新型3D推靠自适应坐封取样系统的研发与应用

Novel sampling systems of 3d radial adaptive setting probes

随着勘探开发的深入,人们遇到越来越多的低渗甚至超低渗等复杂油气储层.此外,海上井下流体取样的时效性和样品代表性也变得愈来愈重要.目前,国内现有地层测试技术无法满足此类储层流体取样的需求.因此开发相应的流体取样技术和装备十分必要.本文首先简单综述了国外最新电缆地层测试器和3D径向探针.其次,研发了具有自主知识产权的适用于EFDT地层测试器的新型3D推靠自适应坐封取样系统.然后,给出了基于探针形状因子的泵抽速率与压降关系,基于球形流的滤液污染率计算方法以及基于线性混合规则的段塞流过程中油-水分率计算方法.最后,详细讨论了3D推靠自适应坐封取样系统和这些方法应用于海上低渗油井取样的实际案例.结果表明:(1)对于海上低渗油层,新型3D推靠自适应坐封取样系统不仅能在合理的压降(2.76 MPa)和泵抽速率(6.01 cm^(3)/s)的条件下取得合格的高纯度油样,而且大大提高了取样时效;(2)在相同压降条件下其取样效率约为标准探针的4倍;(3)模型预测的滤液污染率与现场放样分析的结果吻合很好.新型3D推靠自适应坐封取样技术可为低渗或超低渗储层流体取样提供有效方法,并且降低海上作业风险和成本.

With the expansion of exploration and development,more and more complex oil and gas reservoirs with low or even ultralow permeability are encountered.In addition,the efficiency and representativeness of offshore downhole fluid sampling become more and more important.At present,the domestic existing formation testing technology cannot meet the needs of fluid sampling in such reservoirs.Therefore,it is necessary to develop the corresponding fluid sampling technology and equipment.In this paper,first of all,the latest wireline formation testers and 3D radial probes abroad are briefly reviewed.Secondly,a sampling system of 3D radial adaptive setting probes with independent intellectual property rights are developed suitable for the EFDT formation tester.Then,the relationship between pumping flowrate and pressure drop of various probes based on probe shape factor as well as the calculation methods of filtrate contamination based on spherical flow and oilwater fractions in slug flow based on a linear mixing rule are presented.Finally,the application of the novel 3D radial adaptive setting probes and the aforementioned calculation methods is discussed in detail to oil sampling in an offshore low permeability reservoir.The results show that:(1)the novel 3D radial adaptive setting probes cannot only obtain qualified high-purity oil samples under reasonable pressure drop(2.76 MPa)and pumping flowrate(6.01 cm^(3)/s),but also greatly improve the sampling efficiency;(2)under the same pressure drop,the sampling efficiency of the novel 3D radial adaptive setting probes is as about 4 times high as that of the standard probe;(3)the results predicted by the models are consistent with those of the on-site analysis.The novel 3D radial adaptive setting probes can provide an effective tool for fluid sampling in low permeability or ultra-low permeability reservoirs,and reduce the risk of offshore operation in a cost effective manner.