Lease Automatic Custody Transfer

Lease automatic custody transfer, abbreviated as LACT, is a system used in the oil and gas industry to accurately measure and transfer the ownership of crude oil or other petroleum products from one party to another.  LACT systems are commonly employed at well sites, production facilities, and pipeline terminals where oil is being transferred from the producer (often referred to as the lessor) to a purchaser or transporter (often referred to as the lessee).

The primary purpose of a LACT system is to ensure that the transfer of oil between parties is both accurate and equitable.  This is important because the value of oil is determined by its quantity and quality, and small discrepancies in measurement can lead to financial disputes.  LACT systems automate the measurement process and provide a reliable record of the volume of oil transferred, reducing the potential for discrepancies and disputes.

Key Points about Lease Automatic Custody Transfer System

Flow Measurement Equipment  -  LACT systems typically use sophisticated flow meters, such as turbine meters or positive displacement meters, to accurately measure the volume of oil being transferred.
Controls and Automation  -  LACT systems are equipped with control mechanisms that ensure consistent and accurate measurement.  These controls regulate the flow rate, monitor the process, and calculate the volume of oil based on the flow meter readings.
Sampling  -  Some LACT systems also include provisions for taking representative samples of the oil being transferred.  These samples can be used to analyze the quality and properties of the oil, which can affect its value.
Data Recording and Communication  -  LACT systems often integrate with data recording and communication systems.  This allows the measured data to be recorded electronically and transmitted to both the lessor and lessee, ensuring transparency and accuracy.
Safety Features  -  Safety measures are an integral part of LACT systems to prevent spills, leaks, and other hazards during the transfer process.

LACT systems help streamline the transfer process, reduce human errors, and ensure compliance with industry regulations.  They are widely used in the oil and gas industry to facilitate fair and efficient transactions between producers and purchasers while maintaining accurate records of the transferred volumes.

Components

Each LACT Unit is different and is typically designed for each application depending on process conditions, gravities and individual companies' specifications and shipping method. However, certain components are common in all LACT units.  From inlet to outlet, the components are listed below.

Cut Probe

A cut probe or oil water detector determines the amount of water in the line.  Depending on the specification of the customer, the amount of water may vary from 1 to 5 percent water.  Before the oil enters the cut probe, it goes through a static mixer to ensure a homogeneous mixture.  

Reject Valve

Downstream of the cut probe, a reject valve determines where the oil goes.  Should the amount of water exceed the predetermined specification, the valve will divert the flow and not allow the fluid to pass through the meter.  From here, the oil may enter a reject tank or back into the LACT tank for further treatment.  

Sampler

Prior to metering, the oil must be sampled to determine the meter factor.  An isokinetic sampler takes sample of the production stream.  Prior to sampling, the oil is again mixed to ensure a homogeneous mixture.  After sampling, the oil is stored in a sample container where the cut is read to determine the average cut during metering.

Meter

After the cut passes through the reject valve, it then goes through the meter.  There are two different types of meters curently in use.  They are a positive displacement or Coriolis Meter.