Drilling Formulas and Drilling Calculations

[...]   There are many components that make up the drill string as shown in this graphic. Drill pipe is a strong but relatively lightweight pipe. Crew members attach it to a top drive or Kelly. [...]

[...] major component of the entire drillstring. Typically, 90% – 95% of the total length is drill pipe. Thread connection of drill pipe is called “Tool Joint”. One end of drill pipe has [...]

[...] and guide are run down to the sea floor. After the conductor pipe penetrates the sea floor the drill pipe is released and pulled back to the vessel. A large drill bit connected to the bottom of the [...]

[...] This article demonstrates basic knowledge understanding of tensile capacity of the drill pipe and some calculation. First of all we need to know basic of material strength and for our case [...]

[...] Shoe   Figure 1 – Top of Gas Kick Below Casing Shoe As you can see in Figure 1, hydrostatic pressure above the casing shoe remained constantly because the fluid column is the same. The [...]

[...] in drilling breaks (ROP change) – If the differential between formation pressure and hydrostatic pressure created by drilling mud decreases, there is possibility to increase rate of penetration [...]

[...] the vertical height of mud column does not change. It means that you still have the same hydrostatic pressure. Additionally, gas in the horizontal section will migrate up to high side of the wellbore [...]

[...] will move up and mud will goes down due to gravity (see – Figure 1). Mud leg will provide hydrostatic pressure in order to prevent mud going through the separator into the rig. Figure 1 - Mud Gas [...]

[...] IBOP valve should not be used for shut the well in while tripping. Reference book:  Well Control Books [...]

[...] equivalent mud weight in order to prevent the well control situation. Reference books:  Well Control Books [...]

[...] can be made on time. Always listen to the well and you will be fine. Reference books:  Well Control Books [...]

[...] the abnormal pressure zones are occurred and we will discuss it later on. Reference books:  Well Control Books [...]

[...] Choke line friction pressure will increase bottom hole pressure while circulating to kill the well therefore it must be compensated in order to maintain [...]

[...] pressure. Gas is compressible but fluid is incompressible. The formula to determine the bottom hole pressure of dry gas well is shown below; Where; Pbh = bottom hole pressure in psia (absolute [...]

[...] is so small. However, the choke line friction in deepwater operation has a big effect bottom hole pressure. Killing the well without considering the CLF will add excessive pressure and it increases [...]

[...] circulation is to kill the well with kill weight fluid. During the first circulation, the bottom hole pressure remains constant due to maintain drill pipe pressure constant while circulating. For the [...]

[...] the well due to low flow rate Casing pressure is 0 psi due to fully opened choke,  the shoe pressure be determined by the following calculation process. Figure 1 - Shoe Pressure with [...]

[...] Many people ask us a lot of questions regarding shoe pressure while circulating kick (wellbore influx) out of the wellbore. We will summarize all the [...]

[...] for a while. There is high chance for wellbore to collapse and pack the drillstring. Casing Shoe Pressure Shoe will be exerted the maximum pressure when top of gas kick is at the casing shoe. Once the [...]

[...] annular pressure loss in the well due to low flow rate Figure 2 - Example of CLF What is the shoe pressure if we bring pump up to speed without considering CLF? Figure 2 is the diagram based on the [...]

[...] the fracture dashed line curve. Then draw the vertical line from Point C to intersect the formation pressure dashed line curve at Point D. This is the section casing string which should be set from 3, [...]

[...] Influx Height = 1000 + 454 = 1454 ft   Figure 3 – Height of 50 bbl kick What is formation pressure at 10,000’MD/10,000TVD? Formation pressure = 0.052 x 10.5 x 10,000 = 5,460 psi What [...]

[...] Current hole depth is 10,000’MD/10,000’TVD and current mud weight is 12.5 ppg Expected formation pressure at 10,000’TVD is 12.0 ppg Annular capacity = 0.0515 bbl/ft Drillstring capacity = 0.0178 [...]

[...] equation • Estimate type of influx • Final Circulating Pressure (FCP) • Formation pressure from kick analysis • Hydrostatic Pressure Loss Due to Gas Cut Mud • Initial [...]

[...] drilling into a pay window, it might be a good idea to flow check in order to check if the mud weight is good for well control before drilling deeper into the zone. Plan the horizontal section to [...]

[...] off test pressure, ppg = (Surface pressure to break formation, psi ÷ 0.052 ÷ shoe TVD, ft) + Mud weight, ppg Maximum Allowable Surface Pressure (MASP) Maximum Allowable Surface Pressure (MASP) is [...]

[...] mud keeps fluids in the formation from coming to the surface. For several reasons however, the mud weight can become lighter than is necessary to offset the pressure in the formation. When this [...]

[...] ’s take a look at the table. In Figure 1, it shows the main page and you can select the mud weight range from 4.0 ppg to 19.0 ppg.   Figure 1- Main Page BF Table For instant, we choose 8.0 [...]

[...] demonstrate some calculations related to this topic. Please feel free to leave any comments. Reference books:  Well Control Books [...]

[...] mud or use oil based mud drilling into clay formation Pump out of hole instead of pulling out Reference books:  Well Control Books [...]

[...] , you can use the same procedure to measure the frictional pressure at the kill line too. Reference books:  Well Control Books [...]

[...] reduced by water column, more casing strings are required to reach the plan casing depth. Reference books:  Well Control Books [...]

[...] change when the gas kick moves from a horizontal section to a vertical section. This make casing pressure profile increase drastically when compared to vertical or deviated wells. Kick detection in [...]

[...] in the vertical section ­­­ What are Responses of Shut In Drill Pipe Pressure and Shut In Casing Pressure in Horizontal Wells? In horizontal wells, kicks can come into the well and you will see pit [...]

[...] do this. In this topic, we will demonstrate how kick volume will affect wellbore and surface casing pressure. Main concept of minimizing kick coming into the wellbore is to minimize surface casing [...]

[...] = Hydrostatic Pressure in Annulus + Casing Pressure Figure 1 – Bottom hole pressure at static condition At dynamic condition – the bottom hole [...]

[...] following factors used to determine casing setting depths. o   Pore pressure and fracture gradient – Based on the pore pressure and the fracture gradient of the well, you will be able [...]

[...] (ECD) = ρeff + ρa  — Equation 4 Equivalent Circulating Density (ECD) = Fracture Gradient (FG) — Equation 5 With those relationships above, we can derive the maximum ROP into [...]

[...] : According to the previous example, this is the casing design based on pore pressure and fracture gradient (Figure 1). Figure 1- Casing Design Based On Pore Pressure and Fracture Gradient The casing [...]

[...] the pore pressure dashed line at Point C. Then draw a vertical line from Point C to the fracture gradient dashed line at Point D (Figure 4). The Casing must be set from 1,800’ TVD to 4,500& [...]

[...] based on water based mud and gas kick.  First Scenario – Top of Gas Kick Below Casing Shoe   Figure 1 – Top of Gas Kick Below Casing Shoe As you can see in Figure 1, [...]

[...] , you will have a chance to fracture the weakest formation in the wellbore such as formation at casing shoe. You need to remember that more influx equals to more surface pressure. We will do basic [...]

[...] for a while. There is high chance for wellbore to collapse and pack the drillstring. Casing Shoe Pressure Shoe will be exerted the maximum pressure when top of gas kick is at the casing shoe. [...]

[...] is Leak of test pressure (LOT). LOT is the surface pressure that breaks down formation at a casing shoe for each section of the well. Leak off test pressure formula is listed below; Leak off test [...]

[...] pumps have two cylinders with double acting. It means that pistons move back and take in drilling mud through open intake valve and other sides of the same pistons, the pistons push mud out [...]

[...] to focus on the mechanical way when they want to prevent failure. Chemicals dissolved in the drilling mud that can cause the issue are as follows; Oxygen (O2) – Small amount of oxygen (less than [...]

[...] from shoe to surface and the planned cement weight is 14.0 ppg. The displacement fluid is drilling mud currently used. Please determine the following items. Air weight of casing string Buoyed [...]

[...] oil weight = 7.0 ppg Water weight = 8.6 ppg ρs = 21.06 ppg Total density of solid in the drilling mud is 21.06 ppg. Reference book =>  Formulas and Calculations for Drilling Operations& [...]