bluuebunny/crossref_metadata_2025_split huggingface dataset:
Deliverability of Wells in the Gas Condensate Reservoir
Authors: Du Y. , Guan L. , Li D. 
Published: December 2007

Abstract
Underground flow in gas condensate reservoirs usually consists of single-phase gas flow at initial reservoir conditions (reservoir pressure Pr larger or equal than dew point pressure Pd). However, with the depletion of the gas condensate reservoir, when its flowing bottom-hole pressure of a producer falls below the dew point pressure of the corresponding reservoir fluids, a relatively high liquid saturation will build up near the wellbore, which is named as "condensate blocking".
The formation of this "condensate blocking" in the near-well region will lead to the reduction in gas relative permeability and result in loss of well deliverability. This deliverability loss is also indicated by the field production data from many gas condensate wells. In this paper, this loss is investigated by conducting a series of fine-grid numerical compositional simulations with the reservoir data. The well deliverability index (PI) at initial reservoir pressure, slightly above dew point pressure for a single-phase gas flow was found to drop rapidly due to condensate banking. The gas PI at a reservoir pressure equal to half of dew point pressure is only about 20% of the value at a reservoir pressure, slightly above dew point pressure for low permeability cases (permeability less than 100md).
We also found that PVT properties of reservoir fluids, absolute permeability, and production pressure drawdown of the producer all have significant influence on the well gas deliverability.
Direct Application of Geopyphiscal/Seismic Methods for N/G Calculation
Authors: Vanaki Mohammadreza , Sede Bahman Samimi , Behzad Ramin 
Published: December 2007

Abstract
There are several methods for Net/Gross calculation by seismic methods which are as follows:

-AVOprocessing and Attribute analysis for lithology and pore-fluid detection on seismic data:
Amplitude versus offset is one of important method for detect anomalies associated with presence of hydrocarbons in the subsurface.

-Elastic parameter:
In this method P-wave velocity (Vp), S-wave velocity (Vs) and bulk density should be caculated. Then Vp/Vs ratio to be calculated by these parameters.after that Poisson's ratio, bulk modulus, rigidity modulus, Lame's constant, Young's modulus can be calculatedby Vp/Vs ratio.This parameters indicate the kind of litho logy and shale content. At last the porosity of reservoir can be calculated by these parameters.

-Seismic attributes:
One of the most important seismic attributes for calculating N/G ratio is amplitude. Gross porosity and fluid content could be given by amplitude analysis.
Instantaneous is the seismic attribute that has important rule in N/G ratio calculation.litho logical contrasts and fluid content could be resulted by this attribute.
In this paper we will explain above methods then we will calculate N/G by elastic parameter in a field with real data.
At last we will compare results of this method with petrophysical method.
Pressure and Pressure Derivative Analysis for Linear Homogeneous Reservoirs without using Type-Curve Matching
Authors: Escobar Freddy H. , Saavedra Nestor F. , Hernández Claudia M. , Hernández Yuly A. , Pilataxi Juan F. , Pinto Diego A. 
Published: December 2007

Abstract
A significant number of well pressure tests are conducted in long, narrow reservoirs with closed and open extreme boundaries. It is desirable not only to appropriately identify these types of systems but also to develop an adequate and practical interpretation technique to determine their parameters and size, when possible. An accurate understanding of how the reservoir produces and the magnitude of producible reserves can lead to competent decisions and adequate reservoir management.
So far, studies found for identification and determination of parameters for such systems are conducted by conventional techniques (semilog analysis) and semilog and log-log type-curve matching of pressure versus time. Type-curve matching is basically a trial-and-error process which may provide inaccurate results. Besides, a limitation in the number of type curves plays a negative role.
In this paper, a detailed analysis of pressure derivative behavior for a vertical well in linear reservoirs with open and closed extreme boundaries is presented. We studied independently each flow regime, especially the linear flow regime since it is the most characteristic "fingerprint" of these systems. We found that when the well is located at one of the extremes of the reservoir, a single linear flow regime develops once radial flow and/or wellbore storage effects have ended. When the well is located at a given distance from both extreme boundaries, the pressure derivative permits the identification of two linear flows toward the well and we called that "dual-linear flow regime". This is characterized by an increment of the intercept of the ½-slope line from π0.5 to π with a consequent transition between these two straight lines. The identification of intersection points, lines, and characteristic slopes allows us to develop an interpretation technique without employing type-curve matching. This technique uses analytical equations to determine such reservoir parameters as permeability, skin, well location and reservoir limits for both gas and oil linear reservoirs. The proposed technique was successfully verified by interpreting both field and synthetic pressure tests for gas and oil reservoirs.
Numerical Welltest Analysis
Authors: Nnadi Magnus , Onyekonwu Michael 
Published: December 2007

Abstract
The importance of reservoir and well parameters estimated from BHP analysis, has made it necessary to analyze field pressure data as practically as possible. This has lead to the application of numerical solutions to BHP analysis. It involves the proper griding of reservoir and subsequent numerical solution of the resulting partial differential equation. This incorporates heterogeneity of reservoir properties into BHP analysis, thereby broadening its applicability to reservoir description, unlike analytic solution, which does not offer the details it requires.
Although, analytical methods give reasonable estimate for simple cases, they are not suitable for real complex cases, due to the limiting assumptions inherent in their development.
This paper assessed the applicability of numerical solution to BHP analyses. It solved some field examples analytically and numerically, first for a known simple case and then for real complex cases. Furthermore, test design data were generated using field data in a heterogeneous system. The test was analyzed using both analytical and numerical approaches. The results obtained show that although analytical solutions can be employed for some heterogeneous systems, they are highly idealistic and limited to some convenient cases and that numerical solution models field data realistically.
Information Management in E&P - the Shell Nigeria Experience
Authors: Peterson Tim , Oluwole Olubunmi , Akano Tonie , Olatinwo T. K. 
Published: December 2007

Abstract
In Shell Petroleum Development Company Nigeria Limited, SPDC, the business of Exploring and Producing Hydrocarbon relies a great deal on the provision of adequate and proper information for the day-to-day activities. This paper will focus on how the subsurface communities business activities have been enabled by the provision of the right information and the underlying Information Technology. This has been highly effective due to the setting up of special IM (Information Management) organizations to
identify the information needs of the professionals responsible for the finding/producing new hydrocarbon. proffer the most appropriate and cost effective Information Technology develop the annual IM business plan acquire and deploy the fit-for-purpose Information Technology tools and train the professionals in the use of these tools.
The themes of this paper are as follow: Data and Document ManagementIntegration, Collaboration & Workflow InitiativesOptimization of IM PortfolioGlobalization of IM Tools & ProcessesTraining the CustomersHealth, Safety, Environment & Security
Some key technologies, recently deployed, will be show cased.
Acoustic Sand Monitor Trials in the Offshore CVX-NMA: Results and Lessons Learned
Authors: Fariyibi F. L. , Umurhohwo J. O. , Olson S. G. , Scott K. C 
Published: December 2007

Abstract
Several of the Offshore CVX-NMA wells have been produced on small choke sizes from a concern about sand production. A review of the historical impact of such constraint showed a significant production loss in the past ten years. Looking into the future, nodal analysis has shown that by producing some of the wells on small choke sizes, they can pre-maturely load-up and die, and in some cases producing high GORs due to choke restriction. Also some of the fields in the offshore locations are at their mature stage with increasing water cuts, thereby susceptible to "higher than normal" sand production.
A Pilot acoustic sand monitoring was, therefore carried out to validate sand production rates and test opportunities to "un-constrain" wells by opening chokes and increasing oil rates. Plans were developed for deployment, training and monitoring. The team made critical decisions in selecting choke sizes during the trials and documented results.
This paper presents the results and lessons learned from the field trials in the Offshore areas of CVX-NMA The exercise proved the effectiveness of sand detector technology to diagnose the severity and characteristics of our sand production and enhance the practise of Operational Excellence in a timely manner. The first phase of the Field trials yielded a total production gain of ~ 3,300 bopd. Long term gains expected include decrease in OPEX (choke replacement, CTU cleanout, Operations vessel cleanouts etc).
Production Optimization using Genetic Algorithm Approach
Authors: Tavakkolian M. , F. Jalali F. , Emadi M. A. 
Published: December 2007

Abstract
The objective of the research presented in this paper is to investigate the effectiveness of "Genetic Algorithm " technique in optimising the performance of hydrocarbon producing wells.
The performance of a production well is a function of several variables. Examples of these variables are tubing size, choke size, and separator pressures. Changing any of the variables will alter the performance of the well.
The advantages of nonlinear optimization methods are many. Using nonlinear optimization techniques, there is no limit to the number of decision variables that can be optimized simultaneously.
Through this paper, a new method for analysis of an oil and gas condensate production system is presented. This method is a new stochastic method which enables us to analyze a system of mathematical equations containing a great number of decision variables and determine the optimum values of them, that should give the most economic result. The presented method is referred to as "Genetic Algorithm" (GA). Here a mathematical model approach is initially applied for the well and surface facilities and then the result is analyzed and further optimized to enhance profitability.
The production facilities considered in this paper consist of tubing, choke, and separators. The method applied is able to consider dual sized tubing (combination of tubing and casing). Furthermore, it is able to determine the optimum number of separators.
The developed code in MATLAB environment, based on GA, is able to obtain the most optimum size(s) for the tubing (single size or dual sized tubing), the depth at which the tubing size should vary (in case dual sized tubing is selected), choke size, number of separators, and separator pressures. The optimisation of these parameters should result in improved hydrocarbon liquid production.
Finally, this method and the developed code have been applied to the production system of a real oil field and the obtained results have been compared to those of Prosper simulator. The results show that GA is a powerful tool to analyze the production system of hydrocarbon fields.
Well Integrity Management in Shell Nigeria
Authors: Wakama Miebaka , Eta Edirhin , Adeniyi Ade 
Published: December 2007

Abstract
Well Integrity is a vital aspect of well design, construction, operation, maintenance and abandonment. As put by SPDC, "all wells shall be designed, constructed, operated, maintained and abandoned in a manner that safeguards their integrity, minimize Health, Safety and Environmental risks and ensure their planned availability throughout their life-cycle". As a consequence of this policy, all wells are monitored to ensure their integrity is guaranteed at all times. By implication all wells that fall short of standards are secured or closed-in unless a short-term deviation or waiver is granted.
Well integrity problems may occur in producing and non-producing wells, especially older wells that were completed as per the prevailing completion standard of their completion dates. The completion standards have changed over time with respect to safety requirements (e.g. wells without top packers, wells without SCSSVs). There may also be some wells that meet current safety standards but still have some integrity-related problems (e.g. leaking packer or silted well slots-swamp locations).
Although, the necessity to enhance the integrity of wells is recognized, enhancement activities have been limited by past budget constraints. The identified activities often rank low in oil generating economics when compared with other projects within the portfolio competing for funds. It therefore became necessary to effectively manage the wide range of well integrity problems, by adopting a concept of ‘Well Integrity Management System ’. In 2003 a dedicated team was set up to assemble a coherent process from the practices of the past and the present and inventorise work that needed to be carried out to ensure that well integrity issues are being adequately addressed.
This paper discusses the initiative by SPDC, Nigeria to put in place a Well Integrity Management System (WIMS) and successes so far.
Productivity Enhancement through Single Well Numerical Modeling
Authors: Ezuka I. O. , Egbele E. E. , Harcourt Port , Onyekonwu M. O. 
Published: December 2007

Abstract
There have been many different aims, relevance and results justifying single well study. Yet little or none has been said about its relevance in production enhancement
Single well modeling is the act of using numerical reservoir simulation equation to study well performance. It is very insightful in evaluating completion strategy, study coning/cusping behavior, well reserves, and relative permeability pseudo-functions for wells in full field models, complex pressure transient data analysis and well economics. This paper presents the applications of single well modeling in productivity enhancement.
The productivity of a well is going to be modeled by using the numerical simulation equations coupled with well production parameters. A combination of several production strategies will be evaluated. Having matched the well model, the combination and strategy that gives the optimum production from the well is to be recommended. The advantage of this is that it couples the reservoir conditions, near wellbore fluid distribution, near wellbore reservoir description, production mechanism with completion strategy to predict well performance. The matched model with a level of uniqueness can predict the well performance to an acceptable level of accuracy.
The challenge of handling excess water production and its impact on the overall well productivity can met through Single Well Numerical Modeling. Single well modeling can be used to determine the optimum well operation and production approach.
The result of the numerical modeling indicates that Single Well modeling is a powerful tool for production enhancement. In water cusping cases, the best strategy for maximum recovery from the well is to avoid early water breakthrough. Re-perforation is not the best economic solution for a well experiencing water cusping. It is a good practice to numerically simulate a well to determine its cone and cusp free rate prior to production. This will aid to archive maximum recovery from the well. Single Well modeling is a good tool for Well economic analysis.
A case study of two wells that penetrated a Niger Delta reservoir will be used.
Prediction of Critical Foam Velocity for Effective Cuttings Transport in Horizontal Wells
Authors: Li Yibing , Kuru Ergun 
Published: December 2007

Abstract
A mathematical model and a numerical analysis of the cuttings transport with foam in horizontal wells have been presented earlier. The model has been incorporated into a computer program and used for finding a closed form critical foam velocity (CFV) correlation.
The new CFV correlation can be used to predict minimum foam flow rate required to remove, or prevent the formation of stationary cuttings beds on the low-side of the highly deviated and horizontal wells.
Effects of key drilling parameters (i.e. drilling rate, annular geometry, foam quality, bottomhole pressure and temperature) on the critical foam velocity have also been investigated.
Numerical examples are presented to illustrate how the CFV correlation can be used to determine required gas and liquid flow rates at the downhole conditions
How to Obstruct Divistiture of Clean Properties
Authors: Holliday George 
Published: December 2007

Abstract
Obtaining funding for the purchase of existing facilities can be daunting, particularly, if the seller has not maintained adequate records. This paper presents a troubled case history of the transfer of assets, where the seller did not conduct adequate due diligence during the previous transfer and could not satisfy the prospective buyer's lender request for proof of previous disposal of solid waste. In addition, the paper offers recommendations for avoiding data acquisition problem.
Small operators must obtain financing for the acquisition of existing facilities to enhance their market share. With the strenuous environmental regulations existing in the United States, lenders are reluctant to provide funds unless the purchaser/seller can provide proof of a clean facility and environmental compliance with existing regulations. No proof of a clean facility and compliance, no funds are made available!
Most technical papers considering acquisitions concentrate on evaluating oil and gas reserves payout or property value. These issues are important, but even with the best economic situation; a lender is hesitant to loan funds for a purchase having an environmental "cloud" or non-compliance issues.
The recommendations contained in this paper are based on an actual acquisition almost stopped in its tracks by a Resource Conservation and Recovery Act question.
Improved MMP Correlations for CO2 Floods Using Analytical Gas Flooding Theory
Authors: Yuan H. , Johns R. T. , Egwuenu A. M. , Dindoruk B. 
Published: December 2007

AbstractLocal displacement efficiency from CO2 gas injection is highly dependent on the minimum miscibility pressure (MMP). Correlations are often used to estimate the MMP where the injected fluid may or may not contain impurities such as methane. These correlations, however, are based on a limited set of experimental data and as such are not widely applicable. They also do not accurately account for the more complex condensing/vaporizing displacement process.This paper presents new MMP correlations for the displacement of multicomponent oil by CO2 and impure CO2. The approach is to use recently developed analytical theory for MMP calculations from equations-of-state (EOS) to generate MMP correlations for displacements by pure and impure CO2.1–8 The advantage of this approach is that MMPs for a wide range of temperatures and reservoir fluids can be calculated quickly and accurately without introducing uncertainties associated with slim-tube MMPs and other numerical methods. The improved MMP correlation is based solely on the reservoir temperature, molecular weight of C7+, and percentage of intermediates (C2 − C6) in the oil. The MMPs from the improved correlation are compared to currently used correlations and 41 experimentally measured MMPs. Correlations are also developed for impure CO2 floods, where the injection stream may contain up to 40% methane. The new correlations are significantly more accurate and applicable than currently used correlations.
Lean gas injection into an extra light oil reservoir-Initial results and further steps
Authors: Palásthy Gy. , Benedek L. , Pipicz V. , Lövei A. , Papp I. 
Published: December 2007

ABSTRACT
The Tisza-1 reservoir is situated at the top of the SE part of Algyo field, Hungary. The 1700 m depth reservoir has been developed in the uppermost sandstone series showing good reservoir quality. The well sortiered, middle and coarse grain sandstone contains extra light crude: the reservoir volume factor is near 4,0 res.bbl/bbl and the oil quality is 63 API. The extreme characteristics of the reservoir oil mean that the intermediate content is above 34 mol%. The production started as early as 1986. The 17 year exploitation history has proved, the strong bottom water drive as primary driving mechanism. By the end of 2002 a 45% of oil recovery was reached and the reservoir pressure drop was 8.3 bars with average water cut of about 23%. Control logs have indicated that about 35% of the net pay pore volume has been unaffected by the bottom water. The main aim of the reservoir management was to increase the recovery of mid-components and to sweep the oil from the upper zones by using dry gases. A 3D, compositional simulation model was developed to evaluate the potential of the gas injection. The static model has been up-scaled to flow units corresponding to the interconnected reservoir rock bodies of identical depositional environment. Comparing the production forecast cases the gas injection showed an additional 11% of mid-component recovery. During the modeling different gases were investigated to use. The economical evaluation was highly affected by the developed gas market environment but finally the lean gas was chosen for injection purpose. The gas injection project started in 2000 after a 4 year planning and preparation. This case study summarizes the planning, preparation of the gas injection project, highlights the dilemmas of the economics and shows the latest results of the process.
Effect of Composition of a Polyacrylamide-Chromium(III) Acetate Gel on the Magnitude of Gel Dehydration and Disproportionate Permeability Reduction
Authors: Nguyen T. Q. , Green D. W. , Willhite G. P. , McCool C. S. 
Published: December 2007

Abstract
For some polymer gels applied in reservoirs to control water flow, a favorable disproportionate permeability reduction (DPR) occurs in which permeability to water is reduced to a much greater extent than to oil. Also, when the gels are subjected to an applied pressure gradient partial dehydration can occur, i.e., some solvent is forced out of the gel structure. In this study of a partially hydrolyzed polyacrylamide crosslinked with chromium acetate, the magnitudes of DPR and gel dehydration volumes were measured as a function of gel composition and the pressure gradients imposed on the gels following placement in unconsolidated sandpacks. For the range of parameters studied, the reduction of permeability to water and oil and the DPR were strong functions of gel composition and applied pressure gradients, although gel dehydration volumes varied by only a small amount.