Stimulation Mechanism of SDS Nanoemulsion in Tight Gas Reservoirs

2011 ◽  
Vol 418-420 ◽  
pp. 82-85
Author(s):  
Ming Liang Luo ◽  
Jia Lin Liu ◽  
Le Jun Liao ◽  
Zi Long Jia ◽  
Hou Tai Sun
Keyword(s):  
Water Saturation ◽  
Sodium Dodecyl ◽  
Tight Gas ◽  
Gas Reservoirs ◽  
Gas Reservoir ◽  
Initial Water ◽  
Core Flow ◽  
Tight Gas Reservoir ◽  
Water Block ◽  
Flow Experiments

The stimulation mechanisms of sodium dodecyl sulfate (SDS) nanoemulsion in tight gas reservoir were analyzed by capillary force, core spontaneous imbibitions, cleanup effect and core flow experiments. The results show that SDS nanoemulsion could hold back capillarity effectively, reduce the water absorption and reduce water block damage. The initial water saturation of core decreases by 85.12% and the gas effective permeability regains by 42.03%, which improves the stimulation effect in tight gas reservoir substantially

scholarly journals Threshold Pore Pressure Gradients in Water-Bearing Tight Sandstone Gas Reservoirs

Energies ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 4578
Author(s):  
Yong Wang ◽  
Yunqian Long ◽  
Yeheng Sun ◽  
Shiming Zhang ◽  
Fuquan Song ◽  
...  
Keyword(s):  
Water Saturation ◽  
High Water ◽  
Linear Regression Method ◽  
Tight Gas ◽  
Gas Reservoirs ◽  
Tight Sandstone ◽  
Gas Reservoir ◽  
Gas Seepage ◽  
Tight Gas Reservoir ◽  
Core Permeability

Tight gas reservoirs commonly occur in clastic formations having a complex pore structure and a high water saturation, which results in a threshold pressure gradient (TPG) for gas seepage. The micropore characteristics of a tight sandstone gas reservoir (Tuha oilfield, Xinjiang, China) were studied, based on X-ray diffraction, scanning electron microscopy and high pressure mercury testing. The TPG of gas in cores of the tight gas reservoir was investigated under various water saturation conditions, paying special attention to core permeability and water saturation impact on the TPG. A mathematical TPG model applied a multiple linear regression method to evaluate the influence of core permeability and water saturation. The results show that the tight sandstone gas reservoir has a high content of clay minerals, and especially a large proportion of illite–smectite mixed layers. The pore diameter is distributed below 1 micron, comprising mesopores and micropores. With a decrease of reservoir permeability, the number of micropores increases sharply. Saturated water tight cores show an obvious non-linear seepage characteristic, and the TPG of gas increases with a decrease of core permeability or an increase of water saturation. The TPG model has a high prediction accuracy and shows that permeability has a greater impact on TPG at high water saturation, while water saturation has a greater impact on TPG at low permeability.

scholarly journals Study on Rheological Properties of Nanofluids

2021 ◽  
Vol 2132 (1) ◽  
pp. 012049
Author(s):  
Yan-qing Bian ◽  
Pu-cheng Wu ◽  
Jing Hao ◽  
Quan Shi ◽  
Guo-wei Qin
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Oil And Gas ◽  
Loss Modulus ◽  
Production Capacity ◽  
Tight Gas ◽  
Water Control ◽  
Gas Reservoirs ◽  
Gas Reservoir ◽  
Tight Gas Reservoir

Abstract Based on the previous research on the rheological properties of nanofluids by many scholars at home and abroad, to solve the problem that the viscosity of conventional polymer water control agents is large and cannot meet the demand for increasing production capacity in the process of tight gas reservoir exploitation, this paper takes self-made nanofluids as the research object, tests the rheological properties of self-made nanofluids by rheological experiment, and systematically studies the effects of concentration, temperature and shear action on the viscosity of nanofluids, and the dynamic viscoelasticity and thixotropy of nanofluids were discussed. The results show that the rheological type of nanofluid belongs to power-law fluid, but it is related to the shear rate. The viscosity of nanofluids increases with the increase of concentration; when the temperature increases, the viscosity of nanofluids decreases and the fluidity increases; under the shear action, the viscosity of nanofluid changes very little and has good shear resistance; the dynamic viscoelastic test shows that the storage modulus G´ of the nanofluid is larger than the loss modulus G”, showing elastic characteristics; the thixotropy test shows that when the shear rate is accelerated, the viscosity decreases with time, and when the shear rate is slowed down, the viscosity recovers rapidly with time, which has good thixotropy. The research results provide an important theoretical basis for further research on the application of nanomaterials in tight oil and gas reservoirs.

Assessment on Pore Structure of Western Sichuan Reservoir through Mercury Intrusion Porosimetry

2012 ◽  
Vol 226-228 ◽  
pp. 2082-2087
Author(s):  
Chi Guan ◽  
Zhang Hua Lou ◽  
Hai Jian Xie
Keyword(s):  
Pore Structure ◽  
Mercury Intrusion Porosimetry ◽  
Water Saturation ◽  
Absolute Permeability ◽  
Tight Gas ◽  
Gas Reservoir ◽  
Western Sichuan ◽  
Mercury Intrusion ◽  
Irreducible Water Saturation ◽  
Tight Gas Reservoir

Mercury intrusion porosimetry injection is important in assessing microscopic pore structure of reservoirs. This paper introduces an estimated function for investigating the pore characteristic of western Sichuan tight gas reservoir based on VG model. Better correlations between the measured and estimated results have been obtained using VG model. Representative parameters were obtained by fitting the predictions of VG model to the experimental data, and then the estimated formulation was proposed for the studied reservoir. Correlation analysis of the parameters of VG model confirms that absolute permeability and irreducible water saturation are important in mercury injection porosimetry. The approach applied in this paper is helpful in investigating tight reservoirs, especially in the common cases when measurement is difficult to carry out, partly because of complicated variability in the field, and partly because measuring is time-consuming and expensive.

Pressure Transient Modeling of Fractured Horizontal Wells in the Closed Tight Gas Reservoir

2012 ◽  
Vol 616-618 ◽  
pp. 749-752
Author(s):  
Meng Ya Xu ◽  
Xin Wei Liao ◽  
Xiao Liang Zhao
Keyword(s):  
Steady State ◽  
Horizontal Wells ◽  
Tight Gas ◽  
Gas Reservoirs ◽  
Gas Reservoir ◽  
Transient Model ◽  
Pressure Transient ◽  
Tight Gas Reservoir ◽  
Important Means ◽  
Fractured Horizontal Wells

Fractured horizontal well is the important means for the development of tight gas reservoirs. Based on the geologic characteristics of the tight gas reservoir, a pressure transient model for fractured horizontal wells is established by the Green functions and Newman product principle. The model considers the seepage resistances and the inferences from fractures each other. Practical application presents the pressure changes and flow rate distribution of fractures at non-steady state and quasi-steady state, and the suggestions for field operation are given as well.

Study and Apply of Seepage Law on Multi-Stage Fractured Horizontal Wells in Tight Gas Reservoirs

2014 ◽  
Vol 1030-1032 ◽  
pp. 1394-1398
Author(s):  
Ping Wang ◽  
Zhao Hui Xia ◽  
Wei Ding ◽  
Chao Bin Zhao ◽  
Yun Peng Hu ◽  
...  
Keyword(s):  
Scientific Evidence ◽  
Horizontal Wells ◽  
Tight Gas ◽  
Gas Reservoirs ◽  
Gas Reservoir ◽  
Tight Gas Reservoirs ◽  
Multi Stage ◽  
Tight Gas Reservoir ◽  
Commercial Value ◽  
Fractured Horizontal Wells

Because the extremely low permeability for tight gas reservoirs, lead to the way to seepage and the shape of production curves different with the convention reservoirs; this will increase the difficulty to develop the tight gas reservoirs; on the other hand, the convention exploit cannot recover the tight gas with commercial value, with this problem, the main solution is the technology of multi-stage fractured horizontal wells, the fractured can provide the channel for gas to transport, the horizontal wells can increase the seepage area of tight gas, it’s the guarantee to get the commercial value. But, at present, the study on the tight was dependent on the method of convention gas reservoirs, the production curve get from this method also the same with the convention gas reservoirs, in order to close with the really exploitation of tight gas reservoirs and provide the more accurate scientific evidence, we must study based on the feature of tight gas reservoir, in this situation, we can get the suitable production curves for tight gas reservoirs. This paper based on the feature of tight gas reservoir, combine with the model of multi-stage fractured horizontal wells, and get the production equation of tight gas, combine with the yield of discard time, we can get the type curve, and then get the C level reserves of region.

scholarly journals A Three-Fold Classification of Tight Gas Based Primarily on Dynamic Relationship Between Gas Charging History and Reservoir Tightening Process and its Application

2015 ◽  
Vol 8 (1) ◽  
pp. 51-57
Author(s):  
Lei Zhang ◽  
Lunwei Zhu ◽  
Jianian Shen ◽  
Qifei Huang
Keyword(s):  
Source Rock ◽  
Tight Gas ◽  
Gas Generation ◽  
Gas Reservoirs ◽  
Gas Reservoir ◽  
Tight Gas Reservoirs ◽  
Gas Accumulation ◽  
Dynamic Relationship ◽  
Tight Gas Reservoir

Building upon the foundation of the prior investigations, a three-fold classification of tight gas reservoirs is proposed in this paper which is based primarily on dynamic relationship between gas charging history and reservoir tightening process, coupled with tectonic evolution, source-reservoir relationship, migration and charging pattern. The three categories of tight gas are: (1) “pre-existing” basin-centered gas reservoir, in which the reservoir sands experienced earlystage tightening processes, occurring before peak gas generation, expulsion from source rock, and charging of reservoir; (2) “pre-existing subsequent-improved” tight gas reservoir, in which the reservoir sands were also tightened before gas charging and then underwent reservoirs improvement mainly caused by the tectonic activities; and (3) “subsequentconventional” tight gas reservoir where reserved sands were tightened after the peak of gas generation, expulsion from source rock, and charging of reservoir. This type of tight gas initially formed conventional gas accumulation during gas charging of reservoir, and subsequently modified to tight gas reservoir. All the three categories of tight gas have different geological conditions of gas accumulation and gas accumulation patterns, which can be used as characteristics to classify these tight gas systems, and thus have distinctive control on regional gas distribution. The results of applying this tight gas classification for an actual basin show that correctly distinguishing these three kinds of tight gas reservoirs from each other could contribute greatly to the exploration and development of tight gas reservoirs.

scholarly journals Secondary formation damage of low-pressure layer during commingled production in multilayered tight gas reservoirs

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Jingchen Ding ◽  
Changhui Yan ◽  
Yongming He ◽  
Changcheng Wang
Keyword(s):  
Water Saturation ◽  
Low Pressure ◽  
Working Fluid ◽  
Formation Damage ◽  
Tight Gas ◽  
Gas Reservoirs ◽  
Back Flow ◽  
Tight Gas Reservoirs ◽  
Secondary Formation ◽  
Tight Gas Reservoir

AbstractThis paper experimentally investigates fluid back-flow behavior and formation damage during commingled production in multilayered tight gas reservoirs. The development of fluid back-flow in commingled tight gas reservoirs was simulated using a newly designed experimental platform. The results indicate that when there is a pressure difference between different layers during commingled production from tight gas reservoir, water produced from the high-pressure layer will invade the low-pressure layer along with gas back-flow and will accumulate in the near-wellbore area. This will lead to an increase in water saturation and a decline in permeability in the low-pressure layer and result in a significant reduction in ultimate recovery. The outcomes of these experiments demonstrate that as well as the formation damage caused by the working fluid during drilling and fracturing, “Secondary Formation Damage” also occurs during commingled production in multilayered tight gas reservoirs. This secondary formation damage mainly occurs in the near-wellbore area of low-pressure layers and is more severe with greater proximity to the wellbore. Through further experimentation to assess the factors influencing secondary formation damage, it is shown that the degree of secondary formation damage increases with decreasing original formation pressure, original water saturation, and permeability in the lower-pressure layer.

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