Assessment and management of abandoned radioactive logging sources in Halfaya oilfield well

Abstract

Each drilling operation has some degree of risk which is related to uncertainty in terms of cost overruns that may affect the feasibility to accomplish well construction operations successfully. In oil and gas wells, drilling operation is considered as most risky and highly associated with health and safety.  Managing drilling risk means; small problems are not allowed to become bigger. Knowing and understanding drilling problems; their causes and solutions are necessary to reduce the overall well cost and reaching the target successfully. All drilling and well operations shall have a risk management process, which will include identification, analysis, response and control. In Halfaya oilfield in southern Iraq, problems occurred in Well HF. The wire line logging tool was stuck in the bottom of the well. Several attempts were unsuccessful to free the wire line logging tool and two radioactive logging sources had to be left in the well due to the deformation in 9⅝ inch casing. The decision to Plug and Abandonment (P&A) Well HF was taken after numerous attempts to retrieve the radioactive logging sources. The results of investigation and analysis showed 9⅝ inch casing deformation was occurred due to salt creeping of Lower Fars formation. In this study, Landmark (Stress Check) software was used for new casing design. It is proposed to change 9⅝ inch casing specifications of Well HF.Re-entering this well by retrieving the lost radioactive logging tools in the hole or to sidetrack and re-drill the well to a new bottom hole location is one of the proposals for this well