A step change in the development of real-time pig tracking

Removing the challenges of Pigging by knowing exactly where they are

November 2019 saw the dawn of a new era in real-time pig tracking when Halliburton Pipeline and Process Services successfully validated a live pig tracking method based on patented transient wave theory, the foundation of their unique InnerVue™ suite of services.

A negative pulse InnerVue™ Survey is best described as being similar to a sonar response technique. A controlled hydrodynamic wave is induced into a pressurised pipeline system and the position of a significant flow impairment such as a blockage or pig can be determined by identifying reflexes visible in the recorded data trace. This method is suitable for use in both fluid and gas systems, though the analytical approach for either is very different.

InnerVue ™  - Removing Uncertainty

With a focus on this application in gas systems, it is imperative that the acoustic velocity of the medium being transported in the pipeline is known as accurately as possible. Largely based on ideal gas theory and adiabatic propagation, unrestrained acoustic velocity is calculated and thereafter extrapolated into a restrained velocity profile specific to the pipeline. Characteristics are adjusted to reflect the operating parameters of the pipeline at the time of surveying; flow, pressure, and temperature all impact the density and compressibility of the gas. This has a direct effect on relative bulk modulus and the equivalent speed of sound at any given point in the system, which in turn, in addition to the considerations taken toward the specific shape of the wave generated, render the transit of any pulse within the pipeline as totally unique.

Throughout the latter half of 2019 Halliburton Pipeline and Process Services successfully executed an extensive pipeline precommissioning campaign in the East Mediterranean . During the proceedings a lost pig occurrence prevented completion of the dewatering workscope of an 18” pipeline. Halliburton Pipeline and Process Services were hired by the EPC contractor to carry out an InnerVue™ survey to locate the lost pig. The successfully deployed survey provided critical information necessary to develop a pig recovery plan once discovering that the lost pig was located 16.5km from the platform. Working closely with the EPC and field operator, a reverse pigging operation, involving Halliburton managing a combination of specialist services onshore, offshore and remote deepwater, was conducted to recover the pig.

A foam pig was launched from the deepwater pipeline end and travelled towards the platform over the course of five days. The propellant was nitrogen gas supplied from a membrane spread transferring N2 gas via the twin gathering pipeline and a crossover at the subsea manifold which presented a serious challenge to accurate pig location which traditional methods were not able to overcome.

Pig tracking specific InnerVue™ surveying was performed on board the production platform throughout the reverse pigging operations. In live conditions, pressure waves were transmitted through the system allowing real time monitoring of the now-found-pig location. Once the foam pig reached this location, both pigs in unison began moving towards the platform. Surveying continued throughout and provided a real-time location, speed and estimated time of arrival. Upon pig receipt a final survey was performed to confirm that all pigs had been recovered. The survey results showed that there was still a pig in the line at the subsea isolation valve location, 364m from the platform. Flow resumed until the final pig was received allowing cessation of operations and removal of the temporary topside launcher / receiver.

The next phase of InnerVue™ Live Pig Tracking development is underway. It focuses on a commercialized practical solution deployable as an integrated offering with the flexibility to enhance pigging operations no matter the scenario or stage of the asset life. Halliburton Pipeline and Process Services are proud to bring a step-change in Pig Tracking Technology and confidence to pigging operations throughout the industry.