Systems, processes, and modeling methods for drilling in hot dry rock using supercritical or dense phase carbon dioxide
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Solution Overview
Problem
Current drilling technologies for Dry Hot Rock (DHR) are limited by high temperatures (>350°C) that exceed the operational limits of Measurement-While-Drilling (MWD) and directional tools, restricting drilling to vertical or uncontrolled deviated wells, as existing solutions like vacuum insulated drillpipe and enhanced MWD components are either challenging to handle or not yet available.
Innovation Solution
A system utilizing supercritical CO2 (sCO2) with a closed-loop recycle system, downhole chokes, and Joule-Thomson cooling to manage temperature and pressure, allowing for robust well trajectory control, efficient cuttings transport, and safe operation of MWD components by creating a pressure drop and cooling effect across MWD tools.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional drilling methods are used in Dry Hot Rock, then drilling can proceed without special cooling systems, but MWD components cannot operate because temperatures exceed 350°C which is above their operational limit of 150°C
Solution Approach 1:
The cooling system is segmented into multiple downhole chokes positioned at different locations within the drill string. Each choke creates a localized pressure drop and cooling effect, allowing distributed temperature management along the drill string rather than requiring a single complex cooling system.
Solution Approach 2:
Supercritical CO2 is introduced as an intermediary cooling fluid that flows through the drill string and annulus. This intermediary substance absorbs heat from MWD components and transports it to the surface, enabling temperature control without direct thermal contact between the hot formation and sensitive electronics.
2Productivity
If horizontal wells are drilled to efficiently extract DHR heat, then heat extraction efficiency improves, but well trajectory control becomes difficult because MWD tools cannot operate at the required temperatures
Solution Approach 1:
Multiple downhole chokes are positioned at different depths and locations within the horizontal wellbore. This segmentation allows for localized pressure and temperature control at different sections of the horizontal well, enabling precise well trajectory management while maintaining efficient heat extraction across the entire well length.
Solution Approach 2:
The system dynamically adjusts pressure and temperature parameters along the horizontal well trajectory by controlling the flow rate and positioning of supercritical CO2 through multiple chokes. This enables optimization of both heat extraction efficiency and well trajectory control by changing operational parameters rather than altering the well geometry.
3Reliability
If supercritical CO2 is used for cooling, then MWD component temperatures can be maintained below 150°C, but the system complexity increases due to the need for closed-loop CO2 recycle systems and pressure control
Solution Approach 1:
The supercritical CO2 system performs multiple functions simultaneously: it cools MWD components, transports drill cuttings to the surface, and provides pressure control throughout the drilling operation. This multi-functionality reduces the need for separate dedicated systems, thereby lowering overall system complexity despite the advanced cooling requirements.
Solution Approach 2:
The closed-loop CO2 system is designed to automatically recycle and reuse the cooling fluid without requiring external intervention. The CO2 that exits the wellbore is automatically compressed, cooled, and re-injected, creating a self-sustaining cycle that reduces operational complexity and maintains reliable cooling continuously.
4Temperature
If downhole chokes are used to create pressure drop and cooling effect, then temperature management improves, but the device complexity and handling difficulty increase
Solution Approach 1:
The cooling function is divided into multiple downhole chokes positioned at different locations rather than using a single complex surface cooling system. Each choke is a relatively simple component that can be independently handled and positioned, making installation and operation easier while achieving distributed temperature control throughout the wellbore.
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
Enables drilling in DHR wells with temperatures above 350°C by maintaining MWD components below 150°C and annulus temperatures below 100°C, facilitating more efficient and safe horizontal well drilling while managing pressure and flow rates to transport cuttings effectively.
Implementation Method 1
A system utilizing supercritical CO2 (sCO2) with a closed-loop recycle system, downhole chokes, and Joule-Thomson cooling to manage temperature and pressure, allowing for robust well trajectory control, efficient cuttings transport, and safe operation of MWD components by creating a pressure drop and cooling effect across MWD tools.
Implementation Method 2
The supracritical CO2 pump is configured to deliver the supracritical CO2 to the drill bit at a rate ranging from about 10 to about 20 kilograms per second at a pressure ranging from about 5,000 to about 7,500 psi
Data Source
AI summary
Systems and processes for dry hot rock drilling operations using sCO2 expanded across one or more downhole J-T valves or chokes to cool MWD components. Methods of modeling same.