石油钻采工艺
石油鑽採工藝
석유찬채공예
Oil Drilling & Production Technology
2015年
5期
78-81,88
,共5页
致密油层%混合压裂%临界排量%复杂缝网%应力干扰
緻密油層%混閤壓裂%臨界排量%複雜縫網%應力榦擾
치밀유층%혼합압렬%림계배량%복잡봉망%응력간우
tight oil formation%mixed fracturing%critical lfow rate%complex fracture network%stress interference
针对鄂尔多斯盆地致密油层施工排量和簇间应力干扰作用对形成复杂缝网的影响开展了相关研究。采用离散缝网模型及有限元软件进行模拟分析，选择产层相同、压裂增产方案相近的2口试验水平井，进行压裂设计参数对比、产量对比及微地震监测结果对比。研究表明，施工排量过小，压裂效果以常规双翼缝为主，大排量是保证复杂缝网形成的条件；储层存在实现复杂缝网的临界排量，大于该临界排量时，主裂缝变短，次生缝网增加，带宽变大；多簇压裂时，主裂缝不同步开裂易引起主裂缝不同步延伸，率先延伸的主裂缝会抑制周围主裂缝的延伸甚至开裂，后延伸的主裂缝周围易产生剪切诱导的次生裂缝，利于形成复杂缝网。因此，选取大于临界排量的施工排量有利于增加储层改造体积，而多簇压裂时开裂延伸的主裂缝数量有可能小于设计簇数。
針對鄂爾多斯盆地緻密油層施工排量和簇間應力榦擾作用對形成複雜縫網的影響開展瞭相關研究。採用離散縫網模型及有限元軟件進行模擬分析，選擇產層相同、壓裂增產方案相近的2口試驗水平井，進行壓裂設計參數對比、產量對比及微地震鑑測結果對比。研究錶明，施工排量過小，壓裂效果以常規雙翼縫為主，大排量是保證複雜縫網形成的條件；儲層存在實現複雜縫網的臨界排量，大于該臨界排量時，主裂縫變短，次生縫網增加，帶寬變大；多簇壓裂時，主裂縫不同步開裂易引起主裂縫不同步延伸，率先延伸的主裂縫會抑製週圍主裂縫的延伸甚至開裂，後延伸的主裂縫週圍易產生剪切誘導的次生裂縫，利于形成複雜縫網。因此，選取大于臨界排量的施工排量有利于增加儲層改造體積，而多簇壓裂時開裂延伸的主裂縫數量有可能小于設計簇數。
침대악이다사분지치밀유층시공배량화족간응력간우작용대형성복잡봉망적영향개전료상관연구。채용리산봉망모형급유한원연건진행모의분석，선택산층상동、압렬증산방안상근적2구시험수평정，진행압렬설계삼수대비、산량대비급미지진감측결과대비。연구표명，시공배량과소，압렬효과이상규쌍익봉위주，대배량시보증복잡봉망형성적조건；저층존재실현복잡봉망적림계배량，대우해림계배량시，주렬봉변단，차생봉망증가，대관변대；다족압렬시，주렬봉불동보개렬역인기주렬봉불동보연신，솔선연신적주렬봉회억제주위주렬봉적연신심지개렬，후연신적주렬봉주위역산생전절유도적차생렬봉，리우형성복잡봉망。인차，선취대우림계배량적시공배량유리우증가저층개조체적，이다족압렬시개렬연신적주렬봉수량유가능소우설계족수。
Relevant research has been conducted to the effect of fracturing displacement in tight oil reservoirs in Ordos Basin and the inter-cluster stress interference on creation of complex fracture network. The discrete fracture network model and ifnite element software were used, and two wells were selected for comparison on fracturing design parameters, production and the results of micro-seismic monitoring. The research ifndings show that, large displacement and large liquid volume are the basis to guarantee creation of complex fracture network. There exists a critical pumping rate to create complex fracture network under certain formation conditions and fracturing parameters. In case of multi-cluster fracturing, the non-synchronous cracking of major fractures will lead to non-synchronous extension of major fractures. The ifrstly extended major fractures may suppress the extension or even initiation of the surrounding major fractures, but around the lately extended major fractures may occur shear-induced secondary fractures, which is favorable for creation of complex fracture network. Therefore, in hybrid fracturing design, a fracturing displacement which is larger than the critical pumping rate helps increase the area of stimulated reservoir and increase the oil well production, while the number of major fractures initiated and extended during multi-cluster fracturing may be less than the designed cluster quantity.
