Sequential Multiwell Steam Huff ‘n’ Puff in Heavy-Oil Development

Abstract Steam huff and puff, generally thought of as a single well process, has seen interwell interactions such as steam channeling and/or watering out of neighboring producer by condensed steam at the later stage resulting in the poor production performance. In contrast to the single well huff and puff (also named CSS), sequential multi-well steam huff and puff (SMWSHP) is a method in which some wells go to injecting, soaking and producing sequentially or at the same time. This method could avoid steam disturbance and interwell channeling and improve the production performance of huff and puff. Feasibility study on sequential multi-well huff and puff in developing heavy oil reservoir is presented in the paper. The mechanism and sequence (manner and overlapped time) of SMWSHP and also the pilot test have been studied in a heavy oil reservoir from Xinjiang Oil Field. Both the field pilot test and the theoretical study show that SMWSHP could economically prolong the production period, improve the production performance of steam huff and puff, and increase the oil recovery by 5~7%. The mechanisms of SMWSHP are as follows: (1) Injecting steam into several wells at the same time can avoid the interwell steam channeling, extend the heating area and increase the reservoir pressure. (2) Injecting steam in various sequences could displace oil into different direction and so, improve the sweep efficiency.