基于“逆推思维”的储量工作方法

Reserves Working Method Based on Inverse Thinking

基于"逆推思维"的储量工作方法是以勘探苗头或发现为出发点,以规模储量发现为目标,逆推寻找制约规模增储的关键问题,围绕关键问题开展勘探部署、老井试油、储量研究等工作,最终把好苗头培育成规模增储区块。以大民屯沙四段砂砾岩体为例,详细阐述了该方法的实际操作流程。以培育规模储量为最终目标,通过全面分析研究找出制约该区储量大发现的关键问题:岩性复杂造成井间横向难对比;多期砂体叠置,沉积相带难确定;砂体含油层段差异较大,平面及纵向有效储层难预测。围绕关键问题成立攻关项目组,加强岩心联测,明确了该区岩性分类,将该区主要岩性划分为泥岩、粉细砂岩、细砂岩、中粗砂岩和砂砾岩五大类岩性,并制定了相应的岩性定性、定量评价标准;开展井震结合,追踪砂体横向及纵向展布范围;优选有利目标进行钻探及老井试油:沈354、沈358两口井钻探获得工业油流,沈263、沈351两口老井试油获得成功,不但在平面上扩大了储量控制面积,而且在纵向上增加了油层厚度。最终将该区培育成4000×10~4t级的储量规模,实现了将勘探苗头培育成规模储量的目标。

Reserves working method based on the ＂inverse thinking＂ is to find the key issues that restrict scale of reserves increasing by backstepping with the goal of large-scale reserves from the beginning of ex- ploration probability or discovery,and then to carry out exploration and deployment,oil test in old wells and reserves research focusing on the key issues,eventually to develop good signs into the blocks with reserves increasing at large scale.The glutenite in Sha4 Member of Damintun illustrated the actual operation process of this method.In order to develop large-scale reserves as the ultimate goal,the key issues that restrict the largest discovery of reserves were known through comprehensive study.That is,well-to-well lateral correlation is hard to be done for complex lithology;sedimentary facies are difficult to be determined for multi-period sandbody superimposition;and plane and vertical effective reservoirs are difficult to be predicted for great dif- ference among oil-beating intervals of the sandbody.Key project team was set up to solve the key issues. Core combination measurement was strengthened.The main lithology in this area was clear and divided into five types： mudstones,fine sihstones,fine sandstones,medium coarse sandstones and glutenites,and correspond- ing qualitative and quantitative evaluation standards for the lithology weres developed.Well-to-seismic integra- tion may trace horizontal and vertical distribution range of the sands.Favorable targets were selected to drill and test for oil.Well Shen354 and Shen358 gained industrial oil flow through drilling,and oil tests in Shen263 and Shen351 two old wells were successful.Not only the reserves control area was enlarged on the plane ,but also the thickness of the reservoir was increased on the vertical.Thisarea was developed into the one with 4000×10^4t of reserves finally,and the goal of turning the exploration probability into the large-scale reserves was realized.