Due to the presence of starting pressure of low permeability reservoir, so researching on starting pressure gradient of low permeability reservoir is necessary. while starting pressure gradient is relevant to permeability and porosity, it can be obtained through laboratory experiments¡¢well testing interpretation method¡¢theory derivation combined with practical application method . The result of a large number of laboratory experiments shows: starting pressure is related to permeability .The greater the permeability is, the smaller the starting pressure is. They both present the similar hyperbolic relationship; the greater the viscosity of the oil is, the greater the starting pressure is. In this paper, we get the starting pressure gradient formula through the method of theory derivation combined with practical application, meanwhile we put forward the relationship between starting pressure gradient and permeability, porosity¡¢viscosity .

The study research the productivity formula in low permeability reservoir with vertical wells combined with fracturing well of the five point rectangular pattern, seven spot pattern, nine spot pattern, as well as the productivity of anti-nine rhombus fractured vertical well mixed pattern, and to which of the five-point rectangular pattern and the law rectangular fracturing well pattern optimization analysis. The analysis revealed widening well spacing, narrow row spacing, so that the shape factor well network within a certain range, can improve the development effectiveness, and when length of the crack and area of well spacing were given, can determine the length and width of rectangular pattern.

Formation porosity near the wellbore can be changed by massive sand production, so it is impractical to use the initial formation porosity in downhole operation design in unconsolidated sand reservoir. The numerical method for sand prediction is limited for its complicated calculation procedures. An analytical model for porosity variation calculation is developed by coupling the material balance equation with the critical fluid drag force. With the result of sand production simulated test, the model can quantify the relation between sand production rate and formation porosity variation. Application of the model in oil field shows that it is simple and practicable for field engineering design.

Downhole Gas Compression (DGC) is an entirely new powered artificial lift technology specifically for natural gas wells. The technology offers the opportunity to increase production by 30-50%, significantly improve reserves and delay the onset of liquid loading. Key application of DGC is for use in deeper partially depleted reservoir wells encountering liquid loading. The research progress of DGC is introduced in this paper and the results of theoretical and experimental study of DGC are investigated. Moreover, the adaptability and application prospect of this new technology is analyzed. There are many gas fields in China faced with problems about effective drainage and recovery enhancement, such as the mature gas fields in Sichuan and Ordos Basin. DGC will have a good application prospect in China and further study of the DGC technology is recommended.

The so-called water flooding characteristic curve refers to the oilfield water injection (or natural water drive) development process, a relationship between curve cumulative oil production, cumulative water production and accumulation of fluid production. These curves have been widely used for water injection development of dynamic and recoverable reserves forecast. After many years of practical application, summed up the four kinds of water drive characteristic curve, they have a good practical significance. Recoverable reserves are important indicators of field development is the main basis for planning and design, the application of waterflooding characteristic curve can be predicted oil recoverable reserves. Four water flooding characteristics discussed above curve is mainly applied in high-permeability oil field, which did not consider starting pressure, but should consider the impact of low permeability oilfield actuating pressure gradient on the moisture content.