Induced and natural fracture interaction in tight-gas reservoirs

2012 ◽  
Vol 52 (1) ◽  
pp. 611
Author(s):  
Mohammad Rahman ◽  
Sheik Rahman
Keyword(s):  
Hydraulic Fracture ◽  
Development Planning ◽  
Natural Fracture ◽  
Tight Gas ◽  
Gas Reservoirs ◽  
Differential Stress ◽  
Tight Gas Reservoirs ◽  
Reservoir Development ◽  
Well Spacing ◽  
Tight Gas Reservoir

This paper investigates the interaction of an induced hydraulic fracture in the presence of a natural fracture and the subsequent propagation of this induced fracture. The developed, fully coupled finite element model integrates a wellbore, an induced hydraulic fracture, a natural fracture, and a reservoir that simulates interaction between the induced and natural fracture. The results of this study have shown that natural fractures can have a profound effect on induced fracture propagation. In most cases, the induced fracture crosses the natural fracture at high angles of approach and high differential stress. At low angles of approach and low differential stress, the induced fracture is more likely to be arrested and/or break out from the far-end side of the natural fracture. It has also been observed that the propagation of the induced fracture is stopped by a large natural fracture at a high angle of approach, when the injection rate remains low. At a low angle of approach, the induced fracture deviates and propagates along the natural fracture. Crossing of the natural fracture and/or arrest by the natural fracture is controlled by the shear strength of the natural fracture, natural fracture orientation, and the in situ stress state of the reservoir. In tight-gas reservoir development, the optimum well spacing and induced hydraulic fracture length are correlated. Therefore, fracturing design should be performed during the initial reservoir development planning phase along with the well spacing design to obtain an optimal depletion strategy. This model has a potential application in the design and optimisation of fracturing design in unconventional reservoirs including tight-gas reservoirs and enhanced geothermal systems.

scholarly journals Analysis on the effect of different fracture geometries on the productivity of tight gas reservoirs

2020 ◽  
Vol 16 (2) ◽  
pp. 201-211
Author(s):  
Temoor Muther ◽  
Adnan Aftab Nizamani ◽  
Abdul Razak Ismail
Keyword(s):  
Hydraulic Fracture ◽  
Constant Width ◽  
Hydraulic Fractures ◽  
Tight Gas ◽  
Gas Reservoirs ◽  
Fracture Geometry ◽  
Tight Gas Reservoirs ◽  
Constant Height ◽  
Tight Gas Reservoir ◽  
Half Length

Tight gas reservoirs are unconventional reservoir assets which have been the focus of major research in the petroleum industry owing to the global decline in conventional reservoirs. They are widely unlocked by creating hydraulic fractures in the formation to increase the flow capacity and productivity. The objective of this paper is to analyze different fracture geometries and their effect on tight gas production. The reservoir simulation model of the tight gas reservoir has been built with single porosity approach. A single vertical well with a single stage fracture has been used in the model to predict the behavior of fracture geometry. The major parameters of fracture geometry studied are fracture half-length, fracture width, and fracture height. Four sensitivities are run over different fracture geometry that is constant height and constant width, constant height and changing width, changing height and constant width, and changing height and changing width, while increasing the fracture half-length from 100 ft to 500 ft in each case. Sensitivity analysis exhibited that keeping the hydraulic fracture at constant height and constant width while increasing the fracture half-length resulted in enhanced tight gas productivity i.e. 11.63%, 14.14%, 16.06%, 17.48%, and 18.89% at hydraulic fracture half-lengths of 100 ft, 200 ft, 300 ft, 400 ft, and 500 ft, respectively, compared to other types of fracture geometry.

A Reservoir Simulation Study of Naturally Fractured Lenticular Tight Gas Sand Reservoirs

1990 ◽  
Vol 112 (4) ◽  
pp. 231-238 ◽  
Author(s):  
R. D. Evans ◽  
S. D. L. Lekia
Keyword(s):  
Gas Flow ◽  
Gas Production ◽  
Department Of Energy ◽  
Natural Fracture ◽  
Tight Gas ◽  
Gas Reservoirs ◽  
Tight Gas Reservoirs ◽  
Reservoir Performance ◽  
Tight Gas Reservoir ◽  
Naturally Fractured

The results of parametric studies of two naturally fractured lenticular tight gas reservoirs, Fluvial E-1 and Puludal Zones 3 and 4, of the U.S. Department of Energy Multi-Well Experiment (MWX) site of Northwestern Colorado are presented and discussed. The three-dimensional, two-phase, black oil reservoir simulator that was developed in a previous phase of this research program is also discussed and the capabilities further explored by applying it to several example problems. The simulation studies lead to the conclusion that 1) at early times the reservoir performance does not depend on lenticularity; 2) the initial reservoir performance does not depend on natural fracture concentration, although at later times the performance predictions of systems with lower natural fracture concentrations begin to fall below the ones with higher concentrations; 3) porosity change with time and pressure leads to double performance prediction reversals when comparing gas flow rates and cumulative gas production from naturally fractured and non-naturally fractured tight gas reservoirs; 4) the assumption of zero capillary pressure in the fractures can lead to erroneous predictions in the simulation of naturally fractured tight gas reservoir performance; and 5) the simulator developed in a prior phase of this project is capable of handling a reservoir block that is blanket sand, lenticular, completely fractured, partially fractured or completely unfractured and is amenable to an anisotropic heterogeneous reservoir whether the reservoir is fractured or not.

Impacts of Diverse Fluvial Depositional Environments on Hydraulic Fracture Growth in Tight Gas Reservoirs

2013 ◽  
Vol 28 (01) ◽  
pp. 8-25
Author(s):  
Patricia H. Cuba ◽  
Jennifer Miskimins ◽  
Donna S. Anderson ◽  
Mary M. Carr
Keyword(s):  
Hydraulic Fracture ◽  
Depositional Environments ◽  
Tight Gas ◽  
Gas Reservoirs ◽  
Tight Gas Reservoirs ◽  
Fracture Growth

Liquid loading in wellbores and its effect on cleanup period and well productivity in tight gas sand reservoirs

2010 ◽  
Vol 50 (1) ◽  
pp. 559
Author(s):  
Hassan Bahrami ◽  
M Reza Rezaee ◽  
Vamegh Rasouli ◽  
Armin Hosseinian
Keyword(s):  
Numerical Simulation ◽  
Gas Production ◽  
Production Performance ◽  
Tight Gas ◽  
Gas Reservoirs ◽  
Liquid Loading ◽  
Performance Modelling ◽  
Well Productivity ◽  
Tight Gas Reservoirs ◽  
Tight Gas Reservoir

Tight gas reservoirs normally have production problems due to very low matrix permeability and significant damage during well drilling, completion, stimulation and production. Therefore they might not flow gas to surface at optimum rates without advanced production improvement techniques. After well stimulation and fracturing operations, invaded liquids such as filtrate will flow from the reservoir into the wellbore, as gas is produced during well cleanup. In addition, there might be production of condensate with gas. The produced liquids when loaded and re-circulated downhole in wellbores, can significantly reduce the gas production rate and well productivity in tight gas formations. This paper presents assessments of tight gas reservoir productivity issues related to liquid loading in wellbores using numerical simulation of multiphase flow in deviated and horizontal wells. A field example of production logging in a horizontal well is used to verify reliability of the numerical simulation model outputs. Well production performance modelling is also performed to quantitatively evaluate water loading in a typical tight gas well, and test the water unloading techniques that can improve the well productivity. The results indicate the effect of downhole liquid loading on well productivity in tight gas reservoirs. It also shows how well cleanup is sped up with the improved well productivity when downhole circulating liquids are lifted using the proposed methods.

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