Through-tubing drilling and completion is a cost-effective technology for increasing production and recovery. TTDC is a generic term for drilling sidetracks in existing producers and injectors and covers both coiled tubing drilling (CTD) and through-tubing rotational drilling (TTRD), including installing the associated lower completion, typically liners or screens.
The main advantage of the technology is that new reservoir sections can be reached without having to remove the existing, the completion of the production casing, thereby reducing operational time significantly compared to a “standard” slot recovery or side-track. TTDC- wells are particularly useful for accessing pockets of isolated oil and gas in mature fields. Due to the deep side-tracks achieved with this technique, it is possible to minimize borehole lengths and avoid drilling problems in overlying formations.
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Through tubing rotary drilling |
WELL MATRIX STIMULATION WITHOUT HCl
Well acidizing is a common practices in the oil industry and hydrochloric acid (HCl) has been used as the main acid for limestone stimulation purposes There are several concerns with the use of HCl acids: health and safety of the field crew, corrosive nature of the acids for the flow lines and equipment, and environmental effects of the produced HCl.
A new product called FF-01 is an environmentally-friendly and equipment-friendly product. It is a conversion to an organic base to maintain very low pH as a vehicle for aggressiveness, along with the creation of buffers and surface tension relievers. Low pH, slower reaction rates with limestone, a small amount of residue after a reaction, safety, minimum damage to equipment, and longevity are the properties of this product.
Tests have been conducted to develop this new product and study possible improvements in this blend. It has been observed that FF-01 dissolves limestone rock samples with smaller reaction constants compared to HCl However, it will dissolve the same mass of rock if enough time is given, and it lasts longer during the course of reaction while leaving fewer residues.
HCl performs better in cleaning the near-wellbore rock while FF-01 performs better in generating long wormholes and higher effective permeability compared to the cores that were treated using HCl.
UNCONVENTIONAL STIMULATION
The acoustic stimulation technology has the potential to provide a low-cost procedure for enhancing oil recovery in mature fields. Low-frequency shock waves produced downhole can increase the oil production and are currently producing well with high WC mobilizing immobile oil in ¾ mile range. Application of this technology well suits well/field having the following properties:
- Oil Viscosity less than 10 cP
- High water cut, ideally greater than 80%
- Low GOR, ~10 m3 per m3 of fluid produced is ideal
- Minimum spacing of 400 m between source wells with production wells spaced within 300 m radius “stimulation zone”, if multiple tools are run.
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Credits: Oil and Gas portal
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