**4. Conclusions**

disposal wells where they are injected into deep rock layers that are isolated from fresh water supplies. The disposal wells are licensed by both the DEQ and the U.S. Environ‐ mental Protection Agency, and must be tested periodically to assure well integrity. Instruction 1-2011 requires reporting of the volume of flowback water recovered after a

**4. Surface spills.** Spills of chemical additives or flowback water can have adverse environ‐ mental or public health impacts. Michigan requires secondary containment under tanks, wellheads, and other areas where spills may be most likely. If a spill does occur, it must be reported immediately to the DEQ, and all spills must be promptly recovered and

**5. Identification of chemical additives.** Instruction 1-2011 requires oil and gas operators to provide to the DEQ copies of all Material Safety Data Sheets (MSDSs) for additives used in hydraulic fracturing. The MSDSs include information on physical characteristics, toxicity, health effects, first aid, reactivity, storage, disposal, protective equipment, and spill response. The DEQ will post the MSDSs on the Department's web site for public review. While the details on some of the chemical compounds used in hydraulic fracturing are exempted from disclosure on the MSDSs under federal law, the MSDSs will provide

The regulations enforced in Michigan was designed for the state specifically, in the instance

**•** It most likely will not be possible to dispose of brine by re-injection into deep wells unless an exception in relation to the Water Act is obtained. This will introduce another issue which

**•** The volume of material produced over the lifetime of a well field might require some engineering adaptation and/or disposal in dedicated waste storage facility constructed just

**•** On the issue of water use, there is currently enough usable water available to proceed with hydraulic fracturing in the Karoo basin; but it will require planning and development of

**•** Desalination plant efficiencies will need to be increased as the systems are currently sensitive to inflow water quality. It will most likely be associated with a multi-stage facility to remove organics (BTEX, PAHs) from the produced water and total dissolved salts. The composition of the salts is assumed to be mostly Na/Cl but it is expected that Ca, Fe and Mg salts will also be present. The presence of Fe salts might also pose interesting processing challenges

**•** The presence of dolerite formations and thermal springs indicate that there might be a possible upward migration pathway for contamination migration. The probability of this occurring in the vicinity of the well field cannot be ruled out; especially if control measures

and well field integrity is not measured over the lifetime of the well.

is disposal of solids and brines that is produced from water purification processes.

for this purpose. It is still an open question as to how this will be managed.

small scale well fields to abstract adequate volumes.

for these plants.

hydraulic fracturing operation.

232 Effective and Sustainable Hydraulic Fracturing

cleaned up according to strict requirements.

enough information for the DEQ to track and monitor spills.

of South Africa the following key differences will need to be considered.

South Africa has in the past been heavily dependent on its rich coal resources to supply it of electricity and fuel; with the discovery of an unconventional terrestrial gas resource it is currently entering a new age of energy independence. The development of this resource has put a strain on local communities due to fears of contaminated surface water and groundwater resources. The area currently being investigated, has both a historical and national significance and emotions are running high. Due to the sensitivity of South Africans regarding the Karoo, a great deal of care is required when gas exploration and eventual development occurs in this area. Key concerns is that the environment will be impacted to such an extent that it will be irrevocably changed. The geology of the area is to a certain extent complex and has dolerite sills and dykes which intrude the country rock. However, the Ecca formations of the Karoo has a considerable carbon content and suitable thickness to make it an ideal target for shale gas development. In this paper the process of hydraulic fracturing have been investigated from a hydrochemical perspective. Firstly, the composition of hydraulic fracturing fluids and the possible risks it pose to the surface and subsurface systems. Secondly, backflow water was evaluated for the Marcellus Shale since no current hydraulic fracturing program has been initiated in South Africa to target the Ecca shale formations. A summary of the key parameters were discussed as well as the production of flowback water and salt loading. Issues relating to salt loading were mainly related to treatment plants and the ability to effectively dispose of the produced brines and salts. A limited set of samples were incorporated into this paper from the Soekor core holes, and similar trends in water type was observed for both the Soekor sites and Marcellus samples.

Environmental impacts due to hydraulic fracturing activities were discussed. Due to South Africa's recent introduction to unconventional gas development a number of important regulatory processes does not exist, i.e. well and site inspectors. The state of Michigan's proactive approach to regulating shale gas development addressed most of the issues which will be prevelent in the South African regulators mind. Finally, key differences between the regulatory environments were presented as well as unique challenges that faces South Africa in developing the unconventional gas resource.
