Hydraulic fracturing using high-boiling fraction of oil as a fracturing fluid
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2023-07-18 |
| Journal | Kazakhstan journal for oil & gas industry |
| Authors | Moldir A. Mashrapova, Nurbol Tileuberdi, Dairabay Zhumadiluly Abdeli, S. M. Ozdoyev, Ardak S. Iskak |
| Institutions | Satbayev University, Institute of Geological Sciences |
| Analysis | Full AI Review Included |
Technical Documentation & Analysis: Advanced Hydraulic Fracturing using High-Boiling Oil Components
Section titled âTechnical Documentation & Analysis: Advanced Hydraulic Fracturing using High-Boiling Oil ComponentsâExecutive Summary
Section titled âExecutive SummaryâThis research validates a novel, cost-effective hydraulic fracturing (HF) method using high-boiling oil components (hydrocarbons with C atoms $\ge$ C8) as the fracturing fluid, addressing critical challenges in low-permeability, heterogeneous oil reservoirs.
- Problem Addressed: Traditional water-based gel fracturing fluids are ineffective in multi-layer reservoirs due to clay swelling and gel adsorption by long molecules in the formation pores, severely limiting permeability.
- Core Innovation: Utilization of a high-boiling oil fraction, derived via a simple, single-stage separation process from degassed crude oil, as the primary fracturing fluid.
- Performance Improvement: Experimental results show that this method significantly increases formation permeability, achieving up to a 5-fold increase in the permeability coefficient (e.g., from 4.17 ”m2 to 18.96 ”m2).
- Economic Advantage: The oil-based treatment resulted in an average increase of 400 tons/month in oil production and reduced operational costs by approximately 35% compared to water-based treatments.
- Material Stability: The high-boiling oil fraction is stable at high reservoir temperatures (up to 220°C), maintaining its properties where water-based gels would degrade or lose effectiveness.
- Relevance to 6CCVD: The success of this HPHT (High Pressure/High Temperature) and chemically complex process relies on advanced, inert materials for monitoring and tooling, areas where 6CCVDâs CVD diamond excels.
Technical Specifications
Section titled âTechnical SpecificationsâThe following hard data points were extracted from the experimental results and methodology:
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Target Hydrocarbon Size | $\ge$ C8 | Atoms | Minimum carbon atoms in high-boiling fraction used as HF fluid |
| Separation Temperature | 200-220 | °C | Temperature range for single-stage separation of crude oil |
| Arystan Reservoir Viscosity (Initial) | 4-12 | mPa*s | Viscosity of crude oil in the reservoir |
| Heavy Fraction Viscosity (HF Fluid) | 57 | mPa*s | Viscosity of high-boiling fraction at reservoir temperature |
| Permeability Increase (Core 2) | 4.17 to 18.96 | ”m2 | Highest observed permeability coefficient increase (approx. 4.5x) |
| Permeability Increase (Core 4) | 0.44 to 1.77 | ”m2 | Lowest observed permeability coefficient increase (approx. 4x) |
| Oil Production Increase (Average) | 400 | t/month | Average monthly oil production increase after oil-based HF |
| Operational Cost Reduction | 35 | % | Cost savings compared to water-based HF (excluding base fluid cost) |
| Reservoir Compartmentalization | 10-20 | Layers | Number of interlayers indicating strong heterogeneity |
Key Methodologies
Section titled âKey MethodologiesâThe experimental study focused on simulating the impact of high-boiling oil components on the bottomhole formation zone using specialized laboratory equipment.
- Core Sample Preparation: Core samples were prepared using a laboratory machine for diamond drilling, followed by high-pressure air injection (using a compressor) to clean dust and particulates from the pores.
- Fracturing Fluid Preparation: A novel, cost-effective method was developed for single-stage separation of degassed crude oil.
- Crude oil is heated in a tubular furnace to 200-220°C.
- The heated oil enters a two-section installation containing horizontal plates (trays).
- The upper trays collect the light fraction (boiling point < 200°C, C atoms < C8).
- The lower trays collect the high-boiling fraction (boiling point $\ge$ 200°C, C atoms $\ge$ C8), which is used as the fracturing fluid.
- Laboratory Setup: Experiments utilized installations for determining rock permeability (liquid and gas), oil viscosity, and a specialized setup for pumping fracturing fluid into a reservoir core model.
- Hydraulic Fracturing Simulation: The HF process on the core model involved sequential injection:
- Pumping light oil to saturate the core.
- Pumping the high-boiling component fracturing fluid (C $\ge$ C8) at high pressure (exceeding local rock stress, PHF > Prock).
- Pumping an acid mixture.
- Pumping a driving fluid (degassed oil) to displace the fracturing fluid.
- Data Analysis: Permeability coefficients (Kpr) were calculated before and after treatment using the formula Kpr = QML / [10F (P1 - P2)], where Q is flow rate, M is viscosity, L is length, F is cross-sectional area, and P1 and P2 are pressures.
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & CapabilitiesâThe successful implementation and scaling of this advanced high-boiling oil hydraulic fracturing technique require materials capable of withstanding extreme pressures, high temperatures (up to 220°C), and corrosive hydrocarbon/acid environments. 6CCVD specializes in providing the CVD diamond materials necessary for the next generation of EOR tooling and monitoring systems.
| Research Requirement / Application | 6CCVD Solution & Material Recommendation | Technical Specification Match |
|---|---|---|
| HPHT Optical Monitoring & Seals | Optical Grade Single Crystal Diamond (SCD): Required for robust, chemically inert optical windows and high-pressure seals in downhole sensors or laboratory flow cells operating at 220°C. | Material: SCD (0.1”m - 500”m thickness). Polishing: Ra < 1nm for superior optical clarity and sealing integrity. |
| Electrochemical Fluid Analysis | Heavy Boron-Doped Diamond (BDD) Electrodes: Ideal for real-time electrochemical sensing to monitor the purity, viscosity, and chemical breakdown of the complex high-boiling hydrocarbon and acid mixtures. | Material: BDD films on custom substrates. Metalization: Internal capability for Au, Pt, or Ti/Pt/Au contacts for sensor integration. |
| High-Precision Core Preparation | Polycrystalline Diamond (PCD) Plates/Inserts: Used for manufacturing high-wear, high-precision cutters and inserts for the laboratory diamond drilling machine used to prepare core samples. | Dimensions: PCD plates up to 125mm diameter. Substrates: Up to 10mm thick for robust tooling. |
| Custom Sensor Integration & Tooling | Custom Dimensions and Metalization Services: We provide custom-sized SCD/PCD plates, wafers, and substrates, laser-cut to fit proprietary laboratory flow models, high-pressure pumps, or downhole tool designs. | Customization: Custom dimensions and geometries available globally. Shipping: Global shipping (DDU default, DDP available). |
| Engineering Support | In-House PhD Material Science Team: 6CCVD offers expert consultation to assist engineers and scientists in selecting the optimal diamond grade (SCD, PCD, or BDD) and geometry for similar Enhanced Oil Recovery (EOR) projects, high-pressure fluid dynamics, and complex chemical sensing applications. | Support: Material selection, design optimization, and custom fabrication assistance. |
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
Background: In recent years, there has been a trend towards deterioration in the structure of residual reserves at the fields of Kazakhstan. A significant part of the reserves is located in low-permeability reservoirs and in the zones not covered by flooding. The main factor negatively affecting the productivity and efficiency of development is the heterogeneity of oil reservoirs. Oil-saturated formations are an alternation of permeable oil-saturated sand or limestone and impermeable clay or dolomite layers, lenses and interlayers. Up to 1020 interlayers can be distinguished within the reservoir, which indicates a strong compartmentalization of the reservoirs. Due to the complexity of the structure of oil deposits, it is very difficult or impossible to ensure complete drainage of the entire volume of the deposit and complete coverage of oil displacement by water into production wells through injection wells. Aim: Increasing oil recovery in a cost-effective way. Materials and methods: Experimental studies of the processes of impact on the bottomhole formation zone with high-boiling oil components were carried out using a laboratory machine for diamond drilling, an installation for determining the permeability of a rock in terms of liquid and gas, an installation for determining oil viscosity, and an installation for pumping fracturing fluid into the reservoir model. Results: As a result of applying the hydraulic fracturing method using high-boiling oil components, it is possible to increase the permeability of low-permeability formations and significantly increase oil recovery. Conclusion: Due to the geological structure of multi-layer oilfields, water-based gel fracturing fluids to increase oil flow to wells are considered ineffective due to the adsorption of gels with long molecules in the pores of the formation and swelling of the clay particles of the reservoir when they interact with the water-based fluid.