复合强凝胶调剖体系在百色油田百49块裂缝油藏的应用

百49油藏为低渗透裂缝性油藏,平均孔隙度为15.5%,平均空气渗透率为16.3×10-3μm2。该区块曾历经多次大规模压裂改造,但由于调剖有效期短,调堵剂耐压强度低,抗冲刷能力差,导致效果不明显。至2008年底,水驱效率下降,产量大幅度下降。综合考虑膨胀倍数、强度和韧性,筛选出A作为封堵有机填充剂,B作为裂缝封堵剂,并根据实验结果和现场取样分析,最终选用配方为0.5%强凝胶。2008年、2009年百49块共进行了两个井组4井次的调剖施工,水井从过去被动周期小剂量注水转变为可连续稳定注水,累计有效温和注水18077.9m3。其中百水1井组注水压力平均提高8.2MPa,吸水指数平均下降0.81m3/(d.MPa)。证实复合强凝胶体系适合低渗裂缝性油藏,能够有效封堵窜流通道,达到了深部调剖的目的,具有较好的增油降水效果,区块累计增产原油152.7t。

The Application of Profile Control System of Composite Strong Gel in the Fractured Oil Reservoirs,Bai49 block,Baise Oilfield

Bai 49 is a fractured oil reservoir with 16.3×10^-3μm2 of the average air permeability and 15.5% of average porosity.The block has experienced several large-scale fracturing,but the result is not good because of short term of validity of profile control ,low compression strength of the agent and poor capacity of antiscour.The production has declined greatly and water flood efficiency as well by the end of 2008 in the block.Comprehensive consideration of expansion times,strength and tenacity,A is selected as organic filling agent and B is selected as blocking agent for fractures.Strong gel with 0.5% is finally fixed based on the experiment result and field coring analysis.Four well-times profile control was made in two well groups in Bai 49 block in 2008 and 2009.For the water injector,the way of water injection changed from passive and small dose by circle to continuous and stable injection.Cumulative effective moderate injection is 18077.9m3.A- mong them,the injection pressure has enhanced 8.2MPa and water injectivity index has dropped 0.81m3/（d· MPa） averagely in Baishuil well group.It proves that composite strong gel system is suitable for the low-permeability fractured oil reservoir for effective blocking of channeling,deep profile control and good results of oil production increment and water production decrease.The incremental cumulative oil production is 152.7t in the block.