大情字井油田油层保护技术

Reservoir protection technology in Daqingzijing Oilfield

针对大情字井油田储层具有非均质、低压、低孔、低渗、易漏、易塌、易卡、部分区域垂直裂缝发育的特征,进行了流速敏感性、水敏性、储层盐敏性和碱敏性的分析评价。根据试验井的大量数据,得出了钻井过程中储层损害的主要原因,揭示了储层潜在损害因素,评价出储层损害类型与程度,明确了储层损害机理。提出了开发过程储层保护的措施。即:①进行大情字井油田整体油层保护方案的研究及设计;②制定单井的油层保护方案。并引入钻井设计之中;③坚持每口井的油层保护措施检查及打开油层前的验收。检查不合格时,不准打开储层;④每口井坚持打开油层前、后及完井前的井浆粘度、钻井完井液性能及油层保护材料的化验分析并作为验收凭证;⑤采取监督住井制度,随时检查监督。经现场应用表明.采取油层保护措施的井,采油指数是未采取油层保护措施井的1.46倍,产油量提高了30.9％,取得了较好的经济效益。

To further investigate such reservoir characteristics as inhomogeneity, low formation pore pressure, low porosity, low permeability, lost circulation, sloughing and sticking tendency, and the vertical fracture development in some zones, analysis and evaluations on flow velocity sensitivity, water sensitivity, formation salt sensitivity and alkali sensitivity were conducted. Based on the vast amount of data from the testing well, the main causes of formation damages during drilling and the potential damaging factors were determined, and the mechanism of formation damage was also revealed. The types and degrees of formation damage were evaluated, and some reservoir protection measures during development were also presented accordingly, i. e. , 1. Make out the integral reservoir protection plan for Daqingzijing oilfield; 2. Make out the reservoir protection plan for each well and introduce in the drilling plan; 3. Check the fulfillment of reservoir protection measures and inspect before hitting the payzone, and no production zone might be penetrated when negative results obtained; 4. Laboratory tests should be carried out on the viscosity of well fluid, the performance of drill-in fluid and reservoir protection materials before and after penetrating into the production zone and before completion; 5. Supervisors should he on site at any time. Field application of the technology showed that the production index of well with protection measures taken was 1. 46 times of that of without protection measures, and the production rate improved by 30. 9% , good economic results were achieved.