linked vertical well vs crip technology

Which UCG technology does CXY utilise at Kingaroy - Linked Vertical Well Technique or CRIP?

I'm pretty sure Link are using the older Linked Vertical Well Technique employed for decades at Angren in the old Soviet Union. Please can someone clarify this?

Link have proclaimed that their technology is the world's best and yet appraisal of various UCG techniques applied around the globe highlight that LVW has been far surpassed in its reliability and effectiveness by CRIP technology:

http://www.cleancoalucg.com/index.php?option=com_content&view=article&id=87&Itemid=124

The Linked Vertical Well Technique and CRIP
The Linked Vertical Well Technique
This older technique uses two vertically drilled wells as the Injection and Production wells. Different techniques, such as reverse combustion, hydro-fracking, electro-linking, explosive and in-seam linking are used to link the two wells. Although still used by some companies, this technique is not suited to modern, deep UCG projects (see below).

The Controlled Retracting Injection Point Technique
The modern CRIP technique uses a combination of conventional and directional drilling to drill the process wells. First, the vertically-drilled Production Well is drilled until it intersects the coal seam. Then the vertical section of the Injection Well is drilled to a pre-determined depth, after which directional drilling is used to deviate the hole and drill along the coal seam until it intersects the Production Well. This technique enables the injection point (i.e. the end of the coiled tubing) to be retracted back along the coal seam, which is of benefit because it allows for fresh coal to be accessed each time the syngas quality drops as a result of cavity maturation. Retraction of the injection point along the coal seam is known as a CRIP manoeuvre, and between 10 and 20 such manoeuvres are expected during the course of a module?s (see below) lifetime.

With the recent improvements in drilling, modern UCG is now principally based on directional drilling as this allows for a better control of where in the coal seam the oxidants are injected. This is important because early UCG trials using LVW technique, showed strong evidence that maintaining the injection point at a low position in the coal seam is essential for obtaining good syngas quality and gasification efficiency. However, the strong tendency for the injection point to migrate to the top of the coal seam in the LVW technique, led to the development of the CRIP technique, where the position of the injection point can be much more carefully controlled.

The third benefit of the CRIP technique is that, due to longer inseam borehole lengths, fewer process wells are required. Consequently, the CRIP method has a significantly smaller surface footprint compared to the LVW technique,

Based on these considerations, the method applied by CCL for high efficiency UCG is the CRIP technique.


The CRIP Module Concept and its Commercial Development
A pair of linked Injection and Production Wells is known as a module (Figure 1). The Pilot Phase will involve the operation of a single module for about 3 months, whereas the Commercial Phase will involve the simultaneous gasification of multiple CRIP modules in different stages of development. A line of operating CRIP modules is called a Panel. Continuous UCG operations are achieved by relaying the gasification down parallel lines of CRIP Panels.

http://www.cleancoalucg.com/images/stories/illustrations/crip_cavity.jpg


Figure 1. Schematic representation of the CRIP module concept.


It is the relatively recent developments in directional drilling in the oil and gas and coal bed methane sectors that has, to a large extent, resulted in the recent resurgence of interest in UCG. This fact has also contributed to the current situation where relatively few practicing experts with practical experience of UCG projects are available to the UCG industry. Most former experts, who were active in the 1970s until the early 1990s, are mostly retired or at the end of their career. CCL has a clear advantage in being able to draw exclusively on several UCG experts, while also training the next generation who will oversee the full commercialisation of the technology in the coming decades.