摘要
塔里木盆地牙哈高压凝析气田一直通过循环注气保压开采的方式进行开发,两个主力气层之间以及同一气层内都存在着较大的储层物性差异,笼统注气不仅导致气藏储量动用不均,而且也进一步加剧了高、低渗透层之间的开采矛盾。为此,依据该气田目前的气井井身结构、地面设施状况和分层注气要求,设计了同心油管分层注气管柱结构,配套了分层注气井口装置,由此完成了分层注气井完井投产作业施工,并满足了分层注气工艺生产的需要。同时,针对同心管方案设计了两种油管组合方式(?114.3mm+?73.0 mm油管组合、?114.3 mm+?60.3 mm油管组合),并按照不同工况配产对两种油管组合的井筒温度场、压力场以及管柱安全性进行了理论分析与评价。结果表明:(1)?114.3 mm+?73.0 mm油管组合在内管和外管分别达到最大注气量50×10~4 m^3/d和20×10~4 m^3/d时,需要的井口注气压力小于42 MPa,现有地面注气设备能力可以达到该值且内、外管注气压差较小,有利于注气作业;(2)?114.3 mm+?73.0 mm油管组合安全系数大于一般设置的参数(1.5),再对注气工况1、2下进行抗内压强度校核,对注气工况3、4下进行抗外挤强度校核,均表明该油管组合能够满足强度要求。结论认为,?114.3 mm+?73.0 mm油管组合作为同心油管分层注气管柱是可行性的。
The Yaha high-pressure condensate gas field in the Tarim Basin has always been developed by maintaining the reservoir pressure through cyclic gas injection. The reservoir physical properties vary greatly between two major gas layers, and even in the same gas layer, so commingled gas injection not only leads to uneven reserves producing level, but also intensifies the production conflicts between high-permeability and low-permeability reservoirs. In this paper, separate-layer gas injection strings with concentric tubing were designed on the basis of gas well structures, the ground facility conditions and separate-layer gas injection requirements. Then, the corresponding wellhead equipments were supported. And in this way, a separate-layer gas injection well was completed and put into operation and the technical requirements of separate-layer gas injection were satisfied. And in addition, two combination modes of tubing were designed for concentric tubing programs, i.e., φ114.3 mm ＋ φ73.0 mm and φ114.3 mm ＋ φ60.3 mm. And both of them were theoretically analyzed and evaluated in terms of wellbore temperature and pressure fields and string safety at different allocations. It is shown that the required wellhead gas injection pressure is lower than 42 MPa when the maximum gas injection rate is up to 50×10^4 m^3 and 20×10^4 m^3/d respectively in the internal and external tubing of the former combination of φ114.3 mm ＋ φ73.0 mm. And based on the existing ground gas injection facilities, the pressure can be reached with less gas injection pressure difference between the internal tubing and the external tubing, which is favorable for gas injection. The safety coefficient of this former tubing combination is higher than the common one（1.5）. The first and second gas injection conditions were verified in terms of internal pressure strength and the third and fourth were verified in terms of external extrusion strength. It is demonstrated that this combination can meet the strength requirements. It is concluded that the tubing combination of φ114.3 mm ＋ φ73.0 mm is feasible for separate-layer gas injection strings with concentric tubing.
出处
《天然气工业》
EI
CAS
CSCD
北大核心
2016年第4期48-54,共7页
Natural Gas Industry
关键词
塔里木盆地
牙哈高压凝析气田
分层注气
同心油管
油管组合
井口装置
安全性
Tarim Basin
Yaha high-pressure condensate gas field
Separate layer gas injection
Concentric tubing
Tubing combination
Wellhead equipment
Safety
