Ann: Cuba Block 9 Update, page-135

This is going to be some work over!! 20% flowed at 1500 100% could flow hard and 5000-10000 shouldn’t surprise. I wouldn’t be surprised if the acid goes down the hole as early as Jan 1 either. They haven’t stopped working on site since last announcement


The production after a normal acid wash and workover treatment for a typical **Varadero oil well** (2000 m deep) depends on several factors, including the reservoir's characteristics, the initial production rates, the extent of formation damage, and the efficacy of the treatment. Here's a general outline:

### **What to Expect:**
1. **Initial Production Improvement:**
- An **acid wash** is used to remove scale, rust, and deposits in the wellbore, while a **workover** addresses mechanical and operational inefficiencies.
- If the formation near the wellbore is mildly damaged, production rates can **increase by 10–50%** compared to pre-treatment levels.

2. **Reservoir Characteristics:**
- **Carbonate reservoirs** respond well to acidizing, often resulting in significant production boosts.
- **Sandstone formations** may see more moderate improvements, especially if fines migration or paraffin buildup caused the damage.

3. **Restoration Potential:**
- For wells that experienced a **gradual decline** due to scaling or clogging, these treatments can often restore production to **near-original rates** temporarily.

4. **Duration of Improvement:**
- Production improvements from acidizing and workovers typically last for **6 months to 2 years**, depending on reservoir pressure, fluid compatibility, and flow rates.

### **Specific Estimates for Varadero Wells:**
- In **Varadero fields**, production rates may vary from **100 to 800 barrels of oil per day (BOPD)** depending on reservoir pressure and porosity.
- After treatment, an increase of **20–30% in production** is a reasonable expectation for typical wells, assuming no severe underlying issues like water breakthrough or depletion.

### **Challenges and Risks:**
- **Potential Over-Acidization:** If acid reaches unwanted zones (e.g., water zones), it may cause water coning.
- **Reservoir Damage Beyond Acid Wash Scope:** In some cases, additional treatments like hydraulic fracturing or advanced stimulation techniques might be required.

Would you like further insights on optimizing these treatments or understanding the costs and risks associated?