一种新型低成本防结垢复合盐高密度无固相压井液

A New Low-Cost High-Density Solids Free Anti-Scaling Compound Salt Kill Mud

高温高压油气藏所用的普通压井液包含的溴盐、锌盐、重钙等与地层水配伍性差、易污染地层、具有高腐蚀性,且甲酸盐高密度压井液成本高,针对这些难题采用高效阻垢技术并研制了一种新型加重剂,同时广泛选用廉价的无机盐用于配制基液,研发了一种新型低成本防结垢复合盐高密度无固相压井液体系。该体系不含固相成分,不含钙镁等易结垢的二价离子,全部为一价盐,密度最高可达1.70 g/cm3,且与同级别甲酸盐体系相比成本可降低50%以上,同时保留了甲酸盐体系的全部优点,满足国家新安全环保法低损害、低成本、高密度、无固相、无毒性的要求。该技术在大港油田先导性应用1口井,平均恢复期1 d,平均恢复率100%,油层保护效果显著。

Bromide,zinc salts and heavy calcium salts used in kill mud for HTHP reservoirs have poor compatibility with formation waters,formation contamination and high corrosivity.High density kill muds formulated with formats are quite expensive.A new weighting agent was recently developed with the help of efficient scale inhibiting technology.Using this weighting agent,a low-cost high-density solids free anti-scaling compound salt kill mud was formulated.The base fluid of the kill mud was formulated with some cheap inorganic salts.This kill mud is free of calcium and magnesium ions,all salts presented in the kill mud are monovalent salts.The maximum density of the kill mud is 1.70 g/cm3.This kill mud,with its cost being only 50%of a formate kill mud of the same density,retains all the advantages of the formate kill mud.The new kill mud is low damage,lost cost,high density,solids free and nontoxic.,satisfying the requirements of the new national safety and environment protection laws.Pilot test of the new kill mud on a well drilled in Dagang Oilfield showed that the average yield recovery period of the well was 1 d and the average percent recovery of yield was 100%,demonstrating that the kill mud has the capacity of reservoir protection.