Asphaltene Precipitant Additives for Heavy Hydrocarbon Upgrading
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Solution Overview
Problem
Current in situ upgrading processes for heavy hydrocarbons require high solvent-to-oil ratios, leading to increased operating and capital expenses, and existing asphaltene precipitants are limited in penetration due to being solids at room and reservoir temperatures, restricting their effectiveness in enhancing API gravity and asphaltene precipitation within the formation.
Innovation Solution
Incorporating asphaltene precipitant additives with C—H, C—C, and/or C—O bonds that thermally crack to generate free radicals in the vapor phase, allowing for deeper penetration and increased asphaltene precipitation, thereby reducing the need for solvents and enhancing the API gravity and viscosity reduction of heavy hydrocarbons.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If large amounts of solvent are injected to precipitate asphaltenes downhole, then API gravity improvement and viscosity reduction are achieved, but operating expenses and capital costs increase due to high solvent inventories and larger surface facilities
Solution Approach 1:
The patent introduces an asphaltene precipitant additive as an intermediary substance that works synergistically with the solvent. This additive precipitates asphaltenes more efficiently, allowing the same upgrading effect to be achieved with less solvent. The additive acts as a catalyst-like agent that enhances the solvent's effectiveness without being consumed in large quantities.
Solution Approach 2:
The patent changes the chemical parameters of the injection system by adding the asphaltene precipitant additive, which has specific molecular structures that promote asphaltene precipitation. This parameter change (adding a new chemical component) transforms the system from requiring high solvent volumes to requiring lower solvent volumes combined with the precipitant additive, thereby reducing solvent inventory requirements.
2Manufacturing precision
If existing asphaltene precipitants are used, then asphaltene precipitation is achieved, but penetration into the formation is limited because they are solids at room and reservoir temperatures
Solution Approach 1:
The patent utilizes phase transition by injecting the asphaltene precipitant additive in a vapor phase that condenses in the formation. The additive is introduced as a vapor or gas that can penetrate deep into the formation, then condenses to its liquid or solid state to perform the asphaltene precipitation function. This phase transition enables both deep penetration and effective precipitation.
Solution Approach 2:
The patent employs pneumatic principles by using vapor-phase injection to deliver the precipitant additive deep into the formation. The vapor acts as a carrier that can travel through the porous media much farther than liquid or solid forms, utilizing pressure gradients and gas flow dynamics to achieve deep penetration before the additive condenses and performs its function.
3Productivity
If multiple horizontal wells are drilled for additive injection, then production from single well is enhanced, but cost of labor and equipment increases
Solution Approach 1:
The patent extracts the precipitant additive function from the well infrastructure itself by using the vapor phase of the additive as the delivery mechanism. Instead of requiring separate injection wells, the system uses the production well's vapor flow to carry the additive through the formation, eliminating the need for additional horizontal injection wells while maintaining enhanced production capabilities.
4Productivity
If huff and puff technique is used for heavy hydrocarbons, then some enhanced production is achieved, but API gravity improvement is insufficient
Solution Approach 1:
The patent merges two functions into a single process: the huff and puff production enhancement mechanism combined with the asphaltene precipitant additive's API gravity improvement capability. By introducing the precipitant additive during the huff and puff cycles, the system simultaneously achieves both production rate enhancement and significant API gravity improvement, whereas traditional huff and puff only provides modest production enhancement.
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
The process achieves significant asphaltene precipitation and API gravity improvement with reduced solvent usage, enabling cost-effective and efficient in situ upgrading of heavy hydrocarbons, with the asphaltene precipitants effectively penetrating farther into the formation and remaining in the reservoir, thus minimizing the need for additional wells and surface facilities.
Implementation Method 1
one or more asphaltene precipitant additives comprising compounds having C—H, C—C and/or C—O bonds that thermally crack to generate free radicals that are predominantly in the vapor phase after injection into the reservoir
Implementation Method 2
precipitated asphaltenes, in the reservoir. The upgraded hydrocarbon is produced from the production well without the precipitated asphaltenes such that the precipitated asphaltenes remain in the reservoir
Data Source
AI summary
In-situ upgrading of heavy hydrocarbons includes injecting into a reservoir solvent, an asphaltene precipitant additive and optionally steam, at a ratio of solvent to heavy hydrocarbon between 0.1:1 and 20:1 under reservoir conditions. The additive has C—H, C—C and/or C—O bonds that thermally crack to generate free radicals in the vapor phase after injection. Formed downhole are a blend containing an upgraded hydrocarbon, and precipitated asphaltenes. The upgraded hydrocarbon is produced such that the precipitated asphaltenes remain in the reservoir. The upgraded hydrocarbon has a greater API gravity, lower asphaltene content, and lower viscosity than the heavy hydrocarbon. The precipitated asphaltenes are present in a higher amount than a similar blend not containing the additive. A method for selecting the additive includes identifying candidate additives having bonds that crack to generate free radicals in the vapor phase at the operating temperature, and calculating percent increase of asphaltenes precipitated for each.