Did you know that in a high angle well, poor hole cleaning results in lower ECD? This is contrary to the popular belife that ECD increases when hole cleaning is poor. The reason that ECD decreases with poor hole cleaning is that only cuttings suspended in the mud contributes to ECD while cuttings laying on the low side of the hole does not. When hole cleaning is poor, there will be less cuttings suspended in the mud in the near vertical section of thr well, as such, lower ECD.

In the example below, a high angle tangent 16" section was drilled. The rotary speed was reduced from 150 rpm to 70 rpm for directional control reasons from 3,250m (10,660') onwards to section TD at 3,800m (12,465'). ROP remained at 50-60 m/hr (160-200 ft/ hr) while flow rate was constant at 5,500 lpm (1,450 gpm). Both pick up and slack off drag trend increased indicating insufficient hole cleaning due to the reduction in rotary speed. However, both the ESD and ECD were showing a decreasing trend from 3,250m (10,660') onwards to section TD at 3,800m (12,465'). The measured ESD and ECD were lower than the hydraulics model prediction. This example clearly shows that ECD decreases with poor hole cleaning and lower than expected ECD relatively to the model should not be taken as everything was going well.

In high angle or extended reach wells, Torque is generally not a good indicator of hole condition – in most cases torque friction factors actually REDUCE over the course of a long drilling section. In the example below, a 6000ft section of high angle 9⁷⁄₈” hole was drilled. Right after drilling out the previous casing shoe surface torque was 4k ft-lb and equivalent to a 0.50 friction factor. Looking ahead to TD, if the friction factor stayed the same, torque would have been nearly 20k ft-lb. Even more concerning, with that friction factor rotation of the 7” liner string would have been impossible. But as drilling progressed, the torque friction factor was continuously reducing. Two factors drive this very common phenomenon: 1) while rotating at high speed (for hole cleaning) the tool-joints are polishing the inside of the previous casing creating a lower friction surface and 2) as a cutting bed develops the drill pipe is supported by the cuttings and the hard, oil coated cuttings act effectively as ball bearings. It’s always important to monitor torque in any complex well – but don’t expect it to tell you if the hole is clean!

K&M Technology's Proprietary Software Platform ERA (Extended Reach Architecture) features a “steady state” circulating temperature model that is used to correct fluid density, downhole rheology, and metallurgical properties of tubulars to adjust for temperature effects. The temperature in the well is computed based on the heat transfer between formation, pipe and fluid in the annulus. The model accounts for the heat generated by the bit, torsional friction and fluid friction. ERA allows to calibrate the circulating temperature model using three main parameters - Geothermal Temperature – Usually the largest source of heat. Simple or complex definition of geothermal temperature is possible. This should be based on offset wells or temperature surveys. - Inlet Temperature – A fixed value or a function of flowline temperature - Heat Transfer Factor – Calibration factor to account for unknowns related to the fluid composition and annular conditions. The biggest uncertainty.

K&M Technology's Proprietary Software Platform ERA (Extended Reach Architecture) Sweeps and Tripping Circulation feature allows you to see the pressure (ECD) at any point in the wellbore while a sweep moves through the annulus.

K&M Technology's Proprietary Software Platform ERA (Extended Reach Architecture) has a Built in Sensitivity Analysis feature. ERA allows the user to see results with sensitivity to practically any drilling, tripping or cementing parameter. You can choose which parameter to run sensitivity on or rely on ERA’s built in set of standard plots which is populated with the most common sensitivities.

K&M Technology's Proprietary Software Platform ERA (Extended Reach Architecture) Time Based Data feature (imports bulk time data from drilling recorders and filters out T&D measurements and other drilling parameters)

K&M Technology's Proprietary Software Platform ERA (Extended Reach Architecture) Wellpath Builder feature builds well paths from scratch using our built-in design profiles. Just choose your desired profile, enter simple parameters, like desired DLS, TVD and Inclination, and ERA calculates the rest for you. Add targets to drive the design and tie into existing surveys. Proximity to other wells is calculated and displayed to help guide your design.

K&M Technology Group’s ERA (Extended Reach Architect) Software Driller’s View plots allow the user to see expected loads at the surface as the bit depth increases? This helps identify any discrepancies from normal, which leads to early trouble detection.

K&M Technology Group’s ERA (Extended Reach Architect) Software has Integrated Geomechanics - When basic log data is input, users can build their own mechanical earth model to calculate earth stresses and rock properties, or users can directly enter this data from third party MEMs. ERA will then compute geomechanical limits for any well path. Calculated limits include breakdown and breakout thresholds for several different failure criteria and variable risk levels. ERA will also compute wellbore damage (via pseudo-caliper and/or pseudo-image logs) for planned operating conditions, or postmortem.

There seems to be a belief that doglegs are “smoothed out” while drilling and especially after casing runs.

• In the example below, a well was sidetracked due to a shallow fish that was left in hole.
• The well was a deep TVD well with high tension loads across the shallow doglegs at the sidetrack point. This resulted in high normal forces and risks causing a casing wear problem.
• Given a fixed tension load, the normal forces are directly proportional to the size of the dogleg.
• A gyro was run to determine how much lower the doglegs were after running the intermediate casing across the sidetrack point.
• The result of the gyro confirmed that the doglegs had not been reduced and in fact were higher than measured with the MWD. The first graph below shows the MWD survey. The second graph shows the Gyro survey compared to the MWD.
• Confirming that the doglegs still posed a significant risk of wear to the casing resulted in the operator utilizing non-rotating drill pipe protectors (NRDPPs) to drill the 8½” section to protect the 9⅝” casing.

Using Auto-fill equipment reduces surge pressures and mitigate risk of mud losses during tight clearance casing deployment? High surge pressure can result in mud losses and formation damage, which can jeopardize successful cement placement and zonal isolation. Accurate modeling of surge pressures with open and closed string set up during planning stage will help you evaluate if the use of auto-fill equipment can be beneficial to your operations, without the need for costly design changes to your well! What is happening: Due to low annular clearance, surge loads can exceed the formation loss gradient even at low running speed. This is particularly apparent in challenging wells with narrow mud window, such as Extended Reach or deep-water projects. If running the casing conventionally as closed ended, the fluid in the annulus is pushed up-ward generating high surge pressure; however, with the installation of auto-fill, the drilling fluid will flow freely into and up the casing, reducing both the surge and swab pressure loads felt by the formation. Reducing surge pressure will mitigate risk of mud losses and also can allow increased running speed. To ensure useful application of auto-fill equipment, optimum hole cleaning and following equipment operating procedures will you help mitigate risk of tool plugging or auto-conversion during the run.

K&M Technology Group’s ERA (Extended Reach Architect) Software Snapshot View plots allow the user to see loads throughout the string or hole at a specific bit depth. This helps determine exactly where a failure may occur so you can easily design against it.

K&M Technology Group’s ERA (Extended Reach Architect) Software focuses on a Holistic Design Structure- ERA’s unique configuration keeps the user centered over the entire well. This approach allows the user to develop the well as a system, rather than focusing on piecemeal components only.

Are you concerned on a challenging geological target interception, or Well collision avoidance? Designing a complex platform exit strategy? Managing your large well surveying database? K&M team has the unique capabilities and expertise to provide support on the key aspects of the Surveying Management

Did You Know?

When you have a stuck pipe incident on a long horizontal well, we are told to work the pipe in the opposite direction to which it was moving when it became stuck. However, if you don’t pick up the pipe enough distance to overcome the drill string stretch, then you might not get free ever.
What is happening: Normally the stuck pipe gets stuck at the BHA. When you put tension on the drill string, the amount of pipe movement at surface is not all transferred to the BHA due to friction.
If you pull the pipe a distance that is less of the pipe’s stretch, then you will never get the pipe free. You need to first estimate how much pipe stretches or compresses when stuck at the BHA. In this example you will need to pull at least 40 ft (for a 0.20FF) at surface before any movement gets transferred to the bit and BHA located at 23,000 ft measured depth on this horizontal well

Your Maximum Overpull can be well below the tension limit of your drill pipe? That shallow doglegs can greatly reduce your maximum overpull?
What is happening: What your drill pipe feels during an overpull even is not just tension – but is a combined load of tension, torque (if present), and bending. Shallow doglegs can cause high side forces and bending stresses!
If taking only the drill pipe published tension limit, the example below would think that an overpull of 100 kips (at the bit) is no problem – however, the shallow doglegs and associated bending stresses show that the overpull limit is not felt at surface – but rather at ~1,100’!