Drilling Simulator: User Manual

01Quick start

The simulator drills a well in real time (or faster). Nothing is scripted: kicks, losses, stuck pipe and vibration all emerge from the numbers you choose, just as they do on a rig.

1. Look at the starting well. The 12-1/4" bit is on bottom at 2,300 ft, below 13-3/8" casing set at 2,000 ft, in a 10 ppg mud. Target depth is 10,000 ft.
2. Press ▶ Start. The pumps and rotary start and the bit begins to drill. Watch ROP, depth and the well picture.
3. Tune the faders on the left: WOB, RPM and Flow Rate. Find the combination that gives the best ROP without raising an alarm.
4. Watch the alarms and the pressure window on the right. Keep the mud pressure (EMW) between the pore pressure and the fracture gradient.
5. Every 93 ft the simulator stops to make a connection (about 2 minutes, pumps off). Then it drills on.
6. At target depth the log says so. Press Tripping to pull out, change the bit, or practise trip procedures.

02The screen

The State shown in the bottom strip tells you what the rig is doing right now: READY, DRILLING, ON BOTTOM, OFF BOTTOM, CONNECTION, FLOW CHECK, SHUT IN, CIRC. KICK, POOH (pulling out), RIH (running in), HOLDING or STUCK.

03Header buttons

Each control is a solid glossy button with its own colour, so you can find it at a glance. The button that is on has a ring and glow around it; the inactive mode button (Drilling or Tripping) is dimmed.

04Drilling parameters (Drilling tab)

The three faders

Drag the knob up for more. The number on top is the current value.

The WOB colour bar

The bar above the WOB fader warns you about buckling, using the weight of the collars in the hole (reduced by mud buoyancy):

• SAFE: WOB is at or below 80% of the buoyed BHA weight.
• 80% LIMIT: you are past the 80% rule. The neutral point is moving up into the drill pipe.
• BUCKLING (blinking): WOB exceeds the full buoyed BHA weight. The pipe will buckle. Reduce WOB or add collars.

Hover over the bar to see the exact limits. You can raise the limit by adding drill collars in the BHA tab.

Mud properties

Tick Change mud to unlock the sliders: Mud weight (7 to 20 ppg), PV (5 to 60 cP) and YP (0 to 50 lb/100ft²). Heavier mud holds back pressure but raises ECD and the risk of losses and differential sticking. Higher PV and YP carry cuttings better but raise pump pressure.

Operations

Make connections every 93 ft stand: when on, the rig stops each stand to add a joint of pipe. Pumps and rotation stop for about 2 minutes. With the pumps off, the annular friction part of ECD disappears, so a thin pressure margin can let the well flow during a connection.

05Tripping

Press Tripping. WOB, RPM and flow drop to zero and a Tripping group appears on the Drilling tab.

• ▲ Pull out and ▼ Run in set the trip speed to 2,500 ft/hr up or down. You can also drag the Trip speed slider (up to 6,000 ft/hr either way). Set it to 0 to hold the pipe still.
• Auto-fill hole on pull-out (trip tank): when on, the trip tank replaces the steel you pull out. When off, the mud level drops and the hydrostatic pressure falls, so a kick becomes likely. The alarm panel says Hole not full, FILL THE HOLE.
• Swab and surge: pulling fast lowers the pressure at the bit (swab); running in fast raises it (surge). A swab that drops EMW near pore pressure can pull in a kick. The tighter the gap between pipe and hole, the worse it is. Slow down.
• Hookload rises when pulling (drag) and falls when running in. Tight hole through a cuttings bed gives overpull.
• When the bit reaches the surface the log says Bit at surface. You can then change the bit in the BHA tab.
• Run in to the bottom before going back to Drilling. The bit cannot drill while it is off bottom.

06Geometry tab: casing, liner and target depth

Casing

Casing size is a dropdown of standard API casing (7" to 20"), each showing its weight and inside diameter. Shoe depth is a number you type (100 to 10,000 ft); it is applied when you press Enter or click away. Below the shoe the hole is open and rock is exposed to the mud.

Liner (optional)

Tick Run a liner to hang a smaller casing string inside the casing. Choose a liner size (sizes that do not fit inside the casing are greyed out), a hanger depth (set inside the casing, at least 50 ft above the casing shoe, so the two strings overlap) and a liner shoe depth (at least 100 ft below the casing shoe and no deeper than the hole drilled so far).

The well picture then shows a second cased section. From that point the open hole starts at the liner shoe: kicks, losses, sticking and swabbing all use that depth. The liner's inside diameter also sets the annulus size. A note under the fields warns you if the current bit will not pass through the liner.

Target depth

Where the well ends (500 to 20,000 ft). Drilling stops there and the log says Target depth reached.

07BHA tab: bit, nozzles and collars

The bottom hole assembly (BHA) is the heavy part of the string just above the bit.

• Bit size: 6, 6.75, 8.5, 9.875, 12.25, 14.75 or 17.5 inches. Choose a bit smaller than the casing or liner above it, so it can pass through.
• Bit type: PDC (fast in most rock, prone to stick-slip), roller cone (more robust, slower) or diamond (for hard, abrasive rock).
• Change bit: available in Tripping mode with the bit at surface. It resets bit wear and hours.
• BHA list, top to bit: add heavyweight pipe, drill collars, stabilizers, a mud motor, MWD/LWD, a jar, a non-magnetic collar, a crossover or a shock sub. Type a new length for any item, or use the bin to remove it. The summary shows total length and weight.
• Nozzles: 2 to 5 nozzles, 8 to 22 thirty-seconds of an inch. Smaller nozzles raise jet velocity and bit pressure drop (and hole-cleaning energy), but also raise standpipe pressure. TFA, jet velocity and nozzle pressure drop are shown.

The BHA and bit can only be changed with the simulation paused and the bit out of the hole.

08Formations tab

This is a read-only table of the rock layers: the depth each starts at, the rock type, its hardness (UCS, in psi), its pore pressure (PP) and its fracture gradient (FG), both in ppg of equivalent mud weight.

• If the mud pressure (EMW) falls below PP in a permeable rock that is exposed in open hole, fluid flows in: a kick.
• If the mud pressure rises above FG, the rock fractures and mud is lost: lost circulation.
• Hard rock (high UCS) drills slowly and wears the bit faster. Shale and chalk can ball up the bit. Sandstone and other permeable rock can kick and can stick the pipe.

The formations are fixed for the life of a well. To use different geology, start a ＋ New well and enter the layers in its form.

09The well picture

• Coloured, textured bands are the rock layers, labelled with their rock, PP and FG. Each rock has its own texture (see the table below). While drilling, the picture shows the whole well from the surface to target depth. In Tripping mode it zooms to a 600 ft window that follows the bit.
• Casing is drawn as two steel walls with cement outside, drilling fluid inside and a yellow shoe marker. A liner, if you run one, has a cyan hanger and shoe.
• Mud fills the hole in a colour that changes with weight. A blue dashed line marks the mud level if the hole is not full.
• The drill string shows the pipe, the BHA and the bit. The bit spins as you rotate.
• Wellhead and BOP sit at the top. They show BOP CLOSED, SHUT IN when you shut the well in.
• Bit cam (lower left, once the bit is below the surface): a magnified view of the bit, with wear and bit type in its title.
• EMW window (right edge): lines for pore pressure, your EMW and the fracture gradient against depth. You want the EMW line between the other two.
• Warning labels appear on the picture: gas in the annulus, lost-circulation zone, stuck-pipe point and pack-off pressure. A flashing banner at the top announces a kick or lost circulation.

Rock textures

The same texture is shown on the bit cam, so you can tell what the bit is cutting.

10The dashboard (right panel)

11Events and how to respond

These are all caused by your choices and the geology. None is random scripting.

12Well control

Spotting a kick

Signs: pit gain, a drilling break, flow out greater than flow in, and the flashing KICK banner (pit gain above 2 bbl, or gas in the hole). The Well control card appears on the right at the same time. When in doubt, press Flow check. The pumps stop for 45 simulated seconds, then the log reports either well static or WELL IS FLOWING, SHUT IN NOW.

The kill sequence

1. Shut in: in the Well control card on the right (it appears when a kick is detected), press Shut in well (close BOP). Rotation and pumping stop. The pressures build and settle over the next minute or so, giving you SIDPP (shut-in drill pipe pressure) and SICP (shut-in casing pressure). Shutting in with a pit gain under 5 bbl is flagged as a good catch.
2. Read the kill mud weight: KMW = mud weight + SIDPP ÷ (0.052 × depth). The dashboard shows it, along with the initial and final circulating pressures (ICP and FCP).
3. Circulate the kick out: press Circulate kick out (choke). The simulator pumps at 300 gpm, holding bottom hole pressure on the choke (Driller's method, first circulation). Gas expands as it rises; the simulator bleeds it off at the surface.
4. Weight up and open the well: once the gas is out, press Weight up and open well. The mud weight is raised to the kill weight plus 0.2 ppg, the BOP opens and normal operations resume.

13Locks and Test mode

The simulator follows rig rules for when things can be changed. A locked section shows a padlock and a note saying why.

Test mode lifts all of these locks so you can test anything at any time. It lights up pink while on. Turn it off to return to rig rules.

14New well

Press ＋ New well. A warning explains that all data from the current well will be erased (depth, time, pits, events, BHA, bit wear, liner, formations, casing and mud). Choose No, keep this well to cancel, or Yes, erase it and continue to open the well-data form:

• Well: name, target depth, and the depth already drilled (where the bit starts, on bottom, at least 200 ft below the casing shoe).
• Casing: size and shoe depth.
• Mud: mud weight, PV and YP.
• Formations: an editable table, starting from the current layers. Add or remove layers and set rock, UCS, PP and FG for each.

The form checks your entries and lists any problems before it creates the well: for example, the first layer must start at 0 ft, no two layers can start at the same depth, and pore pressure must be below the fracture gradient. The bit is automatically set to the largest size that clears the casing. The well name appears next to the logo.

15Scenarios

The ⚡ Scenario… menu adds a problem to the geology ahead of the bit, so you can practise on demand:

16Practice exercises

17How the model works

The simulator recalculates everything many times per second from the state of the well. In brief:

• Rate of penetration: a drilling model based on weight, RPM, rock hardness, bit type and size, hydraulic energy at the bit, bit wear, bit balling and stick-slip. WOB above the founder point is much less effective. Drilling into a permeable zone while underbalanced gives a drilling break (about 30% faster).
• Hydraulics: Bingham plastic pressure losses through the drill pipe, bit nozzles, annulus and surface lines give standpipe pressure and ECD.
• Pressures: bottom hole pressure comes from mud hydrostatic, annular friction (while pumping), suspended cuttings, any gas in the annulus, swab or surge, and any unfilled hole. EMW is that pressure expressed as a mud weight.
• Kicks and losses: influx starts when EMW is below the pore pressure of a permeable exposed formation; losses start when EMW exceeds the lowest fracture gradient. Gas rises, expands as pressure drops, and unloads the hole if it reaches the surface with the well open.
• Hole cleaning: annular velocity against the cuttings slip velocity decides how well cuttings are carried. Low velocity builds a bed (up to 400 ft); high velocity erodes it. A loaded annulus packs off.
• Weights: components have real weights per foot; buoyancy comes from mud weight (factor = 1 − MW ÷ 65.4). The buckling limit is 80% of the buoyed BHA weight.
• Connections: every 93 ft (one stand) the pumps and rotary stop for about 2 minutes.
• Stuck pipe: differential sticking needs a stationary string and a high overbalance across a permeable formation; mechanical sticking needs a sustained pack-off.

18Limits and glossary