THE saga of Cluff Oil (Hong Kong), a joint venture between some of the territory's most powerful companies, has taken a further twist with the entry of the Hwang family, creators of Hong Kong Parkview, as the largest shareholders. However, Hongkong Bank and Swire Pacific have sold their stakes, leaving Hutchison Whampoa, Wheelock and Co, Inchcape and Britain's Cluff Oil and others as shareholders. The Hwang family's oil company, Primeline Petroleum Corp, now holds 30 per cent of Cluff Oil (Hong Kong) and its managing director, Victor Hwang Yiou-hwa, joined its board in November. Mr Hwang said Cluff Oil (China), a joint venture, 49 per cent owned by Cluff Oil (Hong Kong) and 51 per cent by Primeline, had on December 12 signed a 30-year oil supply agreement with China National Oil Corp (CNOC) on its concession areas in the East China Sea. 'Towards the end of 1996 we will start drilling wildcat wells,' he said. This year, Primeline will seek a listing on a stock market - probably in London, Canada or Singapore - to become the first listed oil exploration company with large China exposure. Mr Hwang said the group had secured concessions in two major areas covering 23,000 square kilometres, 64 per cent of the land area of Taiwan. One is adjacent to a block in which Xinhua (the New China News Agency) this week reported that Texaco had started drilling. Texaco and Cluff Oil are among 16 foreign companies to sign offshore oil contracts with CNOC. However, all the concessions of Cluff Oil (China) are in areas described as by analysts as 'high risk, potential high return'. Four are large blocks in the northern sectors, and one, a smaller block in the southern sector that has received more interest from overseas oil giants. Mr Hwang said: 'The oil exploration business is a high risk, high return business.' He stressed it was not part of the Hong Kong Parkview Group, which was listed in Hong Kong. The powerful shareholders in Cluff Oil (Hong Kong) had not helped its exploration record: all four of its previous attempts to find oil failed. Before its last attempt to find oil 15 km off the coast of Jiangsu province in April 1993, it said it would disband if oil was not struck. However, Mr Hwang said the structure was being maintained because it brought useful contacts, though their stake and funding requirements were greatly reduced. The effective interest of Primeline in the current concessions, expected to swallow US$15 million to $20 million in exploration costs over seven years, is 65 per cent. This would include three wildcat wells. Wang Tao, CNOC president, was quoted by the China Daily over the weekend as saying output from the Daqing field, which supplies 40 per cent of China's output, would begin to decline in three years.