A Lease Automatic Custody Transfer (LACT) unit is a crucial system to include when measuring the volume of crude oil and petroleum products as they are transferred from the production site to trucks, pipelines, or storage tanks. Necessary for generating revenue from a production facility, these units are installed on lease stock tank outlets, and offer the chance to automate measurement as little or as much as each company desires. A critical component to LACT units is the Micro Motion flowmeter which provides reliable and highly accurate measurements of the transferred product.

How LACT Units Work

A charge pump generates flow through a LACT unit, while centrifugal pumps provide smooth flow output. Sediment and water (S&W) monitors measure the dielectric constant of the flowing fluid to determine if the flowing crude oil is merchantable–that it has an S&W content below (typically) 0.5% of volume. Appropriate inlets divert oil that does not meet standards while continuing the flow of merchantable oil through to the Micro Motion® ELITE® Series sales flowmeter.

Operating LACT Units

The LACT unit begins to operate once a lease stock tank level has reached a normal high level setting, and stops once the tank has reached a normal low level setting. Manual start and stop commands can be used to control a LACT when no gathering pipeline exists and product is pumped into a gathering truck trailer instead.

Typically, these units operate on a set contract run period, sometimes monthly or per truck load. Measurement tickets are generated at the end of the run period using Net Standard Volume calculations. These tickets are based on several different inputs:

  • Reading the meter opening/closing sales volume
  • Recording temperature flow-weighted average (TWA)
  • Determining the average API Gravity (ρb )
  • S&W content from the composite sample analysis

LACT unit functionality can automate calculations in order to generate measurement tickets, delivering the information on-site or to a remote location. This provides an audit trail for easy reference and enables adherence to API MPMS 21.2 requirements.

The heart of the comprehensive LACT unit performance is the measurement, as the flowmeter delivers essential accuracy for the custody transfer process. Micro Motion leverages its extensive experience and thorough knowledge of high level processing automation—our specialty—to perfect a system that ensures highly accurate measurement. Experience incredibly precise custody transfer measurement utilizing the unparalleled technology of Micro Motion Coriolis flowmeters.

Learn more about lease automatic custody transfer (LACT) units in this white paper.