The use of integrity reliability science is becoming a prevalent element in the pipeline integrity management process. One of the key elements in this process is defining what integrity reliability targets to achieve in order to maintain the safety of the system. IPC2016-64425 presented different industry approaches around the area of defining reliability target levels for pipelines. It discussed the importance of setting operators’ specific integrity target reliability levels, how to choose such targets, and how to determine the safety of a pipeline asset by comparing the probability of failure (PoF) against an integrity permissible probability of failure (PoFp) while keeping an eye on the estimated expected number of failures. Building upon the previous discussion, this paper reviews a risk-based approach for estimating integrity reliability targets that account for the consequence of a potential release. Given available technical publications, the as low as reasonably practicable (ALARP) concept, and operators’ specific risk tolerances, there is room for improving the communication of integrity reliability along with selected targets. The paper describes how codes, standards, and operators set reliability targets, how operator specific targets can be chosen, and how industry currently recommends liquid pipelines reliability targets. Moreover, the paper proposes different approaches to define practical reliability targets coupled with an integrity risk-informed decision making framework.

Integrity reliability analysis is becoming an important component of effective pipeline integrity management systems. It aims at utilizing reliability engineering to address integrity uncertainties and check pipeline reliability measures against safety objectives/targets. In current practice, pipeline safety is typically verified using simplified deterministic procedures based on a safety factor approach that is tailored to the design of new pipes. A more realistic verification of actual safety performance of existing pipelines can be achieved by probabilistic methods where uncertainties of basic random variables are considered and the impact on the reliability of the system is analyzed. To enable such an approach, specification of integrity target reliability levels is required in order to benchmark the safety level of an existing pipeline system. The probability of failure (PoF) per pipeline segment or unit length is quantified and then checked against an integrity permissible probability of failure (PoFp) or integrity target reliability (1-PoFp). This check against a specified reliability target allows the operator to confidently determine whether a segment of pipe is safe at current operating conditions while considering identified uncertainties. However, the main challenge around reliability targets is choosing such targets to begin with. This paper presents a semi-quantitative validation approach for estimating integrity reliability targets based on calibrating past failure incidents and evaluating PoF at the time of failure. Accounting for both aleatory and epistemic uncertainties in assigning the integrity targets, pipeline operators can gauge how to choose such targets and how to be flexible in terms of customizing integrity targets based on their asset performance and adopted integrity programs. A brief summary of published reliability targets in pipeline and non-pipeline industries is presented herein.

While North American pipeline integrity codes and regulations provide substantive prescriptive or goal setting objectives, there currently is not a consistent measurement approach for defining the levels of safety achieved. Standardized targets would drive consistent operator safety culture, enhance transparency for the public, and focus industry collaboration on technologies and innovation. This paper provides the perspective of an operator on current status of where the pipeline industry is related to safety targets and social license in addition to where the pipeline industry could go in this arena. The intent is a ‘call to action’ for the leaders in the pipeline industry to collaborate on the establishment of the technical systems which define the current industry safety condition, the targets that must be achieved, and to show that the industry is innovating for further improvements; elements considered to be important to the achievement of social license. A review of the current practices as well as a framework for industry advancement and advocacy will be explained. This will include an examination of safety measurement systems from around the world including other notable industries such as aviation and nuclear. Several measurement models will be highlighted including qualitative, semi-quantitative and quantitative. Importantly, this paper will highlight how operators, regulators, and codes organizations can link together for this common purpose and contribute to “social license”.

This paper describes the integrity management framework utilized within the Enbridge Liquids Pipelines Integrity Management Program. The role of the framework is to provide the high-level structure used by the company to prepare and demonstrate integrity safety decisions relative to mainline pipelines, and facility piping segments where applicable. The scope is directed to corrosion, cracking, and deformation threats and all variants within those broad categories. The basis for the framework centers on the use of a safety case to provide evidence that the risks affecting the system have been effectively mitigated. A ‘safety case’, for the purposes of this methodology is defined as a structured argument demonstrating that the evidence is sufficient to show that the system is safe.[1] The decision model brings together the aspects of data integration and determination of maintenance timing; execution of prevention, monitoring, and mitigation; confirmation that the execution has met reliability targets; application of additional steps if targets are not met; and then the collation of the results into an engineering assessment of the program effectiveness (safety case). Once the program is complete, continuous improvement is built into the next program through the incorporation of research and development solutions, lessons learned, and improvements to processes. On the basis of a wide range of experiences, investigations and research, it was concluded that there are combinations of monitoring and mitigation methods required in an integrity program to effectively manage integrity threats. A safety case approach ultimately provides the structure for measuring the effectiveness of integrity monitoring and mitigation efforts, and the methodology to assess whether a pipeline is sufficiently safe with targets for continuous improvement. Hence, the need for the safety case is to provide transparent, quantitative integrity program performance results which are continually improved upon through ongoing revalidations and improvement to the methods utilized. This enables risk reduction, better stakeholder awareness, focused innovation, opportunities for industry information sharing along with other benefits.

It has been established that rate of penetration (ROP) is directly related to rotational speed (RPM) of the drill bit in most formations. The Wembley area of northwest Alberta shows a proportionate increase in drilling rate with increases in rotary speed. Pan Canadian Petroleum Ltd. (PCP) optimized bit RPM by supplementing the rig's rotary capability with downhole motors. This paper will summarize the results of using downhole motors to Increase penetration rates in the Wembley field and will provide the drilling plan which PanCanadian uses to optimize vertical drilling with downhole motors. Introduction The relationship for soft and medium soft formations, between rate of penetration and rotational speed has been established as(1): (1) R = KWN a where: R = Rate of penetration K = Lithology factor N = Rotary speed W = Weight on bit a = exponent (equal to 1 for Wembley) For Wembley area this equation may be reduced to: (2) R = constant ( N ) Although the constant includes the bit weight, which is a variable, by drill off tests and manufacturer's recommendations bit weight has been optimized at a relatively constant value between 18 000 and 20 000 daN. Equation (2) suggests the rate of penetration can be enhanced through rotary speed increases. Factors which place an upper limit on rotary speed include:Drill string limitations.Drilling rig limitations on rotary speed.Drill bit limitations.Mechanical hole erosion.Casing wear. Drill string limitations include resonant vibration, joint strength, wear due to erosion and cyclic bending fatigue. Contractors limit rotary speed to 150 RPM or less and will not warrant the operational integrity of the string at higher rotary speeds. An excellent reference paper has been prepared by D. Dareing of Maurer Engineering Inc. (Ref. SPE 11228). Therefore most conventional drilling rigs are limited to rotary speeds of 150 RPM. Chain drive rotary tables are in common use and are usually coupled from the drawworks power take-off directly to the rotary drive pinion. Due to substructure space limitations it is not often possible to include a transmission on the rotary table. Chain sprockets also tend to be fixed by rotary torque requirements and chain speed limits. Torque tubes and electric drive rotaries have added flexibility to available RPM but these systems are not always available. Retrofit on existing rigs cannot be economically justified unless a long-term rig commitment is possible. Drill bit manufacturer's suggest RPM limits for their products but recent developments in premium sealed bearings have allowed greater flexibility. Also, insert bits have been improved in the bonding of carbide teeth to the cone matrix, allowing higher rotary speeds. Casing wear is a concern to all operators and, in some cases, optimum drilling performance has been sacrificed to limit wear. Non-rotating stabilizers have been used successfully but, again, stabilizer wear increases substantially when the drill string is rotated above 100 RPM.