformed these last two decades. First, the use of the recent molecular techniques have permitted to discover the large diversity of this microbial world. Second, undeniable proofs of attack of alkanes in strict anaerobic conditions by various groups such as sulfate-reducers, denitrifying bacteria and consortia including acetogenic bacteria and Archaea have been presented. Further progress will involve the study of key limiting factors of in-reservoir overall microbial activities, through better elucidation of available sources of nutrient and electron acceptors.
Permeability Prediction Using Hydraulic Flow Units and Hybrid Soft Computing Systems
Authors: Soto B. R. , Garcia J. C. , Torres F. , Perez G. S. 
Published: December 2007

AbstractIn the last years, the concept of hydraulic flow units (HFU) has been used in the petroleum industry to improve prediction of permeability in uncored interval/wells. This concept is strongly related to the flow zone indicator (FZI) which is a function of the reservoir quality index (RQI). Both measures are based on porosity and permeability of cores. It is assumed that samples with similar FZI values belong to the same HFU. Thus the FZI, along with other significant variables such as porosity, can be used directly to estimate the permeability in a zone; however, the FZI has to be estimated first. In this paper, a novel method based on hybrid soft computing techniques is used for permeability predictions. The technique is known as adaptive network-based fuzzy inference systems or ANFIS, and is based on adaptive neural networks and fuzzy inference systems (FIS). The final inference on FZI is made by a FIS but the parameters of this FIS will be estimated through a learning procedure based on input data; such procedure is typically used in neural network training. The technique is applied in 3 steps: (1) Identification of the dominant variables in rock type behavior, (2) Development of an ANFIS which best suits the real model, using the dominant variables as input and the FZI as output. (3) Estimation of permeability from FZI and porosity values.These steps are applied on a sample case and the results show that hybrid soft computing techniques offer powerful tools for further improving permeability predictions.
Water In Crude Detecting Devices and Their Application to Royalty and Custody Transfer Measurements
Authors: Basrawi Y. F. 
Published: December 2007

Abstract
The paper talks about the technology and operations of the various water-in-crude detecting devices and their possible application to royalty and custody measurements of crude and hydrocarbon products. It highlights the operations, current research, field test studies and viability of such devices for better precision and higher accuracy in the measurement of volumetric through puts for exports and domestic consumption. Through finer precision and higher accuracy, proper accountability can be achieved and tremendous cost savings realized. The contents of the paper will contain a brief introduction and will talk about the principles of operations of water in crude detection Devices, their types, applications, evaluations and a final conclusion.
Improved Determination of Oil/Water Drainage and Imbibition Saturation Functions of Chalk Core Plugs from Flooding Experiments
Authors: Bech N. , Nielsen C. M. , Olsen D. 
Published: December 2007

Abstract
This paper presents improvements to a recently developed experimental method, which is particularly suitable for the determination of oil/water capillary pressure and relative permeability for water wet samples of chalk for both drainage and imbibition. Inherently chalk has high capillary pressure, and conventional laboratory determinations of saturation functions on such material are complicated by strong scale effects, particularly by the capillary end effect. The end effect does, however contain detailed information about the saturation functions of the sample and this information is utilized in the method.
The saturation functions are represented by analytical expressions that are determined by matching simulated results and measured data. A five-step core-flooding scheme provides the fluid distributions and production data from which the relative permeabilities and capillary pressures are computed for both drainage and imbibition by a least squares technique. A chemical shift NMR technique is used for fluid distribution determination while the simulation of the experiments is carried out by a commercial reservoir simulator.
In our previous work with this method simple power functions were used to represent relative permeability functions. The present paper demonstrates the use of more flexible analytical expressions for the oil relative permeability that enables a better representation of certain function shapes. Also an improved representation of capillary pressure is incorporated in the method. The new technique is applied to a chalk sample from the North Sea.
Determining Relative Permeability Exponents Near the Residual Saturation
Authors: Laroche Catherine , Chen Min , Yortsos Yanis C. , Kamath Jairam 
Published: December 2007

Abstract
In a recent study1 it was shown that the ratio of the flow rates of the produced fluids in an immiscible displacement can be used to identify geometrical and petrophysical characteristics of a reservoir. In this paper we develop an extended version of this approach and apply it to displacements in 1-D laboratory cores. Because of the possible importance of capillary effects, we pay attention to the capillary end effect at the outlet and to late times.
It is shown that the exponent in the power-law dependence of the relative permeability to saturation, near its residual value, can be determined from a segment of the curve of the outlet fractional flow sometime after breakthrough. The asymptotic predictions are verified by obtaining an analytical solution to the full problem, including end-effects, for a model case corresponding to Burgers’ equation. Experimental results for the high-rate displacement of some gas-liquids pairs are reported. In agreement with the theoretical predictions, a power-law segment in the outlet fractional flow curve can be identified, before capillary effects set in. The exponents obtained are discussed in terms of pore-scale models for gas-liquid displacement.
Multicomponent Fractionator Calculations Using The Relative Operability Technique
Authors: Maddox R.N. , Takaoka Shigeyoshi 
Published: December 2007

Publication Rights Reserved
This paper is to be presented at the 38th Annual Fall Meeting of the Society of Petroleum Engineers of AIME in New Orleans, La., on Oct. 6–9, 1963, and is considered the property of the Society of Petroleum Engineers. Permission to publish is hereby restricted to an abstract of not more than 300 words, with no illustrations, unless the paper is specifically released to the press by the Editor of the Journal of Petroleum Technology or the Executive Secretary. Such abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in Journal of Petroleum Technology or Society of Petroleum Engineers Journal is granted on request, providing proper credit is given that publication and the original presentation of the paper.
Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting and considered for publication in one of the two SPE magazines with the paper.

Introduction
Distillation is one of the most generally used methods for performing the separation of a liquid mixture into various products. Calculational methods for simple fractionators (one feed and two products) are well known and widely applied. For the case of complex fractionators (more than one feed and/or more than two products) there are rigorous calculation techniques available in the literature. The work reported here fills a particular need in this area - a calculational procedure that can be applied to multicomponent complex fractionators and yet is short and quick enough to be used on a small size digital computer or even a desk calculator.

LITERATURE SURVEY
Underwood and Gilliland almost simultaneously, but independently, proposed a calculational method for multicomponent fractionation in a simple distillation column. They proposed to develop a series of equations very similar to the Fenske equation. The difference being that the Fenske equation applies to a column operating at total reflux, and the proposed equations were to describe the fractionation obtainable in a column operating at some finite reflux rate. This was accomplished through the "relative operability" which for the rectifying section of the column is defined as:
(1)
The term "relative operability" comes from the combination of material balance terms into a ratio for two components.
The relative operability can be used to relate the composition of passing streams in a distillation as follows:
(2)
If we include now the equilibrium calculation across a theoretical plate, we have
(3)
The Effect of Fracture Spacing on Gas/Oil Gravity Drainage in Naturally Fractured Reservoirs
Authors: Clemens Torsten , Wit Krijn 
Published: December 2007

Abstract
Fractured carbonate reservoirs contain a large amount of the world oil reserves. A large number of these reservoirs are produced by gas/oil gravity drainage (GOGD).
Historically, it was assumed that the spacing between vertical fractures is so small that gas/oil gravity drainage can be approximated by one-dimensional vertical flow in the matrix. Recently, the emphasis of research shifted towards reservoirs with larger fracture spacing.
This article describes the effects of the fracture spacing on reservoirs under GOGD for a matrix column with a sealed bottom. Up to a fracture spacing/formation column height ratio of 0.3, the flow in the matrix can indeed be approximated by one-dimensional flow.
For larger values of the ratio, simulations using the onedimensional flow approach are significantly overestimating the gravity drainage rate (for a fracture spacing/formation column height of 2.5, the gravity drainage rate reduces effectively to 30 %!).
In this article, a correlation has been derived to determine a reduction factor in the drainage rate as a function of the fracture spacing/column height ratio. This reduction factor can be incorporated in the gravity drainage shape factor of dualpermeability simulations.
Characterizing Disproportionate Permeability Reduction Using Synchrotron X-Ray Computed Microtomography
Authors: Seright R. S. , Liang J. , Lindquist W. Brent , Dunsmuir John H. 
Published: December 2007

Abstract
X-ray computed microtomography was used to investigate why gels reduce permeability to water more than that to oil in strongly water-wet Berea sandstone and in an oil-wet porous polyethylene core. Although the two porous media had very different porosities (22% versus 40%), the distributions of pore sizes and aspect ratios were similar. A Cr(III)-acetate-HPAM gel caused comparable oil and water permeability reductions in both porous media. In both cores, the gel reduced permeability to water by a factor 80 to 90 times more than that to oil. However, the distributions of water and oil saturations (versus pore size) were substantially different before, during, and after gel placement.
The disproportionate permeability reduction appeared to occur by different mechanisms in the two porous media. In Berea, gel caused disproportionate permeability reduction by trapping substantial volumes of oil that remained immobile during water flooding. With this high trapped oil saturation, water was forced to flow through narrow films, through the smallest pores, and through the gel itself. In contrast, during oil flooding, oil pathways remained relatively free from constriction by the gel.
In the polyethylene core, oil trapping did not contribute significantly to the disproportionate permeability reduction. Instead, oil films and a relatively small number of pore pathways provided conduits for the oil. For reasons yet to be understood, the small pore pathways appeared largely unavailable for water flow.
Networking Intelligent Subsea Completions Using Industrial Standards
Authors: Hiron Stéphane 
Published: December 2007

Abstract
Intelligent completions are expected to play a growing role in all future major subsea fields, giving the capability to maximize hydrocarbon recovery while reducing production costs and number of interventions. In the present mature "pressure monitoring" market, single-point pressure sensors are traditionally acquired by third-party subsea control pods. There is no dedicated software associated with the tool at topside for any computation more complicated than applying polynomial equations. The communication protocols over umbilicals are generally proprietary to each pod vendor, which requires a new interface card for each application, increasing risks and lead time by months, and affecting system reliability by lack of repetitiveness. Intelligent completions require typically 10 times more communication bandwidth than currently available, 10 to 100 times more power than pressure gauges, dedicated software processes at topside, and increased reliability of the interface links. Traditional practices need to be revisited for accommodating such new requirements.
We propose a modern networking approach for intelligent subsea completions using common practices of the process control and information technology (IT) industries. Downhole sensing and control would operate on fieldbus-like protocols, widely used in automated plants and petroleum refineries. For interfacing intelligent completions from the seabed to topside supervision, our approach uses transmission control protocol running on top of internet protocol (TCP/IP). These communication layers (Levels 3 and 4) in the open systems interconnection (OSI) model bring full flexibility for dynamic device configuration and reconfiguration, data file handling capability, compact and modular software interfaces at topside, and flexible interface with various vendors. This initiative is now endorsed by the Intelligent Wells Interface Standardization (IWIS) panel1, which is now drafting an International Standard Organization (ISO) standard for the industry.
For subsea operators, the networking approach using industry standards offers a seamless integration between topside systems and various downhole vendors, and opens future options of object-oriented protocols among all topside processes. Seamless integration reduces interface costs and decreases software interface developments. The overall system reliability will increase, thanks to standards and mature equipment widely supported by all the telecom and computer industries.