NEW ADDITION
Larry Burleson has joined BE as Director of Business Development in November 2015. Larry was one of the early hires for Joe Bowden at Wild Well Control and has spent over 30 years of his career working for well control service providers. He has extensive experience with IOC, NOC, independents, gas storage operators and drilling contractors.
THE HOT ZONE
Spring 2016
THE HOT ZONE is a semi-annual newsletter from Blowout Engineers. Blowout Engineers is the well control division of Sierra Hamilton and provides the full scope of well control engineering, capping and well kill services to clients worldwide.
The newsletter is a compilation of technical well control information for Sierra Hamilton's clients and consultants. The focus of THE HOT ZONE is non-conventional well control topics.
This edition contains information on the following: • Article comparing kick computer
simulations to hand calculations • Article regarding well integrity
Larry has worked worldwide on well control intervention projects and has spoken at numerous industry forums.
Larry can best be reached on his cell phone at 1.713.410.3984 or his email at
What's New?
Here's what's happening at Blowout Engineers. • Recent projects include the following.
o UGBO intervention in West TX.
o Gas storage capping and dynamic kill contingency planning in France.
o Speech on Well Control Trends at SPE Drilling Symposium in Houston, TX.
o Well control orientation program development for major US workover rig service provider.
o Contingency planning for H2S injection well in NM.
o Expert witness work for blowout in Canada.
o Real-time kick simulation during kick circulation for drilling operation in NM.
o Shallow Water Source Control committee.
o Industry Steering Committee on Wellbore Survey Accuracy (ISCWSA) ebook committee.
Well Control Reference Guide
BE has developed a Well Control Reference Guide. The guide contains calculations, narrative and "rules of thumb" for a variety of well control topics.
The guide is available as a PDF download at www.blowoutengineers.com or the Blowout Engineers page www.sierra-hamliton.com. . A hard copy (tally book insert) version will also be available this summer 2016. The mobile device app version is also currently being developed. For more information please contact
Dan Eby at 832.702.6945 Jace Larrison at 713.715.8218 Larry Burleson 713.410.3984
Toll Free Emergency Number
WELL CONTROL KICK MODELING
Well control modeling has seen significant improvement in recent years with the introduction of multiphase flow simulators. These tools, when coupled with experience, can be very useful to the drilling engineer when planning a wellbore, or even during a well control event to plan a well control remediation operation. The techniques used in the past have referenced the consideration of a "single bubble" within the wellbore. This consideration makes the calculation process for pressure predictions more feasible to hand calculations or spreadsheets. This calculation method simplifies the scenario and makes some basic assumptions to facilitate the calculation process. However, this is often not a true reflection of what has occurred within the wellbore, and therefore can result in poor predictions of what is actually witnessed at the wellsite.
This document provides a comparison of the modern multiphase modeling with the previously published techniques involving the use of the single bubble concept. Personnel at the wellsite are the frontline of defense for well control. This discussion provides rig personnel with insight into the pressure reactions during a well control event. This comparison can also provide the drilling engineer with a better understanding of the pressure responses during a kick.
In many cases, decisions are made based on the divergence of "expected" pressure reactions from what actually occurs at the well. Therefore, it is necessary to understand how the single bubble theory compares with the modern well control simulations in order to have a clear understanding of what to expect when circulating out a kick. Well control flow simulators are designed to provide a more realistic expectation of pressure response than the simple single bubble theory techniques.
A summary comparison between transient simulations and single bubble calculations for various kick sizes is as follows:
• The casing pressure peak in the simulations occurred before the predicted peak with the single bubble predictions. This is likely due to the time factor and the fact that the simulator accounts for migration of the gas during the simulation.
• The peak casing pressure was less with the simulations than with the single bubble. This was true with WBM and OBM systems. This is likely due to the gas bubble getting "strung out" due to migration during the circulation.
• The kick reaches the surface sooner than expected in the simulations when compared to the single bubble calculations. This holds true for all of the cases examined so this should be expected by rig personnel.
• The simulated kicks in an OBM provided a lower resultant casing pressure than in WBM. This is likely due to solubility of the gas in OBM which is considered in the simulation.
• When the transient (time) component is added to the system, simplified calculations like the single bubble predictions diverge significantly from the software predictions.
• The uncorrected single bubble calculations are very conservative when compared to the software simulations.
It should be noted that the simulations are sensitive to time, much like actual events. This is not accounted for the simplified calculations and is likely the cause of the deviations between the two calculation techniques. The simplification assumptions associated with the single bubble calculations limit the accuracy of these techniques, but can still provide a conservative worst-case result for casing pressure.
An example graph for a vertical well to 10,000' TVD demonstrates the differences between the two methods. The wellbore is a "standard" design and the calculations are valid for different conventional wellbore geometries.
The example illustrates the limitations of the single bubble calculations. The intent is not to discredit these calculation techniques, but rather provide a comparison to the current modeling software outputs and establish some deviations in the predicted trends. The comparison provides an expectation of where that deviation may occur on a well control event. This information will allow rig and office personnel to be better prepared to handle a kick and prevent issues with mishandling of well control events.
This example has prompted the need for further studies into the nature of the methods used for kick modeling and predications. For additional details, please reference a more comprehensive paper with additional examples on the Blowout Engineers website, www.blowoutengineers.com,or the Blowout Engineers LinkedIn page. Further topics to be examined will be the effects of a horizontal section on the simulations as compared to the single bubble calculations. This is likely to be of significant interest as many of the wells drilled in the continental US have a lateral section. Continue to check the website for further papers in this series and additional topics.
WELL INTEGRITY
The data for the number of wells in the US varies depending on the source. The US Energy Information Agency reports that over 500,000 oil wells (as of 2011) and over 500,000 gas wells (as of 2014) are in some state of use in the US. These are the active wells. Estimates show the total number of wells as high as more than 1.5 million. Regardless of the actual number of wells, it is easy to conclude that there are a significant amount of wells that need to be maintained and monitored for well integrity issues.
NOROSK D-010 defines well integrity as "Application of technical, operational, and organizational solutions to reduce risk of uncontrolled release of formation fluids throughout the life cycle of a well."
This can be a daunting task that gets little attention due to several factors. • ownership of the well changes
• funds available to address well problems fluctuate depending mostly on the oil price.
• postponed plugging operations due to redirected priorities of personnel and funds
• operational philosophy • unforeseen corrosion issues • environmental impact • unexpected events
Old wells are assumed by many to be prime candidates for well integrity issues. These wells can have serious problems especially where the surrounding area is wet.
Wellhead equipment has evolved to the point where it is extremely robust. There are hundreds of examples of wells that are secure with very suspect wellheads. In fact, the casing strings usually fail long before the wellhead does.
Orphaned wells are prime candidates for a barrier failure. Many operators have inherited these wells sometimes without their knowledge until a well control problem is discovered. A review of all wells drilled in the area is prudent whenever ownership of a field asset takes changes hands.
Well integrity can also be a problem in new wells. Well construction problems have resulted in numerous well control events. The most common issue relates in some way to cementing. Lost circulation during cement jobs can lead to annular pressure and can expose the casing to corrosive water sands. Unfortunately the best repair for these situations is perforating and squeezing (or circulating) cement. This is usually not the choice when the casing is used for production.
Production operations problems such as gas lift leakage, water and/or CO2injection and induced annular pressure have resulted in
serious blowout events. These factors can also affect even affect new wells being drilled nearby. There are numerous tools available for diagnosing well integrity issues.
• Structured risk and assessment management firms • Computer programs for identifying and tracking well assets • Risk assessment for wells with suspected integrity issues
None of this is new to most people involved in daily oilfield operations.So what can be learned?Here are three takeaways to consider: • Well integrity is not usually an issue that is forefront until there is a known barrier failure.
• Well integrity problems that result in well control events are usually due to casing being corroded (near surface or downhole). • New wells can have integrity issues due to problems experienced during drilling and/or completion operations.
CONTACTS
1.888.505.6346
These contacts act as First Responders to a well control event and can be reached 24 hr/day for any type of well control emergency. Houston, TX. Dan Eby [email protected] 832.702.6945 Jace Larrison [email protected] 713.715.8218 Brendyn Emerson [email protected] 386.283.3291 Larry Burleson [email protected] 713.410.3984 Blake Patton [email protected] 713.956.0956 Rick Daab [email protected] 713.956.0956 Lafayette. LA. Al Bellaire [email protected] 337.984.2603 Midland, TX. Russ Ginanni [email protected] 432.425.7450
Oklahoma City, OK.
Josh Bradley [email protected] 405.843.5566 Denver, CO. Steve Biggs [email protected] 303.709.4035 Morgantown, W.V. Mike Reel [email protected] 304.629.8053
BLOWOUT ENGINEERS
Blowout Engineers provides operators the full complement of well control engineering and services.
• Blowout Control
• Well Control Project Management • Relief Well Design and Execution • Underground Blowouts
• Pressure Control • Special Services
• Well Integrity Assessments
• Dynamic Kill Modeling and Execution • Kick and Kill Modeling
• Emergency Response Plans • Rig Well Control System Audits • Expert Witness
Blowout Engineers personnel have worked in over 40 countries and have a wide range of experience in addition to blowout control operations.
www.blowoutengineers.com
SIERRA HAMILTON
Sierra Hamilton is one of the largest providers of outsourced engineering, technology solutions and on-site supervision services to the oil and gas industry. But Sierra Hamilton is about more than size. We're about the extraordinary talent of our people. We have a highly experienced and well-established base of independent consultants. In the last five years, we have provided consultants for more than 15,000 drilling and completion jobs and more than 3,000 hydraulic fracturing jobs. We work with most of the large multinational oil & gas corporations and independent E&P firms and specialize in helping them reduce their fixed operating costs. We do this by leveraging the most highly skilled and experienced independent consultants in the industry.
