Modified Nanometer Calcium Carbonate for Shale Borehole Stabilization
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Solution Overview
Problem
Conventional nanometer plugging materials for drilling fluids have small particle sizes, large specific surface energies, and a tendency to agglomerate, making them difficult to disperse in liquids and ineffective at plugging micro-nano pores in shale formations, leading to borehole instability and fluid invasion.
Innovation Solution
An oil-based drilling fluid composition incorporating modified nanometer calcium carbonate with lipophilicity and strong pressure-bearing capacity, prepared through ultrasonic mixing, activation treatment, and ball milling, which allows for effective dispersion and plugging of micro-cracks in shale formations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If nanometer plugging material is used to plug micro-nano pores, then the particle size is reduced to nanometer level, but the material is prone to agglomerate and cannot disperse in liquid phase at nanometer level
Solution Approach 1:
The patent introduces a surface modification agent as an intermediary substance that coats the nanometer calcium carbonate particles. This modification agent acts as a mediator between the nanometer particles and the oil-based drilling fluid, preventing direct contact and agglomeration of particles while enabling stable dispersion in the liquid phase.
Solution Approach 2:
The patent changes the surface properties of nanometer calcium carbonate through chemical modification, altering its hydrophobicity and surface energy. This parameter change enables the particles to maintain individual dispersion in the oil-based fluid rather than agglomerating, while still maintaining nanometer size for effective pore plugging.
2Manufacturing precision
If nanometer plugging material is used to plug micro-nano pores, then the particle size is reduced to nanometer level, but the pressure bearing capacity is poor and cannot prevent propagation of pressure
Solution Approach 1:
The patent creates a composite structure by coating nanometer calcium carbonate particles with organic modification agents. This composite material combines the small size advantage of nanometer particles with the enhanced mechanical strength provided by the modification layer, resulting in particles that both plug micro-nano pores effectively and bear formation pressure.
Solution Approach 2:
The surface modification process changes the physical and chemical parameters of the nanometer particles, including surface hardness and structural integrity. These parameter changes enhance the pressure bearing capacity while maintaining the nanometer size necessary for plugging micro-nano pores in shale formations.
3Stability of the object's composition
If conventional treating agent with particle size of 0.1-100 μm is used, then the treating agent can be easily dispersed in liquid, but it is difficult to form mud cake in low-permeability stratum and cannot plug micro-nano pores
Solution Approach 1:
The patent fundamentally changes the particle size parameter from conventional micrometer range (0.1-100 μm) to nanometer range (1-100 nm), enabling the plugging material to enter and block micro-nano pores in low-permeability strata. The surface modification ensures that despite this size reduction, the particles maintain stable dispersion in the drilling fluid.
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 modified nanometer calcium carbonate enhances the drilling fluid's ability to stabilize borehole walls by reducing permeability and delaying pore pressure propagation, improving drilling efficiency and safety with a high plugging rate and adaptability.
Implementation Method 1
The borehole wall instability of the stratum mainly occurs in a hard and brittle shale stratum containing fractures, a majority of the stratum has the closed or opened stratification and micro-cracks, which have strong capillary action force
Implementation Method 2
prepared through ultrasonic mixing, activation treatment, and ball milling
Data Source
AI summary
An oil-based drilling fluid composition, includes a base fluid and a treating agent. The base fluid comprises a base oil and an inhibitor; the treating agent comprises an organic soil, a main emulsifier, an auxiliary emulsifier, a plugging agent, a weighting agent, a humectant, an alkaline regulator and a filtrate reducer. 5-25 parts by weight of the inhibitor, 5-12 parts by weight of the organic soil, 1-6 parts by weight of the main emulsifier, 2-8 parts by weight of the auxiliary emulsifier, 3-18 parts by weight of the plugging agent, 5-30 parts by weight of the weighting agent, 2-6 parts by weight of the humectant, 2-7 parts by weight of the alkaline regulator and 2-10 parts by weight of the filtrate reducer are used, based on 100 parts by weight of base oil.