We are the missing link between rig heave and conditions downhole. Our proprietary simulation technology predicts variations in downhole pressure and flow, induced by rig heave during drilling and completion operations carried out from floating rigs. This helps managing risks related to breaching well pressure margins or damaging downhole tools as well as reduces weather-related non-productive time (WOW).

Read about our surge & swab simulation services


Our field-proven simulation technology has been utilized by operator companies worldwide. We can provide accurate rig heave limits throughout your well when drilling and/or installing liners, casings and completions. You will know exactly how much rig heave your well can take at all depths and for all operations. We can also calculate maximum recommended speed (RIH/POOH) for uncompensated tripping. Click here to see how our clients saved up to $1,000,000 investing only around $50,000 in simulations during well planning.


Reduce costs by tripping faster (optimized tripping speed throughout the well)


Reduce Waiting On Weather (WOW) by optimizing heave limits based on properties of YOUR well


Manage risk through early warning possible breach of well pressure margins


Safer drilling operations with less emissions



When the drill pipe is put in slips during break-out or connection of the next stand, the topside heave compensation of the drill string is disabled. The whole drill string starts to move up and down with the rig. Same thing happens when running liners/casings or installing completions.


When drill string, liner/casing, or completion moves downwards, there is a sudden increase in downhole pressure ("surge"), which can surpass fracture pressure and severely damage the well impairing its future productivity.


When drill string, liner/casing or completion moves upwards, there is a sudden decrease in downhole pressure ("swab"). If downhole pressure falls below the pore pressure hydrocarbons can start flowing into the wellbore. If downhole pressure falls below hole collapse limit the well section can collapse.


Surge & swab induced by rig heave causes annular flow surges. Some tools in the string such as slips/packers are triggered by an increase in annulus flow. Completion string might be set prematurely if the flow limit is exceeded, leading to costly downtime. Other downhole tools might be damaged by excessive annulus flow. Heave limit recommendations, provided by equipment suppliers are usually generic and not tailored to your well.



We are experts at simulating the motion of the bit (and/or the end of the completion string, liner or casing) in relation to rig heave. Using our proprietary surge & swab simulator we perform calculations that take into account downhole surge & swab, pressure margins of your well and completion tool annulus flow limitations. Based on these calculations we come up with a recommendation of how much rig heave your well can take during connections and uncompensated tripping before the margins are breached. We provide customized recommendations for different depths in the well and different operations (drilling, running of liners/casings and installing completions). Our goal is that you know exactly how much rig heave your well can take at all times when heave compensation is disabled (for example during connections).


We are specialists in simulations of downhole pressure and flow and our services are cost-efficient and quick. We have experience with performing a wide range of studies where downhole conditions are in focus, for example operability studies for floating rigs in harsh weather environment based on limits of the wells to be drilled. Get in touch with us to discuss your needs and we will come up with a solution!

Simulations are available now! 

Get in touch with us for an offer



Our simulator is a precise numerical model of the fluid dynamics coupled with the string dynamics. Specific heave time series can be applied as input to simulations, or they can be based on statistical wave data combined with a vessel specific response amplitude operator (RAO).


Flows and pressures inside the string and in the annulus, as well as below the string are dynamically simulated. String stress and velocity are also simulated to include the important effects of elasticity. A Herschel-Bulkley type rheology is used for the fluid, with frictional pressure drop calculations based on API recommended practice. Use of floating fluid inside the string can be configured for simulation of floating liners and casings.


The geometry configuration allows for different cross-sectional flow areas along the pipe and annulus, representing the different sections of a well such as riser, cased sections, liners, and open hole. A 3D well curvature is possible to configure, resulting in changed hydrostatic pressure and additional contact friction between the pipe and well wall/casing.

We get the drilling & well data and agree on the goals of the simulation

We develop timeseries with multiple simulations of downhole pressure variations at selected connection depths (usually 5-10 per well section)

We continuously compare simulated surge & swab pressures with provided well pressure margins and define maximum allowed rig heave that corresponds to surge & swab being equal to the well pressure margins at connection depth in question. To calculate rig heave limit related to maximum allowed flow past completion string packers we use simulated flow in the well induced by rig heave through surge & swab.

We provide a rig heave profile (we call it Dynamic Rig Heave™) through the well sections of interest.

We can also provide recommendations for running speed (RIH/POOH) for drill string, liners/casings and/or completion string. We are able to account for heave effects downhole if your rig is not equipped with active heave compensation of if you trip using elevators.


“No-one is offering a comparable commercial solution today, either for pre-planning or real time”

– Major operator company





Determination of Dynamic Limits for Rig Heave and Running Speed Based on Drilling Parameters, Well Data and Completion Tool Limitations - Case Studies

March 2021

This paper is co-authored by Norske Shell and OMV. We present novel methodology for how to utilize rig heave limit in drilling & well operations and case studies from two wells in Norway.


Presentation at the SPE/IADC Drilling Conference and Exhibition (virtual)

Significant Surge and Swab Offshore Brazil Induced by Rig Heave During Drill Pipe Connections

The paper was presented by John-Morten Godhavn (Equinor). We simulated surge & swab during connections when drilling pre-salt reservoir section of a well on the Bacalhau field. Surge & swab magnitude was comparable to what we earlier recorded in the North Sea at higher rig heave. This can be explained by very long vertical trajectory of the well offering little friction to hold the drill string in place during connections. SPE-200518. The paper was also published in the SPE Drilling & Completion Journal.

October 2020

Presentation at the SPE/IADC MPD Conference and Exhibition (virtual)

Flow Loop Trial of an Autonomous Downhole Choke for Compensation of Rig Heave-Induced Surge & Swab

May 2019

Presentation at the SPE One Day Seminar (Bergen, Norway)

The paper was co-authored by Techni, NTNU and Equinor.


Influence of Well Geometry, Weather Conditions and Rig Type on Surge & Swab During Drill Pipe Connections in the Barents Sea

March 2019

Presentation at the SPE Workshop on Innovative Arctic Technologies (Harstad, Norway)

The paper was co-authored by OMV, Vår Energi, NTNU and Equinor.

Verification of Downhole Choke Technology in a Simulator Using Data from a North Sea Well

March 2019

Presentation at the SPE/IADC Drilling Conference and Exhibition (The Hague, The Netherlands)

the paper was co-authored by NTNU and Equinor. SPE-194143, also published in the SPE Drilling & Completion Journal.

White paper on the HeaveLock™ autonomous downhole tool

August 2018

Published in SPE The First

This paper described the downhole choking concept and its utilization as an enabler for implementation of MPD on floating rigs in harsh weather environment.

Attenuating Heave-Induced Pressure Oscillations using Automated Down-hole Choking

April 2018

Presentation at the SPE/IADC Drilling Conference and Exhibition (Houston, USA)

The paper was co-authored by NTNU, Techni and Equinor. SPE-189657.




Dynamic rig heave limit calculated during well planning and utilized in well operations

OMV 6505/11-10 HADES/IRIS

Dynamic rig heave calculated retrospectively to explore potential savings.


Surge & swab during connections calculated for drilling of an infill well. Simulations validated using MWD data.


Field development project. Surge & swab during connections calculated for drilling and completion of several wells.


Specialized surge & swab calculations used internally in a rig improvement project.


Field development project. Surge & swab during connections calculated for drilling of several wells. Rig operability based on well limits estimated.


Surge & swab during connections calculated for drilling of an exploration well. Simulations validated using MWD data.


Dynamic rig heave limits calculated for running liners and casings on Geographe offshore natural gas field in Otway basin.






Visitor Address: 

Havnegata 7

7010 Trondheim


Postal Address: 

Heavelock Solutions AS

Postboks 1284 Torgard

7462 Trondheim



Tel: +47 481 40 339



  • Hvit Linkedin Ikon

Senior Adviser, Drilling and MPD

Rob has spent more than 30 years working with drilling in service and operator companies across the globe. He specializes in advanced drilling solutions such as UBD, MPD and Coiled Tubing drilling. 


  • Hvit Linkedin Ikon

Senior Adviser, Technology

Thomas graduated with a PhD in Chemical Engineering from NTNU and spent the first 10 yers of his career with Statoil in various positions within R&D and projects. His latest position was CTO in Resman.


  • Hvit Linkedin Ikon

Co-Founder and CEO

MSc in Cybernetics from the NTNU and business studies at BI. More than 10 years of experience within oil & gas projects. Prior to joining Heavelock AS Martin had worked 8 years for Norwegian oilfield service company Reinertsen with maintenance and modifications on the Norwegian Continental Shelf.



  • Hvit Linkedin Ikon

Co-Founder and CTO

PhD in Process Technology and MBA in Technology Management. Background from various technical, project and operational roles with Norske Skog, Reinertsen, BRI Cleanup and Equinor in Norway and abroad. Considerable offshore experience from NCS, South-China Sea and offshore Brasil. 



  • Hvit Linkedin Ikon

Chairman of the board

20 years of experience developing, financing and leading technology companies.  


  • Hvit Linkedin Ikon

Board director

CEO of Techni, one of the largest design & engineering houses in Norway.


  • Hvit Linkedin Ikon

Board director

Professor of cybernetics at NTNU. Expert in drilling control and simulation.


  • Hvit Linkedin Ikon

Board director

Professor of petroleum technology at NTNU. Expert in drilling and petroleum technology. 

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