About 60% of oil well footage is drilled in clays and shales. These rocks are neither hard nor abrasive and, thus, should be easy to drill. Problems arise, however, because of the soft and sticky nature of the cuttings produced. These cuttings absorb water from the drilling fluid, swell, and stick to the Drilling Bit. Balling …
When weighted muds are used in highly deviated wells, there is the tendency for barite to settle towards the low side of the hole, creating a stratification of lighter mud on top and heavier mud on the bottom. The heavier layer then begins to migrate downwards along the length of the hole due to the …
Barite plug use is usually limited to extreme or emergency conditions where it is imperative that some measures be taken to seal off the bottom section of the wellbore. This type of plug is applicable in several situations, including: Objectives of Setting Barite Plugs A Barite plug is a barite slurry pumped down the drill …
Usually, Mud Engineers design drilling mud to be able to carry out mud basic functions. Thus, As the concentration of Cement contamination increases in a drilling mud system, there will be a detrimental effect on its performance. In general, we can define the contaminant as any material that causes undesirable changes in drilling fluid rheology …
Calcium sulfate occurs in nature as Gypsum (CaSO4 l H2O) or Anhydrite (CaSO4 ). It is found in thick sections, stringers, in make-up water, embedded in silts as in evaporite formations and sometimes in the caprock of a salt dome. Causes of Anhydrite/Gypsum Contamination Calcium sulfate causes aggregation and flocculation of a fresh water mud, …
Flow Regimes are the behavior of the fluid while flowing in a well. The most common regimes are laminar, turbulent, and transitional. Unfortunately, it is impossible to define each type in the well clearly. For example, mudflow may be predominantly laminar, although the flow near the pipe waIls during pipe rotation may be turbulent. Laminar …
Why It Is Important To Understand Drilling Hydraulics? The drilling hydraulics system serves many purposes in the well. Since it is centered around the drilling mud circulating system, the purposes of mud and hydraulics are often common to each other. The hydraulics system has many effects on the well. Therefore, the reasons for giving attention …
Points to be checked before rig acceptance 1. Weld 30” riser (weld two x 3” valves on the bottom of the conductor casing to be used to take a return to the caller if required, check the conductor for any junk inside before welding. 2. Install the cellar jet and function test it (fill the …
Reaming & Backreaming Guidelines Reaming is a high risk operation that accounts for a large proportion of stuck pipe incidents. If reaming operations are conducted too fast, solids from wash-outs and cavings are introduced into the circulating system faster than the hole is being cleaned. This results in a drilling pack off. Do not assume …
Mechanical Pipe sticking is when any part from the Drill String such as Drill Pipe, Heavy Weight Drill Pipe HWDP, Drill Collars, Drilling Bit, or Bottom Hole Assembly BHA is stuck in a borehole due to mechanical reasons such as cutting accumulation, junk, extensive cement cutting and changing drill String geometry and cannot be recovered from …