A gathering system does not exist in isolation - the gas or liquid it collects eventually has to hand off to a larger transmission line, a processing plant, or a neighboring operator's system. A gathering line interconnect is the physical and commercial point where that handoff happens: a tie-in where one pipeline connects to another, usually built around a meter station because the two operators need an agreed measurement of what crosses between them. This guide explains what an interconnect is, the custody-transfer point it creates, and how flow and pressure at the tie-in are measured and coordinated between the operators on each side.
Gathering Line Interconnect in one line: A gathering line interconnect is the tie-in point where a gathering line connects to another pipeline system - typically a transmission line, a processing plant, or another gathering system - so product can pass from one operator's line into the next. Because ownership and responsibility change at that point, an interconnect is usually built around a meter station that measures the volume crossing, making it a custody-transfer point. Operators on each side coordinate flow, pressure, and measurement at the interconnect so the handoff is accurate and both systems stay within their limits.
An interconnect is where a pipeline stops being one system and becomes part of another. On a gathering system it commonly appears at the downstream end, where the gathered product ties into a larger transmission or trunk line that carries it to market, or into a processing plant that treats it. It can also join two gathering systems, letting one operator move product across into another's network, or create a receipt point where an outside producer's line feeds into the gathering system. In each case the interconnect is the boundary at which product, and responsibility for it, passes from one party to another.
Physically, an interconnect is more than a bare weld between two pipes. It typically includes isolation valves on each side so either operator can shut in the connection independently, check valves or control valves to manage the direction and rate of flow, and the meter station that measures what crosses. Filtration, pressure regulation, and sometimes sampling or gas-quality analysis are added where the receiving system needs the incoming product to meet a specification before it will accept it. The result is a small station in its own right, sitting at the seam between two systems.
Because the point is a boundary of ownership, the interconnect is also where the two operators' commercial agreement takes physical form. The meter reading at the tie-in is the number both sides bill and settle against, and the specifications the receiving system enforces - pressure limits, gas quality, liquid content - are the terms of accepting the product. An interconnect is as much a contractual point as an engineering one.
The meter at an interconnect is doing custody-transfer measurement: it establishes the volume that legally and commercially moves from one party's account to the other's, so it is held to tighter accuracy standards than a meter used only for internal balancing. The measurement chain typically includes a primary element sized and installed to a measurement standard, pressure and temperature compensation, and often gas composition from a sampler or analyzer so the metered volume can be corrected to standard conditions and, for gas, to an energy basis. This is the number that money changes hands over, so its integrity is the point of the whole station.
Many interconnects are bidirectional, meaning product can flow either way depending on which system needs supply and which has surplus. A tie-in between two gathering systems, or between a gathering system and a line that can serve as both an outlet and a source, has to measure flow accurately in both directions, which means the meter and its associated valving are configured to establish custody in whichever direction the product is moving. Getting the direction and the corresponding measurement right is essential, because a volume delivered one day and received back another must both be captured correctly for the two operators' balances to reconcile.
Pressure at the interconnect is the constraint that governs whether flow can happen at all. Product moves from the higher-pressure side to the lower, so the gathering system's operating pressure has to exceed the receiving system's pressure at the tie-in for delivery to occur, and if the receiving line's pressure rises the gathering system may be unable to push into it. Coordinating these pressures - and the regulation that manages them at the station - is part of keeping the interconnect flowing without either system exceeding its own limits.
An interconnect is one of the highest-value points to monitor in real time, because it carries both custody measurement and the pressure interaction between two systems. The essential SCADA signals are the metered flow crossing the tie-in, the pressure on each side, and the position and status of the isolation and control valves. Together these tell an operator not just how much is moving, but whether it can keep moving - a receiving-side pressure creeping up toward the gathering system's delivery pressure is an early sign that flow could back off or stop.
A cloud SCADA such as Merobix brings the interconnect's meter, pressures, and valve states onto one screen and logs them continuously, which serves both the operational and the commercial purpose. Operationally, it lets the gathering operator see a delivery point that is starting to restrict and act before production has to be curtailed upstream. Commercially, the logged, time-stamped meter data at the tie-in is the record that supports settlement and lets discrepancies between the two operators' figures be investigated against a common trail rather than reconstructed after the fact.
Because an interconnect sits between two parties, coordinated visibility matters on both sides. When the delivering and receiving operators can each see the tie-in's flow and pressure in their own SCADA, a change - a nomination that shifts, a downstream restriction, a decision to reverse a bidirectional connection - can be managed cooperatively rather than discovered as a surprise. For a gathering operator running many interconnects across a field, that live picture of every delivery and receipt point is what keeps the whole system balanced and every handoff accurately measured.
In practice they usually coincide, but they are distinct ideas. An interconnect is the physical tie-in where one pipeline system connects to another, while custody transfer is the commercial event of product passing from one party's account to another's. Because ownership changes at most interconnects, they are built around a custody-transfer meter, so the tie-in and the measurement point are the same location - but an interconnect could exist within a single operator's system where no custody changes hands.
A bidirectional interconnect can pass product in either direction depending on which system has surplus and which needs supply. This is common between two gathering systems or between a gathering line and a connection that can act as both an outlet and a source. The meter and valving must establish accurate custody measurement in whichever direction product is flowing, so both delivered and received volumes are captured correctly for the two operators' balances to reconcile.
Product flows from the higher-pressure side to the lower, so the delivering system's pressure at the tie-in must exceed the receiving system's pressure for flow to occur. If the receiving line's pressure rises toward or above the delivering pressure, flow can back off or stop entirely, potentially forcing production to be curtailed upstream. Monitoring pressure on both sides of the interconnect lets operators see a developing restriction early and coordinate before it becomes a shut-in.
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