(Formation Water Treatment Technology Research On The Lower Paleozoic Gas Reservioirs Of Jingbian Gas Field)

JingBian gas field is a typical low permeability gas field, the Lower Paleozoic gas reservoir is the main reservoir in JingBian gas field. No edge and bottom water exist, but there are resident water with relative high water saturation and mobile ability. During the recovery process, part of wells produce water to different degrees. There exist some relative rich water areas and multiple water production points in the reservoir, which brings a series of problems and difficulties for the balance recovery, the stable production of the gas field and continuous and stable production of gas wells. The main performances are:(1) Along with the recovery, wells producing water increase gradually. As outputs of gas wells are commonly low, water can not be carried out and wells with liquid loading increase; (2) For low yield and low pressure gas wells, back pressure increase as the liquid loading increase, which makes it difficult for gas wells to load water, even makes the wells dead; (3) The salinity of formation water is high in JingBian gas field, which causes accelerated corrosion of the tubing and casing below the liquid level; (4) As there exist different distributions of water and the earlier measures are not in-depth, that has resulted in imbalance of pressure distribution and impacted the development effect of the gas field.Therefore, this paper carries out comprehensive treatment technology research of the Lower Paleozoic gas reservoir water production in JingBian gas field, mainly obtains the following understandings:(1) The study of reservoir structure, sedimentary facies and reservoir characteristics of the Lower Paleozoic gas reservoir are deepened in JingBian. The reservoir perform for complex ancient landform form and strong heterogeneity characteristic overall; The production characteristics of different development stage are analyzed. At present, relative rich water areas with unequal size and multiple water production points exist.(2) The water production characteristics and the law of gas and water production are analyzed. JingBian formation water is a typical accumulation retention water, for the calcium chloride type, with the salinity in 38.06?221.57g/L and PH value during 5.0 and 6.4, showing weak-middle acid. According to the gas, water production rate, the main aquifer position and the rule of GWR, one hundred and eleven formation water production wells are analyzed by classification. Gas production rate is 1.65 × 104m3 per well per day and water production rate is 2.14m3 per well per day. Water production Wells account for more than 70% in MaWu reservoir and the overall WGR is stable.(3) Through the productivity and influencing factors towards the water production wells, this paper analyzes the damage of liquid loading towards reservoir and the influence towards the production. Calculation results show that average open production is 23.71 × 104m3/d before the water production, while potential average open flow is 10.41 × 104m3/d, a drop of 56.11%.(4) Through the production system node pressure loss analysis towards water production wells, the formation and wellbore pressure loss are analyzed, finding that the average formation pressure loss is 4.36MPa, wellbore 5.28MPa. Due to the instable flow and serious slippage in water production wells, the pressure gradients increase, which increases back pressure at the bottom.(5) For the development of the Lower Paleozoic gas reservoir in JingBian, the comprehensive treatment study should be carried out; Through the water deliquification process test, combined with gas well production characteristics, the adaptability of water deliquification technologies are experimented and analyzed, finding that the most efficient drainage technology are obtained. Research shows:the main drainage technology for gas wells should be foam drainage and gas lift. Through the test, the application of automatic charging foaming agent, defoaming agent and solid defoamer defoaming process can improv labor efficiency, reduce running cost.(6) Through the development effect evaluation, the paper takes gas reservoir analysis, drainage gas recovery process optimization and ground process optimization into comprehensive consideration, formulates technical countermeasures suitable for the development of relative rich water areas and single well points. At present, the main rich water areas turn to be stable gradually, the encroachment rate slows down and gas wells produce steadily.