RAM Study Consultancy: Reliability, Availability and Maintainability Analysis for Oil & Gas

A RAM study quantifies the production availability of an oil and gas facility before a single piece of equipment is procured. iFluids Engineering delivers RAM analysis and RAMS analysis for upstream, midstream, LNG, and refinery projects across India, Qatar, and the Gulf, from early concept through FEED to detailed design.

What Is a RAM Study in Oil and Gas?

A RAM study applies Monte Carlo simulation to a Reliability Block Diagram (RBD) of a production facility, calculating the probability that the system delivers its design output over a defined operating life. ISO 14224 failure rate data and OREDA field statistics feed the model. RAM analysis quantifies production losses, justifies redundancy decisions, and reduces life cycle cost (LCC) from the FEED stage onward.

The three attributes a RAM study measures:

• Reliability (R): The probability that equipment operates without failure for a specified period under defined conditions. Expressed as Mean Time to Failure (MTTF) or Mean Time Between Failures (MTBF).
• Availability (A): The fraction of time the system is in a functional state, accounting for both failure frequency and repair duration. Calculated as: A = MTTF / (MTTF + MTTR), where MTTR is Mean Time To Repair.
• Maintainability (M): The ease and speed with which a failed item is restored to its functional state. Expressed as MTTR and governed by maintenance philosophy, spare parts strategy, and crew mobilisation time.

When Safety is added as a fourth attribute, the study is termed a RAMS analysis.

RAM, RAMS, and the Risk Assessment Matrix: Clearing Up the Acronym

Two completely different tools share the same acronym in oil and gas. A RAM study (Reliability, Availability, Maintainability) is a production performance model. A Risk Assessment Matrix is a qualitative consequence-likelihood grid used in hazard management. They are unrelated. This page covers RAM modelling only. For risk matrix methodology, see iFluids’ process safety management services.

Engineer’s Note The most common mistake iFluids sees in RAM study briefs: clients request a RAM study when their contract actually requires a RAMS analysis (with the Safety attribute). IEC 60300-3-4 defines the distinction. Confirm the contractual deliverable before scoping the study.

Difference between maintainability and availability

The above figure explains the relationship between Reliability (R), Availability (A) and Maintainability (M) and their definition. Maintainability is the function of difficulty and speed where the system remains functional given the occurrences of Failures. Whereas Availability is the function of Time with all inputs provided so that the system remains functional.

From the above figure and the definition, it is clear that a system will perform optimal when these factors are considered into the design and operation of the system. Hence a proper RAM analysis will result in achieving maximum system ability as per its design. As a result a better decision for productivity, service utilization, maintenance and functioning of equipment is implemented.

RAM Analysis vs RAMS Analysis: Scope and Standards

RAM analysis and RAMS analysis share a common Monte Carlo simulation engine but differ in scope, governing standards, and project phase of application. ISO 14224 and OREDA provide the failure rate data for both. IEC 60300-3-4 governs dependability data collection. iFluids delivers both study types, scoped to the contractual requirement and operator specification.

Attribute	RAM Analysis	RAMS Analysis
Reliability	Yes	Yes
Availability	Yes	Yes
Maintainability	Yes	Yes
Safety	No	Yes
Governing Standard	ISO 14224, OREDA, IEC 60300-3-4	Above + IEC 61508 / IEC 61511
Primary Output	Production availability, LCC	Above + Safety Integrity Level input data
Typical Project Phase	Concept, FEED, Detailed Design	FEED, Detailed Design, Pre-commissioning
Common Contractual Driver	Operator engineering specification, lender requirement	Regulatory submission, SIL classification input

Both study types feed directly into  asset integrity management and maintenance planning. Neither replaces a  Quantitative Risk Assessment (QRA), which models major accident hazard frequencies, not production system availability.

RAM Study Methodology: From RBD Construction to Monte Carlo Simulation

A RAM study for a gas compression facility follows a defined sequence: system boundary definition, Reliability Block Diagram construction, failure rate data assignment from ISO 14224 and OREDA, Monte Carlo simulation across 10,000 or more lifecycle runs, and criticality analysis to identify the equipment items driving the greatest production loss. iFluids executes each stage internally, with outputs validated against client engineering specifications before the final report is issued.

Step 1: Define System Boundary and Functional Block Diagram

The study boundary defines which equipment items enter the model and which are excluded. iFluids engineers work from the Process Flow Diagram (PFD) and equipment list to produce a Functional Block Diagram (FBD) showing production-critical systems in series and parallel configuration. Utility systems, flare systems, and non-production-critical items are typically excluded unless the operator specifies otherwise.

Boundary agreement with the client at this stage prevents scope creep and ensures the simulation reflects the actual production architecture, not a conservative abstraction of it.

Step 2: Build the Reliability Block Diagram (RBD)

The RBD translates the FBD into a mathematical model. Each equipment item becomes a block with assigned failure rates and repair times. Series blocks represent systems where any single failure causes a production loss. Parallel blocks represent redundant configurations where one unit can fail without stopping production.

The RBD captures:

• Active and standby redundancy configurations (2×100%, 2×50%, 3×33%, and so on)
• Shared services and single-point failures
• Maintenance bypass arrangements and their impact on effective availability
• Capacity derating scenarios (partial production loss from a degraded but still-running unit)

Step 3: Assign Failure Rate Data (OREDA, ISO 14224, and Plant History)

Failure rate data is the single largest source of uncertainty in a RAM study. Three sources are applied, in order of preference:

1. Plant historical data: Equipment-specific field data from the client’s existing operations. Highest accuracy; available only for brownfield and late-FEED projects.
2. OREDA (Offshore and Onshore Reliability Data): The DNV-managed handbook covering failure rates, failure modes, and repair times for oil and gas equipment across global field operations. The 7th edition (2021) is the current reference.
3. ISO 14224 generic data: Used where OREDA does not cover the specific equipment type or operating context. API 689 provides equivalent U.S.-framework data.

All data sources are documented in the RAM study basis document and agreed with the client before simulation begins. Assumptions about MTTR, crew mobilisation time, and logistics delay (particularly relevant for offshore and remote onshore projects) are stated explicitly.

Step 4: Run Monte Carlo Simulation and Validate Results

Monte Carlo simulation runs the RBD through thousands of randomised lifecycle iterations. Each run assigns failure and repair events to every equipment item according to its statistical distributions. The simulation outputs a probability distribution of system availability across the full operating life, typically expressed as P10, P50, and P90 availability values.

iFluids runs a minimum of 10,000 Monte Carlo iterations per simulation. Sensitivity checks on key assumptions (failure rate, MTTR, redundancy configuration) are run before the final results are presented. Production profile inputs (from well decline curves or process capacity models) are incorporated where the operator provides them, shifting the output from deliverability to production availability.

Step 5: Criticality Analysis and Bottleneck Identification

Criticality analysis ranks every equipment item by its contribution to total production unavailability. The output is a Pareto chart showing which systems and components drive the greatest downtime. This is where RAM analysis earns its project value: the criticality ranking directly informs redundancy decisions, spare parts holdings, maintenance intervals, and inspection priorities.

Compliance Alert FEED-stage RAM studies for LNG and major offshore projects in Qatar (QatarEnergy specification) and India (OISD guidelines) are contractual deliverables, not optional analyses. Lenders financing projects under Equator Principles also require documented production availability studies before financial close. Scope the RAM study at Concept or early FEED; a post-FEED study cannot change the design configuration it is meant to validate.

Method to use RAM in risk assessment:

Apply the RAM correctly and regularly as a common way to communicate and plan for HSE improvement. An Example of Ram Risk Assessment Matrix is shown below.

As a Batch exercise, consider the possible events that would occur and plot those events on the RAM based on its severity and likelihood of occurring. Observe how the risk of the event happening can be minimized through changing how the work occurs or fabricating in additional safeguards.

Evaluating the risk of a specific scenario should be done in chronological order, i.e. first the possible outcomes are guessed and only then the possibility of such events happening are assigned. (A scale of outcomes from 0 to 5 is used to stipulate escalating severity). After evaluating the outcomes, the possibility on the horizontal axis is guessed on the scope of historical confirmation or experience that such outcomes occurred earlier.

Make sure that the Risk Assessment entails people in all disciplines who are involved in the tasks being discussed as they will understand the issue and know which response will work. People responsible for planning activities (i.e Managers and Supervisors) should be included for the changes to happen.

RAM Study Deliverables: What iFluids Provides at Project Close

A RAM study deliverable is a documented, auditable analysis package that supports investment decisions and engineering sign-off. iFluids issues a final RAM study report structured to operator or lender specification, covering methodology, data sources, simulation results, and ranked recommendations. Typical study duration is four to eight weeks from data receipt to final report issue.

The standard iFluids RAM study deliverable package includes:

• RAM Study Basis Document (scope, system boundary, data sources, assumptions)
• Functional Block Diagram and Reliability Block Diagram (electronic and PDF)
• Equipment failure rate and MTTR database (traceable to OREDA or ISO 14224)
• Monte Carlo simulation results: P10, P50, P90 availability by system and overall facility
• Production availability and production efficiency calculations
• Criticality analysis: Pareto ranking of equipment by unavailability contribution
• Sensitivity analysis: impact of key assumptions on availability results
• Bottleneck identification and redundancy optimisation recommendations
• Life Cycle Cost (LCC) comparison of design alternatives (where specified)
• Final RAM Study Report: methodology, results, conclusions, and recommendations

All deliverables are issued in client-specified format. iFluids supports operator review cycles and incorporates comments before final issue.

Data Sources Used in a RAM Study: OREDA, ISO 14224, and Plant History

The reliability of a RAM analysis is only as good as the failure rate data feeding the model. OREDA and ISO 14224 are the primary data sources for oil and gas RAM studies globally. OREDA provides equipment-specific failure rates from actual field operations; ISO 14224 defines the data collection and classification framework those rates are built on. iFluids applies both standards on every study, supplemented by client plant history data where available.

Data Source	Coverage	Best Application
OREDA 7th Edition (2021)	Offshore and onshore O&G equipment: compressors, pumps, valves, heat exchangers, rotating equipment	Greenfield upstream, offshore, LNG projects where no plant history exists
ISO 14224:2016	Framework for data collection and exchange; generic failure rates across petroleum and natural gas industries	Supplementary data; non-OREDA equipment types
API 689	U.S.-framework reliability data; equipment in refinery and petrochemical service	Refinery projects with U.S. operator or EPC specifications
Client Plant History	Facility-specific failure and repair records	Brownfield projects; late-FEED optimisation studies
IEC 60300-3-4	Dependability data collection guide; supports both RAM and RAMS study data frameworks	When RAMS (with Safety attribute) is required

Data source selection is agreed with the client in the RAM Study Basis Document. iFluids documents every assumption and data substitution, providing full traceability between the simulation inputs and the published data source.

When Is a RAM Study Mandatory?

A RAM study is not universally mandated by a single regulation. It becomes contractually required through operator engineering specifications, lender conditions, and project-phase gating criteria. The trigger is the project context, not a standalone standard.

RAM studies are required when:

• The operator’s engineering specification mandates production availability targets (typically expressed as 95%+ facility availability over design life)
• Project financing involves export credit agencies or multilateral lenders applying Equator Principles, which require documented production performance assumptions
• QatarEnergy project specifications require FEED-stage RAM analysis for gas processing and LNG facilities
• OISD (Oil Industry Safety Directorate) guidelines for Indian onshore facilities require documented reliability assessments for production-critical systems
• The project involves a novel or complex production architecture (multi-train LNG, deepwater subsea tiebacks, integrated refinery-petrochemical complexes) where design alternatives need quantitative comparison
• A brownfield debottlenecking project requires justification of proposed redundancy changes against production loss data

A RAM study conducted at the concept or early FEED stage influences design. One conducted at detailed design confirms a design that can no longer be changed without cost and schedule impact. iFluids recommends initiating the study at the earliest stage where a validated PFD and equipment list are available.

RAM Study Applications: Upstream, Midstream, LNG, and Refinery

RAM analysis applies across every sector of the oil and gas value chain where production availability targets drive design and maintenance decisions. The methodology is identical across sectors; the equipment database, redundancy philosophy, and logistics model change with the operating context.

Upstream and Offshore: RAM studies for wellhead platforms, FPSOs, and gas compression facilities model the full production train from wellhead to export metering. Logistics delay for offshore crane maintenance and helicopter crew mobilisation are modelled explicitly, as these dominate MTTR for offshore equipment.

Midstream and Pipeline: Compressor station and pipeline pump station RAM studies assess the impact of compressor unavailability on throughput. Studies conducted during FEED establish the minimum number of compression units required to meet contractual send-out obligations.

LNG Facilities: LNG train availability studies are among the most complex RAM analyses performed. Multiple gas treatment, liquefaction, and storage systems operate in partial interdependence. iFluids has completed RAM studies for LNG FEED projects with simulation models containing more than 400 equipment items.

Refinery and Petrochemical: Refinery RAM analysis focuses on critical rotating equipment: crude distillation unit (CDU) pumps, hydrotreater charge pumps, and reformer compressors. Maintenance window optimisation and turnaround scheduling are key outputs.

iFluids RAM Study Services: India, Qatar, and Gulf Projects

iFluids Engineering has completed RAM and RAMS studies for upstream, LNG, refinery, and petrochemical clients across India, Qatar, UAE, and Southeast Asia. ISO 9001:2015 certification covers every stage of the study workflow from data receipt to final report, with direct access to the reliability engineer managing the project throughout.

Our RAM analysis team works from offices in Chennai and Doha, with project experience covering:

• Offshore gas production platforms, Qatar
• Onshore crude oil processing facilities, India (OISD-compliant studies)
• LNG receiving terminal, South and Southeast Asia
• Refinery expansion projects, India and UAE
• Subsea production systems, deepwater India

Request a scoped RAM study proposal within 48 hours. iFluids provides a fixed-scope, fixed-price proposal based on your PFD, equipment count, and contractual deliverable requirements.

Related services: Asset Integrity Management | Quantitative Risk Assessment | Process Safety Management