Dissertation Title:Research On Development Potential Of Low Palaeozoic In Tao2And Tao7Well Area Of Sulige Gasfield

Through researching Tao2and Tao7areas respectively located in the middle and northern part of Sulige gas field, the paper proves that main production layers of Jingbian gas field enjoy the conditions for extending towards the area. Ma5section is divided into10subsections, namely, Ma51—a510subsection in accordance with three representative layers and the stable "black-grey section"(Ma5limestone) of Jingbian gas field as well as sedimentary cyclicity and phase sequence. Relatively good succession is demonstrated between layers of the researching field, many rows of small nose-like bulges are developed in the gently west-dipping large monocline. At the top of Ma513layer, those can be identified from south to the north are primary nose-like bulges featuring east-west orientation.Relatively good succession exists between small layers in Tao2and Tao7areas for research. Generally, there is an obvious character of high in the east and low in the west. In addition, many rows of small nose-like bulges are developed in the gently west-dipping large monocline. Nose-like structure enjoys certain function of controlling on hydrocarbon enrichment, and it is obvious that unimpeded flow capacity of wells located in frontonasal and nosewing areas is higher than that of wells located in nosal pit areas. Each frontonasal tectonic region marks a relatively separated gathering area of natural gas, gathering belt of natural gas is under control of frontonasal tectonic belt located in the middle of frontonasal tectonic region.By far, in low palaeozoic of Tao2area,15trail pits have been completed, among which there are10wells of unimpeded testing flow capacity with the average value of16.37×104m3/d, and mean allocation production for single well of2.94×104m3/d; the other five are single trail pits with the average unimpeded flow capacity of40.617×104m3/d, among which the Tao2-9-24obtains the unimpeded flow capacity of101.961×104m3/d. According to research on the gas testing result, great differences exist in production capacity of single wells in low palaeozoic of Tao2area, which is predominantly influenced by reservoir parameters and process transformation.According to production experience of Jingbian gas field, it is suggested to extend anhydrous period for gas production, confirm reasonable capacity of gas well, and improve control of well pattern on reserves and layer replacement. For watered-out oil wells, measures should be taken respectively following such three cases:1. For wells with declining water-gas ratio, try to avoid well closing, open them and produce in a constant manner with normal and reasonable production. Take out stratum water with its own energy, and maintain a stable production.2. For wells with relatively stable water-air ratios, which are on average located in water rich areas, maintain their normal production.3. For wells with increasing air-water ratios, realizing the purpose of reducing water influx and increasing recovery ratio by taking strict water control and gas production measures to control drawdown pressure and water influx rate.