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基质酸化和酸化压裂措施已广泛应用于油气增产过程中。成功的酸化增产需要将酸液均匀分布到各个层段,特别是对于处理裸眼完井的直井、水平井、延伸井及多分支井尤为重要。黏弹性表面活性剂体系的特殊性质可以阻塞高渗透率层段的流动,使处理液转向进入低渗储层。据最新的SPE文献报道,作为转向酸的清洁处理液在基质酸化和酸化压裂过程中,特别是在处理低渗储层及衰竭式开采的气藏中,由于需要更长的回流时间,产生了地层伤害。在水力压裂和压裂充填过程中发展了内部破胶技术,内部破胶剂能控制黏弹性胶体的破胶时间和地点,使其易于返排。本文介绍了一种含有破胶剂的清洁转向酸来处理碳酸盐岩储层。这种酸液体系很独特,酸岩反应之前黏度很小。当酸液耗尽或者鲜酸到达新的位置时,体系中的表面活性剂黏度达到最大。酸化处理过后,内部破胶剂活化使黏弹性表面活性剂破胶,体系黏度降低,同时残酸酸液在生产过程中返排,最大程度地减少了可能存在的伤害。实验结果证实,酸化过程中的黏弹性胶体溶液在低剪切速率下产生了很高的黏度,且其在接触烃类物质后才加速破胶。进一步研究了在控制内部破胶剂降低残酸黏度的可行性。碳酸盐岩岩心流动实验表明,在矿物油清洗过程中,使用不含破胶剂的清洁处理液在蚓孔中产生的压降要高于使用含破胶剂的清洁处理液产生的压降。
Substrate acidification and acidification fracturing measures have been widely used in oil and gas production process. Successful acidification and production increase the need for uniform distribution of acid into all layers, especially for vertical wells, horizontal wells, extension wells and multilateral wells that handle openhole completions. The special nature of the viscoelastic surfactant system can block the flow in the high permeability zone and divert the treatment fluid into the low permeability reservoir. According to the latest SPE literature, as a diverting acid cleaning solution, during the matrix acidification and acid fracturing, especially in reservoirs dealing with low permeability reservoirs and depleted mined gas reservoirs, due to the longer reflux time required Stratum damage. Internal fracturing techniques have been developed during hydraulic fracturing and fracturing. The internal breaker can control the breaking time and location of viscoelastic colloids, making them easy to return to. This article describes a clean diverting acid that contains a breaker that treats carbonate reservoirs. This acid system is unique and has little viscosity prior to acid rock reaction. When the acid is depleted or fresh acid reaches a new location, the viscosity of the surfactant in the system is maximized. After the acidification treatment, the internal breaker activates the viscoelastic surfactant to break the gel and the viscosity of the system decreases. At the same time, the residual acid can flow back into the process of production to minimize the possible damage. The experimental results confirm that the viscoelastic colloidal solution during acidification produces a high viscosity at low shear rates and accelerates gel breaking after exposure to hydrocarbon species. The feasibility of reducing the residual acid viscosity by controlling the internal breaker was further studied. Carbonate core flow experiments show that in the mineral oil cleaning process, the pressure drop in the wormholes using the cleaning solution without gel breaker is higher than that with the cleaning solution containing the breaker .