曙光油田杜229块蒸汽吞吐后期转蒸汽驱试验技术

Experimental study on converting to steam flooding after cyclic steam stimulation for Du 229 Block in Shuguang Oilfield

杜229块超稠油油藏蒸汽吞吐开发采出程度达到22.5%,可采储量采出程度高达96.3%,转换开发方式势在必行。针对该油藏地质特点及开发现状,开展转蒸汽驱方式可行性研究。结果表明,该油藏适合蒸汽驱开发,可提高采收率25%。综合研究后确定,在该块中部选取4个井组开展蒸汽驱先导试验,并对井组注采参数进行优选。经过一段时间的试验,先导试验井组已进入蒸汽驱驱替阶段,瞬时油汽比达到0.16,井组年综合递减率下降10%,蒸汽驱见到初步效果。该研究对于区块下步转换开发方式及稳产起到了保障作用,对同类型油藏转蒸汽驱开发具有重要的指导意义。

Du 229 Block,an ultra heavy oil reservoir,has 22.5% reserve recovery by cyclic steam stimulation and 96.3% recovery of recoverable reserves. A conversion of development scheme is imperative. Feasibility study of converting to steam flooding has been conducted according to the reservoir characteristics and development status. The result indicates that this reservoir is fit for steam flooding which can improve recovery factor by 25%. Four well groups in the middle of the block have been selected through synthetic study to perform a pilot test of steam flooding,and the injection-production parameters were optimized. After a certain test period,the well groups have entered steam flood displacement stage with instant oil-steam ratio reaching 0.16 and annual decline rate reducing 10%,showing a good beginning. This study is of importance to future conversion of development scheme and production stabilization,and may guide similar reservoirs converting to steam flooding.