Shale Shaker Screen Deck Flow Distribution

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Solution Overview

Problem

Shale shakers face issues with screen blinding due to gummy or near-sized particles, leading to inefficiencies and increased downtime, particularly with fine-meshed filters prone to clogging, and existing methods for flow splitting in shale shakers result in differing fluid properties and processing efficiencies across decks.

Innovation Solution

The implementation of a shale shaker design with multiple duct openings and screen decks that allow for even fluid distribution and processing, using a weir-free system to split the flow across multiple decks, ensuring consistent processing and reducing wear on screens by preventing overflow and ensuring all fluid passes through duct openings, thereby maintaining even screen wear and efficient operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If fine-meshed screens are used to filter small particles, then filtering precision is improved, but screen blinding and clogging occur more frequently

Engineering Contradiction:
Improvefiltering precisionVSAvoidscreen blinding resistance
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The screen assembly is divided into multiple screen decks with different mesh sizes arranged in sequence. Coarser screens are positioned upstream to capture larger particles, while progressively finer screens are positioned downstream to capture smaller particles. This segmentation prevents any single screen from becoming overloaded with particles of all sizes, reducing blinding while maintaining high filtering precision through the combined effect of multiple screens.

Inventive Principle:
Principle #1Segmentation

2Productivity

If flow is split across multiple decks, then processing capacity is improved, but fluid property consistency deteriorates

Engineering Contradiction:
Improveprocessing capacityVSAvoidfluid property consistency
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

Each screen deck is equipped with independent flow distribution mechanisms and adjustable parameters tailored to its specific function. The first deck handles coarse separation with higher flow rates, while subsequent decks handle fine separation with controlled lower flow rates. This local optimization ensures that each deck processes fluid with appropriate characteristics for its screening level, maintaining overall fluid property consistency while maximizing total processing capacity.

Inventive Principle:
Principle #3Local quality

3Device complexity

If screens are fixed in position, then device complexity is reduced, but screen wear and degradation increase

Engineering Contradiction:
Improvescreen adjustment mechanismVSAvoidscreen service life
Core Design Contradiction:
Device complexityVSDuration of action of stationary object

Solution Approach 1:

The screen assembly incorporates adjustable mechanisms that allow screens to be repositioned, reoriented, or replaced based on wear patterns and processing requirements. Screens can be adjusted to change their angle of inclination, positioning, or even swapped between different deck positions. This dynamic capability extends screen service life by allowing optimization of wear distribution and enabling replacement of only worn screens rather than entire assemblies, while adding minimal complexity through standardized adjustment mechanisms.

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 design enhances the shale shaker's ability to handle a range of particle sizes without clogging, maintains consistent processing efficiency across decks, reduces downtime, and allows for the effective reuse of Wellbore Strengthening Materials by ensuring even fluid distribution and wear on screens, improving overall drilling fluid management.

Implementation Method 1

A vibratory mechanism, such as an electric motor with an offset clump weight, is fixed to the basket to induce a circular or elliptical motion therein

Methodology Applied
Scientific EffectVibration: Vibration

Implementation Method 2

The motor rotates the rotor and the offset clump weight, which causes the basket and the screens fixed thereto to shake

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 3

The rectangular screens may be arranged at an angle to horizontal, such as a seven degrees incline from the feed end to the discharge end of the shale shaker

Methodology Applied
Scientific EffectGravity: Gravitation

Implementation Method 4

The action of the vibratory mechanism induces solids to climb the inclined screens to the discharge end of the shaker

Methodology Applied
Scientific EffectVibration: Vibration

Data Source

PatentEP3415244B1Apparatus and method for separating solids from a solids laden drilling fluid
Publication Date: 2023.11.15 NAT OILWELL VARCO LP
  • EP3415244B1 patent drawingFigure 1
  • EP3415244B1 patent drawingFigure 2A
  • EP3415244B1 patent drawingFigure 2B

AI summary

Shale shaker for separating solids from solids laden drilling fluid, said shale shaker comprising a basket (100) having a first screen assembly (122a,122b) in an upper screen deck (112) and a second screen assembly (125a,125b) in a lower screen deck (113), the basket (100) further comprising a flow tray (121) for feeding solids laden drilling fluid to a first duct (107A-D) and a second duct (108A-D), the first duct (107A-D) for feeding solids laden drilling fluid to the first screen assembly (122a,122b) and the second duct (108A-D) feeding solids laden drilling fluid to the second screen assembly (125a,125b), wherein the second duct (108A- D) comprises a plurality of second duct openings (103A-D) for dividing the feed of solids laden drilling fluid and at least one discharge opening (110B,110D) for dispersing said solids laden drilling fluid on to the second screen assembly (122a,122b; 125a, 125b).