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What is a choke in well control?

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A choke is a special valve used in well control situation and its primary purpose is to generate back pressure in a well, effectively increasing bottomhole pressure to manage formation flow during the removal of an influx. Chokes come in two types: positive or non-positive sealing, with adjustable features necessary for well control applications, as opposed to fixed chokes used in production or testing. These components are offered in various sizes and pressure ranges, and adjustable chokes can be either manually operated or hydraulically controlled from a remote console.

There are two main categories of chokes: manual chokes and hydraulic chokes.

Manual Chokes:

Operated by hand using a handwheel, manual chokes are not the primary choice for well control operations. The manual adjustment process is less effective for controlling pressure in the wellbore during circulation.

Manual Chokes

Manual Chokes

Hydraulic Chokes:

Hydraulic chokes provide easy adjustment and enable precise remote regulation of choke pressure. A notable feature of most hydraulic remote chokes is their placement in the choke manifold, while control occurs remotely from a panel displaying casing and drill string pressures.

Hydraulic Choke

Hydraulic Choke

In scenarios with multiple chokes, the manifold design should facilitate the isolation and repair of one choke while another remains active. Additionally, it is crucial to have spare parts for the chokes readily available at the rig site.

References 

Cormack, D. (2007). An introduction to well control calculations for drilling operations. 1st ed. Texas: Springer.

Crumpton, H. (2010). Well Control for Completions and Interventions. 1st ed. Texas: Gulf Publishing.

Grace, R. (2003). Blowout and well control handbook [recurso electrónico]. 1st ed. Paises Bajos: Gulf Professional Pub.

Grace, R. and Cudd, B. (1994). Advanced blowout & well control. 1st ed. Houston: Gulf Publishing Company.

Watson, D., Brittenham, T. and Moore, P. (2003). Advanced well control. 1st ed. Richardson, Tex.: Society of Petroleum Engineers.

 

What are differences between Back Pressure Valve (BPV) and Two-Way Check Valve (TWCV)?

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Learn key differences between Back Pressure Valve (BPV) and Two-Way Check Valve (TWCV) so you can choose the right one for a particular operation.

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What are Surface Controlled Subsurface Safety Valves (SCSSV)?

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Surface Controlled Subsurface Safety Valves (SCSSV) are a critical component of well completions, preventing uncontrolled flow in the case of catastrophic damage to wellhead equipment. SCSSV’s are strategically positioned within the tubing string beneath the surface, or mudline in offshore scenarios. Their primary function is to automatically close and secure the well in the event of a catastrophic incident at the surface that poses a risk of severe damage or loss to the wellhead. These valves are governed by a slender steel control line, running externally from the surface down to the valve. In the unfortunate scenario where the wellhead sustains significant damage, leading to the rupture of the control line, the resulting loss of pressure prompts the valve to close, effectively sealing off the tubing. The image below show the actual SCSSV prepared for completion string.

Certainly! Here's a rewritten version of the article: Surface Controlled Subsurface Safety Valves (SCSSV)


Certainly! Here’s a rewritten version of the article:
Surface Controlled Subsurface Safety Valves (SCSSV)

There are primarily 2 designs for these valves: wireline retrievable and  tubing retrievable. Wireline retrievable valves offer the advantage of extracting and servicing or replacing the major components of the valve (excluding the body) without the need to pull the entire tubing string from the well. On the other hand, the tubing retrievable model necessitates the removal of the tubing string from the well to gain access to the valve. These valves, often referred to as “flapper type,” can be secured in the open position using wireline tools. This facilitates access to the tubing string beneath the valve, enabling additional wireline operations as needed.

Surface Controlled Subsurface Safety Valves (SCSSV) can be called in different names ie Tubing Retrievable Valve (TRSV), Down Hole Safety Valve (DHSV), Sub Surface Safety Valve (SSSV). If you see these names, they are  (SCSSV).

References

Cormack, D. (2007). An introduction to well control calculations for drilling operations. 1st ed. Texas: Springer.
Crumpton, H. (2010). Well Control for Completions and Interventions. 1st ed. Texas: Gulf Publishing.
Grace, R. (2003). Blowout and well control handbook [recurso electrónico]. 1st ed. Paises Bajos: Gulf Professional Pub.

Why do we use High-Vis Sweep in drilling operation?

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In oil and gas industry, a specialized drilling fluid known as high-vis sweep is often used and its primary purpose is to optimize hole cleaning and remove cuttings from the wellbore. What distinguishes this fluid is its heightened viscosity, a quality achieved by incorporating polymers or other additives into the base drilling fluid. This augmented viscosity empowers the sweep fluid to transport cuttings up the annulus out of the well.

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