胜利海上疏松砂岩油藏分层防砂分层采油技术

Separate Layer Sand Control and Oil Production Technology in Offshore Unconsolidated Sandstone Reservoirs of Shengli Oilfield

胜利海上疏松砂岩油藏存在油层多、井段长、夹层厚、层间非均质性强和易出砂等问题,采用笼统防砂电动潜油泵合采,层间矛盾突出,不能充分发挥各产层的作用,制约了其有效开发。为此,进行了适用于海上疏松砂岩油藏的分层防砂分层采油技术研究。针对笼统防砂充填不密实、防砂后通径小的问题,研发了大通径分层充填防砂技术,实现了分层防砂,并增大了防砂后的通径,方便了后期实施分层采油;研制了遇油遇水膨胀封隔器和在线电动调节阀,形成了分层采油技术,实现了分层开采和各层流量的在线调节。在海上的埕北20C-A井进行了分层防砂试验,各油层实现了差异充填防砂,使各油层潜能得到了释放;在与胜利海上疏松砂岩油藏储层物性相近、油井的完井工具尺寸相同的陆上GO2-17-A井和GO4-19-B井,进行了分层采油试验,2口井均实现了分层开采和各油层产液量的精确调控,提高了产油量,降低了含水率。现场试验表明,采用分层防砂分层采油技术解决了海上疏松砂岩油藏合采层间矛盾突出的问题,可以充分挖掘各油层的潜能,提高开发效果。

The offshore unconsolidated sandstone reservoirs in Shengli are characterized as having multiple oil layers,long well sections,thick interlayers,strong inter-layer heterogeneity,and easy sand production.Electric submersible pumps are used for commingling production with overall sand control,accompanied by prominent inter-layer contradictions,but they cannot give full play to each producing layer and restrict the development of offshore oil fields.Therefore,separate layer sand control and oil production technology for the offshore unconsolidated sandstone reservoirs was studied.Considering the loose compaction of packing and small diameter after overall sand control,a large diameter separate layer packing sand control method was developed.With the method,separate layer sand control was achieved and the diameter was enlarged for following separate layer oil production.In addition,an oil and water swelling packer,and an online electric regulating valve were developed.A separate layer production technology was then formed,with which the separate layer production and online regulation of the flow from each layer were realized.The separate layer sand control test was done on Well 20C-A of Chengbei Sag offshore,resulting in differentiable packing sand control and thus exploiting the potential of production for each layer.The separate layer production tests were conducted on GO2-17-A and GO4-19-B onshore,for they have the similar formation physical properties and the same size of completion tools for oil wells of the offshore unconsolidated sandstone reservoirs in Shengli.Both the wells achieved separate layer oil production and accurate regulation of liquid-producing capacity for each layer,with increasing oil production and decreasing water content.The field application shows that the technology has solved the prominent inter-layer contradictions in commingling production of offshore unconsolidated sandstone reservoirs,and it can fully exploit the production potential of each layer,which resulted in oil production improvement.