Well Test interpretation Model on Power-law Non-linear Percolation Pattern in Low-permeability Reservoirs

Author(s):  
Shun Liu ◽  
Kai Zhang ◽  
Rui Han
2012 ◽  
Vol 594-597 ◽  
pp. 456-459
Author(s):  
Tong Jing Liu ◽  
Bao Yi Jiang ◽  
Rui Liu ◽  
Peng Xiang Diwu

The speed of development of well test technology has been faster than well test interpretation technology in low permeability reservoirs. One of the main research directions for well test soft technology was specific interpretation theory and interpretation techniques. In recent years, well test was put forward higher request by the production complex and low permeability reservoirs. Test interpretation results urgently need to be applied to reservoir engineering analysis in-depth and quantitatively. One of the limited reality conditions of well test application was lack of the comprehensive research combined with the reservoir engineering. Combining with the test examples, the investigation radius change between injection-production wells was studied, and the build-up well test cycle in low permeability reservoir was optimized. According to the actual process situation, it was proposed that take 20d as the upper limit of well test cycle, and 10d block as the lower limit of well test cycle of build-up well test in a typical low permeability reservoir.


2020 ◽  
Author(s):  
Li Li ◽  
Wei Liang ◽  
Zhenghe Yan ◽  
Kun Wang ◽  
Qiyuan Luo ◽  
...  

2011 ◽  
Vol 383-390 ◽  
pp. 243-247
Author(s):  
Ying Hao Shen ◽  
Shun Li He ◽  
Hong Ling Zhang

Pressure-rate deconvolution method based on the newly robust solution algorithm is applied to low permeability reservoirs, and deconvolution codes were developed for the study based on Schreoter deconvolution algorithm in this paper. The application of this method in a low permeability oilfield shows that deconvolution can provide much more information than the conventional well test interpretation methods, and this deconvolution method can interpret the whole test sequence but doesn’t be limited in pressure build-up period. It is proved that the pressure-rate deconvolution algorithm works well in well test interpretation of low permeability reservoirs.


Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-19
Author(s):  
Kun Wang ◽  
Li Li ◽  
Xiao Chen ◽  
Wei Liang ◽  
Yong Yang ◽  
...  

In the numerous low-permeability reservoirs, knowing the real productivity of the reservoir became one of the most important steps in its exploitation. However, the value of permeability interpreted by a conventional well-test method is far lower than logging, which further leads to an inaccurate skin factor. This skin factor cannot match the real production situation and will mislead engineer to do an inappropriate development strategy of the oilfield. In order to solve this problem, key parameters affecting the skin factor need to be found. Based on the real core experiment and digital core experiment results, stress sensitivity and threshold pressure gradient are verified to be the most influential factors in the production of low-permeability reservoirs. On that basis, instead of a constant skin factor, a well-test interpretation mathematical model is established by defining and using a time-varying skin factor. The time-varying skin factor changes with the change of stress sensitivity and threshold pressure gradient. In this model, the Laplace transform is used to solve the Laplace space solution, and the Stehfest numerical inversion is used to calculate the real space solution. Then, the double logarithmic chart of dimensionless borehole wall pressure and pressure derivative changing with dimensionless time is drawn. The influences of parameters in expressions including stress sensitivity, threshold pressure, and variable skin factor on pressure and pressure derivative and productivity are analyzed, respectively. At last, the method is applied to the well-test interpretation of low-permeability oil fields in the eastern South China Sea. The interpretation results turn out to be reasonable and can truly reflect the situation of low-permeability reservoirs, which can give guidance to the rational development of low-permeability reservoirs.


Author(s):  
Guzyal F. Asalkhuzina ◽  
Alfred Ya. Davletbaev ◽  
Ildus L. Khabibullin ◽  
Rina R. Akhmetova

The article discusses the aspects of conducting and analyzing the results of hydrodynamic studies of wells (well test) at steady-state injection modes conducted in injection wells in order to assess reservoir pressure and injectivity. The main goal of this work is to determine the necessary duration of injection modes at which reservoir pressure will be determined at the maximum research radius. In view of the considerable duration of the study, in low-permeability reservoirs, the work of the environment wells is taken into account, which, in the process of well research, should have a minimal impact on the results of data interpretation. To this end, we simulated the dynamics of pressure changes for this type of well test for various parameters of the reservoir and the duration of injection modes, taking into account the influence of the work of the surrounding production wells. To solve this problem, we used a numerical model of fluid filtration in an element of a nine-point development system in a low-permeable reservoir. The production and injection of fluid is carried out in wells with main technogenic fractures of hydraulic fracturing. During the simulation, the filtration parameters of the “fracture-formation” system and the duration of the well operating modes were varied, and synthetic data on the change in pressure in the wells were reproduced. Pressure and flow rates at the well operating modes were analyzed by plotting the indicator diagram (ID). Estimates of the extrapolated pressure from the ID graphs were compared with the pressures in the numerical model, in particular, the pressure on the supply circuit and on the study radius. It is shown that for low-permeability formations when studying injection wells using the steady-state injection method, it is necessary to take into account the research radius, which depends on the permeability of the formation and the duration of the injection regimes. Also, the research radius must be taken into account when constructing isobar maps along with the reservoir pressure value.


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