Introduction of the horizontal wells
The technology of the horizontal wells attained the viability during the 1980s, and ever since it has encouraged its testing in geographic regions as well as geologic areas. The first horizontal well was constructed in the year 1939 in one of the shallow fields that were depleted using the pump, vacuum and the natural seepage. The horizontal well drilling has several categories with one of the category being short, medium and the long radius. These wells have been used widely, and this has proved to be productive regarding production. The attainable horizontal bore hole expanded rapidly with the increased use of technology. The primary role of the horizontal well is to expose a large surface of the reservoir so that it may be able to achieve the conventional vertical well. However, when it comes to the process of desiring the horizontal well, it is important to make sure that all the risks that are related to the drilling of the well are adequately addressed. The primary objective of this paper is about the factors then I should consider before drilling the horizontal well.
The description of the horizontal well
The horizontal wells have become familiar due to their positive impact on the society. However, the horizontal wells drilling aims at attaining the following outputs; It is first intended at increase the ultimate recovery. However, during the horizontal well drilling, it is important to ensure that the horizontal Well is analyzed by the simulation technique to make sure the profitability is high. The only challenge is that horizontal drilling is expensive and it is also hard than the conventional and the vertical technologies. However, the following are the benefits of the horizontal well; serve the irregular reservoirs with no other wells, maximize the efficiency of the reservoir, limiting the invasion of the formation fluid and increasing the production of the optimize the production from low energy reservoir. Several factors play an integral role in the implementation of a horizontal well, and these facts include the long radius, medium radius, and the short medium. The analysis of these factors helps in determining the suitable horizontal well to be implemented by providing their practical designs
The Long radius
In a long radius horizontal well, that contains a hole section of the borehole; this implies that the inclination rates of 1-100 feet and the horizontal should be close to 3000ft. This is the reason long radius horizontal wells are highly applicable in the elongation process so as to reach drilling. The long radius is appropriate to the off-shore and the packs with the objection of extending until they reach the surface location. It is also capable of going as far as to the deep end of the rivers, the lakes and the mountains that cannot be accessed by anyone. The following is a diagram of a long radius horizontal well;
The benefits of a horizontal well are the fact that conventional drilling equipment can easily be used, the torque, as well as the drag, are lower compared to the wells with the short radius. The exposed open hole is less when this is compared to the short radius wells, and the sizes of the holes are not restricted as it is with the short radius wells.
The Medium radius well
These are known to use many of similar hole assembly component and applies the same technique to the one used in high radius wells. However, the existing difference between the two wells is the fact that the medium radius constructs limitations on its capacity to rotate, which have impacts to the entire well. Additionally, the BHA that is applicable in the drilling cannot turn in the section because both the motor and the MWD are strained. However, the section to be constructed first is used in starting and kicking off the angle up to 45 degrees. Further, The radius of curvature of a building assembly can also be deduced from the configuration of the offset angle is only introduced at the top of the sub and the bottom of the upper joint that can shaft. The following is an image demonstrating how the medium horizontal well can be drilled.
Although the long radius horizontal is considered as the best over the medium horizontal well, the following are the positive sides of the medium horizontal wells; there is only little strata that are exposed, almost 100% of the motor that is drilled is steerable, it is less torque and drag. There is also a small hole below the dogleg, and this is the bit setting the other holes that can easily be logged. These are the advantages that have made the medium horizontal to operate close to the long radius well.
The short radius well is believed to be the hardest to be drilled given the fact that it requires a share build rate of close to 35ft that is closely followed by the short horizontal section of approximately 300 to 400 feet. It is also difficult to do both the bottom hole assembly as well as the drilling operations, and this calls for the use of hard drilling tools for the completion of the wells. The following is the image of a short radius well;
Despite the difficult in designing the short radius well, the following are the advantages of this well; It has a sharp curve part of then well, There is accuracy in definition, It can be applied to small businesses, it can reach the shallow reservoirs quickly, and it needs minimum measured depth in order to attain the horizontal height.
To limit the cases of coning water and the formation of gas at the bottom, the length of the well will be increased. This is important since it will provide an exposure allowing the production rate be high when the pressure is low. As a result, this will lead to reduced coning as shown in the diagram;
In conclusion, the designing of the horizontal wells is a long process that requires the commitment and keen observation. This horizontal well serves critical roles and is applicable in many useful areas. However, comparing the three radii, the long radiuS horizontal well turns out to be more advantageous compared to the other because of the following; the convectional drilling equipment can easily be used, the torque, as well as the drag, are lower compared to the wells with the short radius. The exposed open hole is less when this is compared to the short radius wells and the sizes of the holes are not restricted as it is with the short radius wells.