The original name will be set by the geology or exploration department. There are three categories of well which need to be coded.:
1) Wells With The Same Well Head And The Same Target 2) Wells With The Same Well Head Different Targets 3) Wells With Different Well Heads And The Same Target
15.1. WELLS WITH THE ORIGINAL WELL HEAD CO-ORDINATES AND TARGET 15.1.1. Vertical Well
Is defined as having the same well head and target co-ordinates as defined in the well programme.
The well code will be:
Prospect/Field name: Amelia Well Number: 1
Therefore the name/number is:
Illustration Line 1) Amelia 1 15.1.2. Side Track In A Vertical Well.
The term Side Track will only be used when there is a mechanical Side Track due to operational problems. If a new hole is drilled due to a operational problem maintaining the same target co-ordinates, this does not alter the well name.
To permit the identification of the various side-tracks each is given a number. 1 is the original hole, 2 is the first side-track, 3 the second, etc. This is shown in the figure and in the following example:
Illustration Line 1) Field name: Amelia 1
Illustration Line 2) 1st Side Track: Amelia 1 (hole No. 2) Illustration Line 3) 2nd Side Track: Amelia 1 (hole No. 3)
1
1 2
3
15.1.3. Directional Well
Is defined directional as a well where the target co-ordinates are different from the well head co-ordinates. (see Figure). The well code will be
Field name: Amelia Well number : 1 Code: DIR
So the final well code will be:
Illustration Line 1) Amelia 1 DIR 15.1.4. Side Track In Directional Well
This is considered the same condition as for a vertical well:
Illustration Line 1) Original Well name/number: Amelia 1 DIR Line 2) Side Track: Amelia 1 DIR (hole n. 2)
15.1.5. Horizontal Well
Is defined as a well that has a final hole path with a inclination of 90°.
The name will be:
Field name: Amelia Well number: 1 Extension: OR
Therefore the final well code will be:
Illustration Line 1) Amelia 1 OR
Note: The pilot hole into the reservoir will
also be deemed part of the horizontal well.
15.1.6. Side Track In A Horizontal Well
This is considered the same condition as for a vertical well:
Original well name/number Amelia 1 OR
Illustration Line 2) Side Track: Amelia 1 OR (hole n.2)
1
1
1
1 2
2
15.2. WELLS WITH THE ORIGINAL WELL HEAD CO-ORDINATES AND DIFFERENT TARGETS
In this category are wells with:
The original well head ordinates with more than one hole and different target co-ordinates.
Each new hole will be given a new code as will the operations necessary to prepare for the side-track (cement plug, casing window operation, etc.).
The name of the first hole will have the original code (AMELIA 1), the following holes will be added to the original code with one of the following two additions:
The first one indicates the well type:
• DIR, directional well
• OR, horizontal well
• APPR, deepened well
The second one indicates the targets new co-ordinates:
• A, second target
• B, third target
Example #1
Illustration Line 1) Original well (vertical) Amelia 1 Illustration Line 2) Directional hole: Amelia 1 DIR (A) Illustration Line 3) Horizontal hole: Amelia 1 OR (B)
Example #2
Illustration Line 1) Original Directional Well: Amelia DIR
Illustration Line 2) Directional Well with the second target:
Amelia 1 DIR (A)
1 1
2 2 3
Example #3
Illustration Line 1) Original Directional Well: Amelia 1 DIR Illustration Line 2) Vertical well with a second target:
Amelia 1 (A)
Example #4
Illustration Line 1) Original Vertical Well: Amelia 1 Illustration Line 2) Horizontal hole with a second target:
Amelia 1 OR (A)
Illustration Line 3) Horizontal hole with a third target:
Amelia 1 OR (B)
Example #5
Illustration Line 1) Original Directional Well: Amelia 1 DIR Illustration Line 2) Directional hole with a second new target:
Amelia 1 DIR (A)
Illustration Line 3) Horizontal well with a third target:
Amelia 1 OR (B)
Example #6
Illustration Line 1) Original Vertical Well: Amelia 1 Illustration Line 2) Directional hole with a second target:
Amelia 1 DIR (A)
Illustration Line 3) Deepened well with a third target:
Amelia 1 APPR (B)
Illustration Line 4) Deepened well with a fourth new target:
Amelia 1 DIR APPR (C)
1 1
1 2
2
2
1 3
2
3
3
4
15.3. WELLS WITH DIFFERENT WELL HEAD CO-ORDINATES AND SAME ORIGINAL TARGETS
In this category are the wells where the target co-ordinates remain the same while the wellhead location has been moved. This condition can only occur where there has been a drilling problem in the well.
There are two different cases:
Case 1
When there is one or more strings of casing set, it can be considered that every hole is a single well, so the name of the wells after the first will be the original well plus the code to define the well type (DIR OR) with the added code BIS for the second well, TRIS for the third well, etc.
Example #1
Illustration Line 1) Original vertical well: Amelia 1 Illustration Line 2) Second well: Amelia 1 BIS Illustration Line 3) Third well: Amelia 1 TRIS
Case 2 (no casing set)
When no casing string has been set, it can be considered that every hole is part of a single well. The code for the following holes is the original well plus (1) for the first hole, (2) for the second hole, etc.
Example #2:
Illustration Line 1) Original well: Amelia 1 Illustration Line 2) Second hole: Amelia 1 (2°) Illustration Line 3) Third hole: Amelia 1 (3°) Illustration Line 4) Fourth hole: Amelia 1 (4°) Illustration Line 5) Fifth hole: Amelia 1 (5°) Illustration Line 6) Sixth hole: Amelia 1 (6°)
1 2
3
1 2
3 4
5 6
15.4. FURTHER CODING
Further codes may be added to give additional information about a well with regard to its location in a field or if it is a marine well, i.e.
Location Code Example Field Description
Marine, Mare M Belaym 113 M 35 Belaym 113 Mare 35 North, Nord N Beniboye N 5-2 Beniboye North 5-2
South, Sud S Imbondeiro S 1 Imbondeiro South 1
East, Est E Samabri E 1 Samabri East 1
West, Ovest W Belaym M N W 2 Belaym Mare North West 2
When the well code/name is written out in full the full code name must be placed in front of the field name.
Example :
a) North Darag 1 b) Est Makerouga 2 c) South pass 75-2 d) West Butte 9-34-13-20
Listed in the following table 15.a are the definitions and the parameters to identify other well characteristics.
DEFINITION PARAMETER
EXTENDED REACH WELL Long
Radius
1000÷1600 286 ÷ 573 0.2 ÷ 0.1 3 ÷ 6
LATERAL WELL All the Horizontal wells
MULTI LATERAL WELL As showed in chapter 2 example 5
RE-ENTRY WELL Well re-entered to put in production, by drilling operations, a old suspended well. See example in chapter 2
BRANCH WELL Più drain hole con partenza da un unico extended reach
DEFINITION PARAMETER
WATER WELL Producing water well
WATER INJECTION WELL Well for water injection
GAS INJECTION WELL Well for gas injection
Table 15.A - Well Definitions and Characteristics