scholarly journals Geomechanical model and sanding onset assessment: A field case study in Vietnam

2021 ◽  
Vol 10 ◽  
pp. 40-46
Author(s):  
Văn Hùng Nguyễn ◽  
Thị Thuỳ Linh Bùi
Keyword(s):  
Rock Strength ◽  
In Situ Stress ◽  
Reservoir Pressure ◽  
Sand Production ◽  
Geomechanical Model ◽  
Field Case ◽  
Sand Control ◽  
Maximum Drawdown

Sand production is a key issue when selecting and applying completion solutions like open holes, screens or perforated liners. This problem can be seen in several types of reservoirs such as weakly consolidated and non-consolidated carbonates. The paper presents a method to model wellbore failures for sanding prediction. Our study shows that the potential sand risk in this field is defined by the rock strength rather than the in-situ stress. If the rock is sufficiently competent, the potential of sand production is negligible, and the development wells can be completed conventionally without any downhole sand control for the reservoir pressure above 1,280 psi and the maximum drawdown pressure of 2,380 psi.

Sand production assessment considering the reservoir geomechanics and water breakthrough

2015 ◽  
Vol 55 (1) ◽  
pp. 215 ◽  
Author(s):  
Sadegh Asadi ◽  
Khalil Rahman ◽  
Hoanh V. Pham ◽  
Thao Le Minh ◽  
Andy Butt
Keyword(s):  
Rock Strength ◽  
Development Planning ◽  
Production Plan ◽  
Reservoir Pressure ◽  
Water Production ◽  
Sand Production ◽  
Future Production ◽  
Sand Control ◽  
Well Trajectory ◽  
Bottomhole Pressure

Sand production assessment is essential from the early stages of field development planning for completion design and later for the production optimisation. Unconsolidated and weakly consolidated sandstones are prone to fail at a low flowing bottomhole pressure during hydrocarbon production. To predict the critical flowing bottomhole pressure or a safe drawdown, a geomechanical model that integrates in situ stresses, rock mechanical properties, the well trajectory, reservoir pressure, the production plan and the depletion trend is required. For a given stress field, well trajectory and production plan, the rock strength index is a key parameter that has significant impacts on the sanding risk. This paper presents the results of a study investigating the potential of sand production from primary and secondary target reservoir rocks in a petroleum field in offshore Vietnam. A poroelastic analytical approach was used to investigate if sands will be produced from the open holes or perforations. The criterion of sanding was formulated to be the effective maximum principal stress to be greater than the effective rock strength. Observations of sanding or no sanding during drill stem tests (DSTs) were used to calibrate the sanding model to be used for sanding predictions of future production wells. The effects of reservoir pressure depletion on sanding risks were investigated using the stress arching theory. Since the water production from target reservoirs was observed in the nearby fields, the analysis was performed to investigate the effects of water production on rock weakening that may cause higher risks of sanding. The results showed low risks of sanding for majority of the reservoirs, with drawdowns as high as 3,000 psi at the original reservoir pressure. The drawdown was, however, required to reduce to 500 psi to produce sand-free after depleting the reservoir by more than 90% of its original pressure. The results of this study led to the decision of completing the wells without using sand control equipment and to avoid sanding by controlling drawdown for the life of the well.

Rock Overstressing in Deep Tunnel Excavation of Pahang-Selangor Raw Water Transfer Project

2015 ◽  
Vol 802 ◽  
pp. 16-21 ◽  
Author(s):  
Romziah Azit ◽  
Mohd Ashraf Mohamad Ismail ◽  
Sharifah Farah Fariza Syed Zainal ◽  
Norzani Mahmood
Keyword(s):  
Rock Strength ◽  
Stress Measurement ◽  
In Situ Stress ◽  
Water Transfer ◽  
Stress Factors ◽  
Raw Water ◽  
Tunnel Excavation ◽  
In Situ Stress Measurement ◽  
Assessment Approach

Tunneling under high overburden and in-situ stress may cause tunnel instability because of rock overstressing. Evaluating overstressing in deep hard rocks is crucial to minimize excavation risks. The excavation of the Pahang-Selangor Raw Water Transfer Tunnel is evaluated in this study. A potential overstressing problem is expected at a tunnel depth more than 500 m. Therefore, the possibility of rock overstressing is assessed based on the evaluations of in-situ stress measurement, rock strength, and actual observations during the tunnel excavation. An analytical method is used to analyze the behavior of the tunnel under high overburden stress based on rock strength and tangential stress factors. The empirical assessment approach to the observation of actual overstressing appeared to be valid for the prediction of overstressing. These approaches facilitate the reasonable prediction of tunnel behavior under different rock conditions, support systems, and overburden stresses, which serve as useful tools in the observational design and construction method of long and deep tunnels.

Determination of in‐situ stress and rock strength using borehole acoustic data

2009 ◽  
Author(s):  
Colin M. Sayers ◽  
Zsolt Nagy ◽  
José Adachi ◽  
Vasudev Singh ◽  
Kwasi Tagbor ◽  
...  
Keyword(s):  
Rock Strength ◽  
In Situ Stress ◽  
Acoustic Data

Coring damage extent of rock cores retrieved from high in-situ stress condition: A case study

2017 ◽  
Vol 21 (7) ◽  
pp. 2946-2957 ◽  
Author(s):  
Peng Yan ◽  
Qi He ◽  
Wenbo Lu ◽  
Yanli He ◽  
Wei Zhou ◽  
...  
Keyword(s):  
Stress Condition ◽  
In Situ Stress ◽  
High In Situ Stress ◽  
Rock Cores ◽  
Damage Extent
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