Fishing Technology (1)

Fishing Technology Manual

JOB PLANNING AND RECORD KEEPING


Overview

In fishing jobs, the customer is looking to you to provide an assessment of
the problem and a plan for resolving the problem. They will need you to
respond as quickly and as efficiently as possible so that they can resume
productive operations. You will earn their confidence by being
professional, thorough, and precise in your planning, coordination, and
execution of fishing operations.
At the end of the job, the customer will expect to be charged a fair price for
fishing services. In order to satisfy this need, you will need to plan an
efficient operation and keep accurate records of equipment used and
services performed.

Job Planning

Description

Successful fishing jobs start with excellent job planning. You will need to
do extensive research about the fish and hole conditions before the job is
even started. Appropriate paperwork must be maintained throughout all
phases of the job, including the planning stage.

Purpose

Proper preparation ensures that:
  1. the best option for fishing is determined
  2. time and money are not wasted on an unfishable job
  3. equipment, personnel, and other assets are available when needed.

Components

In planning for a job, you will need to:
  1. gather important information about the job
  2. determine the dimensions of the fish
  3. develop a fishing plan
  4. obtain approval for the fishing plan
  5. schedule personnel and equipment for the operation.

Gathering important information

Several important details should be obtained about the company, job
location, well parameters, work string, fish, and the operation at the time of
the incident. Important questions to ask include:
  1. What are the hole size, angle, and depth?
  2. What are the size, weight, and depth of all casings and liners?
  3.  What are the connections on the work string and drill collars?
  4.  What is the depth and condition of the top of the fish?
  5.  Does the job require jars? Are there jars in the hole? If so, are they working?
Additionally, you should request that a copy of the bottom hole assembly
(BHA) be faxed to you. This document will list everything that is included
in the BHA along with the specifications for each part. This will be
especially important for you to be familiar with because it is often what you
will be fishing out.
When you have gathered all of the job information, research previous
fishing jobs with similar characteristics. The documentation from these jobs
may help you to anticipate problems that may be encountered and learn
about some of the best practices that have been used.

Determining fish dimensions

It is very important to determine all possible dimensions of the fish. This
can be done by obtaining a complete well profile, if one is available.
The following information should be included in the well profile:
  1.  OD, ID, and length of the fish
  2.  OD, ID, and length of the fishing tool assembly
  3.  OD, ID, and length of the work string
  4.  location of the top of the fish
  5.  tensile and torsional strengths of everything that is run into the hole. The strength of the fish must be either memorized or noted in a readily accessible location. You may need to pull this information quickly and not have the time to calculate or research maximum pull values. Remember that pull strength is 80% of the tensile strength.
Other resources for information about the fish include the composite
catalog, technical manuals, and manufacturer’s drawings. These resources
can provide you with the critical points of recovering, burning over, or
milling up the fish. One of the first steps in planning a fishing operation is
studying how the manufacturer recommends releasing or picking up the
specific tool.
Important: You should have an exact replica of the fish (e.g., same type
packer, etc.) delivered to the location. It is far more valuable than drawings,
specification sheets, or photos.

Table 1-1:
Maximum OD of Tools to Run in Casing Excluding Overshots




Enhanced Oil Recovery (Powerwave)

Powerwave

Its a new technique used to improve the performance of waterflooding.
In a perfect world the injection of a liquid would create a piston-like displacement of the remaining oil in place. What actually happens is the non-ideal situation where "fingers" of water bypass the oil.



The Tool Used

a downhole vibration tool based on whirling orbital vibrator.
 
 
 
Operation

Create seismic waves from 5 to more than 500 hertz, and is capable of generating 
controllable force levels up to many tens of thousands of pounds.
The direct mechanical contact with the formation allows the device to transmit the 
vibration energy from the backward whirling mass into the producing formation. 
 
Mechanisms of Increased Recovery
 
 
Changes in Wettability.
Coalescence and/or dispersion of oil drops.
Reduced viscosity
Surface tension



Water Flooding (Enhanced Oil Recovery )


Water Flooding
assume that this has been folded in the middle, so that it now has trapped oil within all the pores of the rock

assuming that I have a layer of rock that is 300 ft thick, five miles wide and thirty miles long , and it has a porosity of 20% .
 
So first let's do a bit of arithmetic :
 300 x 5 x 5280 x 30 x 5280 = 1,254,528,000,000 cu.ft.
 At 20% porosity, this means that some 250,905,600,000 cu. ft. are not rock, and in this case are going to be full of oil.
This is equivalent to 44,685,092,571 barrels of oil.
 
If the oil is light , and the rock properties allow oil to flow easily through the cracks,
Then ,we can recover up to 50% of oil.
So , URR=22.5 billion barrels.
Firstly,well drill vertical wells one quarter of a mile apart.
The total recoverable oil for each well is roughly 10 million barrels
  


After some years (say;five years) we notice that the volume coming out of the well is not as much as it used to be .
If we pump water into the ground under the oil well, then the water will fill the holes left as the oil leaves, and we can keep the pressure in the oil up, and the oil flow will not drop as fast.
  


Limits to Water Flooding: