Study On Clay Anti-swelling Technology Of LJ Block On Gaosheng Oilfield

Clay minerals Widely Present in the oil-gas reservoir, 97% of the world’s oil reservoir are different degrees of contain clay mineral. The hydration and scattering migration of the clay mineral is one of the primary reasons causing oil/gas layers damage. The function of clay stabilizing agent to protect oil formation are to prevent clay particles from hydrating swelling and scattering migration which will block flowing porous channel, lead to permeability declining and has an important meaning for protecting the water-sensitivity oil layers with low permeability.Block LJ of GaoSheng oilfield use steam stimulation to exploitation heavy oil,for the stratum has high level of clay(>5%) and strong water sensitivity, if no measures are taken against clay swelling, it could easily lead to high gas injection pressure in the gas injection well and poor steam stimulation. The anti-swelling agent must be used to stabilize clay minerals in the stratum so as to protect the permeability of the oil and gas bed. The anti-swelling agent being currently used is mainly inorganic; despite its anti-swelling effects in the initial stage, it requires higher dosage and anti-swelling cost and the effect can only last for a short time. Though the ordinary organic anti-swelling agent has longer cycle time, it has poor temperature resistance and is unsuited for development of the steam stimulation. Hence, it is necessary to study the new clay stabilizer that has higher temperature resistance and can be effective for longer time based on stratigraphic features of the steam-stimulated well in LJ Block on Gaosheng oilfield as well as confirm the injection parameter so as to work out solutions for the water sensitivity harm of the steam-stimulated well in this block, and to protect the reservoir stratum’s environment.This is extremely important to the continued and efficient development of the reservoir stratum.Based on the condition of the reservoir physical property in Gaosheng oilfield and researches at home and abroad, this paper finds the best solution by studying reasons for oil layer damages caused by the clay and comparing various kinds of clay stabilizers. And then this paper evaluates performance of the anti-swelling agent being currently used by analyzing various static and dynamic experiments on reservoir core and anti-swelling agent. Based on this, this paper screens and makes recipe for the new anti-swelling agent, offers information including anti-swelling rate of the claystabilizer, core retention rate, optimum concentration, optimum dosage, injection speed and core harm by comparing, evaluating and analyzing all performances of the new clay stabilizer. In addition, a comprehensive evaluation of the new recipe on temperature resistance, compatibility, washing resistance, and durability is also introduced in this paper.