What are well cuttings?

Cuttings are small bits of a rock formation derived from a borehole, the rock chips are carried to the surface by the drilling fluid. As the hole is drilled, cuttings are collected and analyzed to identify lithology and fluids encountered at depth.

What is a cutting sample?

Cuttings are the small pieces of rock that are chipped away by the bit while a well is being drilled.

Why it is important to remove the drilled cuttings during drilling operations?

Of the many functions that are performed by the drilling fluid, the most important is to transport cuttings from the bit up the annulus to the surface. If the cuttings cannot be removed from the wellbore, they will soon impede drilling.

Are drill cuttings hazardous?

Impacts of drilling waste on the environment The major impacts of great concerns are pollution of water bodies, pollution of land, as well as air pollution. Improper disposal of contaminated drill cuttings into water bodies (ocean) exposes marine life to danger.

Why are water wells important?

Wells are extremely important to all societies. In many places wells provide a reliable and ample supply of water for home uses, irrigation, and industries. Where surface water is scarce, such as in deserts, people couldn’t survive and thrive without groundwater, and people use wells to get at underground water.

What are the types of drilling waste?

Drilling and exploration activities generate two types of waste: drilling cuttings and used drilling fluids. Most of the wastes associated with oil & gas drilling activities pose significant threats to the environment.

What are the three basic components of a drilling fluid?

The three main categories of drilling fluids are: water-based muds (WBs), which can be dispersed and non-dispersed; non-aqueous muds, usually called oil-based muds (OBs); and gaseous drilling fluid, in which a wide range of gases can be used….Minimize impact on environment

• Barite.
• Bentonite.
• Diesel.
• Emulsifiers.
• Water.

What is the most common drilling fluid?

Aqueous drilling fluids, generally referred to as water-base muds, are the most common and the most varied of the three drilling fluid types (Figure 1). They range in composition from simple blends of water and clay to complex inhibitive, or clay stabilizing, drilling fluid systems that include many components.

What controls the size of particles removed during drilling?

Note that spindle speed and the amount of push or pull force required to drill are important factors on the particle size of the cuttings. One of the most important objectives in solids control is to remove as many of the large particles as is practical the first time that these solids are pumped out of the borehole.

How are drill cuttings used in well planning?

Both the sample interval and the number and types of sample sets are usually determined at the start of the well (see Well planning ). Typically, drill cuttings are caught or collected as composite samples that reflect the various lithologies drilled over a 10-ft interval.

How to calculate the grain size of a well cutting?

Grain size estimation from well cuttings requires the use of a Grain Size Comparison Chart that can be viewed beside the sample through the microscope. Such charts, either printed on translucent film, or consisting of actual sand grains cemented to a card, are available from geological supply houses or service companies.

How are rock cuttings tested for hydrocarbons?

To test for these, the rock samples may then be treated with an appropriate organic solvent while being viewed under UV light. “Streaming” fluorescence may be noted (streamers or wisps of hydrocarbon) as it moves from the rock cutting into the solvent surrounding the cutting.

How are drill cuttings cleaned after mudlogging?

The remainder of the sample is packaged for later analysis and archiving. These samples are washed and sieved before they are analyzed. Consolidated cuttings are cleaned by washing or hosing the sample in a container of water to remove the mud film.