Formation damage simulation of a multi-fractured horizontal well in a tight gas/shale oil formation

Abstract

Formation damage in drilling comes from drilling fluid invasion due to high differential pressure between a wellbore and the formation. This mechanism happens with fracture fluid invasion of multi-fractured horizontal wells in tight formations. Some multi-fractured wells show production rates and cumulative productions far lower than expected. Those damaged wells may sustain further impact such as well shutting due to unexpected events such as the COVID-19 outbreak and then experience a further reduction in cumulative production. This paper focuses on the root causes of formation damage of fractured wells and provides possible solutions to improve production. A simulation study was conducted using Computer Modelling Group software to simulate formation damage due to fracture fluid invasion and well shut-in. Simulation results revealed that the decrease in cumulative hydrocarbon production due to leak-off and shut-in of the simulated well could range from 20 to 41%, depending on different conditions. The results showed that the main causes are high critical water saturation of tight formations, low drawdown, and low residual proppant permeability under formation closure stress. The sensitivity analysis suggests two feasible solutions to mitigate formation damage: optimizing drawdown during production and optimized proppant pack permeability of the hydraulic fracturing process. Optimizing pressure drawdown is effective in fixing leak-off damage, but it does not mitigate shut-in damage. Formation damage due to shut-in should be prevented in advance by using an appropriate proppant permeability. These key findings enhance productivity and improve the economics of tight gas and shale oil formations.

Multivariable Regression 3D Failure Criteria for In-Situ Rock

“…Usually, in-situ condition rock break-out done by the compression and rock fracture is due to the combination of compression and tension (Bui et al, 2023;Ghassemi, 2017;Lee et al, 2012). Experimental data on true triaxial compression tests are available in the literature review.…”

Simulation of reservoir dynamic damage and influencing factors of horizontal wells in heterogeneous carbonate reservoirs

“…The horizontal well significantly enhances the contact area between the wellbore and the reservoir by passing through a longer length, ultimately leading to an improvement in the production rate of the oil and gas well, acceleration of production speed, and enhancement of development efficiency of the oil and gas field. During the drilling and completion process of the horizontal well, the working fluid soaks the reservoir for an extended period and covers a significant area 1–4 . As a result, both its solid and liquid phases enter the reservoir around the wellbore, creating a widespread damage zone.…”

“…During the drilling and completion process of the horizontal well, the working fluid soaks the reservoir for an extended period and covers a significant area. [1][2][3][4] As a result, both its solid and liquid phases enter the reservoir around the wellbore, creating a widespread damage zone. This causes more severe and complex damage to the reservoir compared to the vertical well, significantly impacting the horizontal well's production.…”