www.Primo.com: Drilling of Oil and Gas.

Who is not amazed at offshore drilling platforms? Stands firmly in the middle of
the sea by flaring which continued to burn. However, ever curious as to what activities offshore drilling? How to drilling on land?

The following reviews summarily.

Drilling oil or gas wells not like to drill water wells. A lot of preparation to be done, drilling techniques, sorts and goals drilling and safety aspects. Here we review the various oil and gas drilling.
All right, before we begin a review of how the actual process of drilling oil and gas wells, we will limit this review only on the core process briefly. Because it will be very long when we discuss the start of the preparation phase until the end. The process of preparation, implementation and explanation of the equipment will be discussed at the next review, and can be read here.

Drilling by the goal is divided into three, namely exploration drilling, delineation drilling and exploitation drilling. What is the difference? Consider the following.

1. Drilling Exploration.

The purpose of the exploration drilling is to prove the presence or absence of oil or gas in the basin. Exploration drilling has yet to have accurate data about the nature of rock will be penetrated. Thus, the process of exploration drilling has a high level of problems. Therefore, the exploration wells are often also dubbed Wild Cat. That is, during the drilling operation will be found many problems affecting the length of time and the high cost of drilling.
In general, the point of this drilling location is above the reservoir shaped anticlinal crest Trap.
At the reservoir layer, it appears there are three layers of fluid that is composed from top to bottom according to density. The first or top layer is a gas that has followed the lightest density of oil and water. Generally, there is a layer of oil under water as the lower limit of an oil reservoir.

The fluid contained in the three layers that insulate example, the boundary line between the fluid gas with oil fluid called Gas Oil Contact (GOC) and the boundary between oil and water fluid called Oil Water Contact (WOC). When drilling at peak trap did not find hydrocarbons, the reservoir is considered empty or dry hole.

2. Delineation Drilling.

Type of drilling is intended to determine the spread of the reservoir, looking for boundaries, as well as the thickness of the reservoir. At this existing drilling well data from the results of exploration drilling. To determine the limits of the reservoir was drilled with certain distances from the wells first. Suppose there will be three wells to be drilled to determine the boundaries of the reservoir, with the first well is an oil well with high deposit thickness.

Drilling a second well is expected to penetrate the oil zones with a thickness very thin and thick water zone. It can be said as the oil reservoir boundary. However, when drilling still penetrate the thick oil zone with the thickness of a thick water as well then it can not be said to be the limit of the reservoir. Thus, it is necessary that the third well was drilled. When the third well found no oil and only discovered the water was very thick, then the reservoir boundary is between the second well and the third well.

To determine the limits of the oil reservoir is based on the thickness of the oil from each well drilled. Furthermore, based on the data the thickness of the oil can be made isopach maps used to calculate the volume of rock containing oil.

3. Drilling Exploitation.

This drilling aims to take oil reserves stored in reservoirs. This exploitation drilling usually requires a more affordable cost because it already has data such as the thickness of the reservoir, the type and nature of the rocks, and others. Exploration wells can be transferred into the wells as long as exploitation of the exploratory wells to be produced economically.

Onshore Rig-owned PetroVietnam

The next grouping is based on its location. Based on the location of the point of location, drilling can be divided into:

1. Drilling Army (onshore)

Onshore drilling is all drilling activities are located at the point of the mainland. Usually called onshore drilling.

Onshore Rig in Texas

2. Drilling Offshore (offshore)

Offshore drilling is drilling that point located at sea off the coast to the deep waters. However, if the point of drilling locations in an aqueous environment such as in rivers, swamps, lakes or with a certain depth can also be categorized as offshore drilling.

Onshore and offshore drilling

The third grouping of the drilling activity is based on the shape of the hole created during the drilling process. In this group, the drilling is divided into two, namely drilling upright (straight hole drilling / vertical drilling) and directional drilling (directional and horizontal drilling).

1. Drilling Upright (straight hole drilling / vertical drilling).

Drilling is also called drilling straight vertical or straight hole drilling, which means drilling conducted from the starting point on the surface is maintained kelurusannya until it reaches the target. Drilling vertical drilling meet the criteria if:

a. Drilling is still in a cone with a cone angle of 5o to an altitude of 10000 feet. This cone is formed from the starting point of drilling on the surface to a depth of 10000 feet with a cone slope of 5o. During the holes formed in the drilling operation is still within the cone, then the drilling is categorized as vertical drilling.

b. Actually, though still within the cone hole 5o, but very difficult to maintain the straightness of the hole. Why? One factor is the rock formation in which may be very different from one layer to the next layer. Of course, this will affect the drilling process. Holes may be turning or not straight origin no more than 3o every 100 feet and still be inside the cone. Diversion hole dog leg is often called because of its shape similar to a dog's paw.

2. Drilling trending (directional and horizontal drilling).

Directional drilling in this case is the process of drilling a hole wells directed at a certain angle to hit the target. Typically, rig or platform is not located vertically with the reservoir.
Conducting the process of drilling a formation was ideally maintaining the concept of vertical drilling. Because maintaining wellbore kelurursan apart in the operation much easier, cost is also cheaper. However, there are a number of reasons and factors that forced to do directional drilling. The following reasons:

a. Inaccessible Location Drilling.

Some reservoirs are under the surface that can not be done drilling vertically but is perfect when reached by horizontal drilling techniques. This technique is very commonly used for drilling in the reservoir which is difficult to reach such as reservoir under the city, agricultural land / plantation, etc.

b. Multiple Well Drilling.

In addition to the reservoir position factors that are difficult to reach, directional drilling is also done because there are many reservoirs, but the limited area on the surface so it is not possible to build a rig or platform within walking distance. Then, perform the drilling of multiple wells using only a single plaform with directional drilling method to reach all of the reservoirs. This technique is usually performed on offshore drilling / offshore.

c. Salt Dome Drilling.

In the area found the salt dome (salt dome) that is located above the reservoir, vertical drilling is risky because of the potential for greater blow-out occurred. Therefore, taking the side of the salt dome to the reservoir can be a wise choice.

d. Side Tracking or Straightening.

Sometimes in performing drilling operations occur straight or deflection severe deviation in the wellbore so that the drilling direction away from the target, making it necessary to re-align the wellbore. Therefore it is necessary to restore the tracking side toward the wellbore to the original target.

e. Relief Well Drilling.

Relief well is actually a process of disaster mitigation in the drilling process. Oil wells which suffered a blow-out will be handled by this method. Relief well is a well made near the well blow-out experience with the aim of reducing the fluid inside to suppress the effects of a blow out. Create a relief well is usually using directional drilling methods.

That division or classification of drilling for oil and gas based on the purpose, location and shape of the hole.
Thank you for reading this article. Written and posted by Bambang Sunarno. sunarnobambang86@gmail.com
author:
https://plus.google.com/105319704331231770941.
name: Bambang Sunarno.
http://www.primadonablog.blogspot.com/2016/01/drilling-of-oil-and-gas.html
Published Date: January 7, 2016 at 13:47