Cementing in HPHT Gas Environment Using a Novel Flexible And Expandable Cement Technology To Withstand Pressure And Temperature Cycles

Zonal isolation and long-term cement integrity in the high-pressure/high-temperature (HP/HT) environment are critical to optimizing production and minimizing future well intervention and replacement. In addition, the well stresses vary over a large amplitude during construction, testing, and production of such wells. There is, therefore, significant value in avoiding failure of the cement sheath.In 2007, Total E&P Borneo commenced an HP/HT caMPaign in Block B offshore Brunei to drill development wells with deeper exploration sections. These HP/HT wells are the most technically challenging for well cementing in terms of preserving long-term well integrity; these wells are exposed to high temperatures exceeding 165°C, pressures exceeding 69 MPa resulting from different operations, including production. Cementing these wells using conventional cement and practices has proven not to be effective. This leads to the introduction of new technologies and newer cementing techniques to ensure long-term seal of these wells.This study identifies first the risks associated with cement sheath failure under downhole stresses. Then it discusses the successful implementation of a solution that ensures a complete zonal isolation of these HP/HT wells, consequently avoiding unnecessary and costly well intervention.

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Enhancing Zonal Isolation With Expandable Cement System for Gas Field

Tanoto

Kusumawatie

Inayah

et al. 2016

IADC/SPE Asia Pacific Drilling Technology Conference

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HPHT well subjects zonal isolation and long term cement integrity into critical factor to achieve long term production life. Repeated cycles of high differential pressure and temperature tend to break bonding between cement, casing and formation. Microannulus as consequence of debonding will provide space. At gas wells, it will provide space for gas migration which may lead to sustained casing pressure. Providing zonal isolation is also important to ensure there will be no communication between two different formations or reservoirs This paper discusses the design, execution and evaluation of cement technology implemented at 9 5/8-in HPHT intermediate liner. Special softwares were used to simulate gas migration risk and stress analysis to cement sheath. High risk gas migration and microannulus were expected based on sofware results. An expandable cement system was identified as a solution and deployed successfully. In order to achieve better understanding of behaviour of cement slurry at field application, laboratory experiments were performed. To achieve long term cement integrity, it is not only about design of cement slurry, mud removal is one of the key factor need to be considered. Best practices were perfomed to achieve the highest mud removal efficiency. Expansion test was perfomed by using pressure curing chamber at 247°F. Expansion was detected for six days simulation which was considered as enough based on stress analysis simulation of compression, traction and microannulus cement sheath performed. It was indicated that expandable cement managed to eliminate microannulus which was created by pressure and temperature changes. Evaluation was performed by locating pressure sensor at the A annulus of 9 5/8-in liner and 13 3/8-in casing. The sensor indicated zero pressure at the annulus while drilling next two more section and during the production life of the well

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Cementing in HPHT Gas Environment Using a Novel Flexible And Expandable Cement Technology To Withstand Pressure And Temperature Cycles

Cited by 5 publications

References 5 publications

Influence of the initial loaded state on the stress distribution of a wellbore system

Influence of the initial loaded state on the stress distribution of a wellbore system

Ensuring Well Integrity in HP/HT Wells: Brunei Case Study

Enhancing Zonal Isolation With Expandable Cement System for Gas Field

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