To evaluate the economics of an upstream project, the first step is to construct a cash flow model that spans the entire life of the project. In simple terms, a cash flow model provides insights into the funds required to operate the venture and the revenue it generates. The model relies on specific inputs to produce economic indicators as outputs.
The process of forecasting cash flows involves estimating various components of cash inflows and outflows, which are discussed below:
In essence, cash flow is calculated as the difference between total cash inflows and total cash outflows.
Gross revenue consists of the sales proceeds from crude oil, natural gas, and condensates. It may also include tariff income generated from sharing infrastructure, such as pipelines or production facilities. Revenue is simply the product of hydrocarbon volume and sales price. To estimate revenue over the life of a field, it is necessary to forecast the production volume (or rate) for each period and project the market prices of oil and gas.
Production forecasts are determined by reservoir engineers and geologists, who provide the economist with a production profile, which is a time series of production volumes or rates over time. This production profile can also be understood as a revenue profile.
Typically, the production curve of a field follows three key phases. In the early phase, as drilling progresses, the production rate increases, resulting in an upward-sloping production curve. After a certain point, the production rate stabilizes or stops increasing. This middle phase, known as the plateau, does not last long unless additional wells, called incremental wells, are drilled to sustain production. Following the plateau, the production rate begins to decline as reservoir pressure decreases. This decline phase continues until production becomes uneconomical, at which point the field is either shut down or abandoned.
A standard production curve demonstrates these phases clearly. At the start, production ramps up as drilling progresses. Once all wells have been drilled, production stabilizes during the plateau phase. Over time, as reservoir pressure declines, the production rate decreases, marking the beginning of the decline phase.
Standard production curve
It is evident that the decline curve can be influenced by adjustments to the field development and drilling program. In some cases, there may be pre-drilled wells, allowing production to start at the maximum rate immediately after the field begins producing. In such scenarios, there is no ramp-up phase, as production commences at a high level. This high production rate is sustained as long as reservoir pressure is maintained.
However, over time, as reservoir pressure begins to drop, production enters a decline phase. The resulting production profile differs from the standard curve and resembles the "Plan X" curve, represented by the blue dashed line. This type of curve illustrates a scenario where production starts at a high level, remains stable for a period, and then gradually declines as reservoir pressure decreases.
At times, field development planners may opt to extract hydrocarbons at a slower rate. In such cases, drilling is done at intermittent intervals to maintain production at a steady level. This slower extraction rate helps preserve reservoir pressure for a longer duration. As a result, the production profile features an extended plateau, as shown in the “Plan Z” curve. In fact, this approach may lead to a higher total ultimate recovery of crude compared to the faster extraction plans, such as Plan X and Plan Y.
If the goal is to maximize early production, it is necessary to complete the necessary facilities and drilling programs early in the project. This requires a significant upfront investment, resulting in higher cash outflows. On the other hand, if a slower production rate over a longer period is preferred, some of the early investments can be delayed, allowing for a phased development of the field. While this approach may require the same overall cash outlay, the costs are spread over a longer time frame. These decisions must be carefully considered, as they impact the project's economics, particularly through the time value of costs and production. Although the total cash flow over the life of the field may remain the same, the Net Present Values (NPVs) and Internal Rates of Return (IRRs) could vary significantly depending on the field development strategy chosen.
In most cases, water is produced alongside crude oil. This happens because crude oil and water often coexist in the well, with the crude lying on top of the water. As reservoir pressure decreases and crude production begins to decline, the volume of water produced increases, a phenomenon known as the "water cut." This can affect the project's economics, as the cost of separating the water from the crude may increase and impact the overall profitability.
The production profile is generated through the collaborative efforts of geophysicists, petrophysicists, reservoir engineers, and production engineers. These experts analyze geological data and interpret seismic and log data to build and simulate the reservoir model. The accuracy of the data and the quality of the interpretation play a crucial role in estimating the reservoir volume and production profile.
For the economist involved in project valuation, all of this technical information serves as background. What truly matters is determining the periodic volume and quality of each stream of hydrocarbons produced, as the quality influences the sale price. Revenue is therefore calculated as the volume of each hydrocarbon stream sold, multiplied by its respective sales price, whether it is crude oil, gas, condensates, or natural gas liquids.
The production profile generated by the Geology and Geophysics (G&G) department cannot be estimated with complete certainty. There is always an element of uncertainty and risk associated with the reserve volumes and their profile. This is because the volumes deep within the Earth's crust cannot be physically verified until the hydrocarbons are actually produced.
There is often a range of possible outcomes when estimating reserves. Typically, the oil and gas industry categorizes reserves into three levels of confidence, based on the probability of occurrence. These categories are Proved, Probable, and Possible.
Upstream projects may also generate income from sources other than direct hydrocarbon sales. One such source is tariff income, which is derived from sharing production, processing, or transportation infrastructure with another company. In this case, the company using the facilities pays a ‘rent’ to the owner company. The rental fee is usually based on the volume of crude oil or gas handled by the owning company. Tariff charges are determined through negotiations between the company that owns the infrastructure and the company utilizing the facilities.
Sometimes, the tax implications of tariff income can complicate the economic analysis, particularly when the third party paying the tariff to the owner company is the same company. This situation, known as "self-to-self" tariffing, is not uncommon and can occur in certain circumstances.
For example, let’s consider a scenario where Company A has a 40% working interest in Field X and a 35% working interest in Field Y. Company A may use the processing facilities and pipelines of Field X to process and transport crude oil from Field Y. In this case, Company A would be paying a tariff to itself, which complicates the financial and tax analysis.
Another potential source of cash inflows is payments received from selling an interest in a project, also known as a "farm-out" or acquisition price.
A price forecast is essential for estimating revenue from crude oil and gas sales. Forecasting oil and gas prices is a challenging task due to the many factors that influence crude prices, ranging from supply and demand dynamics to geopolitical events. While previous price trends and estimates of future scenarios serve as a basis, price projections can span up to 20 to 30 years.
Typically, economists use various price scenarios, or "decks," for price forecasts, such as $50/Bbl, $60/Bbl, $80/Bbl, and $100/Bbl, assuming these prices remain flat (constant) over the project life. Price escalators are then applied to adjust these price scenarios to reflect the notional price on the day of analysis.
In some cases, a price differential may also need to be forecasted. Lower-quality crude oil may be sold at a discount to the benchmark market price, or it could command a premium. The price differential is typically based on the quality of the crude oil compared to the benchmark, such as WTI (West Texas Intermediate) or Brent.
For instance, if a crude oil is traded based on the Brent price but is of lower quality than Brent crude, its price will be adjusted downward according to a price discount. This discount, or potentially a premium, can be determined by a formula that links it to specific parameters of the crude quality.
Oil prices are largely set in the international market, while gas prices are primarily determined in the local market. This difference is straightforward to understand. Unlike oil, gas is not easily transported without incurring significant costs, making it "stranded" at the location of discovery. Additionally, gas prices are often based on long-term contracts, which is another factor to consider when making gas price assumptions.
Next, we focus on the items that cause cash to flow out of the business or project. These costs are typically divided into technical costs and fiscal costs. Technical costs include items such as capital expenditures (CAPEX) and operating expenditures (OPEX). Fiscal costs, on the other hand, include royalty payments, bonuses to the government, taxes, and a share of profit oil.
The facilities and process design will dictate the actual property, plant, and equipment (PPE) required for the development and production of crude oil, gas, or both. The development plan established during the exploration and appraisal phases of the project may be preliminary and high-level. However, as the project moves from exploration to development, these plans will become more detailed, realistic, and accurate in terms of cost projections. During the development phase, various options will be analyzed, and economic models will be run to determine the most efficient path forward to maximize the project's value, measured by Net Present Value (NPV). Below, we discuss these technical and fiscal costs in more detail.
Cost estimates for both capital investment (CAPEX) and day-to-day operating costs (OPEX) are made at several stages throughout the project’s lifecycle. These estimates are regularly updated as engineers gain a better understanding of the project, drawing on both the available data and their previous experiences. The quality and accuracy of these estimates depend on the information available, as well as the expertise and experience of cost engineers.
CAPEX refers to expenditures related to physical infrastructure such as platforms, production facilities, pipelines, and wells. These costs are associated with the installation of hardware in the field. Typically, CAPEX is incurred before production starts and during the early phases of the project’s life. From an accounting perspective, any expenditure that creates an asset with a useful life of more than one year is considered a capital expenditure and is capitalized.
A typical CAPEX schedule is illustrated above. It is worth noting that a significant portion of the CAPEX is incurred upfront, before the start of production (from period 4 onward). In this example, there are certain infill wells drilled later in the project’s life, but their number is relatively small.
Examples of CAPEX include:
OPEX, also referred to as production costs, are incurred in the operation and production of hydrocarbons. These costs can be categorized as either fixed or variable. Variable costs depend on the level of production or output, whereas fixed costs remain constant and must be incurred regardless of production fluctuations. Unlike CAPEX, OPEX (often called "Opcost") does not create any asset and is expensed in the period in which it is incurred.
Fixed OPEX is generally estimated as a percentage of cumulative CAPEX. Variable OPEX, on the other hand, is typically expressed as a cost per barrel or per Barrel of Oil Equivalent (BOE).
Examples of OPEX include:
A typical OPEX profile for a project is shown above. It is important to note that there are no OPEX costs incurred before the start of production (i.e., prior to period 4).
Abandex refers to abandonment capital. Once a project reaches the end of its economic life, the site must be restored. Restoration or decommissioning costs may be incurred even before the project officially ends, often several years before its economic life concludes. In most cases, the contracting company is legally obligated to close and restore the operational site to its pre-existing condition. While in certain scenarios—particularly under Production Sharing Contracts (PSC)—the ownership of facilities lies with the government, the responsibility for site restoration usually ends up with the contractor.
Costs incurred for making abandonment provisions are generally tax-deductible. However, if actual abandonment occurs toward the end of the project when taxable revenue may not be sufficient to offset the costs, governments may either provide tax credits (refunds) or allow contractors to claim tax benefits at the time they start allocating funds to an abandonment relief fund.
Regardless of tax implications, Abandex is a cash outflow item that typically occurs during the last economic period of the project. Estimates for Abandex are usually prepared collaboratively by the finance and operations departments. The detailed economics of abandonment will be discussed in a separate session later.
In the early phases of a project, abandonment may not significantly impact project economics due to the heavy discounting effect of future cash outflows. However, as the project nears the end of its life, abandonment costs can become a more important factor in determining value.
In addition to CAPEX, OPEX, and Abandex, projects also incur extra costs that must be factored into cash flow calculations.
Royalty, bonus payments, taxes, and sometimes the government’s share in profits are considered fiscal costs from the contractor’s perspective.
If taxable income is negative (i.e., a loss), the loss may be allowed to offset taxable income in subsequent periods. However, there may be restrictions on the number of periods over which the tax loss can be carried forward, as well as limits on the amount that can be carried forward. In certain tax regimes, losses may also be allowed to be carried back, meaning the current period's loss can offset past profits, enabling the company to claim a tax credit from the government.
In the initial phase of a project's life cycle, the project may generate losses, resulting in minimal tax obligations. Taxes typically become more significant as the project reaches its mid-life.
In some cases, a project may be taxed on a stand-alone basis. This means that losses from other projects cannot be offset against the profits of this particular project. In this scenario, the project is considered "ring-fenced." For example, if a company has two projects, A and B, and Project A generates a profit of $100 million while Project B incurs a loss of $100 million, the company's aggregate profit or loss is the sum of A and B's performance, resulting in a net zero profit (+$100 million profit from A - $100 million loss from B).
If neither project is ring-fenced, the company does not owe tax. However, if Project A is ring-fenced, the company cannot offset Project B’s $100 million loss against Project A’s $100 million profit, and will be liable for tax on the $100 million profit of Project A.
A summary of the different input types required for running a cash flow model is provided below.
In general, upstream oil and gas projects follow a typical cash flow pattern. Initially, these projects experience a series of negative cash flows, reflecting significant investments during the early phase. This is followed by a series of positive cash flows once production begins. However, if there are subsequent development or production maintenance programs during the mid-life phase, the project's cash flow may become negative again for a period.
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