This is one of excellent training video demonstrating the drilling process from start at surface casing to completing of the well in less than 7 minutes. This would be a good tool to teach people about drilling in our oil and gas industry. We also provide video transcription in order to help learners understand the content easily. If you love this content, please feel free to share with your friends.
Full Video Transcription
Once the surface section of the well is drilled, the drill pipe is pulled out of the hole in order to lay the casing. This is done for environmental reasons to hydraulically seal the formation layers containing aquifers from the flowing hydrocarbons later on once the well is completed. The casing string is made of numerous joints the same size screwed together at the collar. The casing pipe is selected according to its outer diameter, its wall thickness, its length its weight by unit length and the grade of steel it is made of.
The selection of grade of casing depends on several variables including the size of the hole, the rugosity of the drilled hole. The expected pressure of the flowing hydrocarbons the H2S content as well as the economic considerations.
Once the entire weight of the casing string is solely suspended by the hangers, the casing is considered laid in place. In order to secure the laid casing string to the formation, cement is pumped through the casing shoe at the bottom of the well letting the cement flow between the casing and the formation, to allow further operations in the well the cement requires sufficient curing time.
Once the cement has dried, the seal of the aquifers would be established. The drilling then continues through the wiper plug, the casing shoe and the cement at the bottom of the hole until the desired depth is reached. This is called total depth or TD and is where the pay zone is anticipated. To evaluate presence and economic feasibility of this pay zone the drill pipe could be equipped with logging while drilling tools to evaluate formation while drilling.
It is a common practice to lower wire line logging tools to evaluate the formation and determine the economic feasibility of the drilled well. This is done by logging the anticipated pay zone through various types of sensors to determine the key properties of the zone. After the pay zone has been determined and deemed feasible, the wall needs to be prepared to extract the discovered hydrocarbons. This process is known as the completion of a well.
A common completion method requires inserting a casing string into the newly drilled open hole to prevent the borehole wall from caving prematurely during the various steps of completion. To allow further operations in the well the cement requires sufficient curing time.
The cementing process is not always a flawless operation and the resulting cementing job might contain some bonding issues that would undermine the strength and integrity of the casing especially during preparation. The bond of this cement with the formation and with the casing is evaluated using a cement evaluation wireline tool. This tool determines whether the cement job is optimal, if not further remedial operations are required.
To establish a path with the hydrocarbons stored in the pay zone, a perforating gun is now lowered to the target depth. Wireline is the preferred conveyance method for short and light gun strings, to deploy long and heavy gun strings a technique referred to as tubing conveyed perforating or TCP is required. Using sensors part of the gun string, the guns can be accurately positioned in front of the targeted reservoir. The charges in the gun are now ready to be ignited using the surface perforating control equipment. Once the correct depth has been confirmed the gun is fired. The charges in the gun explode providing a path through the formation the cement and the casing to the production tubing. The perforating gun is then pulled out of the hole.
Now the well is perforated and the path has been established between the stored hydrocarbons and the well board. While the drilling rig is still in place production tests are performed to confirm the commercial viability of the reservoir before the production string is installed in the well.
A typical production string is made of a tubing string that includes a packer near the bottom end. The production Packer is installed above the top of the perforations to ensure that the flowing hydrocarbons reached the surface only through the production tubing. Before the drilling rig is dismantled and moved away to its next location, the wellhead equipment commonly referred to as the Christmas tree is installed on top of the well. With the well completed the production of hydrocarbons can begin. These hydrocarbons will fill storage tanks or feed pipelines until the day when the production rate has diminished and the well is plugged and finally abandoned.