Field Testing Nonaqueous-based Drilling Fluids

API RP 13B-2: Field Testing Nonaqueous-based Drilling Fluids - An Essential Guide

In the demanding world of oil and gas exploration, maintaining optimal drilling fluid properties is paramount for efficient and safe operations. API RP 13B-2 provides the industry-leading, authoritative standard for field testing nonaqueous-based drilling fluids (NAF), ensuring that engineers have the proven methodologies to monitor and control critical fluid characteristics on-site. This comprehensive recommended practice is an essential resource for any professional involved in drilling operations that utilize NAF systems.

What is API RP 13B-2?

API RP 13B-2, developed by the American Petroleum Institute, is the industry-recognized recommended practice for conducting field tests on nonaqueous-based drilling fluids. Its primary purpose is to establish standardized, reliable procedures for evaluating the physical and chemical properties of these specialized fluids directly at the wellsite. This ensures consistent data quality and facilitates informed decision-making for drilling operations.

Scope & Purpose

This standard specifically governs the field procedures for testing nonaqueous-based drilling fluids, which include oil-based muds (OBM) and synthetic-based muds (SBM). It outlines the necessary apparatus, methodologies, and calculation methods for determining key properties such as density, viscosity, gel strength, filtration characteristics, and fluid composition (water, oil, and solids content). API RP 13B-2 does not cover laboratory-specific analyses or the testing of water-based drilling fluids, which are addressed in separate API Recommended Practices.

Who Must Comply?

• • Primary audience: Drilling engineers, mud engineers, wellsite geologists, drilling supervisors, and operations managers.
• • Industries affected: Oil and gas exploration and production (E&P), particularly those utilizing NAF systems in challenging or sensitive environments.
• • Compliance nature: While API standards are generally voluntary, compliance with API RP 13B-2 is often mandated by drilling contracts, operator specifications, and regulatory bodies, making it effectively a de facto requirement for best practice.
• • Enforcement: Compliance is typically overseen by drilling contract administrators, company representatives, and third-party inspection services.

Key Requirements Overview

The standard requires the use of calibrated equipment to ensure accuracy in all field tests. Professionals must ensure that density is accurately determined using methods like the mud balance or pressurized mud balance, accounting for temperature effects. Key provisions include standardized procedures for measuring viscosity and gel strength using direct-indicating viscometers to assess fluid rheology. The standard also mandates methods for determining static filtration properties, including fluid loss and filter cake characteristics, under simulated downhole conditions. Furthermore, comprehensive procedures for evaluating the volumetric and gravimetric composition of NAF, including oil, water, and solids content, are outlined.

Related Standards & References

API RP 13B-2 works in conjunction with other essential API standards. API RP 13B-1 provides the complementary framework for field testing water-based drilling fluids. Additionally, API RP 13J (Drilling Fluid Processing and Equipment) and API RP 13C (Drilling Fluid Materials) offer supporting information on equipment and material specifications, respectively, which are crucial for understanding the context and application of the testing procedures outlined in RP 13B-2.