Rigging

Brief technical characteristic

(float shoe, check valve, turbulizer, centralizer).

Well cementing                                                                                                                                                                                                                                 

 

CEMENTING HEADS UNIVERSAL

 

 

The Universal Cementing Head (UCH) is designed for casing the wellbore of oil and gas wells with the following objectives:

• ensuring a hermetic connection between the casing string and the injection lines from cementing units;
• preliminary placement, fixation, and subsequent release of separate cementing plugs and control components for staged cementing;
• managing the flow direction of buffer fluids, drilling, and cementing slurries in relation to cementing plugs and control components for staged and annular cementing.

 

STAGED CEMENTING COLLAR

The Staged Cementing Collar (SCC) is designed for equipping casing strings with diameters ranging from 140 to 324 mm and for conducting the well cementing process in two stages, either with or without a time gap.

The application scope of the staged cementing collar includes the following cases:

• when it is not possible to lift the cement slurry behind the casing string to the required height in one go due to formation fracturing and fluid absorption;
• when the anticipated working pressure during single-stage cementing exceeds the technical capabilities of the cementing units;
• for cementing gas and gas condensate wells, as well as wells prone to oil and gas shows;
• for cementing wells using two different cement slurries for isolating formations that differ in temperature or corrosive effects on the casing;
• when it is planned to leave the productive zone uncemented and prevent the cement slurry from being pushed through the casing shoe;
• when single-stage cementing is not possible due to organizational and technical reasons (e.g., when it is not possible to call or simultaneously place a large amount of non-cementing equipment on the drilling rig, such as in offshore drilling conditions).

 

РСТ-TYPE LINE SCRAPER

 

 

 

РСТ-type scrapers are intended for equipping casing strings made of pipes in accordance with GOST 632 and GOST 633 with nominal sizes from 102 to 340 mm in order to destroy and remove the filter cake from the well wall and the mud film from the outer surface of the casing pipes in the course of reciprocating the strings during their running and cementing , which ensures a more dense contact of the cement stone in the well annulus with the walls of the open one. Another purpose of PCT-type scrapers is to serve as reinforcing bars in the reinforced concrete structure of the well support, which prevents cracking of the support when perforating the producing zone of the well and when attaching the conductor shoe and protective string.
The use of PCT-type scrapers in intervals of the presence of cavernous wellbore sections gives a positive side effect, since the spring-loaded scraper cable brushes destroy the structure of the thickened mud masses in the caverns and facilitate their displacement and replacement with cement slurry.
The scope of PCT-type scrapers` application is universal – vertical, directional and horizontal oil and gas wells. There are no restrictions on pressure, temperature and environment aggressivity.
The example of recording the scraper designation for casing pipes with nominal diameter of 146 mm and range of open hole diameters from 191 to 216 mm:
РСТ-146/191-216

The principle of PCT-type scrapers` operation is that the scraper performs its main purpose due to the elastic properties of the cable brushes with the obligatory simultaneous reciprocating the string and flushing the well or pumping cement slurry through the annulus. In this case, the brushes destroy the filter cake, and the upward flow washes the destruction products out of the well. The purpose of the product is to implement the principle of operation in practice. To ensure maximum efficiency of scrapers, the string shall be centered in the well using bow-spring or rigid centralizers.

 

Scraper code	Nominal diameter of the casing, mm	Nominal hole diameter of well, mm	Inner diameter of scraper, mm, min	Overall dimensions in a free state, mm		Weight, kg, no more than
				Outer diameter, ±10	Height, max.
СТ-102/151	101,6	151	104	195	70	1,2
СТ-114/165	114,3	165	116	210		1,3
СТ-127/191	127	191	129	230		1,4
СТ-140/191-216	139,7	191-216	142	260		1,6