The operators of the Horse Hill exploratory oil site near Gatwick have applied to vary their environmental waste permit to allow them to test the well.
The application, by Horse Hill Developments Limited (HHDL), was published by the Environment Agency yesterday. A public consultation runs until 25th June 2015.
One of the partners in HHDL, UK Oil & Gas Investments, claimed last month that it had discovered 100bn barrels of oil in the Weald, based on drilling at Horse Hill. It later issued a clarification saying further testing and drilling was needed before the amount could be confirmed.
The permit application includes details of HHDL’s plans to test three target formations of the well: the Upper and Lower Jurassic limestones and the Portland sandstone.
According to the environmental method statement, for each formation, the process will include:
- Perforating the well
- Circulating dilute hydrochloric acid (acid wash to clean the well)
- Opening the well to flow
The environmental method statement says the acid wash will use at least 48 cubic meters of dilute hydrochloric acid in total (16m3 for each section). Another 48m3 might be required to repeat the process. It adds that the hydrochloric acid will be at 15% concentration.
The application says likely waste products from the well test will comprise spent acid, diesel and water. There is no reference to waste gases or the need for flaring.
Mobilisation of equipment is expected to take one week and perforation of the well, testing and securing the well another four weeks.
- The Environment Agency is currently consulting on a set of standard rules covering acid wash in oil and gas wells. The deadline for responses is 15th June 2015
Horse Hill details
Address Horse Hill, Hookwood, Horley, Surrey, RH6 0HN
Licence area: PEDL 137 – the exploration phases is due to expire on 30th September 2015 and HHDL has applied to the Oil and Gas Authority for a one year extension to 30th September 2016
Planning permission Granted by Surrey County Council on 16th January 2012, reference SCC 2010/0197. Permission is for three years from the start of work.
Well spudded 2nd September 2014