Proper cement and cementing practices are an integral part of ensuring successful well integrity. The API states that, “complete displacement of drilling fluid by cement and good bonding of the cement interfaces between the drilled hole and the casing immediately above the hydrocarbon formation and key parts of well integrity and seal integrity.” The cement is meant to completely isolate the wellbore from the surrounding geological formations with the absence of gaps and voids. In order to achieve this total isolation, the proper type of cement must be used. These types of cement are best suited for use in the varying temperatures and subsurface conditions throughout the wellbore.
Wiper plugs are components used to separate the drilling fluid from the cement slurry. Polydrill use these wiper plugs to minimize the mixing of cement with the drilling fluid as well as ensure that no cement remains on the inside of the casing. Centralizers are also used by Polydrill to center the casing to ensure that it will be completely surrounded by cement allowing for complete isolation. The number of centralizers is specified by state regulations. Once the cement is poured, an eight hour wait time must be observed before further activities to ensure that the cement is fully solidified.
Cement Plugs and Types of Centralizers
Polydrill has carried out various successful primary cementing operations that have resulted in a cement sheath to bond and support casing and provide zonal isolation. Good zonal isolation helped prevent the loss of production, control inter-zonal flow and/or flow to the surface, reduced water production and improved confinement of stimulation treatments.
Some of the common Types of Cementing Processes/Techniques carried out by Polydrill crew depending on the need of the hour over the last 6 plus years :
Polydrill Surface Cementing Equiments
Polydrill with the help of a mix of recent and modern technology uses the said 2 equipment models to carry out various Single & Multistage Cementing jobs. Polydrill also has a fleet of Bulk Handling equipments which gives them the upper hand to completely carry out Cementing jobs independently.
These equipments are tailor made for Polydrill use of Rental & Operation Service.
We also use Wiper Plugs which are used to separate cement from preceding or following fluids. The bottom plug removes mud from the wall of the casing, and prevents this mud from accumulating beneath the top plug.
Casing Centralizers used by us is only to:-
Primary Cementing Techniques followed by Polydrilla. Conductor :-
Single Stage Cementing OperationPolydrill uses this single stage cementing operation often while drilling a well, over here the casing with all of the required cementing accessories such as the float collar, centralizers etc. is run in the hole until the shoe is just a few feet off the bottom of the hole and the casing head is connected to the top of the casing. It is essential that the cement plugs are correctly placed in the cement head. The casing is then circulated clean before the cementing operation begins as shown in the picture:-
Multi-Stage Cementing OperationPolydrill also has carried out various Multi-stage Cementing Operations to reduce :-
What is a Mutli-Stage Cementing Operation?The necessity to split the cement sheath in the annulus into two, one sheath that extends from the casing shoe to some point above the troublesome formations at the hole bottom, and the second sheath that covers shallow troublesome formations. This is normally followed for a long intermediate string of casing that is needed to be cemented. The placement of these cement sheaths is known as a multi-stage cementing operation.