Case Study: UBCTD That Enables Real-Time Decision Making

This blog focuses on the capabilities of Underbalanced Coiled Tubing Drilling (UBCTD) demonstrated in a project led by AnTech in the Texas Panhandle. The project was a two well re-entry campaign, aimed to intercept fractures and access untapped reserves to boost production. Underbalanced drilling was performed  to prevent overbalanced conditions that can have a significant impact on production. A stable underbalanced system allows reservoir characterization while drilling and it is especially important when working with a two-phase fluid.

The wells under consideration were gas producers with condensate and water also being produced. The areas of particular concern were the stability of the build section in the overburden above the pay zone and the risk of hitting water-bearing fractures in the horizontal section within the reservoir. For these reasons, a great deal of time and effort was given to planning the operation in order to drill the wells as planned to avoid any surprises and mitigating challenges. An expandable liner was kept on standby as a contingency for the wellbore stability and inflatable plugs were made available in case of hitting waters.

The parties involved in the project were:

  • the Directional Drilling company (AnTech),
  • the Coiled Tubing service provider (Halliburton),
  • the flow back provider (ADA)
  • and the Operator (Winright Resources)

The role of aggregating the data from all parties involved was also taken by AnTech, by deploying digital technologies in the form of wellsite data acquisition and office support for data analysis and downhole sensors. This allowed all parties to have a complete picture of what was happening in real-time on the wellsite and the speed of decision making could thus be improved.

A workover unit was used to pull the tubing out and carry out the casing exit operation in both wells. The first well was then entirely side-tracked with Coiled Tubing Drilling. The build section of the second well was instead drilled and cased conventionally due to wellbore instability caused by shale intervals; the horizontal lateral was then drilled with Coiled Tubing. This project is a good example of the importance of thinking of an UBCTD campaign as a whole, in which the Return on Investment (ROI) was maximised by using the technologies where they were best suited.

AnTech’s gyro technology was used to pass through the window in the first well. It provided Gyro While Drilling (GWD) capabilities and was used to take a survey and orient the bent housing motor to pass through the window. The technology is incorporated in the BHA in order to assist with passing through windows without getting stuck and for dealing with inaccurate magnetic surveys when close to the existing casing.

Productive fractures and faults were identified by utilising RockSense in combination with production data. The well proved productive until a water bearing fracture was intercepted. It was decided to stop drilling and run two inflatable plugs to seal off the water bearing fracture. RockSense identified the exact location of the fracture in order to set the plugs as close as possible.

The project showed that UBCTD, combined with aggregation of digital surface data, can be run successfully in the challenging US land environment. It also validated the technology and provided a proof of concept to be taken forward to the Operator’s future projects.

The combination of technologies deployed gave four key benefits to the operation. It enabled the wells to be drilled with zero formation damage. It enabled the use of RockSense which meant real-time information on fractures. It enabled real-time data aggregation and therefore real-time decision making. It enabled live well testing and therefore removed the delays inherent in gathering data and analysing it off site before proceeding.

Author: Matteo Gemignani

Read more

How To Achieve Step-By-Step Energy Transition
Read More
AnTech
Case Study: Longest Lateral Drilled in 24hrs on the North Slope using at-balance CTD
Read More
AnTech
Case Study: Coiled Tubing Drilling, Kuparuk Oilfield, North Slope Alaska (SPE 168250)​
Read More
AnTech
Case Study: Western Australia UBCTD Project That Boosts Oil Production
Read More
AnTech
Benefits Of Underbalanced Coiled Tubing Drilling
Read More
AnTech
Coiled Tubing String Retirement​
Read More
AnTech
Coiled Tubing: Repeated Bend Cycling And Microcracks​
Read More
AnTech
Understanding Coiled Tubing Fatigue Damage And Its Influencing Factors​
Read More
AnTech
Underbalanced Coiled Tubing Drilling in Tight Sandstone Case Study: Part Two​
Read More
AnTech
Underbalanced Coiled Tubing Drilling in Tight Sandstone Case Study: Part One
Read More
AnTech
Underbalanced Offshore Coiled Tubing Drilling Case Study: Part Three
Read More
AnTech
Underbalanced Offshore Coiled Tubing Drilling Case Study: Part Two​
Read More
AnTech
Underbalanced Offshore Coiled Tubing Drilling Case Study: Part One
Read More
AnTech
Possible use of Tractors for Coiled Tubing Drilling
Read More
AnTech
Cryogenic vs Membrane Nitrogen in CT Applications: The Big Picture
Read More
AnTech
Casing Exits For Coiled Tubing Drilling Operations
Read More
AnTech
Real-time, at-bit Geosteering for Coiled Tubing Drilling​
Read More
AnTech
Find Your Reason Why: Well Selection For UBCTD​
Read More
AnTech
What Is An Orienter?​
Read More
AnTech
Convert Your CT Unit To E-Coil​
Read More
AnTech
Reservoir Characterisation While Drilling Underbalanced​
Read More
AnTech
The Importance Of A Gyro In A Coiled Tubing Drilling BHA
Read More
AnTech
Modelling And Visualisation Of Drilling A Horizontal Well​
Read More
AnTech
Exploring The Mechanism Of Coiled Tubing Lock-Up
Read More
AnTech
Exploring The Mechanism Of Coiled Tubing Lock-UpExploring The Mechanism Of Coiled Tubing Lock-Up
Read More
AnTech
Applications For Coiled Tubing Drilling​
Read More
AnTech
Horizontal Directional Drilling: What's The Benefit?
Read More
AnTech
Why A Gyro System Is So Important For Horizontal Directional Drilling​
Read More
AnTech
Lesson 101: Setting Up And Operating A Test Facility For HPHT Equipment​
Read More
AnTech
The Importance Of Near Bit Sensors For Coiled Tubing Drilling​
Read More
AnTech
How To Drill An Openhole Sidetrack With Coiled Tubing Drilling
Read More
AnTech
Combating Lost Circulation Using Underbalanced Drilling & CTD​
Read More
AnTech
How Do You Drill A Directional Well With Coiled Tubing?​
Read More
AnTech
Why A Milling Monitoring Tool Is A Good Friend To Have On Plug Mill-Out Operations​
Read More
AnTech
How To Drill Faster With Coiled Tubing​
Read More
AnTech
Introduction to CTD Wellbore Hydraulic Modelling - Part Two​
Read More
AnTech
Selecting a Coiled Tubing Unit for CTD: Part Two
Read More
AnTech
Selecting a Coiled Tubing Unit for CTD: Part One
Read More
AnTech
Introduction To CTD Wellbore Hydraulic Modelling - Part One
Read More
AnTech
How Computational Modelling Contributes To Planning A Successful CTD Campaign
Read More
AnTech
Jointed Pipe Versus Coiled Tubing Underbalanced Drilling​
Read More
AnTech
Ben​efits Of Drilling A Straight Hole With Coiled Tubing Drilling​
Read More
AnTech
Leading The Way - Quality Control Of Directional Measurements
Read More
AnTech
Why A Downhole WOB Sensor Is So Important When Drilling With CT
Read More
AnTech
What Is Underbalanced Drilling & How Does It Work?
Read More
AnTech

Search