Integrated Shale and Oil Reservoir Exploitation via Fluctuating Horizontal Wells

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Solution Overview

Problem

Current methods for exploiting shale and adjacent oil reservoirs are inefficient, particularly when using horizontal well volume fracturing techniques, as they fail to effectively communicate with multiple interlayered oil reservoirs, resulting in low recovery ratios and incomplete resource utilization.

Innovation Solution

The implementation of fluctuating horizontal production wells or vertical wells to connect shale reservoirs with adjacent oil reservoirs, utilizing high-temperature and high-pressure natural gas for gas injection to enhance oil recovery, thereby improving the recovery ratio and resource utilization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If horizontal well volume fracturing technique is used, then exploitation of shale reservoir is attempted, but recovery ratio is very low and large amount of oil remains in adjacent reservoirs

Engineering Contradiction:
Improveoil recovery ratioVSAvoideffectiveness of exploitation
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent segments the exploitation process into two distinct phases: first exploiting the shale reservoir through in-situ conversion to generate gas, then using this gas to drive oil production from adjacent reservoirs through gas injection. This segmentation allows each reservoir type to be optimized for its specific characteristics rather than attempting a single unified approach.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary exploitation of the shale reservoir through in-situ conversion before tackling the adjacent oil reservoirs. By first converting shale organic matter to gas in-place, the system prepares a gas source that can subsequently be used to enhance oil recovery from adjacent reservoirs, creating a sequential dependency that maximizes overall efficiency.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If in-situ conversion technique is used for shale with low to medium maturity, then oil and gas can be exploited, but adjacent oil reservoirs with interlayers cannot be effectively communicated

Engineering Contradiction:
Improveresource utilizationVSAvoidwell pattern complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent merges the exploitation of shale reservoirs and adjacent oil reservoirs into a single integrated system. By combining in-situ conversion of shale with gas injection into adjacent reservoirs, the method creates a unified production approach that leverages both resource types simultaneously through a coordinated well pattern design.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent designs wells with multi-functionality, where the same well infrastructure serves dual purposes: producing hydrocarbons from the shale reservoir through in-situ conversion and simultaneously injecting gas into adjacent oil reservoirs to enhance their production. This universal approach reduces the need for separate dedicated wells for each function.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Ease of operation

If conventional horizontal well technique is used, then some oil can be produced, but the method cannot effectively handle compact oil reservoirs with interlayers

Engineering Contradiction:
Improveexploitation feasibilityVSAvoidrecovery ratio
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The patent introduces gas as an intermediary substance to facilitate oil production from compact reservoirs with interlayers. By injecting gas into the adjacent oil reservoirs, the gas acts as a driving force that overcomes the structural barriers created by interlayers, enabling oil to flow more effectively to production wells without requiring complex wellbore configurations.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 enables high-efficiency production from both shale and adjacent oil reservoirs by determining optimal well patterns and completion strategies based on geological data, significantly improving the recovery ratio and resource utilization compared to existing methods.

Implementation Method 1

utilizing high-temperature and high-pressure natural gas for gas injection to enhance oil recovery

Methodology Applied
Scientific EffectThermal heating: Heating

Implementation Method 2

utilizing high-temperature and high-pressure natural gas for gas injection to enhance oil recovery

Methodology Applied
Scientific EffectPressure gradient drive: Pressure Gradient

Data Source

PatentEP3800324B1Method and apparatus for determining integrated development approach for shale and adjacent oil layers
Publication Date: 2023.12.20 PETROCHINA CO LTD
  • EP3800324B1 patent drawingFigure 1
  • EP3800324B1 patent drawingFigure 2
  • EP3800324B1 patent drawingFigure 3~4

AI summary

The invention provides a method and an apparatus for determining an integrated exploitation approach for a shale and adjacent oil reservoirs, wherein the method includes: determining a thickness of an effective shale, a top effective boundary and a bottom effective boundary of adjacent effective oil reservoirs according to logging data of a target reservoir of interest; determining a maximum seepage radius of each of the adjacent effective oil reservoirs to the effective shale; determining a well pattern for integrated exploitation of the effective shale and the adjacent effective oil reservoirs according to the thickness of the effective shale, the top effective boundary, the bottom effective boundary and the maximum seepage radius; determining a well completion approach according to well pattern for integrated exploitation; and determining a total number of perforation clusters of gas injection wells, a number of perforation clusters corresponding to each of the adjacent effective oil reservoirs, a gas injection amount per unit time of each of the perforation clusters, and a total gas injection amount per unit time of the gas injection wells, according to the well completion approach; wherein the effective shale is in communication with all the adjacent effective oil reservoirs by boring-through of a fluctuating horizontal well or a vertical well. The technical solution realizes the efficient integrated exploitation of shale and adjacent oil reservoirs and improves the recovery ratio of the adjacent oil reservoirs.