Study On Development And Performance Of Protective Film Forming Sealing Agent For Oil And Gas Field Development

According to the theory of water-based drilling fluid sealing technology and the former polymer film theory, we developed a small cationic monomer-trihydroxyethyl allyl chloride (TAAC), with it we synthesis a new sealer-PF-PAAMT. The blocking agent is consist by a polymer film master agent and acid-soluble film-forming auxiliary agent PF-QWY components. The main forming agent was synthesised from acrylamide (AM), a cationic monomer (laboratory-made),2-acrylamido-2-methylpropane sulfonate (AMPS) and methyl acrylate (MA) as raw material monomer and ammonium persulfate as initiator, we synthesized it in solution through uniform design method.Using API fluid loss as the main synthetic indicators,we studied the factors which affect the freshwater base slurry viscosity and the performance of the main film blocking agent. Using uniform design arrangements experiments, the optimal synthesis process film master agent is pH= 7; reaction time is 4 h; reaction temperature is 62℃; monomer ratio is AM: AMPS:MA:TAAC (mass ratio)= 60:10:12:18; the total monomer concentration is 27%; initiator concentration is 0.45%. Products was proved by IR spectroscopy and proved to be the target product.Based on temporary blocking technology, using a visual medium pressure sand tube experiments, preferably the type and amount of film-forming auxiliary agent, and the optimum composition of PF-PAAMT is:3% PF-QWY+1% product.Viscosity behavior of the product was studied under different conditions, the results showed that:PF-PAAMT aqueous solution viscosity increases with increasing amount of added product, the product has a tackifying; due PF-PAAMT containing anionic group, the performance of the product a certain degree of salt sensitivity. With the increase of salt (NaCl, CaCl2) concentration, the apparent viscosity decreases, and then gradually stabilized, but the apparent viscosity of the NaCl is less than the magnitude of the decline in the CaCl2. Analysis of salt products with great ability.Indoor’s results showed that:PF-PAAMT has a good temperature resistance, after high-temperature aging it still has a good plugging performance, mud ball immersion test, anti-swelling and debris recovery experiments indicate that the product has a very good suppression and it indirects prove that the product can be adsorbed on the shale surface film, By analyzing the strong inhibition of drilling fluid sealing performance requirements, add the target product to the CNOOC’s common PEM/KCl system, we developed a set of well performance of water loss property, rheological property, anti-fouling and plugging isolation membrane drilling fluid formulation:2.5% seawater soil slurry+0.2% NaOH+0.15% Na2CO3+0.3% PF-PAC-LV+0.4% PF-PLH+5% KCl+1.5% PF-PAAMT+1% PF-lube +1% PF-SMP-1+1% PF-GBL+0.1% PF-XC+barite. Experimental results show that:the drilling fluid formulation excellent sealing performance, strong sealing film which can prevent borehole collapse, necking sticking, and can effectively block the micro-cracks and protection of oil and gas reservoirs.