Ling Y.,State Engineering Laboratory of Low Permeability Oil and Gas Reservoir Exploration and Development |
Ling Y.,Petrochina |
Li X.,State Engineering Laboratory of Low Permeability Oil and Gas Reservoir Exploration and Development |
Li X.,Petrochina |
And 4 more authors.
Natural Gas Industry | Year: 2014
Characterized by low permeability, low pressure, low yield, high proportion of multilayers and strong heterogeneity, the Sulige Gas Field, Ordos Basin, has become one of the main development blocks of the Changqing gas zone. In order to further enhance development benefit, a study was conducted on key fracturing technologies in the "12th Five-Year Plan" period, a series of new progress in which was summarized as follows. (1) Two main technologies, hydrajet fracturing and open-hole packers, were developed for multi-staged fracturing of horizontal wells, and at the same time, speed-drilling composite bridge plugs and repeatedly-opened/closed sliding sleeves were developed, which have broken the monopoly of foreign technologies. (2) Three major technological series were developed for the multilayer fracturing of vertical wells, including mechanical packers, casing sleeves and coiled tubings. (3) Three sets of low-damage fracturing fluid systems were developed. (4) A significant progress was made in the SRV fracturing of horizontal wells and slim-hole development tests. Key fracturing technological series was established for tight gas reservoirs, so dramatic improvement was made in the technological capability (vertical-well multi-layer fracturing increased from 3 to 11 layers, and hor izontal-well multi-stage fracturing increased from 5 to 23 stages), which greatly improved the yield of a single well. These achievements provided an important technical support for the efficient production development of tight sandstone reservoirs. According to the requirements of 50 million tons oil and gas equivalent of stable production, and with the goals to further enhance single-well production and minimize development costs, technical difficulties were required to be overcome in the following three aspects: horizontal-well SRV fracturing, industrialized fracturing, and re-fracturing of the existing production wells. ©, 2014, Natural Gas Industry Journal Agency. All right reserved.
Li Y.,Petrochina |
Li Y.,State Engineering Laboratory of Low Permeability Oil and Gas Reservoir Exploration and Development |
Xu W.,Petrochina |
Xu W.,State Engineering Laboratory of Low Permeability Oil and Gas Reservoir Exploration and Development |
And 7 more authors.
Natural Gas Industry | Year: 2014
As a typical tight sandstone gas field with great heterogeneity, the Sulige Gas Field in the Ordos Basin has difficulties in its development because its reservoirs are featured by small-scale effective sand bodies, rapid changes, strong plane heterogeneity, and poor connectivity. How to scientifically deploy development wells to improve the recovery ratio is the most important issue to be addressed in the successful development of this kind of gas fields. In view of this, a well inference analysis was conducted to re-understand the impact of well pattern density on the recovery ratio based on the researches of many years on gas field development methods and the summaries of practical effect analysis. In this paper, we put forward for the first time the concept of inter-well interference, revealed the relation between the probability of inter-well interference in the Sulige Gas Field and well pattern density. Then we established a mathematical model for the optimization of a development well pattern based on the combination of a variety of methods such as fine sand anatomy, reservoir engineering, numerical simulation and economic evaluation, and obtained a quantitative description of the correlation between recovery ratio and well pattern density. Finally we figured out a reasonable development well pattern for the Sulige Gas Field based on a comprehensive analysis. This well pattern is a parallelogram in the form, with a density of 3.1 wells per km2, well spacing of 500 m and row spacing of 650 m. Development practices confirmed that this scheme is capable of achieving better economic benefits, making full use of geological reserves, and improving the ultimate recovery of such gas field. ©, 2014, Natural Gas Industry Journal Agency. All right reserved.