Drilling Engineering: Hole Problems

Two preventative measures for borehole closure are utilizing low density mud and controlling the rate of penetration.

Hole enlargement or washout can lead to difficulties with cementing and logging operations.

Borehole collapse can occur when drilling fluid pressure is too low, leading to pipe sticking.

<p>One common solution is to use Lost Circulating Materials (LCM) like granular, fibrous, or flaky materials.</p> Signup and view all the answers

<p>Fracturing occurs when the wellbore drilling fluid pressure exceeds the formation fracture pressure.</p> Signup and view all the answers

<p>Two solutions are to use Lost Circulating Materials (LCM) and to apply squeeze cementing to seal severe loss zones.</p> Signup and view all the answers

<p>Mud weight that is too heavy can cause borehole collapse, while mud that is too light can lead to hole enlargement and washout.</p> Signup and view all the answers

<p>Proper hydraulics involve maintaining adequate annular velocity for hole cleaning and ensuring that the mud density does not exceed the formation pressure.</p> Signup and view all the answers

<p>Pipe sticking occurs when the drill string becomes stuck due to friction with the borehole, while differential pipe sticking happens when the drill pipe is held immobile due to pressure differences between the borehole and the formation.</p> Signup and view all the answers

<ol> <li>Maintain efficient mud properties by controlling density and fluid loss.</li> <li>Minimize the friction factor by using oil-based mud or low water loss mud.</li> <li>Reduce the contact area between the drill string and the borehole by using stabilizers on the drill collar or non-circular drill collars.</li> </ol> Signup and view all the answers

<p>Pumping low density fluid into the drill string can reduce hydrostatic pressure, which can help to free a stuck drill string.</p> Signup and view all the answers

<p>Spotting organic fluid, a mixture of diesel oil and surfactant, helps lubricate the drill string and reduce friction, which can help to free a stuck pipe.</p> Signup and view all the answers

<p>There are two types of lost circulation: total loss, where no mud returns to the surface, and partial loss, where some mud returns, but the mud pit volume decreases.</p> Signup and view all the answers

<p>A fracture can occur in the formation when the hydrostatic pressure of the mud exceeds the rock's breaking strength.</p> Signup and view all the answers

<ol> <li>High flow rates can increase annular friction pressure loss, leading to excessive wellbore pressure.</li> <li>Fast tripping can increase surge pressure, also resulting in excessive wellbore pressure.</li> </ol> Signup and view all the answers

<p>A spinner survey involves rotating a device in the wellbore to measure the rate of fluid loss. This technique allows for determining the extent of lost circulation and provides valuable insights into the specific cause of the problem.</p> Signup and view all the answers

<p>The main advantages are maximum reliability, excellent quality control, and best pressure isolation, which are crucial for safety in hostile environments.</p> Signup and view all the answers

<p>The key disadvantage is that it is often the highest cost option, making it less accessible for some operations.</p> Signup and view all the answers

<p>Workover operations are essential to perform major maintenance and address issues like declining well performance and mechanical failures.</p> Signup and view all the answers

<p>Reasons include mechanical failures, unexpected production rates, and the need for reservoir data collection.</p> Signup and view all the answers

<p>A critical aspect is ensuring mechanical and pressure integrity due to the presence of multiple pressure zones.</p> Signup and view all the answers

<p>Higher complexity in installation may lead to increased risks and challenges in achieving reliable performance.</p> Signup and view all the answers

<p>The primary goal is to restore or enhance the production capabilities of an oil or gas well.</p> Signup and view all the answers

<p>Factors include manufacturing constraints, specific testing requirements, and high demand in high-risk environments.</p> Signup and view all the answers

<p>They provide improved production flexibility and lateral accessibility.</p> Signup and view all the answers

<p>Lateral bore wells remain vulnerable to collapse and lack hydraulic isolation.</p> Signup and view all the answers

<p>Mechanical support is crucial for both the main bore and laterals in unconsolidated formations.</p> Signup and view all the answers

<p>It implies that pressure isolation between different zones is not maintained, which can affect production efficiency.</p> Signup and view all the answers

<p>Re-entry drilling is primarily performed through existing production tubing.</p> Signup and view all the answers

<p>Complex completion equipment is needed due to the requirements for effective mechanical support and installation.</p> Signup and view all the answers

<p>Enhanced wellbore stability reduces the risk of well failure and increases operational lifespan.</p> Signup and view all the answers

<p>Underbalanced drilling (UBD) and managed pressure drilling (MPD).</p> Signup and view all the answers

<p>Better cement isolation is important to prevent fluid migration between zones and maintain well integrity.</p> Signup and view all the answers

<p>Continuous operation without connections and faster tripping times.</p> Signup and view all the answers

<p>Mechanical anchors provide additional support to the main bore, enhancing the overall structural integrity.</p> Signup and view all the answers

<p>Limited weight on bit and higher maintenance requirements.</p> Signup and view all the answers

<p>Fish hook drilling is a specialized form of directional drilling where the wellbore is angled beyond horizontal.</p> Signup and view all the answers

<p>Hybrid operations combine conventional rotary drilling rigs with Coiled Tubing Drilling (CTD) for precise zone penetration.</p> Signup and view all the answers

<p>Re-entry drilling is considered more environmentally friendly.</p> Signup and view all the answers

<p>The typical angle range for the tangent section is between 110º to 140º.</p> Signup and view all the answers

<p>It controls fluids produced from or injected into the well and provides a valve control system.</p> Signup and view all the answers

<p>Tubing Replacement and Wellbore Cleanup.</p> Signup and view all the answers

<p>Fishing tools.</p> Signup and view all the answers

<p>Upper or Lower Master Valve.</p> Signup and view all the answers

<p>It provides intervention access as the uppermost valve.</p> Signup and view all the answers

<p>Running tools inside the wellbore without removing tubing.</p> Signup and view all the answers

<p>It suspends casing and tubulars and provides surface closure.</p> Signup and view all the answers

<p>Conventional Rigs.</p> Signup and view all the answers

<p>Artificial Lift Maintenance.</p> Signup and view all the answers

<p>To monitor well pressure.</p> Signup and view all the answers

A condition when the drill string cannot be rotated or pulled out, indicating a blockage.

Occurs when the drill pipe is motionless due to pressure differences against mud cake.

Strategies to minimize pressure differences and control mud properties to avoid pipe sticking.

A solution to pipe sticking where low density fluid is pumped into the drill string to reduce pressure.

Using a mixture of diesel oil and surfactant to solve pipe sticking issues.

A method to remove remaining parts of the drill string that are stuck in case of pipe sticking.

Occurs when there's uncontrolled mud flow into formation, with possible total or partial loss of mud returns.

Includes hydrostatic mud pressure exceeding rock strength or excessive wellbore pressure from high flowrate.

Wells that have protective casing and cementing to ensure stability and isolate different formations.

The ability to reach and produce from side branches of a well, improving production flexibility.

Structural support provided to prevent collapse of wells in unconsolidated formations.

Separation between different pressure zones in a well to prevent fluid mixing.

Expenses associated with installing and equipping a well for production.

Loose geological formations that require special support techniques for well stability.

The extraction of thick, viscous oil that requires special techniques for production.

Geological zones where the pressure is significantly greater than normal, requiring robust well design.

Narrowing of borehole occurs in plastic flowing shale and salt formations.

Includes risks of pipe sticking and increased torque and drag during drilling.

Hole becomes larger due to hydraulic erosion in shale.

Causing difficulties in cementing and logging operations.

Occurs when drilling fluid pressure exceeds formation fracture pressure, leading to lost circulation.

Happens when drilling fluid pressure is too low, resulting in pipe sticking.

Includes proper mud weight selection, hydraulics, and annular velocity for hole cleaning.

Granular, fibrous, or flaky materials used to prevent fluid loss.

Drilling performed through existing wellbores, often using production tubing.

A drilling technique where the pressure in the wellbore is kept lower than the formation pressure.

A drilling method that optimally manages the pressures throughout the wellbore.

Service operation aimed at retrieving lost tools or equipment from the well.

The process of recording geological data during drilling operations.

A directional drilling technique with an angled wellbore, specifically 110º-140º tangent.

Continuous operation, faster tripping times, better well control, more environmentally friendly.

Includes limited weight on bit, limited hole size, higher maintenance, and lower penetration rates.

Replacing worn-out or damaged tubing to restore production in oil wells.

Removing sand, paraffin, or scale to unblock fluid flow in the wellbore.

Repairing or replacing Electric Submersible Pumps (ESPs) or gas lift valves.

Smaller versions of drilling rigs used for full workover operations in wells.

Equipment used for running tools inside the wellbore without removing tubing.

Controls fluids produced or injected into the well, providing critical valve control.

Devices that monitor the well pressure during operations.

Main isolation valves that control fluid flow in the well.

Parts of the well head including casing head, casing spool, and tubing head.

The highest integrity level for equipment with factory-tested components and maximum reliability.

The process of performing major maintenance on an oil or gas well after it has been in operation.

Includes declining well performance, mechanical failures, reservoir data collection, and well abandonment.

Occurs when a well is not producing at expected rates due to various factors.

Failures in cementing, tubulars, packers, safety valves, or artificial lift equipment in a well.

The process of gathering pressure, fluid samples, and zonal productivity tests.

Temporarily or permanently shutting down a well.

Operations that require maximum reliability in hostile Arctic environments with factory-tested components.