Hydraulic Fracturing Across Large Existing Perforated Interval Unlocks Reserves on Tight Sandstone Reservoir: Successful Workover Experience, Onshore Congo

2014 ◽  
Author(s):  
Francesco Martocchia ◽  
Vignault Rolle Itoua ◽  
Lisa Farina ◽  
Salvatore Baretti ◽  
Luca Martini
Keyword(s):  
Hydraulic Fracturing ◽  
Tight Sandstone ◽  
Sandstone Reservoir

scholarly journals Hydraulic fracturing fracture propagation in tight sandstone reservoir

2021 ◽  
Vol 861 (6) ◽  
pp. 062082
Author(s):  
Xiaojiang Qiu ◽  
Mian Chen ◽  
Yifan Dai ◽  
Xiaoxuan Kou ◽  
Yimeng Wei ◽  
...  
Keyword(s):  
Hydraulic Fracturing ◽  
Fracture Propagation ◽  
Tight Sandstone ◽  
Sandstone Reservoir

scholarly journals Fracability Evaluation Method and Influencing Factors of the Tight Sandstone Reservoir

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Jiageng Liu ◽  
Lisha Qu ◽  
Ziyi Song ◽  
Jing Li ◽  
Chen Liu ◽  
...  
Keyword(s):  
Hydraulic Fracturing ◽  
Horizontal Stress ◽  
High Fracture Toughness ◽  
Hydraulic Fractures ◽  
Anisotropy Coefficient ◽  
Natural Fractures ◽  
Fracture Networks ◽  
Tight Sandstone ◽  
Stress Anisotropy ◽  
Sandstone Reservoir

Fracability evaluation is the basis of reservoir fracturing and fracturing zone optimization. The tight sandstone reservoir is characterized by low porosity and low permeability, which requires hydraulic fracturing to improve industrial productivity. In this study, a systematic model was proposed for the fracability evaluation of tight sandstone reservoirs. The rock mechanics tests and sonic tests demonstrated that tight sandstone reservoir is characterized by high brittleness, high fracture toughness, and weak development of natural fractures. Numerical simulation was used to analyze the change of reservoir parameters during hydraulic fracturing and the influence of in situ stress on fracture propagation. The results showed that when the horizontal stress anisotropy coefficient is small, natural fractures may lead hydraulic fractures to change direction, and complex fracture networks are easily formed in the reservoir. The horizontal stress anisotropy coefficient ranges from 0.23 to 0.52, and it is easy to produce fracture networks in the reservoir. A new fracability evaluation model was established based on the analytic hierarchy process (AHP). The fracability of tight sandstone reservoir is characterized by the fracability index (FI) and is divided into three levels. Based on the model, this study carried out fracability evaluation and fracturing zone optimization in the study area, and the microseismic monitoring results verified the accuracy of the model.

scholarly journals A reservoir quality evaluation approach for tight sandstone reservoirs based on the gray correlation algorithm: A case study of the Chang 6 layer in the W area of the as oilfield, Ordos Basin

2021 ◽  
pp. 014459872199851
Author(s):  
Yuyang Liu ◽  
Xiaowei Zhang ◽  
Junfeng Shi ◽  
Wei Guo ◽  
Lixia Kang ◽  
...  
Keyword(s):  
Quality Evaluation ◽  
Comprehensive Evaluation ◽  
Ordos Basin ◽  
Reservoir Quality ◽  
Pore Throat ◽  
Tight Sandstone ◽  
Evaluation Approach ◽  
Correlation Algorithm ◽  
Gray Correlation ◽  
Sandstone Reservoir

As an important type of unconventional hydrocarbon, tight sandstone oil has great present and future resource potential. Reservoir quality evaluation is the basis of tight sandstone oil development. A comprehensive evaluation approach based on the gray correlation algorithm is established to effectively assess tight sandstone reservoir quality. Seven tight sandstone samples from the Chang 6 reservoir in the W area of the AS oilfield in the Ordos Basin are employed. First, the petrological and physical characteristics of the study area reservoir are briefly discussed through thin section observations, electron microscopy analysis, core physical property tests, and whole-rock and clay mineral content experiments. Second, the pore type, throat type and pore and throat combination characteristics are described from casting thin sections and scanning electron microscopy. Third, high-pressure mercury injection and nitrogen adsorption experiments are optimized to evaluate the characteristic parameters of pore throat distribution, micro- and nanopore throat frequency, permeability contribution and volume continuous distribution characteristics to quantitatively characterize the reservoir micro- and nanopores and throats. Then, the effective pore throat frequency specific gravity parameter of movable oil and the irreducible oil pore throat volume specific gravity parameter are introduced and combined with the reservoir physical properties, multipoint Brunauer-Emmett-Teller (BET) specific surface area, displacement pressure, maximum mercury saturation and mercury withdrawal efficiency parameters as the basic parameters for evaluation of tight sandstone reservoir quality. Finally, the weight coefficient of each parameter is calculated by the gray correlation method, and a reservoir comprehensive evaluation indicator (RCEI) is designed. The results show that the study area is dominated by types II and III tight sandstone reservoirs. In addition, the research method in this paper can be further extended to the evaluation of shale gas and other unconventional reservoirs after appropriate modification.

Sign in / Sign up

Export Citation Format

Share Document