Hydraulic Fracturing QA QC Indispensable to Delivering Both a Successful and Economic Fracture Program

Abstract

It is well known that close quality assurance and quality control (QA/QC) are of vital importance for the successful placement of any hydraulic fracturing treatment. Many complex pieces of equipment and specialized personnel are involved in the fracturing process, and the following of strict QA/QC standards is mandatory to make these operations successful, efficient and safe. BP Oman is using massive hydraulic fracturing treatments to exploit the challenging tight-gas Barik Formation in the Khazzan and Ghazeer Fields. Each treatment is designed to place 1 million pounds of proppant into this tight, high pressure high temperature reservoir, leaving no space for error. Implementing QA/QC and logistic supply measures begins with the mobilization procedures: chemicals checklist/verification and mixing on the base, timely equipment maintenance, bulk plant proppant delivery to ensure a swift and smooth 24 hour operation. Water delivery management loading quality check, logistics, site acceptance and minimum quality checks are another important procedure related to this preparation. Each fracturing stage requires at least 14,000 bbl of fresh water to be available and quality checked on the site before the start of the fracturing treatments. Intensive QA/QC measures continue through the day of the fracturing treatment itself to ensure the equipment is in full working condition. Assurance that all of the supply systems are properly calibrated, all chemicals loaded and levels physically measured. During the fracture treatment itself all parameters are repeatedly measured and visualized in real time. Fluid viscosity is assessed on the fly and data verified with an HPHT viscosimeter also present on the wellsite. After the treatment, all remaining chemicals are measured once again and carefully assessed against the expected inventory values and material balanced. Implementing extensive QA/QC procedures enabled efficient mobilization between wells with mobilization time as low as 6 days despite the complex equipment and material needs for these massive fracturing treatments. Planned logistics and consistent quality checks before, during and after the treatment enabled BP Oman to successfully place more than 100 hydraulic fracturing stages with the amount of proppant exceeding 1 million pounds per stage. The bar has raised even higher with successful placement of 2 million pounds of proppant, the largest single stage hydraulic fracturing treatment in the Eastern hemisphere at the time of execution.