Pressure Control Equipment

Pressure Control Equipment Selection Guide

Understanding the role and capabilities of each pressure control component helps ensure safe and efficient well intervention operations.

Product Comparison Overview

Component	Wireline Valves	Grease Head	Lubricator	Pump-In Sub
Primary Function	Pressure isolation	Dynamic sealing	Containment	Flow control
Position in Stack	Below lubricator	Top of stack	Middle section	Variable
Max Pressure	10,000 PSI	15,000 PSI	Varies by size	High pressure
Configurations	Single/Dual/Triple	Standard	Modular sections	Standard
Key Benefit	Redundant safety	Moving line seal	Pressure barrier	Rapid control

Understanding Pressure Control Stack Configuration

Typical Stack Assembly

Top to Bottom Configuration

A complete pressure control stack for wireline operations typically consists of components assembled in a specific order to ensure maximum safety and operational efficiency:

• Grease Injection Control Head — Top position, creates dynamic seal around moving line
• Lubricator Sections — Modular sections providing tool storage and pressure containment
• Pump-In Sub — Flow control and pressure management access point
• Wireline Valves — Primary pressure isolation, configured based on well pressure and risk

Selecting the Right Wireline Valve Configuration

Single vs. Dual vs. Triple Body

Single Wireline Valve: Ideal for low to medium-pressure wells (typically under 3,000 PSI) where a single sealing barrier provides adequate safety. Cost-effective solution for routine interventions with lower risk profiles.

Dual Wireline Valve: Recommended for high-pressure operations (3,000-7,000 PSI) and critical well interventions. Two independent rams provide redundancy and enhanced safety, essential for deep wells and offshore drilling operations.

Triple Wireline Valve: Maximum safety configuration for extreme high-pressure wells (7,000+ PSI), sour gas environments, or operations with severe consequences of failure. Three sets of rams offer triple redundancy for the most demanding applications.

Operational Best Practices

Pre-Operation Inspection

Critical Safety Checks

• Wireline Valve Function Test — Verify ram operation (manual or hydraulic) before rigging up
• Grease Head Inspection — Check flow tubes, seals, and grease pump operation
• Lubricator Integrity — Inspect hand unions, threads, and pressure test assemblies
• Pump-In Sub Verification — Test ball valve operation and check union connections
• Pressure Testing — Conduct low and high-pressure tests per operational procedures

Grease Injection Control Head Operation

Maintaining Effective Seal

Proper grease head operation requires maintaining grease injection pressure above well pressure at all times during line movement. Monitor grease consumption rates and adjust pump pressure as needed. Excessive grease usage may indicate flow tube wear or improper line size matching.

Lubricator Sizing Considerations

Calculating Required Length

Lubricator length must accommodate the longest tool string plus a safety margin (typically 3-5 feet). For standard slickline operations, calculate: (Longest Tool Length) + (Safety Margin) = Total Lubricator Length. Use 8-foot or 10-foot sections to build the required total length.

Maintenance and Service

Wireline Valve Servicing

Redress Procedures

Wireline valves should be redressed between jobs or after every 30 days of continuous use. Service kits include rams, seals, and wear components. Inspect ram faces for scoring or wear, replace seals showing any deterioration, and pressure test to working pressure after redress.

Grease Head Maintenance

Flow Tube Replacement

Flow tubes require periodic replacement based on line wear patterns. Solid flow tubes typically last longer than concentric designs but may require more frequent grease pumping. Inspect tubes for internal scoring during routine maintenance intervals.

Lubricator Care

Thread and Seal Inspection

• Inspect ACME threads for damage or wear after each job
• Replace O-rings showing compression set or surface damage
• Clean threads thoroughly and apply appropriate thread compound
• Torque hand unions to manufacturer specifications
• Pressure test assembled lubricator stack before each operation

Safety Considerations

Pressure Control Hierarchy

Multiple Barriers Principle

Always maintain at least two independent barriers between wellbore pressure and atmosphere. The grease head serves as the primary barrier during line movement, while wireline valves provide secondary and tertiary barriers. Never rely on a single barrier for well control.

Emergency Procedures

Loss of Primary Barrier

If grease head seal fails (indicated by fluid/gas escape around line), immediately stop line movement and close the uppermost wireline valve. Do not attempt to pull tools through a closed valve. Relieve well pressure above the closed valve before troubleshooting the grease head failure.

Industry Applications

Onshore Vertical Wells

Standard Configuration

Typical onshore vertical well setups use 3" or 4 1/16" equipment with dual wireline valves for wells above 3,000 PSI. Single valve configurations are common in mature, low-pressure fields where wellhead pressures are below 1,500 PSI.

Offshore and Deepwater Operations

Enhanced Safety Requirements

Offshore operations typically mandate triple wireline valve configurations regardless of wellhead pressure due to the severe consequences of well control incidents. 5 1/8" equipment is common for larger bore completions and subsea trees with significant back-pressure.

Horizontal and Unconventional Wells

High-Pressure Considerations

Unconventional wells with high-volume hydraulic fracturing often experience high wellhead pressures during flowback and production. Dual or triple valve configurations rated for 10,000 PSI are standard, with 4 1/16" or 5 1/8" equipment to accommodate larger tool strings and plug setting equipment.