Makers of the specialty cocktails used to crack open the Earth and set loose gobs of oil and gas are sparring once again on behalf of their corner of the energy industry. On the West Coast, oil field services companies are getting a head start pressing state officials to back away from what the industry considers an overreach in chemical disclosure requirements. As California and Alaska consider hydraulic fracturing rules, fracking fluid suppliers Halliburton Co. and Schlumberger Ltd. have come out ahead of their industry associations with objections to the proposals.