| Buoyancy Factor Calculation and Its Application | | | | BF = (65.5 - 13.0) ÷ 65.5 |
| Buoyancy Factor is the factor that is used to | | | | BF = 0.8015 |
| compensate loss of weight due to immersion in | | | | How to use the Buoyancy Factor. |
| drilling fluid. | | | | In order to figure out the actual weight of drilling |
| Before explaining any further, it is very important | | | | string in mud, the air weight of drilling string times |
| to explain the basic concept of Buoyancy. | | | | the buoyancy factor equal to actual drill string |
| Buoyancy is the upward force that keeps things | | | | weight, called buoyed weight, in drilling fluid. The |
| afloat. The net upward buoyancy force equals to | | | | simple equation shows the relationship of actual |
| the amount of the weight of fluid displaced by the | | | | weight in drilling fluid. |
| body volume. This force will make objects lighter | | | | Actual Weight = Air Weight of Drill String x BF |
| when it immerses in fluid. For instant, we feel | | | | If weight in the air of a drilling string is 350 kilo |
| ourselves lighter when we are in a swimming pool | | | | pound (Klb), we can use this relationship to |
| because this is the effect of Buoyancy. | | | | determine the string weight in 13.0 ppg drilling fluid. |
| How to calculate the Buoyancy Factor. | | | | The buoyed weight of drill string in 13.0 ppg mud |
| The formulas below demonstrates how to | | | | is equal to 350 x 0.8015 (280.5 Klb). |
| determine this factor. | | | | According to the calculation, when a drill string is |
| Buoyancy Factor (BF) = (65.5 - mud weight | | | | immersed into drilling fluid, its weight almost |
| density in pound per gallon (ppg)) ÷ 65.5 | | | | decreases by 20%.Therefore, it is very important |
| For example, if the drilling fluid weight is 13.0 | | | | that every personnel working at drilling sites |
| pound per gallon (ppg), as per the equation above, | | | | should be able to calculate the buoyancy factor in |
| the factor can be calculated by simply inputting | | | | order to figure out how mud weight effects the |
| mud weight density into the equation. | | | | total string weight in a wellbore. |