Fishing Operations: When to Call It Quits

You’re staring at the daily cost report, the rig clock ticking, and another fishing run has just come up empty. The pressure builds. Everyone on location feels the weight of the sunk cost, the desire to succeed, and the belief that the next run, this time, will be the one. This is precisely the moment when objective judgment often gets sidelined.

Fishing operations typically end in one of two ways: the fish is successfully recovered, or the operation is abandoned. Abandonment—whether by sidetracking, plugging back, or completing above the fish—is a legitimate engineering decision. Yet, it’s systematically deferred beyond the point where it should have been taken. This isn’t due to incompetence; it’s a consequence of decision-making under conditions almost perfectly designed to produce poor judgment.

The Declining Success Curve: Why “Just One More Run” Rarely Works

The probability of success on successive fishing runs doesn’t stay constant; it falls, and for compounding reasons you need to recognize:

The easy recoveries are attempted first. If the most straightforward approach—say, a simple overshot engagement on a clean fish top—failed, what remains is inherently less likely to succeed. You’ve already tried the low-hanging fruit.
The situation deteriorates. Every day the well is open, conditions degrade. Cuttings settle around the fish, increasing the risk of differential sticking. Hole condition can worsen, leading to increased drag and difficulty getting tools to bottom. The longer the operation, the more likely you are to face issues like wellbore instability or fluid loss.
Each failed run can add damage. A failed engagement might burr or deform the fish top, making subsequent attempts harder. An aggressive jarring campaign could part your fishing string, leaving more junk in the hole. A milling run might generate debris that complicates future cleanouts. Each unsuccessful attempt can leave the well in a worse state than before, increasing the complexity and cost of the next run.

The practical implication is critical: the expected value of run number five is not the same as run number one. Treating each run as an independent, fresh attempt with the same probability of success is a core analytical error that can cost millions.

The Sunk Cost Trap: Why We Keep Fishing

The dominant psychological pressure in a protracted fishing operation is the sunk cost fallacy. After eight days and millions of dollars spent, abandoning the well feels like wasting all that time and money. But those eight days and dollars are gone, regardless of your next decision. The only question that matters is whether the next increment of cost has a better expected return than the alternative of abandoning and moving on.

The eight days already spent are irrelevant to that forward-looking comparison, yet they are precisely what everyone on the team, from the wellsite supervisor to the asset manager, is thinking about. This emotional attachment to past investment blinds us to the objective economic reality of the future.

Building the Comparison: A Forward-Looking Decision

The decision to continue or abandon should be a clear comparison between two forward-looking costs:

Continue Fishing: Calculate the expected additional days required multiplied by the daily operating cost (which can easily run $150k-$300k+ per day for a rig), divided by the estimated probability of success for future runs. To this, add the cost of the alternative if fishing ultimately fails anyway.
Abandon and Take the Alternative: Estimate the cost of sidetracking, plugging back, or completing the well above the fish. Include the value of any reserves or capability lost due to the reduced completion.

The cost of the alternative is generally estimable with reasonable confidence. The “continue fishing” side, however, requires a probability estimate, which is where arguments often arise. But often, the sensitivity is clear enough that extreme precision isn’t needed. If continuing fishing only breaks even at a 70% success probability, and the last four runs have failed with deteriorating well conditions, the answer doesn’t depend on whether the true remaining probability is 20% or 35%—it’s too low either way.

Setting Stopping Criteria in Advance

The most reliable defense against in-the-moment, emotionally charged reasoning is to set stopping criteria before the operation even begins. At this stage, nobody is invested, the reasoning is clean, and objective analysis can prevail. These criteria should be explicitly written into the well program and reviewed regularly.

Useful criteria to consider:

A Day Limit: After N days (e.g., 5, 7, or 10 days, depending on the well and fish complexity), the decision is formally escalated and reviewed by an independent team, not automatically continued.
A Cost Limit: Expressed as a proportion of the value being recovered (e.g., “fishing costs must not exceed 20% of the estimated value of the recovered production”).
A Run Limit: After N unsuccessful engagement attempts with no significant change in approach or outcome, stop and reassess.
A Progress Criterion: Each run must produce new information or measurable progress. Simply repeating an identical failed run does not qualify as progress. If you’re not learning anything new or getting closer to recovery, you’re just spending money.
A Deterioration Trigger: Evidence that continued fishing is making the alternative worse (e.g., a parted fishing string, significant debris accumulation, severe hole degradation, or increasing differential sticking risk) forces an immediate review and likely abandonment.

Crucially, make the criterion trigger a mandatory review rather than an automatic stop. An automatic stop invites people to work around it. A mandatory review, with a named decision-maker who was not directly running the operation, preserves flexibility while removing the immense pressure from the person least able to judge it objectively.

Beyond the Fish: Considering the Alternative

Often, sidetracking or plugging back is mentally priced at its worst-case scenario. However, several factors frequently make the alternative better than initially assumed:

Existing Wellbore: The hole above the fish is already drilled and cased; the sidetrack starts from a known, stable point, not from scratch.
Modern Directional Tools: Kicking off from a cement plug or a whipstock is routine with today’s advanced directional drilling technology. This isn’t the complex, high-risk operation it once was.
Improved Wellbore Position: The sidetrack may allow for a better wellbore position than the original plan. Geological understanding often improves during the drilling of the initial wellbore, allowing for optimization in a sidetrack.
Completing Above the Fish: If the fish is below the productive interval, recovering it may have no value at all beyond tidiness. In such cases, the correct answer on day one might be to simply leave it and complete the well above. Always check this early in the planning phase.

Special cases can also change the calculus. Regulatory requirements in most jurisdictions demand recovery or verified permanent isolation for radioactive sources or explosives downhole, making the decision not purely economic. High-value tools, however, are rarely decisive; their cost is usually small compared to the daily operating cost of recovering them.

Finally, contractual arrangements deserve scrutiny. Where the fishing contractor is paid by the day, misaligned incentives can produce fishing operations that continue far past economic sense. Address this at the contracting stage, not during the operation.

The Bottom Line

The best practice observed in operators who handle fishing operations well is unglamorous: a written stopping criterion in the well program, agreed before spud, with a named decision authority outside the immediate operations team. It costs nothing to implement, it’s written when everyone is thinking clearly, and it converts one of the hardest decisions in well operations from a judgment made under immense pressure into the execution of a pre-agreed plan. Operators who have this stop earlier and spend less; those who don’t, often fish until someone senior enough happens to intervene. Have a question about your well? Reach out via the contact page.