BaraXcel™ system helps operator drill high over balance interval without incident
Download PDFDeliver stable wellbore through depleted formation at high overbalance
Middle East
Unconventional Drilling
A Middle East operator planned to drill a horizontal section through dolomitic limestone and complete the well with a multi-stage fracturing (MSF) operation. The MSF completion previously presented operational problems including stuck pipe, tight spots, and washouts. The fluid density was determined by wellbore stability requirements while drilling in the direction of minimum horizontal stress. The target mud weight resulted in a static overbalance of 3,406 psi. The operator required specific targets on fluid rheology, gel strengths, and tight filtration characteristics. Fluid stability was imperative due to the lengthy static periods expected for logging and running the MSF completion in a 315°F reservoir.
The operator planned to drill a deep gas well with a long horizontal section through depleted dolomitic limestone. The high overbalance and high bottom hole temperature presented risk to the operation. The operator had experienced differential sticking on offset wells during the drilling phase and while running the MSF completion.
The Halliburton team developed a robust laboratory test protocol to qualify a fluid system suitable for the application. BaraXcel™ non-aqueous fluids (NAF) was considered the most suitable fluid technology based on its stability and track record with the operator.
The required rheology and tight filtration characteristics of the BaraXcel NAF were developed with the inclusion of FACTANT™ and LIQUITONE® additives in the formulation. The operator approved the proposed BaraXcel formulation based on the qualification testing.
Savings achieved by avoiding conditioning trip
Degrees Fahrenheit reservoir temperature
Hours saved for well conditioning trip
The BaraXcel NAF was deployed successfully with a notable improvement in HPHT and particle plugging apparatus filtration compared to formulations that had been used on offset wells. The BaraXcel system remained stable through the drilling phase, meeting the required target properties. Challenges with the logging tools resulted in an extended static phase for the fluid of 128 hours. The operator canceled a planned conditioning trip as the hole conditions were satisfactory and BaraXcel NAF had exhibited stable properties for an extended period at high temperatures. The MSF completion was set in one run per customer expectations.
