bluuebunny/crossref_metadata_2025_split huggingface dataset:
Type Curves for Analyzing Naturally Fractured Reservoirs
Authors: Petak K. R. , Soliman M. Y. , Anderson M. F. 
Published: December 2007

ABSTRACT
A solution representing flow at the wellbore in a naturally fractured reservoir is presented in this paper. The model used to develop this solution assumes unsteady state interaction between the fractures and the matrix. Wellbore storage and skin are considered in determining the boundary conditions for this model.
A new set of type curves for analyzing pressure transient data from naturally fractured reservoirs is presented. Each type curve within the set is for a different value of CDe2S. Each type curve presents one radial flow solution with the associated family of curves approximating behavior at intermediate flow times. Each curve within a family is for a different ω′λ′e-2S product, where ω′ and λ′ depend upon fracture/matrix storativity and permeability ratio, respectively. Ambiguity is eliminated when a simultaneous match of data against the dimensionless pressure curves and the differential dimensionless pressure curves is performed. Reservoir and well parameters including permeability, skin, dimensionless wellbore storage, ω′, and λ′ can be calculated from this match. Truer matches against actual natural fracture pressure transient data are obtained by using these curves instead of existing type curves.
The principal advantages of using these curves are discussed. The first advantage is that when sufficient transition period data is measured, Horner data does not have to be available for an analysis to be performed. Actual pressure buildup data is used to illustrate this. Secondly, after reviewing many actual well tests, the upper practical limit on values for permeability ratio has been expanded. Values for λ′ &gt; 10-3 can now be calculated.
Use of these curves is explained in detail. Applicability of the curves is demonstrated by successfully matching actual pressure transient data against the curves.
Cenomanian Stratigraphic Traps in Western Abu Dhabi, U.A.E.
Authors: Loutfi G. , Baslaib S. M. , Abul Hamd M. 
Published: December 2007

ABSTRACT
Cenomanian rocks in western Abu Dhabi comprise a sequence of shallow and deep marine carbonates with terrigenous shales and sandstones. Four rock units, in ascending order; the Shilaif, the Tuwayil, the Ruwaydha and the Mishrif are recognized within the sequence.
The Shilaif Formation is represented by pelagic carbonates, deposited in anoxic intrashelf basin, developed in central Abu Dhabi during the Cenomanian. It proved to be the source rock of the oil reservoired in the overlying Mishrif.
The Tuwayil, consists of shales and sandstones, and represents a period of terrigenous clastic influx, which has formed a large tongue protruded into the Shilaif basin. It includes four sandstone units, which are found oil bearing in some localities. The Ruwaydha represents the last basinal depositional phase of the Cenomanian in the area.
The Mishrif Formation is a thick shallow marine carbonate sequence, exhibiting minor cyclic deposition reflecting periodic oscillation of sea level. It represents deposition on epicontinental shelf, with its margin prograding eastward into the Shilaif basin. It is a good reservoir, known to be oil productive in east Abu Dhabi and offshore Dubai from rudist reefal build-ups and/or accumulations.
Large oil and gas accumulations have been found in the area, mainly in structural traps of the Middle and Lower Jurassic, with moderate oil accumulations in Middle and Lower Cretaceous rocks.
A transitional zone between the Mishrif and Ruwaydha/Tuwayil exists in the area. The width of this transitional zone appears to extend along few kilometres. However, interfingering of the Tuwayil, the Ruwaydha and possibly the Shilaif appear to extend into the Mishrif reflecting possible occurrence of localised paleo-embayments at the Mishrif shelf margin.
Seismic-stratigraphic investigation, helped to define facies limits, patterns and occurrence of prospective stratigraphic traps in both the Mishrif and the Tuwayil Formations. The Tuwayil sandstone and Mishrif carbonate clastics pinching out against structural highs, are prospective localities for stratigraphic hydrocarbon entrapment. In addition, areas where the Mishrif develops possible carbonate build ups and/or rudist reefal accumulations are also of interest and could have hydrocarbon potential.
The sequence of seismo-stratigraphic/facies definition procedure, presented in this paper, were applied to define stratigraphic traps in the Mishrif and Tuwayil Formations.
Design, Implementation, and Interpretation of a "Three-Dimensional Well Test" in the Cormorant Field, North Sea
Authors: Bunn G. F. , Yaxley L. M. 
Published: December 2007

ABSTRACT
This paper describes the design, execution and interpretation of a pair of distributed pressure interference tests in a North Sea Reservoir. The tests were performed in two new development wells which were located some 1500 feet from an existing producer.
The results of the tests were interpreted by numerical simulation and have yielded an improved description of the vertical and horizontal transmissibilities of individual layers, and an improved understsanding of the significance of faulting in the region around the wells.
Reserve Definitions – An Attempt at Consistency
Authors: Keith D. R. , Wilson D. C. , Gorsuch D. P. 
Published: December 2007

ABSTRACT
An alternative system for the categorisation of volumes of hydrocarbons in place and reserves is proposed. The system uses criteria based on level of confidence to define Proven, Proven + Probable and Proven + Probable + Possible categories of fluid in place and reserves. The proposed definitions are compared with the systems of definitions currently in general use and the advantages are outlined. The methods of application of the proposed definitions are detailed and their application to prospects, discoveries and producing fields are discussed.
A Driller's HAZOP Method
Authors: Comer P. J. , Fitt J. S. , Østebø R. 
Published: December 2007

ABSTRACT
A method has been developed for performing Hazard and Operability studies of drilling systems and procedures. The need for such a technique is explained and its development and application are described. Although the Drillers' HAZOP uses the same basic method as the traditional "process" HAZOP, novel features have been introduced for the analysis of those drilling operations which are essentially sequences of mechanical and manual handling operations by teams of people. For these cases, a new type of master document, the Multiple Activity Chart, has been developed and refined to be the basis for critical study by deviation analysis. It has been found that the set of guide word-variable combinations used in the classical HAZOP study is not suitable for analysis of Multiple Activity Charts; an alternative set has been developed and is described. The experience gained in development of the new method through a programme of case studies, and by virtue of its first practical application, is reviewed. This experience has demonstrated that use of the method can result in improved safety and efficiency in drilling operations. Finally, the authors discuss their plans for the future use and development of the technique.
A Probabilistic Strategy for Subsea Inspection of Steel Structures
Authors: Carr P. , Clayton M. , Busby P.L. , Dobson J. 
Published: December 2007

Abstract
A strategy has been developed for determining the relative effectiveness of differing underwater inspection and maintenance regimes (type of inspection, inspection intervals and the policy for responding to defects when found). policy for responding to defects when found). The strategy requires knowledge of inspection records, fatigue test data and jacket analysis results, including redundancy studies. These data are combined using Bayesian statistics, risk analysis methods and a Monte Carlo simulation technique.

Introduction
Safe and economic operation of structures offshore depends on structural integrity. Structural integrity in turn depends on corrective maintenance as decided by regular inspections of condition. Welded joints can present a particular problem in this respect present a particular problem in this respect because of the lack of objective answers to the following questions:Which joints should be inspected?What inspection method should be used?Should the inspection method be the same for all the joints?What should be the maximum interval between return visits to the same joint?When weld defects are detected during inspection, what corrective action should be taken?
In an attempt to provide objective responses to the above questions, a probabilistic strategy has been developed. Essentially, this strategy involves understanding structural behaviour and NDT capabilities, then modelling the processes of decay and inspection/maintenance by means of mathematical models. By analysis of these models, the effectiveness of various inspection and maintenance regimes can be compared and the optimum regime selected for implementation.
Development of a rationale for welded joint inspection and corrective maintenance can be expected to reduce maintenance costs without lowering safety standards. This is achievable by making sure that the right items are inspected using the most cost-effective techniques and return intervals, and by adopting an appropriate response when defects are detected.

INSPECTION AND MAINTENANCE STRATEGY
Offshore installations in UK waters must satisfy the requirements of Statutory Instrument No 289. The Department of Energy have issued guidance notes to clarify the legislation. The requirements of these documents include:a major underwater survey preceding recertification;an additional underwater survey two years after the major survey;an annual above water survey.
Although defining the types of survey required, neither document is specific as to the answers to the questions posed in the introduction to this paper. paper. P. 187
Miscible Gas Drive in Unit 1 of the Statfjord Reservoir
Authors: Broekers M. P. , van Dorp W. G. 
Published: December 2007

ABSTRACT
Miscible flooding with hydrocarbon gas is being applied on a pilot basis to the Statfjord Unit 1 reservoir of the Northern Fault Block of Shell/Esso's Brent field. This is expected to increase the recovery by 14 MMstb (2.2 Mm3) above the 39 MMstb (6.2 Mm3) expected from water flooding this unit.
Simulation studies were undertaken to confirm that the gas drive in the Unit 1 reservoir would be adequately separated from the concurrent water drive in the underlying units. Also critical production/injection rates for cusping have been investigated. The feasibility of this project will continue to be scrutinised.
Deepwater Hydraulic BOP Control Systems
Authors: Vujasinovic A. N. , McMahan J. M. 
Published: December 2007

Abstract
Relatively simple and economical hydraulic blowout preventer (BOP) control systems must be replaced by complex and expensive multiplex electric systems at depths where the hydraulic signal, traveling at the speed of sound, becomes too long for the function to be executed within the prescribed time period.
In subsea applications, the total time to operate (close or open) a BOP can be split into two parts: signal time and fill-up time. The signal time is the time required for the pilot signal from the surface to reach the corresponding valve in the subsea control pod. The fill-up time is the elapsed time between activation of the subsea pod valve and full execution of the BOP function.
This paper deals with innovative approaches to improve both the signal and fill-up time; the result is a hydraulic BOP control system capable of operating in depths approaching 4,000 ft.
Methods to shorten the hydraulic signal time include "fast relief" and "biased" systems. To improve the fill-up time, emphasis is placed on use of the Energy Saving Valve (ESV) system described in general terms in IADC/SPE paper 11379 presented in New Orleans in 1983. This system utilizes the differential area between opening and closing sides of BOP hydraulic operators to shorten the closing time and to substantially reduce the fluid volume used during the closing process.
Methods for the Alleviation of Slug Flow Problems and Their Influence on Field Development Planning
Authors: Shotbolt K. 
Published: December 2007

Abstract
Alternatives for medium-depth marginal and deepwater field developments include subsea wells with floating process facilities, or total subsea developments with multiphase export lines. Hydraulics considerations of productivity, slug flow, wax, hydrates and emulsions need to be assessed together with capital and operating costs when deciding a field development plan. Unexpected slug flow problems have previously caused reductions in productivity.
Situational Drilling and Completion Practices in the Stoney Point Field: A Subnormally Pressured and Fractured Trenton/Black River Reservoir
Authors: Browne B. L. , Parker E. F. 
Published: December 2007

Abstract
The Trenton/Black River has provided Michigan's only giant oil and gas field, the Albion–Scipio Field, and favorable economics at most oil price levels. A recent Trenton/Black River field discovery has again renewed interest in this play. There are reservoir characteristics, however, that do not lend themselves to easy or standard analysis in trying to locate, drill, complete and produce hydrocarbons from this horizon. The Stoney Point Field wells identify these characteristics and show how the actual well conditions encountered while drilling can determine the drilling and completion procedures. Individual well case histories are given to show some of the situational considerations.
Practical Well Test Analysis Methods for Hydraulically Fractured Wells in Dual-Porosity Reservoirs
Authors: Lancaster D. E. , Gatens J. M. 
Published: December 2007

Abstract
Successful analysis of post-fracture well test data in dual-porosity reservoirs is essential to the design and evaluation of stimulation treatments in these reservoirs. Many methods have been presented for analyzing post-fracture well test data from hydraulically fractured wells in single-porosity reservoirs. Little information is available, however, to assist the engineer in analyzing pressure transient data from a well completed in a dual-porosity reservoir which has been fracture stimulated.
As part of a study we are conducting of the Eastern Devonian Gas Shales, a reservoir which is usually described as dual-porosity, we have analyzed post-fracture well test data from a number of wells for the purpose of estimating propped fracture length and fracture conductivity. The purpose of this paper is to present how we have applied available analytical techniques in our analysis of post-fracture well tests for hydraulically fractured wells in a dual-porosity reservoir. Simulated and field examples are presented to illustrate our approach. Guidelines for conducting and analyzing post-fracture well tests in dual-porosity reservoirs are also presented.
The Optimization of Gas Reservoirs
Authors: Van Goldfracht T. , Perrotti G. , Gorini G. 
Published: December 2007

This paper was prepared for the 41st Annual Fall Meeting of the Society of Petroleum Engineers of AIME, to be held in Dallas, Tex., Oct. 2–5, 1966. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor of the appropriate journal provided agreement to give proper credit is made.
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, with the paper, may be considered for publication in one of the two SPE magazines.

Abstract
A simplified method for the optimization of the exploitation of gas reservoirs based on technical and economic considerations has been developed.
It predicts the present-worth value profit of a project by the use of a functional relationship between pertinent variables.
The optimization of the exploitation of a gas field is indicated by the maximum present-worth value of the profit when the rate of production and the number of wells are optimized.
The optimum number of wells is to be considered as the optimum drilling program since, besides the number of wells, the optimum timing of the drilling program is also predicted.
In order to allow a general use of this method, a dimensionless relationship was written and plotted in graphical form. By the use of this graph, simply knowing the so-called C "payout time" 0 =, the optimum rate
qiL 365 of production and the optimum drilling program are quickly obtainable.
The uncertainties on the reliability of reservoir data in the early life of a field have been corrected by the use of a risk factor.
The importance of this risk factor is shown by the higher sensibility of the profit-to-investment ratio.
A sample calculation is given at the end of the paper for a better understanding of the rapidity of the method.

Introduction
In recent years the sales of natural gas and associated products increased commensurate with the increase of energy consumption. This has been evidenced by more intensive exploration and exploitation of deep and low-permeability gas reservoirs, which before were considered uneconomic.
Although reservoir engineering methods for analyzing and predicting the performance of gas reservoirs and gas wells have long been available, it appears that these methods must be applied with economic criteria early in the history of the reservoir in order to give a usable tool for quick and sound decision-making on investment. The aim of this paper is to develop a simplified procedure for fast and accurate prediction of gas production and drilling program in optimum operating conditions.
Production Decline Type Curves for Gas Wells Producing Under Pseudo-Steady-State Conditions
Authors: Aminian K. , Ameri S. , Hyman M. D. 
Published: December 2007

ABSTRACT
Predicting the production rates from a given gas well is of considerable interest in the natural gas industry. The conventional method to predict the performance of the gas reservoirs require a number of data which are often unavailable. This is especially true for low permeability reservoirs. In many cases, the production data is the only available information on the gas wells. In such cases, the production decline type curves have been utilized to predict the future production rate based upon the past production data. However, the published type curves have been generated with certain assumption(s) which limit their applications. These assumptions include consideration of only Darcy flow, use of constant gas viscosity and deviation factor, as well as ignoring the skin factor.
This paper presents a set of new production type curves for gas wells (production forecasting) without any of the above mentioned assumptions. The type curves are generated by utilizing a simple reservoir model which accounts for variations in gas deviation factor and viscosity as well as non-Darcy flow. The results of this study are presented in the form of dimensionless rate-time and cumulative production-time type curves.
The type curves presented in this study can be utilized to estimate the reserves and forecast future production of a given gas well. In addition, the application of the developed type curves was found to be significantly easier than those previously published. Finally, the developed type curves were verified using actual production data obtained from the gas wells in the Appalachian Basin.
Estimation of Reserves and Recovery Performance in Highly Complex Naturally Fractured Reservoirs
Authors: Owusu L. A. , Ershaghi I. 
Published: December 2007

Abstract
A new approach for estimation of oil recoveries from extremely heterogeneous naturally fractured reservoirs under water influx or water injection is developed. A fully-implicit and versatile simulator was developed and used to obtain recovery predictions. Based on model studies conducted, correlations were obtained for the estimation of recoveries and producing water—oil ratios as a function of reservoir properties. Important reservoir characteristics identified include matrix permeability, maximum capillary pressure for the matrix and fracture density.
New Method of Mini-Frac Analysis Offers Greater Accuracy and Enhanced Applicability
Authors: Lee W. S. 
Published: December 2007

Abstract
A new method of pressure decline analysis has been developed in three geometry models, Perkins and Kern, Christianovich and Zheltov, and Penny. This new method greatly expands applicability of the analysis. The results obtained from the new method agree more closely with field observation. The method improves on the existing approach in the following areas:
In the existing method, calculated closure time often does not agree with field observed value. In the new method, fluid loss calculation is evaluated from the beginning of pumping to field observed closure time, thus ensuring better accuracy. In the new method, the total fluid loss is set equal to the pumped volume minus bulk volume of proppant, therefore, it is suitable for full scale fracturing treatment with proppant. The existing method is not suitable for such treatment because the calculated created volume may be less than the bulk volume of proppant. The new method can handle early time pressure rise and fall caused by pressure and temperature effect near wellbore. The existing method is unsuitable for such fluctuation because type curve matching is frequently impossible. Formulas required to determine fracture parameters such as fluid loss coefficient, fracture extension and fluid efficiency have been derived which are simple to use and can be implemented on desk calculators for real-time application.
Short-Radius Lateral Drilling: A Completion Alternative
Authors: Parsons R. S. , Fincher R. W. 
Published: December 2007

Abstract
The drilling of horizontal holes from a vertical wellbore to enhance oil and gas production has become a renewed topic in well completion technology. A concept over 50 years old, lateral drilling was originally thought of as a cure for declining or marginally productive wells. Today, because of improved materials, designs, and manufacturing techniques, lateral drilling has emerged as a promising completion technique in many types of reservoirs.
This presentation will discuss state-of-the-art, short-radius lateral completion technology, specifically the method offered by Eastman Christensen. A Michigan case history will also be discussed in which the technique was used to turn a well destined for abandonment into a commercial success.