Drill String Washing for Upper Completion Cleaning

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Solution Overview

Problem

The existing methods for washing a cased length of a hydrocarbon production well or water injector well are time-consuming and risky, requiring multiple days and involving delicate cleanout strings that are prone to damage, especially when performing an inflow test and cleaning the casing above the reservoir liner.

Innovation Solution

A process and apparatus that allows for the installation of a reservoir liner and simultaneous washing of the wellbore by passing a drill string with a reservoir liner hanger running tool and inflow test tool, enabling cement displacement and fluid circulation without removing the drill string, and performing an inflow test while rotating the drill string to ensure thorough cleaning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a delicate cleanout string is used to wash the casing, then the casing can be cleaned, but the cleanout string is easily damaged and the operation takes many days

Engineering Contradiction:

Improvecleanout string durabilityVSAvoidwashing operation duration

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent combines the drill string (used for liner installation) with the washing function by equipping it with a rotating wash tool and nozzles. This merges two separate operations (liner installation and casing washing) into one continuous process, eliminating the need for a separate delicate cleanout string and reducing overall operation time from many days to a single continuous operation.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The drill string is designed to perform multiple functions: installing the reservoir liner, performing inflow tests, and washing the casing. The wash tool attached to the drill string can rotate and spray wash fluid while the drill string remains in place, allowing the same equipment to handle multiple tasks that previously required separate specialized tools.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Productivity

If the drill string is removed after liner installation to perform washing, then the washing can be done, but the process takes many days and costs more

Engineering Contradiction:

Improvewashing operation efficiencyVSAvoidtotal operation time

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The wash tool is pre-installed on the drill string before liner installation. The drill string is equipped with rotating capability and wash nozzles in advance, so that immediately after liner installation, the washing operation can begin without removing the drill string. This preliminary preparation eliminates the time-consuming sequence of removing equipment and setting up separate washing operations.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The washing operation is performed continuously while the drill string remains in place. The drill string can rotate continuously to distribute wash fluid around the casing, and the wash tool can operate without interruption. This continuous operation replaces the traditional multi-day process that involved stopping, removing equipment, and resetting multiple times.

Inventive Principle:

Principle #20Continuity of useful action

3Manufacturing precision

If the drill string is rotated during washing, then effective washing is achieved, but the drill string must be removed first in traditional methods

Engineering Contradiction:

Improvewashing effectivenessVSAvoidoperation procedure complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The wash tool is designed to rotate with the drill string, creating dynamic washing action that effectively cleans the casing. The rotating motion distributes wash fluid around the casing interior, preventing fluid from simply flowing straight down. This dynamic rotation is integrated into the drill string system, eliminating the need for separate rotating washing equipment and simplifying the overall operation.

Inventive Principle:

Principle #15Dynamics

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach significantly reduces the time required for the washing process, potentially from several days to just a few hours, while minimizing the risk of damaging the cleanout string and avoiding the need for a separate cleanout string, thus saving rig time and reducing hazards.

Implementation Method 1

washing the interior of the casing by passing wash fluid through the drill string and into the casing, whilst rotating the drill string

Methodology Applied

Scientific EffectFluid circulation:

Implementation Method 2

performing an inflow test on the reservoir liner by forming a sealed connection between the drill string and the reservoir liner or reservoir liner hanger

Methodology Applied

Scientific EffectPressure testing:

Implementation Method 3

displacing cement into the reservoir liner annulus by passing completion fluid through the drill string and reservoir liner

Methodology Applied

Scientific EffectFluid displacement:

Data Source

PatentEP3717739B1Method and apparatus for washing an upper completion

Publication Date: 2023.06.28 CONOCOPHILLIPS CO

Figure 1~3
Figure 4~5

AI summary

The invention relates to the cleaning of a wellbore including a reservoir liner 3 and an upper portion 2 of the wellbore, by running in only one string into the wellbore and performing a reservoir liner cementing operation, displacing the cement 7 with completion fluid 8, followed using the same string to circulate mud in the upper completion, perform an inflow test on the reservoir liner 3, wash the upper completion and displace it to completion fluid 8.