SAGD Wellbore Solvent Pre-soaking Accelerates Thermal Communication
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Solution Overview
Problem
The steam-assisted gravity drainage (SAGD) process requires a lengthy start-up phase of three to four months to establish thermal communication between injection and production wells, which is inefficient and increases operational costs due to the need for heated fluids or downhole foam creation.
Innovation Solution
The method involves pre-soaking the wellbores with solvents to reduce viscosity, followed by conductive and convective heating during a pre-heating stage and a short steam injection squeezing stage to accelerate thermal communication establishment between the SAGD well pair.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional independent circulation of injection and production wells is used during start-up, then thermal communication is eventually established, but the process takes three to four months which is time-consuming and increases operational costs
Solution Approach 1:
The patent applies preliminary action by pre-soaking the wellbores with solvent before the actual steam injection begins. This pre-treatment prepares the wellbores and surrounding formation to reduce viscosity and enhance thermal communication, allowing the main steam injection phase to be shorter and more effective, thus reducing the overall start-up time from three to four months to approximately one month
Solution Approach 2:
The patent utilizes parameter changes by introducing solvent to alter the physical properties of the hydrocarbon formation, specifically reducing viscosity. This parameter change enables more efficient thermal communication and faster steam chamber expansion, allowing the system to reach productive conditions much quicker than traditional methods
2Reliability
If high pressure steam is simultaneously injected through tubing string of both wells during start-up, then thermal communication is established through conductive heating, but the process requires heated fluids and downhole foam creation which increases operational complexity and cost
Solution Approach 1:
The patent extracts the complex foam generation system from the steam injection process. By using solvent pre-soaking to reduce viscosity and enhance thermal communication, the system eliminates the need for downhole foam creation while still achieving effective thermal communication between wells, thus reducing operational complexity
Solution Approach 2:
The patent introduces solvent as an intermediary substance that facilitates thermal communication between the injection and production wells. The solvent acts as a mediator that reduces viscosity and enhances heat transfer, allowing steam to more effectively establish thermal communication without requiring complex foam-based systems
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 reduces the pre-heating time from three to four months to one month without adversely impacting production, by utilizing solvent pre-soaking and efficient steam injection to enhance thermal communication and viscosity reduction.
Implementation Method 1
The method involves pre-soaking the wellbores with solvents to reduce viscosity
Implementation Method 2
conductive and convective heating of formation fluids and rock between the SAGD well pair
Implementation Method 3
conductive and convective heating of formation fluids and rock between the SAGD well pair
Implementation Method 4
the steam condenses and heats a layer of viscous hydrocarbons by thermal conduction
Implementation Method 5
The heated, mobilized hydrocarbons (and steam condensate) drain under the effects of gravity towards the bottom of the steam chamber
Data Source
AI summary
A method for accelerating start-up for steam assisted gravity drainage operations comprising the steps of: forming a steam-assisted gravity drainage production well pair comprising an injection well and a production well within a formation; beginning a pre-soaking stage by soaking one or both of the wellbores of the well pair with a solvent; beginning a pre-heating stage by heating the wellbores of the well pair; beginning a squeezing stage by injecting steam into the wellbores of the well pair; and beginning steam-assisted gravity drainage production.