scholarly journals Reducing Uncertainty in Geostatistical Description with Well-Testing Pressure Data

1999 ◽  
pp. 149-162 ◽  
Keyword(s):  

Author(s):  
Igor Caetano Cariello ◽  
Paulo de Tarço Honório Junior ◽  
Grazione De Souza ◽  
Helio Pedro Amaral Souto

<p>A Análise de Testes de Poços é um ramo da Engenharia de Reservatórios no qual<br />empregamos dados de pressão de poço a partir de testes de produção/injeção de fluido em conjunto com modelos físico-matemáticos para caracterizar o sistema poço-reservatório, usando problemas inversos. Nessas situações, aplicamos amplamente soluções analíticas e semianalíticas do modelo físico-matemático que descreve o fluxo. Nesse contexto, o objetivo do presente estudo é 1) realizar uma revisão bibliográfica sobre algumas das soluções analíticas clássicas para determinação da pressão no poço produtor e 2) implementar os códigos numéricos para a criação de uma biblioteca computacional, proporcionando as soluções analíticas voltadas para a determinação da pressão em poços produtores de petróleo. Os sistemas poço-reservatório estudados possuem um poço vertical e levam em consideração os efeitos de condições de contorno, a estocagem na coluna de produção do poço, dano à formação, períodos de fluxo e estática, bem como a presença de fraturas naturais. Obtivemos as soluções analíticas usando a transformada de Laplace e uma inversão numérica, utilizando o algoritmo Stehfest, para calcular a variação de pressão ao longo do tempo.</p><p><br /><strong>Palavras-chave</strong>: Soluções Analíticas, Transformada de Laplace Inversa, Tranformada de Laplace, Algoritmo de Stehfest, Análise de Teste de Poço.</p><p>===================================================================</p><p>Well Testing Analysis is a branch of Reservoir Engineering, in which we<br />employ well pressure data from production tests/fluid injection in conjunction with physical-mathematical models to characterize the well-reservoir system, using inverse problems. In these situations, we widely used analytical and semi-analytical solutions of the physical-mathematical model that describes the flow. In this context, the objective of this work is to 1) carry out a bibliographic review on some of the classic analytical solutions for determining the pressure in the producing well and 2) implement the numerical codes for the creation of a computational library, providing the analytical solutions aimed at determining pressure in oil-producing wells. The well-reservoir systems with a vertical well take into account the boundary effects, wellbore storage, formation damage, drawdown and buildup test analysis, and the presence of natural fractures. We obtain the analytical solutions using the Laplace transform and a numerical inversion, using the Stehfest algorithm, to calculate the pressure variation in the time domain.</p><p><br /><strong>Key words</strong>: Analytical Solutions, Inverve Laplace Transform, Laplace Transform, Stehfest Algorithm, Well Testing Analysis.</p>



Author(s):  
Dario Viberti ◽  
Eloisa Salina Borello ◽  
Francesca Verga

In reservoir engineering, one of the main sources of information for the characterization of reservoir and well parameters is well testing. Among the unconventional well testing methodologies, Harmonic Well Testing (HPT) is appealing from an economic standpoint because it could provide well performance and reservoir behavior monitoring without having to interrupt field production. Recorded pressure analysis is performed in the frequency domain by adopting a derivative approach similar to conventional well testing. To this end, pressure and rate data must be decomposed into harmonic components. Test interpretability can be significantly improved if pressure data are detrended prior to interpretation, filtering out non periodic events such as discontinuous production from neighboring wells and flow regime variations which did not respect the designed test periodicity. Therefore, detrending offers the possibility of overcoming the limitation of HPT applicability due to the difficulty of imposing a regularly pulsing rate for the whole test duration (typically lasting several days). This makes HPT attractive for well performance monitoring, especially in gas storage fields. In this paper, the application of different detrending methodologies to synthetic HPT pressure data generated in different reservoir and operational scenarios is presented and discussed. Moreover, a real case application is also presented.



2017 ◽  
Vol 4 (1) ◽  
pp. 41-52
Author(s):  
Dedy Loebis

This paper presents the results of work undertaken to develop and test contrasting data analysis approaches for the detection of bursts/leaks and other anomalies within wate r supply systems at district meter area (DMA)level. This was conducted for Yorkshire Water (YW) sample data sets from the Harrogate and Dales (H&D), Yorkshire, United Kingdom water supply network as part of Project NEPTUNE EP/E003192/1 ). A data analysissystem based on Kalman filtering and statistical approach has been developed. The system has been applied to the analysis of flow and pressure data. The system was proved for one dataset case and have shown the ability to detect anomalies in flow and pres sure patterns, by correlating with other information. It will be shown that the Kalman/statistical approach is a promising approach at detecting subtle changes and higher frequency features, it has the potential to identify precursor features and smaller l eaks and hence could be useful for monitoring the development of leaks, prior to a large volume burst event.





2011 ◽  
Author(s):  
Alwaleed Rashid Al-Shukaily ◽  
Mandalparthi Umamaheshwar Srinivas


Author(s):  
M. Daud
Keyword(s):  


Author(s):  
A. O. Marnila

Geragai graben is located in the South Sumatera Basin. It was formed by mega sequence tectonic process with various stratigraphic sequence from land and marine sedimentation. One of the overpressure indication zones in the Geragai graben is in the Gumai Formation, where the sedimentation is dominated by fine grained sand and shale with low porosity and permeability. The aim of the study is to localize the overpressure zone and to analyze the overpressure mechanism on the Gumai Formation. The Eaton method was used to determine pore pressure value using wireline log data, pressure data (RFT/FIT), and well report. The significant reversal of sonic and porosity log is indicating an overpressure presence. The cross-plot analysis of velocity vs density and fluid type data from well reports were used to analyze the causes of overpressure in the Gumai Formation. The overpressure in Gumai Formation of Geragai graben is divided into two zones, they are in the upper level and lower level of the Gumai Formation. Low overpressure have occurred in the Upper Gumai Formation and mild overpressure on the Lower Gumai Formation. Based on the analyzed data, it could be predicted, that the overpressure mechanism in the Upper Gumai Formation might have been caused by a hydrocarbon buoyancy, whereas in the Lower Gumai Formation, might have been caused by disequilibrium compaction as a result of massive shale sequence.



2017 ◽  
pp. 56-61
Author(s):  
M. L. Karnaukhov ◽  
O. N. Pavelyeva

The well testing of gas-condensate horizontal wells are discussed in the article and the comparative analysis of borehole flow capacity, depending on the mode of it’s operation is presented. Extra attention is focused on the issue of timely identification of the reasons for the reduction of fluid withdrawal from the reservoir. The presence of high skin effect is proved, which confirms the existence of low-permeability of bottomhole formation zone related to condensation in the immediate area of the horizontal wellbore.



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