A Study of the Interaction Mechanism between Hydraulic Fractures and Natural Fractures in the KS Tight Gas Reservoir

2015 ◽  
Author(s):  
Fuxiang Zhang ◽  
Kaibin Qiu ◽  
Xiangtong Yang ◽  
Jun Hao ◽  
Xuefang Yuan ◽  
...  
Keyword(s):  
Interaction Mechanism ◽  
Hydraulic Fractures ◽  
Tight Gas ◽  
Natural Fractures ◽  
Gas Reservoir ◽  
Tight Gas Reservoir

A Semianalytical Methodology To Diagnose the Locations of Underperforming Hydraulic Fractures Through Pressure-Transient Analysis in Tight Gas Reservoir

SPE Journal ◽  
2016 ◽  
Vol 22 (03) ◽  
pp. 924-939 ◽  
Author(s):  
Youwei He ◽  
Shiqing Cheng ◽  
Shuang Li ◽  
Yao Huang ◽  
Jiazheng Qin ◽  
...  
Keyword(s):  
Production Rate ◽  
Transient Analysis ◽  
Gas Production ◽  
Hydraulic Fractures ◽  
Tight Gas ◽  
Well Performance ◽  
Gas Reservoir ◽  
Pressure Transient ◽  
Type Curves ◽  
Tight Gas Reservoir

Summary The increasing activities in tight reservoir exploitation through fractured wells have attracted interests of pressure-transient analysis (PTA) for well-performance evaluation. The production rates of different fractures were assumed to be equal in previous models. However, different fractures have unequal contributions to the total-gas-production rate because of the differences of fracture scale (e.g., half-length, height), heterogeneity of gas saturation, formation damage, and fracture closure. This paper considers the effect of unequal gas-production rate of each fracture (UGPREF) on pressure-transient behaviors, and develops a semianalytical methodology to diagnose the specific locations of underperforming fractures through PTA by use of bottomhole-pressure (BHP) data. First, new semianalytical solutions of a multifractured horizontal well (MFHW) in a tight gas reservoir are derived on the basis of the Green function (Gringarten and Ramey 1973) and Newman product method (Newman 1936). Second, the model is validated by comparison with the numerical model in KAPPA Ecrin (Saphir) software (Essca 2011). Third, type curves are developed, and sensitivity analysis is further investigated. Results show that there exist clear distinctions among these type curves between equal gas-production rate of each fracture (EGPREF) and UGPREF. The early radial flow is distinguishable and behaves as a horizontal line with the value of 0.5/N* (N* = N for EGPREF, N*≠N for UGPREF) in the pseudopressure-derivative curves when the interferences between fractures do not overlap this period. If the early-radial flow was mistakenly regarded as pseudoradial flow, the interpreted permeability would be N* times smaller than the accurate result. Furthermore, the methodology is applied to a field case of the Daniudi tight gas reservoir in the Ordos Basin, which illustrates its physical consistency and practicability to diagnose the specific locations of underperforming hydraulic fractures through pressure-history matching. It also provides feasible references for reservoir engineers in well-performance evaluation and field strategy (e.g., refracturing, acidizing, or other stimulation treatments) to enhance hydrocarbon production.

Natural fractures in tight gas sandstones: a case study of the Upper Triassic Xujiahe Formation in Xinchang gas field, Western Sichuan Basin, China

2021 ◽  
pp. 1-18
Author(s):  
Yunzhao Zhang ◽  
Lianbo Zeng ◽  
Wenya Lyu ◽  
Dongsheng Sun ◽  
Shuangquan Chen ◽  
...  
Keyword(s):  
Production Capacity ◽  
Gas Production ◽  
Upper Triassic ◽  
Tight Gas ◽  
Natural Fractures ◽  
Carbon And Oxygen Isotopes ◽  
Gas Field ◽  
Xujiahe Formation ◽  
Western Sichuan ◽  
Tight Gas Reservoir

Abstract The Upper Triassic Xujiahe Formation is a typical tight gas reservoir in which natural fractures determine the migration, accumulation and production capacity of tight gas. In this study, we focused on the influences of natural fractures on the tight gas migration and production. We clarified characteristics and attributes (i.e. dips, apertures, filling degree and cross-cutting relationships) of the fractures based on image logging interpretations and core descriptions. Previous studies of electron spin resonance, carbon and oxygen isotopes, homogenization temperature of fluid inclusions analysis and basin simulation were considered. This study also analysed the fracture sequences, source of fracture fillings, diagenetic sequences and tight gas enrichment stages. We obtained insight into the relationship between fracture evolution and hydrocarbon charging, particularly the effect of the apertures and intensity of natural fractures on tight gas production. We reveal that the bedding fractures are short horizontal migration channels of tight gas. The tectonic fractures with middle, high and nearly vertical angles are beneficial to tight gas vertical migration. The apertures of fractures are controlled by the direction of maximum principal stress and fracture angle. The initial gas production of the vertical wells presents a positive correlation with the fracture abundance, and the intensity and aperture of fractures are the fundamental factors that determine the tight gas production. With these findings, this study is expected to guide the future exploration and development of tight gas with similar geological backgrounds.

Characteristics of gas accumulation in a less efficient tight-gas reservoir, He 8 interval, Sulige gas field, Ordos Basin, China

2016 ◽  
Vol 57 (7) ◽  
pp. 1064-1077 ◽  
Author(s):  
Ding Xiaoqi ◽  
Yang Peng ◽  
Han Meimei ◽  
Chen Yang ◽  
Zhang Siyang ◽  
...  
Keyword(s):  
Ordos Basin ◽  
Tight Gas ◽  
Gas Reservoir ◽  
Gas Field ◽  
Gas Accumulation ◽  
Tight Gas Reservoir

scholarly journals Fluid distribution in a tight gas reservoir using the saturation-height model

2021 ◽  
Vol 2 ◽  
pp. 100030
Author(s):  
Svetlana Rudyk ◽  
Amal Al-Lamki ◽  
Malika Al-Husaini
Keyword(s):  
Fluid Distribution ◽  
Tight Gas ◽  
Gas Reservoir ◽  
Tight Gas Reservoir ◽  
Height Model
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